Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 07/13/07

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
530 AM PDT WED JUL 11 2007 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...(TODAY-FRI) WRF MODEL CROSS-SECTION DID A NICE JOB WITH MARINE LAYER DEPTH. LATEST ACARS AND PROFILER DATA HAS MARINE LAYER AT 3000 FT DEEP THIS MORNING. MARINE LAYER COULD REACH NEAR 3500 FT BY DAYBREAK. LATEST SATELLITE IMAGERY INDICATED LOW CLOUDS PUSHING UP AGAINST THE LA/VTU COUNTY MOUNTAINS. LOW CLOUDS HAVE ALSO PUSHED INTO PASO ROBLES FROM THE WEST. ONSHORE GRADIENTS ARE FORECAST TO BE QUITE STRONG LATER TODAY. ALTHOUGH INVERSION IS WEAKER WITH COOLING AT THE UPPER LVLS...WILL BE TOUGH FOR LOW CLOUDS TO BURNOFF ACROSS THE COASTAL PLAIN THIS AFTERNOON DUE TO MARINE LAYER DEPTH. VALLEYS SHOULD SEE BURNOFF BY LATE MORNING...WITH MOST COASTAL AREAS STAYING MOSTLY CLOUDY THROUGH MUCH OF THE AFTERNOON...WITH ONLY PARTIAL CLEARING NEAR THE COAST. WITH SUCH A DEEP MARINE LAYER IN PLACE...WENT AHEAD AND ADDED LOCAL DRIZZLE TO ALL VALLEYS AND COASTAL AREAS TO ALL 4 COUNTIES FOR THE MORNING HOURS. ADJUSTED TEMPS LOWER SLIGHTLY JUST ABOUT EVERYWHERE BELOW 4000 FT TODAY...WITH THE EXCEPTION OF THE ANTELOPE VALLEY WHICH SHOULD REACH THE MID 90S. MID LEVEL CLOUDS THAT AFFECTED MUCH OF THE FORECAST AREA YESTERDAY HAVE MOVED TO THE NORTH. LEFT SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE LA COUNTY MOUNTAINS AND ANTELOPE VALLEY...MAINLY THE SAN GABRIEL MOUNTAINS FOR ANY LEFTOVER RESIDUAL MOISTURE. CONVECTIVE PARAMETERS WERE NOT VERY GOOD...BUT AN ISOLATED TSTM COULD BE POSSIBLE WITH SOME SOUTHERLY FLOW ALOFT OVER THE EASTERN AREA OF SO CAL. DID NOT MENTION FOR VENTURA COUNTY MOUNTAINS AS UPPER FLOW IS MORE SW INFLUENCED DUE TO UPPER LVL LOW NEAR THE CENTRAL COAST. UPPER LVL RIDGE TO THE EAST OF CAL WILL STRENGTHEN ONCE AGAIN ON THURSDAY PUSHING PERSISTENT UPPER LVL LOW FURTHER NORTH OFF THE CENTRAL CAL COAST. TEMPS WILL REBOUND A BIT ON THURSDAY WITH PASO ROBLES AND MOST INTERIOR SECTIONS OF SAN LUIS OBISPO SEEING THE GREATEST INCREASE OF AT LEAST 10 DEGREES OF WARMING. WITH MOST VALLEY AND MOUNTAIN LOCATIONS WARMING UP NEAR 5 DEGREES. COASTAL ZONES SHOULD STAY SIMILAR WITH A DEGREE OR TWO OF WARMING. WITH UPPER HIGH BUILDING BACK OVER THE REGION...EXPECT MARINE LAYER TO FLATTEN A BIT WHICH SHOULD BRING ONLY PATCHY LOW CLOUDS TO THE VALLEYS. THE UPPER LVL HIGH SETS UP ONCE AGAIN OVER THE FOUR CORNERS REGION LATE THURSDAY WITH A NEGATIVE TILT. THIS WILL BE FAVORABLE FOR MORE MID LEVEL MOISTURE TO BE TRANSPORTED UP OUT OF BAJA FOR FRI AND POSSIBLY SAT. DRY LIGHTNING WILL BE OF CONCERN ONCE AGAIN THIS FRIDAY AND SATURDAY ACROSS THE LOCAL MOUNTAINS AND ANTELOPE VALLEY AS THE LOWER LEVELS REMAIN VERY DRY. THE FORECAST HAS 20 PERCENT POPS FOR THE LA/VTU/SBA COUNTY MOUNTAINS AND THE ANTELOPE VALLEY FOR FRI. MINIMUM TEMPS WILL BE SLIGHTLY HIGHER THANKS TO MID LEVEL MOISTURE AND TEMPS WILL CONTINUE TO RISE AS THICKNESS LVLS INCREASE...AND WITH MORE HUMID AIR ACROSS THE AREA...SOME OF THE INTERIOR REGIONS WILL FELL UNCOMFORTABLE WITH THE HEAT AND HUMIDITY. .LONG TERM...(SAT-TUE) GFS CONTINUES TO ADVERTISE MID LEVEL MOISTURE ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA...ESPECIALLY THE LA/VTU COUNTY MOUNTAINS AS WELL AS THE ANTELOPE VALLEY. ADDED 20 PERCENT POPS FOR SAME MOUNTAIN AREAS AND ANTELOPE VALLEY FOR SAT. EXPECT PARTLY CLOUDY SKIES IN THE AFTERNOON AND TEMPS REACHING INTO THE 100S ACROSS PORTIONS OF THE ANTELOPE VALLEY...LOWER MOUNTAIN ELEVATIONS AND THE INTERIOR SECTIONS OF SAN LUIS OBISPO. WITH MOST OTHER VALLEYS IN THE 90S. THE COASTAL AREAS WILL CONTINUE TO BE UNDER MARINE LAYER INFLUENCE KEEPING TEMPS QUITE MILD. SUNDAY THROUGH TUE...EXPECT MUCH DRIER CONDITIONS AS UPPER LVL HIGH SHIFTS OVER BAJA AND PERSISTENT BROAD TROUGH OVER THE EASTERN PACIFIC MOVES SLIGHTLY FARTHER SOUTH. UPPER LVL FLOW WILL SHIFT FROM SE TO SW AND HELP DRY OUT ANY RESIDUAL MOISTURE OVER THE DESERT AND MOUNTAINS. TEMPS SHOULD REMAIN SLIGHT ABOVE NORMAL FROM SUN-TUE WITH TYPICAL NIGHT THROUGH MORNING LOW CLOUDS ACROSS THE COASTAL PLAIN AND COASTAL VALLEYS. && .AVIATION...11/1230Z MARINE LAYER DEPTH HAS DEEPENED OVERNIGHT TO NEAR 3000 FEET WITH CEILINGS AT ALL SITES EXCEPT FOR KPMD AND KWJF. WITH SUCH A DEEP MARINE LAYER...TWO CLOUD DECKS HAVE FORMED. THE LOWER IS A SCT-BKN DECK BETWEEN 008-012...AND THE DEEPER OVC DECK AT 020-025. AS THE MORNING PROGRESSES...CLEARING AT COASTAL SITES WILL BE SLOW IF IT HAPPENS AT ALL. IF CIGS DO CLEAR...EXPECT A RETURN BY 05Z AT THE LATEST. KLAX...TWO CLOUD DECKS...ONE SCATTERED AT AROUND 010 AND ANOTHER OVC AROUND 025 SHOULD LINGER. THERE IS A DISTINCT POSSIBILITY OF THE OVC CIGS REMAINING THROUGH MOST OF THE AFTERNOON. IF CIGS DO CLEAR... EXPECT AN EARLY RETURN BY 05Z AT THE LATEST. KBUR...CIGS AROUND 015 EXPECTED TO BURNOFF NEAR 17Z. USUAL SOUTHERLY AFTERNOON WINDS...WITH A RETURN OF MVFR CIGS BY 08Z. $$ .LOX WATCHES/WARNINGS/ADVISORIES... NONE && $$ PUBLIC...KAPLAN AVIATION...MEIER WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
345 AM PDT WED JUL 11 2007 .SHORT TERM...(TODAY-FRI) WRF MODEL CROSS-SECTION DID A NICE JOB WITH MARINE LAYER DEPTH. LATEST ACARS AND PROFILER DATA HAS MARINE LAYER AT 3000 FT DEEP THIS MORNING. MARINE LAYER COULD REACH NEAR 3500 FT BY DAYBREAK. LATEST SATELLITE IMAGERY INDICATED LOW CLOUDS PUSHING UP AGAINST THE LA/VTU COUNTY MOUNTAINS. LOW CLOUDS HAVE ALSO PUSHED INTO PASO ROBLES FROM THE WEST. ONSHORE GRADIENTS ARE FORECAST TO BE QUITE STRONG LATER TODAY. ALTHOUGH INVERSION IS WEAKER WITH COOLING AT THE UPPER LVLS...WILL BE TOUGH FOR LOW CLOUDS TO BURNOFF ACROSS THE COASTAL PLAIN THIS AFTERNOON DUE TO MARINE LAYER DEPTH. VALLEYS SHOULD SEE BURNOFF BY LATE MORNING...WITH MOST COASTAL AREAS STAYING MOSTLY CLOUDY THROUGH MUCH OF THE AFTERNOON...WITH ONLY PARTIAL CLEARING NEAR THE COAST. WITH SUCH A DEEP MARINE LAYER IN PLACE...WENT AHEAD AND ADDED LOCAL DRIZZLE TO ALL VALLEYS AND COASTAL AREAS TO ALL 4 COUNTIES FOR THE MORNING HOURS. ADJUSTED TEMPS LOWER SLIGHTLY JUST ABOUT EVERYWHERE BELOW 4000 FT TODAY...WITH THE EXCEPTION OF THE ANTELOPE VALLEY WHICH SHOULD REACH THE MID 90S. MID LEVEL CLOUDS THAT AFFECTED MUCH OF THE FORECAST AREA YESTERDAY HAVE MOVED TO THE NORTH. LEFT SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE LA COUNTY MOUNTAINS AND ANTELOPE VALLEY...MAINLY THE SAN GABRIEL MOUNTAINS FOR ANY LEFTOVER RESIDUAL MOISTURE. CONVECTIVE PARAMETERS WERE NOT VERY GOOD...BUT AN ISOLATED TSTM COULD BE POSSIBLE WITH SOME SOUTHERLY FLOW ALOFT OVER THE EASTERN AREA OF SO CAL. DID NOT MENTION FOR VENTURA COUNTY MOUNTAINS AS UPPER FLOW IS MORE SW INFLUENCED DUE TO UPPER LVL LOW NEAR THE CENTRAL COAST. UPPER LVL RIDGE TO THE EAST OF CAL WILL STRENGTHEN ONCE AGAIN ON THURSDAY PUSHING PERSISTENT UPPER LVL LOW FURTHER NORTH OFF THE CENTRAL CAL COAST. TEMPS WILL REBOUND A BIT ON THURSDAY WITH PASO ROBLES AND MOST INTERIOR SECTIONS OF SAN LUIS OBISPO SEEING THE GREATEST INCREASE OF AT LEAST 10 DEGREES OF WARMING. WITH MOST VALLEY AND MOUNTAIN LOCATIONS WARMING UP NEAR 5 DEGREES. COASTAL ZONES SHOULD STAY SIMILAR WITH A DEGREE OR TWO OF WARMING. WITH UPPER HIGH BUILDING BACK OVER THE REGION...EXPECT MARINE LAYER TO FLATTEN A BIT WHICH SHOULD BRING ONLY PATCHY LOW CLOUDS TO THE VALLEYS. THE UPPER LVL HIGH SETS UP ONCE AGAIN OVER THE FOUR CORNERS REGION LATE THURSDAY WITH A NEGATIVE TILT. THIS WILL BE FAVORABLE FOR MORE MID LEVEL MOISTURE TO BE TRANSPORTED UP OUT OF BAJA FOR FRI AND POSSIBLY SAT. DRY LIGHTNING WILL BE OF CONCERN ONCE AGAIN THIS FRIDAY AND SATURDAY ACROSS THE LOCAL MOUNTAINS AND ANTELOPE VALLEY AS THE LOWER LEVELS REMAIN VERY DRY. THE FORECAST HAS 20 PERCENT POPS FOR THE LA/VTU/SBA COUNTY MOUNTAINS AND THE ANTELOPE VALLEY FOR FRI. MINIMUM TEMPS WILL BE SLIGHTLY HIGHER THANKS TO MID LEVEL MOISTURE AND TEMPS WILL CONTINUE TO RISE AS THICKNESS LVLS INCREASE...AND WITH MORE HUMID AIR ACROSS THE AREA...SOME OF THE INTERIOR REGIONS WILL FELL UNCOMFORTABLE WITH THE HEAT AND HUMIDITY. .LONG TERM...(SAT-TUE) GFS CONTINUES TO ADVERTISE MID LEVEL MOISTURE ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA...ESPECIALLY THE LA/VTU COUNTY MOUNTAINS AS WELL AS THE ANTELOPE VALLEY. ADDED 20 PERCENT POPS FOR SAME MOUNTAIN AREAS AND ANTELOPE VALLEY FOR SAT. EXPECT PARTLY CLOUDY SKIES IN THE AFTERNOON AND TEMPS REACHING INTO THE 100S ACROSS PORTIONS OF THE ANTELOPE VALLEY...LOWER MOUNTAIN ELEVATIONS AND THE INTERIOR SECTIONS OF SAN LUIS OBISPO. WITH MOST OTHER VALLEYS IN THE 90S. THE COASTAL AREAS WILL CONTINUE TO BE UNDER MARINE LAYER INFLUENCE KEEPING TEMPS QUITE MILD. SUNDAY THROUGH TUE...EXPECT MUCH DRIER CONDITIONS AS UPPER LVL HIGH SHIFTS OVER BAJA AND PERSISTENT BROAD TROUGH OVER THE EASTERN PACIFIC MOVES SLIGHTLY FARTHER SOUTH. UPPER LVL FLOW WILL SHIFT FROM SE TO SW AND HELP DRY OUT ANY RESIDUAL MOISTURE OVER THE DESERT AND MOUNTAINS. TEMPS SHOULD REMAIN SLIGHT ABOVE NORMAL FROM SUN-TUE WITH TYPICAL NIGHT THROUGH MORNING LOW CLOUDS ACROSS THE COASTAL PLAIN AND COASTAL VALLEYS. && .AVIATION...09/1720Z MARINE LAYER NEAR 030 THIS MORNING AS UPPER LEVEL DISTURBANCE MOVES INTO AREA. MOST AIRFIELDS SHOULD SEE VFR CATS AFTER 20Z...WITH THE STRATUS CLEARING AWAY AS AN UPPER LEVEL DISTURBANCE MOVES OVER SOUTHERN CALIFORNIA. A THREAT OF -TSRA EXISTS AT ALL AIRFIELDS TODAY...BUT THE THREAT IS ONLY LARGE ENOUGH TO WARRANT MENTION AT KWJF AND KPMD. THUNDERSTORMS WILL BE ISOLATED IN COVERAGE...SO BEST LEAD TIME FOR OTHER AIRPORTS WILL BE ON THE ORDER OF AN HOUR. GUSTY DOWNBURST ARE POSSIBLE AS WELL...ESPECIALLY IN THE DESERTS. OTHER THAN THE MARINE LAYER BEING MORE BROKEN UP THAN IT HAS BEEN THAT LAST COUPLE OF DAYS AND CIGS A BIT HIGHER THAN THIS MORNING...LITTLE CONFIDENCE IN WHAT THE MARINE LAYER WILL DO OVERNIGHT. KLAX...SHOULD BE VFR AFTER 19Z. STRATUS WILL ERODE AS UPPER LEVEL DISTURBANCE MOVES IN. LIKELIHOOD OF -TSRA REACHING AIRPORT IS SMALL...BUT CANNOT RULE IT COMPLETELY OUT. WILL MONITOR THE SITUATION AND AMEND TAFS AND NOTIFY TOWER IF CONDITIONS BECOME MORE FAVORABLE. WINDS WILL BE TYPICAL WESTERLY. KBUR...SHOULD BE VFR THROUGH THIS EVENING. THREAT OF A THUNDERSTORM DRIFTING OFF THE MOUNTAINS WILL EXIST THROUGH THE EVENING...WILL MONITOR THE SITUATION AND AMEND TAFS AND NOTIFY TOWER IF CONDITIONS BECOME MORE FAVORABLE. WINDS WILL BE TYPICAL SOUTHERLY. $$ .LOX WATCHES/WARNINGS/ADVISORIES... NONE && $$ PUBLIC...KAPLAN AVIATION...GOMBERG WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS DENVER CO
230 PM MDT WED JUL 11 2007 .SHORT TERM...SCATTERED CONVECTION ONGOING ACROSS MOUNTAINS AND FOOTHILLS BEGINNING TO MOVE SOUTHEAST ONTO PLAINS. PLAINS STILL A BIT CAPPED AS NOTED BY LATEST ACARS SOUNDING. SHOULDN`T TAKE MUCH TO BREAK CAP AS CURRENT TEMPERATURES HAVE REACHED CONVECTIVE TEMPERATURE. RADAR SHOWING CONVERGENCE ZONE FROM EASTERN ADAMS COUNTY SOUTHEAST INTO WESTERN ELBERT COUNTY. SOME CUMULUS BEGINING TO FORM ALONG AND EAST OF THIS BOUNDARY. SHORTWAVE APPROACHING FROM THE NORTHWEST WILL HELP BREAK CAP AND AID IN MOVING CONVECTION ONTO PLAINS. SHOULD SEE SOME SEVERE STORMS...AS LAPS ANALYSIS SHOWING CAPE VALUES IN THE 1500-2000 J/KG RANGE. HAIL AND STRONG WINDS WILL BE THE MAIN CONCERNS...THOUGH ISOLATED TORNADOES CAN`T BE RULED OUT ALONG THE CONVERGENCE ZONE. GPS INTEGRATED PRECIPITABLE WATER VALUES AROUND NINE TENTHS OF AN INCH...SHOULD SEE SOME HEAVY RAIN WITH THE STORMS. COULD SEE SOME MINOR FLOODING AS A RESULT. STORMS SHOULD MOVE OUT OF THE AREA BY MIDNIGHT AS WAVE EXISTS THE REGION. SURFACE PROGS SHOW ANOTHER FRONT MOVING ACROSS PLAINS AFTER MIDNIGHT WHICH WILL ENHANCE LOW LEVEL UPSLOPE. COULD SEE STRATUS ALONG WITH SOME FOG DEVELOPING TOWARDS MORNING. MODELS SHOW SHORTWAVE MOVING SOUTHEAST ACROSS AREA DURING THE AFTERNOON...SHOULD HELP DESTABILIZE ATMOSPHERE. THOUGH BULK OF MOISTURE WILL BE ALONG FOOTHILLS AND EASTERN PLAINS...CROSS SECTION SHOW MODEST INCREASE IN MOISTURE OVER MOUNTAINS...MAINLY IN THE MID LEVELS. SHOULD SEE AFTERNOON CONVECTION FIRST DEVELOP IN THE HIGH COUNTRY...THEN PROPAGATE SOUTHEAST ONTO PLAINS. MODELS SUGGEST DENVER CYCLONE REDEVELOPING DURING THE AFTERNOON AS SURFACE FLOW BECOMES SOUTHEAST. SHOULD SEE SOME SORT OF CONVERGENCE AREA POSSIBLE EAST AND SOUTH OF DENVER WHICH COULD AID IN ADDITIONAL STORM DEVELOPMENT. FORECAST SOUNDINGS SHOWING CAPE VALUES FROM 1000-1500 J/KG...AND ALONG WITH MODEST SHEAR...SOME SEVERE STORMS POSSIBLE. HAIL AND STRONG WINDS WILL BE THE MAIN THREAT...THOUGH ONE CANNOT RULE OUT A BRIEF TORNADO OR TWO ALONG THE CONVERGENCE AREA. WITH FORECAST SOUNDING SHOWING PRECIPITABLE WATER VALUES AROUND AN INCH ACROSS THE PLAINS...SHOULD SEE SOME HEAVY RAIN WITH THE STORMS WHICH COULD CAUSE LOCALIZED FLOODING. COOLER AIR BEHIND MORNING SURGE. TEMPERATURE AND THICKNESS PROGS SUGGEST LOWER 80S FOR HIGHS ACROSS PLAINS. WILL LOWER CURRENT TEMPERATURE A BIT. .LONG TERM...ONGOING CONVECTION THURSDAY AFTERNOON SHOULD AGAIN DEVELOP AND SPREAD SOUTHEAST DURING THE EVENING HOURS. BEST COVERAGE IS EXPECTED SOUTH AND EAST OF THE METRO AREA AS AIRMASS STABILIZES FROM THE NORTH. HEAVY RAIN POSSIBLE AGAIN WITH PRECIPITABLE WATER VALUES AT OR ABOVE 1 INCH AND DEEPER UPSLOPE FLOW IN PLACE. CANT RULE OUT A FEW SEVERE STORMS EITHER BUT INSTABILITY AND SHEAR ARE BOTH WEAKENING SO MAIN THREAT FOR NOW DURING THE EVENING HOURS APPEARS TO BE THE RAIN. BY FRIDAY...TEMPERATURES BEGIN TO MODERATE BUT THE LOWER ATMOSPHERE EAST OF THE MOUNTAINS REMAINS RELATIVELY MOIST AS SELY LOW-LEVEL FLOW KEEPS HIGHER THETA-E AIR IN PLACE. THE MID LEVEL WARMING WILL ACT TO SUPPRESS STORM COVERAGE...BUT STILL ENOUGH MOISTURE AROUND TO FIRE A FEW LATE DAY STORMS ESPECIALLY IN/NEAR THE MOUNTAINS AND FOOTHILLS. THE UPPER LEVEL RIDGE OVER THE DESERT SOUTHWEST IS EXPECTED TO SHIFT SLOWLY NORTH AND EAST ACROSS THE CENTRAL ROCKIES BY EARLY NEXT WEEK. THIS WILL BRING A MORE NORTHERLY FLOW BUT AT THE SAME TIME WARMER TEMPERATURES WITH HIGHS ACROSS THE PLAINS RETURNING TO THE LOWER 90S. STILL CANT RULE OUT ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WITH MOISTURE TRAPPED UNDER THE RIDGE. && .AVIATION...SCATTERED THUNDERSTORMS POSSIBLE THROUGH 02Z...COULD AFFECT DIA WITH LARGE HAIL...STRONG WIND AND HEAVY RAIN. ISOLATED TORNADOES POSSIBLE ALONG A CONVERGENCE ZONE JUST EAST AND SOUTH OF THE AIRPORT. SURFACE FRONT WILL MOVE ACROSS THE AIRPORT AROUND 12Z WITH SURFACE WINDS SHIFTING TO THE NORTHEAST. COULD SEE MVFR CONDITIONS...CEILINGS AND VISIBILITY...DEVELOP AT THAT TIME. SCATTERED THUNDERSTORMS POSSIBLE AFTER 18Z...WITH HEAVY RAIN AND HAIL POSSIBLE. POSSIBLE CONVERGENCE ZONE DEVELOPING EAST AND SOUTH OF THE AIRPORT. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ D-L/BARJENBRUCH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
257 PM CDT WED JUL 11 2007 .DISCUSSION... 257 PM...COOLER AND MUCH DRIER AIR ACROSS THE REGION TODAY AND WILL PERSIST THRU THE END OF THE WEEK. TEMPS STRUGGLING TO REACH MID 70S THIS AFTERNOON. WOULD EXPECT TEMPS TO DROP OFF CONSIDERABLY TONIGHT BUT WITH THE NEXT SYSTEM QUICKLY MOVING ACROSS THE WESTERN PLAINS... WILL SEE AN INCREASE IN MID/HIGH LEVEL CLOUDS OVERNIGHT AS WELL AS WINDS BACKING SOUTHWESTERLY BY MORNING...BOTH AIDING LOWS ONLY DROPPING INTO MID/UPPER 50S. NEXT SYSTEM/SHORTWAVE ARRIVES THURSDAY MORNING AND MODELS ARE NOT HANDLING THIS FEATURE TOO WELL AND IMPACTS ARE NUMEROUS. THE NAM REMAINS THE WETTEST AND COOLEST...WHILE THIS MAY BE OVERDONE... STILL EXPECT A MOSTLY CLOUDY DAY WITH AT LEAST ISOLATED SHOWERS AROUND. INSTABILITY ISN/T GREAT...THUS THUNDER SHOULD BE LIMITED BUT WILL MAINTAIN MENTION. BEAT APPROACH AT THIS POINT IS A COMPROMISE. BUT IF PRECIP BECOMES MORE WIDESPREAD THEN CURRENTLY EXPECTED THEN HIGH TEMPS MAY ONLY MAKE 70/LOWER 70S. PRECIP ENDS THURSDAY EVENING WITH CLEARING INTO FRIDAY MORNING. UPPER TROF REMAINS ACROSS THE LAKES REGION THRU SATURDAY NIGHT BEFORE BEGINNING TO FLATTEN AS THE FLOW BECOMES ZONAL SUNDAY. SEVERAL WEAK IMPULSES CONTINUE TO SWING AROUND THE BASE OF THE TROF BUT APPEAR TO STAY NORTH OF THE CWA. WILL MAINTAIN A DRY FORECAST AFTER THURSDAY EVENING FOR NOW. FOCUS THEN SHIFTS TO BUILDING RIDGE EARLY/MIDDLE NEXT WEEK. MODELS HAVE BEEN FAIRLY CONSISTENT WITH THE HEAT/HUMIDITY RETURNING ACROSS THE REGION. HAVE MADE SIGNIFICANT CHANGES WITH HIGHS IN THE LOWER 90S AND LOWS ONLY IN THE 70S BY TUESDAY NIGHT. IF THESE TRENDS CONTINUE WOULD EXPECT TEMPS TO HAVE TO BE BUMPED UP FURTHER WITH LATER FORECASTS. CMS && .AVIATION DISCUSSION REGARDING 18Z TAFS... 110 PM CDT LATEST VISIBLE IMAGERY AND OBSERVATIONS ARE BEGINNING TO INDICATE CU FIELD DEVELOPING ACROSS NORTHERN ILLINOIS AS SURFACE TEMPERATURES HAVE WARMED INTO THE LOWER AND MID 70S EARLY THIS AFTERNOON...WHICH IS FAIRLY CLOSE TO INDICATED CONVECTIVE TEMPS FROM ACARS/FORECAST SOUNDINGS. HOWEVER MAIN CONCERN THIS AFTERNOON WILL CENTER ON WINDS. RADAR INDICATING LAKE ENHANCED BOUNDARY EXTENDING FROM ABOUT 5 MILES EAST OF MDW EXTENDING SOUTHWARD THROUGH SOUTHERN COOK COUNTY. WEST/NORTHWEST SYNOPTIC WINDS SHOULD KEEP THIS BOUNDARY FROM ADVANCING MUCH FURTHER WEST...AND ONLY GYY SHOULD EXPERIENCE THE NORTH WINDS EAST OF THIS BOUNDARY THIS AFTERNOON. OTHERWISE...NORTHWEST WINDS ACROSS THE REMAINDER OF THE TERMINALS WILL BACK TO THE WEST BY EVENING AS A 1020 HPA SURFACE HIGH DROPS INTO SOUTHERN MISSOURI. AS MIXED LAYER DIMINISHES THIS EVENING...WIND SPEEDS SHOULD DROP BACK TO 5 TO 10 KNOTS EARLY THIS EVENING. AFTERNOON CU SHOULD ALSO DIMINISH THIS EVENING. FOCUS FOR THE OVERNIGHT WILL THEN TURN TO APPROACHING SHORT WAVE FROM SOUTHERN CANADA. MODELS INDICATE ANOTHER BAROCLINIC ZONE DROPPING INTO THE CENTRAL PLAINS/UPPER MS VALLEY WITH THIS SYSTEM...WITH FAIRLY STRONG LOW LEVEL FRONTOGENESIS. NAM/GFS DIFFER ON AMOUNTS OF SOUTHWESTERLY LOW LEVEL WINDS/ISENTROPIC LIFT IN ADVANCE OF THIS SHORT WAVE WITH NAM INDICATING STRONGER ISENTROPIC LIFT AND BETTER MID LEVEL SATURATION. HAVE SOME CONCERN NAM MAY BE TOO AGGRESSIVE IN SATURATING THE MID LEVELS...SO FOR NOW WILL ONLY MENTION PROB30 GROUP FOR RAIN SHOWERS ACROSS TERMINALS BY LATE MORNING. INSTABILITY PROGS ARE RATHER UNIMPRESSIVE AND WILL OMIT THUNDER MENTION AT THIS TIME. MARSILI && .MARINE DISCUSSION... 200 PM CDT SFC GRADIENT HAS BEGUN TO RELAX A BIT THIS AFTERNOON...AND SHIP REPORTS/BUOY OBSERVATIONS CONTINUE TO INDICATE WIND SPEEDS RELAXING THIS AFTERNOON AS DEEP SFC LOW CONTINUES TO PULL OFF TO THE EAST ACROSS WESTERN QUEBEC. HAVE MAINTAINED A SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING MAINLY FOR THE INDIANA NEARSHORE WATERS MAINLY FOR LINGERING HIGH WAVES. NEXT SYSTEM WILL APPROACH FROM SOUTHERN CANADA ON THURSDAY...WITH ANOTHER FRONTAL PASSAGE EXPECTED ON THURSDAY NIGHT. WEST-SOUTHWEST WINDS ARE EXPECTED IN ADVANCE OF THIS FRONT DURING THE DAY THURSDAY...SHIFTING TO THE NORTH AGAIN THURSDAY NIGHT. MAY GET CLOSE TO SMALL CRAFT ADVISORY CONDITIONS AGAIN LATE THURSDAY NIGHT INTO FRIDAY WITH A FAVORABLE FETCH SETTING UP. SFC RIDGE SHOULD THEN BUILD IN BEHIND THIS SYSTEM FOR FRIDAY WITH LIGHTER WINDS...BECOMING SOUTH AGAIN BY FRIDAY NIGHT AND INCREASING TO AROUND 20 KNOTS LATE FRIDAY NIGHT IN ADVANCE OF YET ANOTHER SFC LOW EXPECTED TO TRACK ACROSS THE NORTHERN GREAT LAKES. MARSILI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADV UNTIL 7 PM FROM GARY TO MICHIGAN CITY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
200 PM CDT WED JUL 11 2007 .DISCUSSION...EARLY MORNING GRIDS 245AM...OVERVIEW...TROUGHINESS OVER THE GREAT LAKES DURING REMAINDER OF THE WEEK WILL GIVE WAY TO EXPANDING UPPER RIDGE FROM THE WEST OVER THE WEEKEND. AIRMASS WILL BECOME WARMER AND MORE MOIST FROM SUNDAY ONWARD AS ORGANIZED SW FLOW RESUMES AND PERSISTS. ...DISCUSSION...WITH UPPER SHORT WAVE OVER ONTARIO MOVING ALONG A BROAD AREA OF NW WINDS IS USHERING IN COOLER AND DRIER AIRMASS TODAY. A TIGHTENING GRADIENT ALONG THE WESTERN FLANK OF THIS TROUGH OVER CENTRAL CANADA WILL SUPPORT A TRAILING SHEARED SHORT WAVE SLIDING SEWD INTO HIGH PLAINS LATER TODAY THEN ACROSS WESTERN AND SOUTHERN LAKES THURSDAY. MAIN BAROCLINICITY APPEARS TO BE SHAPING UP ACROSS IOWA AND NRN HALF OF ILL FOR THURSDAY AND EARLY THURSDAY NIGHT. MOISTURE AND INSTABILITY SOMEWHAT LIMITED SO ONLY SCTD SHOWERS AND PERHAPS AND ISOLD TSTM IS EXPECTED MAINLY THURSDAY AFTN AND INTO THE EVENING. BY FRIDAY A SECONDARY PUSH OF COOLER AIR IS EXPECTED. BY THE WEEKEND AIRMASS MODIFICATION SHOULD BEGIN UNDER A STRONG JULY SUN. BROADER UPPER AIR PATTERN CHANGES SHOW THE EASTERN US TROUGH WILL WEAKEN AND SLIDE EASTWARD BY THEN WITH UPPER RIDGE WHICH HAS PERSISTED OVER THE WEST MAKING A MOVE INTO THE CENTRAL STATES AND WESTERN LAKES. WHILE MODELS HAVE BEEN PRETTY UNIFORM IN THE FIRST 4 DAYS OF FCST THERE IS SOME ARGUMENT DEVELOPING OVER THE WEEKEND AND NEXT WEEK. MAIN BONE OF CONTENTION IS THE AMPLITUDE OF THE RIDGE AND LOCATION. ECMWF MAINTAINS A DEEPER TROUGH ALONG THE EAST COAST WHILE GFS IS MUCH FLATTER AND WOULD SUPPORT A MORE SUSTAINED WARMUP. GIVEN TIME OF YEAR AND PROXIMITY OF PLAINS HEAT AS WELL AS EXPECTED BROAD WSW FLOW REGIME SETTING UP A DEFINED WARMING TREND ALONG WITH HIGHER HUMIDITY IS LKLY FROM SUNDAY ONWARD. ANY LLJ RELATED CONVECTION SHOULD BE CONFINED TO THE NRN LAKES. AT THIS POINT CURRENT FCST PUSHING HIGHS TWD 90 BY MONDAY IS REASONABLE. IN SHORTER MORE PLEASANT TIME FRAME..ACARS SOUNDINGS FROM CENTRAL IOWA AND RFD SUGGEST HIGHS WILL PEAK IN THE UPPER 70S TODAY. CLOUDS WILL HOLD TEMPS ABOUT THE SAME THURSDAY THEN PERHAPS AN EVEN COOLER DAY BY A FEW DEG FOR FRIDAY AS 850MB TEMPS FCST TO DIP ANOTHER 3-4 DEG. AFTER THAT THE WARMING BEGINS. ONLY CHC POPS FOR THURSDAY AS MOISTURE IS LIMITED. KML && .AVIATION DISCUSSION REGARDING 18Z TAFS... 110 PM CDT LATEST VISIBLE IMAGERY AND OBSERVATIONS ARE BEGINNING TO INDICATE CU FIELD DEVELOPING ACROSS NORTHERN ILLINOIS AS SURFACE TEMPERATURES HAVE WARMED INTO THE LOWER AND MID 70S EARLY THIS AFTERNOON...WHICH IS FAIRLY CLOSE TO INDICATED CONVECTIVE TEMPS FROM ACARS/FORECAST SOUNDINGS. HOWEVER MAIN CONCERN THIS AFTERNOON WILL CENTER ON WINDS. RADAR INDICATING LAKE ENHANCED BOUNDARY EXTENDING FROM ABOUT 5 MILES EAST OF MDW EXTENDING SOUTHWARD THROUGH SOUTHERN COOK COUNTY. WEST/NORTHWEST SYNOPTIC WINDS SHOULD KEEP THIS BOUNDARY FROM ADVANCING MUCH FURTHER WEST...AND ONLY GYY SHOULD EXPERIENCE THE NORTH WINDS EAST OF THIS BOUNDARY THIS AFTERNOON. OTHERWISE...NORTHWEST WINDS ACROSS THE REMAINDER OF THE TERMINALS WILL BACK TO THE WEST BY EVENING AS A 1020 HPA SURFACE HIGH DROPS INTO SOUTHERN MISSOURI. AS MIXED LAYER DIMINISHES THIS EVENING...WIND SPEEDS SHOULD DROP BACK TO 5 TO 10 KNOTS EARLY THIS EVENING. AFTERNOON CU SHOULD ALSO DIMINISH THIS EVENING. FOCUS FOR THE OVERNIGHT WILL THEN TURN TO APPROACHING SHORT WAVE FROM SOUTHERN CANADA. MODELS INDICATE ANOTHER BAROCLINIC ZONE DROPPING INTO THE CENTRAL PLAINS/UPPER MS VALLEY WITH THIS SYSTEM...WITH FAIRLY STRONG LOW LEVEL FRONTOGENESIS. NAM/GFS DIFFER ON AMOUNTS OF SOUTHWESTERLY LOW LEVEL WINDS/ISENTROPIC LIFT IN ADVANCE OF THIS SHORT WAVE WITH NAM INDICATING STRONGER ISENTROPIC LIFT AND BETTER MID LEVEL SATURATION. HAVE SOME CONCERN NAM MAY BE TOO AGGRESSIVE IN SATURATING THE MID LEVELS...SO FOR NOW WILL ONLY MENTION PROB30 GROUP FOR RAIN SHOWERS ACROSS TERMINALS BY LATE MORNING. INSTABILITY PROGS ARE RATHER UNIMPRESSIVE AND WILL OMIT THUNDER MENTION AT THIS TIME. MARSILI && .MARINE DISCUSSION... 200 PM CDT SFC GRADIENT HAS BEGUN TO RELAX A BIT THIS AFTERNOON...AND SHIP REPORTS/BUOY OBSERVATIONS CONTINUE TO INDICATE WIND SPEEDS RELAXING THIS AFTERNOON AS DEEP SFC LOW CONTINUES TO PULL OFF TO THE EAST ACROSS WESTERN QUEBEC. HAVE MAINTAINED A SMALL CRAFT ADVISORY THROUGH EARLY THIS EVENING MAINLY FOR THE INDIANA NEARSHORE WATERS MAINLY FOR LINGERING HIGH WAVES. NEXT SYSTEM WILL APPROACH FROM SOUTHERN CANADA ON THURSDAY...WITH ANOTHER FRONTAL PASSAGE EXPECTED ON THURSDAY NIGHT. WEST-SOUTHWEST WINDS ARE EXPECTED IN ADVANCE OF THIS FRONT DURING THE DAY THURSDAY...SHIFTING TO THE NORTH AGAIN THURSDAY NIGHT. MAY GET CLOSE TO SMALL CRAFT ADVISORY CONDITIONS AGAIN LATE THURSDAY NIGHT INTO FRIDAY WITH A FAVORABLE FETCH SETTING UP. SFC RIDGE SHOULD THEN BUILD IN BEHIND THIS SYSTEM FOR FRIDAY WITH LIGHTER WINDS...BECOMING SOUTH AGAIN BY FRIDAY NIGHT AND INCREASING TO AROUND 20 KNOTS LATE FRIDAY NIGHT IN ADVANCE OF YET ANOTHER SFC LOW EXPECTED TO TRACK ACROSS THE NORTHERN GREAT LAKES. MARSILI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...SMALL CRAFT ADV UNTIL 7 PM FROM GARY TO MICHIGAN CITY. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
110 PM CDT WED JUL 11 2007 .DISCUSSION...EARLY MORNING GRIDS 245AM...OVERVIEW...TROUGHINESS OVER THE GREAT LAKES DURING REMAINDER OF THE WEEK WILL GIVE WAY TO EXPANDING UPPER RIDGE FROM THE WEST OVER THE WEEKEND. AIRMASS WILL BECOME WARMER AND MORE MOIST FROM SUNDAY ONWARD AS ORGANIZED SW FLOW RESUMES AND PERSISTS. ...DISCUSSION...WITH UPPER SHORT WAVE OVER ONTARIO MOVING ALONG A BROAD AREA OF NW WINDS IS USHERING IN COOLER AND DRIER AIRMASS TODAY. A TIGHTENING GRADIENT ALONG THE WESTERN FLANK OF THIS TROUGH OVER CENTRAL CANADA WILL SUPPORT A TRAILING SHEARED SHORT WAVE SLIDING SEWD INTO HIGH PLAINS LATER TODAY THEN ACROSS WESTERN AND SOUTHERN LAKES THURSDAY. MAIN BAROCLINICITY APPEARS TO BE SHAPING UP ACROSS IOWA AND NRN HALF OF ILL FOR THURSDAY AND EARLY THURSDAY NIGHT. MOISTURE AND INSTABILITY SOMEWHAT LIMITED SO ONLY SCTD SHOWERS AND PERHAPS AND ISOLD TSTM IS EXPECTED MAINLY THURSDAY AFTN AND INTO THE EVENING. BY FRIDAY A SECONDARY PUSH OF COOLER AIR IS EXPECTED. BY THE WEEKEND AIRMASS MODIFICATION SHOULD BEGIN UNDER A STRONG JULY SUN. BROADER UPPER AIR PATTERN CHANGES SHOW THE EASTERN US TROUGH WILL WEAKEN AND SLIDE EASTWARD BY THEN WITH UPPER RIDGE WHICH HAS PERSISTED OVER THE WEST MAKING A MOVE INTO THE CENTRAL STATES AND WESTERN LAKES. WHILE MODELS HAVE BEEN PRETTY UNIFORM IN THE FIRST 4 DAYS OF FCST THERE IS SOME ARGUMENT DEVELOPING OVER THE WEEKEND AND NEXT WEEK. MAIN BONE OF CONTENTION IS THE AMPLITUDE OF THE RIDGE AND LOCATION. ECMWF MAINTAINS A DEEPER TROUGH ALONG THE EAST COAST WHILE GFS IS MUCH FLATTER AND WOULD SUPPORT A MORE SUSTAINED WARMUP. GIVEN TIME OF YEAR AND PROXIMITY OF PLAINS HEAT AS WELL AS EXPECTED BROAD WSW FLOW REGIME SETTING UP A DEFINED WARMING TREND ALONG WITH HIGHER HUMIDITY IS LKLY FROM SUNDAY ONWARD. ANY LLJ RELATED CONVECTION SHOULD BE CONFINED TO THE NRN LAKES. AT THIS POINT CURRENT FCST PUSHING HIGHS TWD 90 BY MONDAY IS REASONABLE. IN SHORTER MORE PLEASANT TIME FRAME..ACARS SOUNDINGS FROM CENTRAL IOWA AND RFD SUGGEST HIGHS WILL PEAK IN THE UPPER 70S TODAY. CLOUDS WILL HOLD TEMPS ABOUT THE SAME THURSDAY THEN PERHAPS AN EVEN COOLER DAY BY A FEW DEG FOR FRIDAY AS 850MB TEMPS FCST TO DIP ANOTHER 3-4 DEG. AFTER THAT THE WARMING BEGINS. ONLY CHC POPS FOR THURSDAY AS MOISTURE IS LIMITED. KML && .AVIATION DISCUSSION REGARDING 18Z TAFS... 110 PM CDT LATEST VISIBLE IMAGERY AND OBSERVATIONS ARE BEGINNING TO INDICATE CU FIELD DEVELOPING ACROSS NORTHERN ILLINOIS AS SURFACE TEMPERATURES HAVE WARMED INTO THE LOWER AND MID 70S EARLY THIS AFTERNOON...WHICH IS FAIRLY CLOSE TO INDICATED CONVECTIVE TEMPS FROM ACARS/FORECAST SOUNDINGS. HOWEVER MAIN CONCERN THIS AFTERNOON WILL CENTER ON WINDS. RADAR INDICATING LAKE ENHANCED BOUNDARY EXTENDING FROM ABOUT 5 MILES EAST OF MDW EXTENDING SOUTHWARD THROUGH SOUTHERN COOK COUNTY. WEST/NORTHWEST SYNOPTIC WINDS SHOULD KEEP THIS BOUNDARY FROM ADVANCING MUCH FURTHER WEST...AND ONLY GYY SHOULD EXPERIENCE THE NORTH WINDS EAST OF THIS BOUNDARY THIS AFTERNOON. OTHERWISE...NORTHWEST WINDS ACROSS THE REMAINDER OF THE TERMINALS WILL BACK TO THE WEST BY EVENING AS A 1020 HPA SURFACE HIGH DROPS INTO SOUTHERN MISSOURI. AS MIXED LAYER DIMINISHES THIS EVENING...WIND SPEEDS SHOULD DROP BACK TO 5 TO 10 KNOTS EARLY THIS EVENING. AFTERNOON CU SHOULD ALSO DIMINISH THIS EVENING. FOCUS FOR THE OVERNIGHT WILL THEN TURN TO APPROACHING SHORT WAVE FROM SOUTHERN CANADA. MODELS INDICATE ANOTHER BAROCLINIC ZONE DROPPING INTO THE CENTRAL PLAINS/UPPER MS VALLEY WITH THIS SYSTEM...WITH FAIRLY STRONG LOW LEVEL FRONTOGENESIS. NAM/GFS DIFFER ON AMOUNTS OF SOUTHWESTERLY LOW LEVEL WINDS/ISENTROPIC LIFT IN ADVANCE OF THIS SHORT WAVE WITH NAM INDICATING STRONGER ISENTROPIC LIFT AND BETTER MID LEVEL SATURATION. HAVE SOME CONCERN NAM MAY BE TOO AGGRESSIVE IN SATURATING THE MID LEVELS...SO FOR NOW WILL ONLY MENTION PROB30 GROUP FOR RAIN SHOWERS ACROSS TERMINALS BY LATE MORNING. INSTABILITY PROGS ARE RATHER UNIMPRESSIVE AND WILL OMIT THUNDER MENTION AT THIS TIME. MARSILI && .MARINE DISCUSSION... 305 AM CDT A DEEP LOW PRESSURE JUST SOUTHWEST OF JAMES BAY WILL CONTINUE TO MOVE RAPIDLY NORTHEAST ACROSS NORTHERN QUEBEC TODAY. AS THIS LOW HEADS FURTHER AWAY FROM LAKE MICHIGAN...WINDS WILL GRADUALLY BACK INTO THE WEST AND DIMINISH. BASED ON CURRENT SHIP AND BUOY OBSERVATIONS...AM EXPECTING TO ALLOW GALE WARNING ON THE NORTH END OF THE LAKE TO EXPIRE AS OF 900 AM CDT. MEANWHILE...A HIGH PRESSURE AREA WILL BUILD SOUTH AND EAST ACROSS THE PLAINS STATES...TO THE MID MISSISSIPPI VALLEY THROUGH THURSDAY. ANOTHER COLD FRONT IS FORECAST TO DROP SOUTHWARD ACROSS LAKE MICHIGAN THURSDAY AFTERNOON AND EVENING AHEAD OF ANOTHER HIGH PRESSURE WHICH WILL BUILD SOUTHEASTWARD ACROSS THE NORTHERN PLAINS STATES. THIS REINFOCING PUSH OF COLD AIR IS NOT EXPECTED TO BE ACCOMPANIED BY WINDS AS STRONG AS THOSE EXPERIENCED THIS MORNING. SMALL CRAFT ADVISORIES FOR THE ILLINOIS AND INDIANA NEARSHORE WATERS ARE EXPECTED TO EXPIRE LATER THIS MORNING AS WINDS SUBSIDE. MERZLOCK && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...SMALL CRAFT ADVZY UNTIL 3 PM FROM GARY TO MICHIGAN CITY. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
645 AM CDT WED JUL 11 2007 .DISCUSSION...EARLY MORNING GRIDS 245AM...OVERVIEW...TROUGHINESS OVER THE GREAT LAKES DURING REMAINDER OF THE WEEK WILL GIVE WAY TO EXPANDING UPPER RIDGE FROM THE WEST OVER THE WEEKEND. AIRMASS WILL BECOME WARMER AND MORE MOIST FROM SUNDAY ONWARD AS ORGANIZED SW FLOW RESUMES AND PERSISTS. ...DISCUSSION...WITH UPPER SHORT WAVE OVER ONTARIO MOVING ALONG A BROAD AREA OF NW WINDS IS USHERING IN COOLER AND DRIER AIRMASS TODAY. A TIGHTENING GRADIENT ALONG THE WESTERN FLANK OF THIS TROUGH OVER CENTRAL CANADA WILL SUPPORT A TRAILING SHEARED SHORT WAVE SLIDING SEWD INTO HIGH PLAINS LATER TODAY THEN ACROSS WESTERN AND SOUTHERN LAKES THURSDAY. MAIN BAROCLINICITY APPEARS TO BE SHAPING UP ACROSS IOWA AND NRN HALF OF ILL FOR THURSDAY AND EARLY THURSDAY NIGHT. MOISTURE AND INSTABILITY SOMEWHAT LIMITED SO ONLY SCTD SHOWERS AND PERHAPS AND ISOLD TSTM IS EXPECTED MAINLY THURSDAY AFTN AND INTO THE EVENING. BY FRIDAY A SECONDARY PUSH OF COOLER AIR IS EXPECTED. BY THE WEEKEND AIRMASS MODIFICATION SHOULD BEGIN UNDER A STRONG JULY SUN. BROADER UPPER AIR PATTERN CHANGES SHOW THE EASTERN US TROUGH WILL WEAKEN AND SLIDE EASTWARD BY THEN WITH UPPER RIDGE WHICH HAS PERSISTED OVER THE WEST MAKING A MOVE INTO THE CENTRAL STATES AND WESTERN LAKES. WHILE MODELS HAVE BEEN PRETTY UNIFORM IN THE FIRST 4 DAYS OF FCST THERE IS SOME ARGUMENT DEVELOPING OVER THE WEEKEND AND NEXT WEEK. MAIN BONE OF CONTENTION IS THE AMPLITUDE OF THE RIDGE AND LOCATION. ECMWF MAINTAINS A DEEPER TROUGH ALONG THE EAST COAST WHILE GFS IS MUCH FLATTER AND WOULD SUPPORT A MORE SUSTAINED WARMUP. GIVEN TIME OF YEAR AND PROXIMITY OF PLAINS HEAT AS WELL AS EXPECTED BROAD WSW FLOW REGIME SETTING UP A DEFINED WARMING TREND ALONG WITH HIGHER HUMIDITY IS LKLY FROM SUNDAY ONWARD. ANY LLJ RELATED CONVECTION SHOULD BE CONFINED TO THE NRN LAKES. AT THIS POINT CURRENT FCST PUSHING HIGHS TWD 90 BY MONDAY IS REASONABLE. IN SHORTER MORE PLEASANT TIME FRAME..ACARS SOUNDINGS FROM CENTRAL IOWA AND RFD SUGGEST HIGHS WILL PEAK IN THE UPPER 70S TODAY. CLOUDS WILL HOLD TEMPS ABOUT THE SAME THURSDAY THEN PERHAPS AN EVEN COOLER DAY BY A FEW DEG FOR FRIDAY AS 850MB TEMPS FCST TO DIP ANOTHER 3-4 DEG. AFTER THAT THE WARMING BEGINS. ONLY CHC POPS FOR THURSDAY AS MOISTURE IS LIMITED. KML && .AVIATION DISCUSSION REGARDING 12Z TAFS... 645 AM CDT POST COLD FRONTAL AIR MASS HAS SETTLED ACROSS TERMINAL AREA WITH SATLT LOOPS SHOWING CLR SKIES UPSTREAM OVR UPR MS VLY AND SFC DEW POINTS FROM MID 40S-LOWER 50S. THIS HAS GREATLY IMPROVED VIS COMPARED TO PAST FEW MORNINGS. EXPECT VFR CONDITIONS THRU TAF PERIOD. WITH DRYING AIR MASS...VIS WILL CONTINUE TO BE UNRESTRICTED. HOWEVER...SOME DIURNAL CU EXPECTED TO FORM LATE THIS MRNG/ERLY AFTN AND CONTINUE INTO THIS EVENING. COVERAGE WILL BE SCT ABV 45 HND FT BASED ON FCST SOUNDINGS. SOME OF THESE CU WILL LIKELY LIFT AND SPREAD INTO A HIGH BASED BKN STRATO CU DECK LATER IN THE AFTN BEFORE DSIPTG ARND SUNSET. NWLY SFC WINDS NR 15 KTS THIS MRNG WILL DMNSH AND BCM MORE WLY THRU THIS AFTN AS HI PRES AREA OVR PLAINS STAS DROPS SEWD...TO W AND S OF TERMINAL AREA. INVADING MID/HIGH LVL CLOUDINESS ASSD WITH ANOTHER DIGGING SHRT WAVE DROPPING SWD FROM CANADA WILL BEGIN TO OVERSPREAD RGN DURING PRE DAWN HRS TNGT....BUT AGAIN...CONDS TO RMN VFR. MERZLOCK && .MARINE DISCUSSION... 305 AM CDT A DEEP LOW PRESSURE JUST SOUTHWEST OF JAMES BAY WILL CONTINUE TO MOVE RAPIDLY NORTHEAST ACROSS NORTHERN QUEBEC TODAY. AS THIS LOW HEADS FURTHER AWAY FROM LAKE MICHIGAN...WINDS WILL GRADUALLY BACK INTO THE WEST AND DIMINISH. BASED ON CURRENT SHIP AND BUOY OBSERVATIONS...AM EXPECTING TO ALLOW GALE WARNING ON THE NORTH END OF THE LAKE TO EXPIRE AS OF 900 AM CDT. MEANWHILE...A HIGH PRESSURE AREA WILL BUILD SOUTH AND EAST ACROSS THE PLAINS STATES...TO THE MID MISSISSIPPI VALLEY THROUGH THURSDAY. ANOTHER COLD FRONT IS FORECAST TO DROP SOUTHWARD ACROSS LAKE MICHIGAN THURSDAY AFTERNOON AND EVENING AHEAD OF ANOTHER HIGH PRESSURE WHICH WILL BUILD SOUTHEASTWARD ACROSS THE NORTHERN PLAINS STATES. THIS REINFOCING PUSH OF COLD AIR IS NOT EXPECTED TO BE ACCOMPANIED BY WINDS AS STRONG AS THOSE EXPERIENCED THIS MORNING. SMALL CRAFT ADVISORIES FOR THE ILLINOIS AND INDIANA NEARSHORE WATERS ARE EXPECTED TO EXPIRE LATER THIS MORNING AS WINDS SUBSIDE. MERZLOCK && .LOT WATCHES/WARNINGS/ADVISORIES... IL...SMALL CRAFT ADVZY UNTIL 10AM COASTAL WATERS. IN...SMALL CRAFT ADVZY UNTIL 10AM COASTAL WATERS. LM...GALE WARNING FOR THE NORTH THIRD OF LAKE MICHIGAN TODAY && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
305 AM CDT WED JUL 11 2007 .DISCUSSION...EARLY MORNING GRIDS 245AM...OVERVIEW...TROUGHINESS OVER THE GREAT LAKES DURING REMAINDER OF THE WEEK WILL GIVE WAY TO EXPANDING UPPER RIDGE FROM THE WEST OVER THE WEEKEND. AIRMASS WILL BECOME WARMER AND MORE MOIST FROM SUNDAY ONWARD AS ORGANIZED SW FLOW RESUMES AND PERSISTS. ...DISCUSSION...WITH UPPER SHORT WAVE OVER ONTARIO MOVING ALONG A BROAD AREA OF NW WINDS IS USHERING IN COOLER AND DRIER AIRMASS TODAY. A TIGHTENING GRADIENT ALONG THE WESTERN FLANK OF THIS TROUGH OVER CENTRAL CANADA WILL SUPPORT A TRAILING SHEARED SHORT WAVE SLIDING SEWD INTO HIGH PLAINS LATER TODAY THEN ACROSS WESTERN AND SOUTHERN LAKES THURSDAY. MAIN BAROCLINICITY APPEARS TO BE SHAPING UP ACROSS IOWA AND NRN HALF OF ILL FOR THURSDAY AND EARLY THURSDAY NIGHT. MOISTURE AND INSTABILITY SOMEWHAT LIMITED SO ONLY SCTD SHOWERS AND PERHAPS AND ISOLD TSTM IS EXPECTED MAINLY THURSDAY AFTN AND INTO THE EVENING. BY FRIDAY A SECONDARY PUSH OF COOLER AIR IS EXPECTED. BY THE WEEKEND AIRMASS MODIFICATION SHOULD BEGIN UNDER A STRONG JULY SUN. BROADER UPPER AIR PATTERN CHANGES SHOW THE EASTERN US TROUGH WILL WEAKEN AND SLIDE EASTWARD BY THEN WITH UPPER RIDGE WHICH HAS PERSISTED OVER THE WEST MAKING A MOVE INTO THE CENTRAL STATES AND WESTERN LAKES. WHILE MODELS HAVE BEEN PRETTY UNIFORM IN THE FIRST 4 DAYS OF FCST THERE IS SOME ARGUMENT DEVELOPING OVER THE WEEKEND AND NEXT WEEK. MAIN BONE OF CONTENTION IS THE AMPLITUDE OF THE RIDGE AND LOCATION. ECMWF MAINTAINS A DEEPER TROUGH ALONG THE EAST COAST WHILE GFS IS MUCH FLATTER AND WOULD SUPPORT A MORE SUSTAINED WARMUP. GIVEN TIME OF YEAR AND PROXIMITY OF PLAINS HEAT AS WELL AS EXPECTED BROAD WSW FLOW REGIME SETTING UP A DEFINED WARMING TREND ALONG WITH HIGHER HUMIDITY IS LKLY FROM SUNDAY ONWARD. ANY LLJ RELATED CONVECTION SHOULD BE CONFINED TO THE NRN LAKES. AT THIS POINT CURRENT FCST PUSHING HIGHS TWD 90 BY MONDAY IS REASONABLE. IN SHORTER MORE PLEASANT TIME FRAME..ACARS SOUNDINGS FROM CENTRAL IOWA AND RFD SUGGEST HIGHS WILL PEAK IN THE UPPER 70S TODAY. CLOUDS WILL HOLD TEMPS ABOUT THE SAME THURSDAY THEN PERHAPS AN EVEN COOLER DAY BY A FEW DEG FOR FRIDAY AS 850MB TEMPS FCST TO DIP ANOTHER 3-4 DEG. AFTER THAT THE WARMING BEGINS. ONLY CHC POPS FOR THURSDAY AS MOISTURE IS LIMITED. KML && .AVIATION DISCUSSION REGARDING 06Z TAFS... 1235 AM CDT SFC ANALYSIS SHOWS COLD FRONT NOW OFF TO E OF TERMINAL AREA WITH WINDS AROUND TO WNW. THIS ALSO SHOWS DEW POINT FRONT RUNNING FROM NWRN IND-W CNTRL IL...ALSO CLEARING SEWD WITH MUCH DRIER AIR MASS MOVG IN FROM NW. BASED ON THIS AND CURRENT SATLT IMAGERY EXPECT VFR CONDITIONS THRU TAF PERIOD. WITH DRYING AIR MASS...VIS WILL BE UNRESTRICTED. HOWEVER...SOME DIURNAL CU EXPECTED TO FORM LATE THIS MRNG/ERLY AFTN AND CONTINUE INTO THIS EVENING. COVERAGE WILL BE SCT AOA 45 HND FT BASED ON FCST SOUNDINGS. COME OF THESE CU WILL LIKELY LIFT AND SPREAD INTO A HIGH BASED BKN STRATO CU DECK LATER IN THE AFTN BEFORE DSIPTG ARND SUNSET. WNWLY-NWLY SFC WINDS NR 15 KTS THIS MRNG WILL DMNSH AND BCM MORE WLY THRU THIS AFTN AS HI PRES AREA OVR PLAINS STAS DROPS SEWD...TO W AND S OF TERMINAL AREA. MERZLOCK && .MARINE DISCUSSION... 305 AM CDT A DEEP LOW PRESSURE JUST SOUTHWEST OF JAMES BAY WILL CONTINUE TO MOVE RAPIDLY NORTHEAST ACROSS NORTHERN QUEBEC TODAY. AS THIS LOW HEADS FURTHER AWAY FROM LAKE MICHIGAN...WINDS WILL GRADUALLY BACK INTO THE WEST AND DIMINISH. BASED ON CURRENT SHIP AND BUOY OBSERVATIONS...AM EXPECTING TO ALLOW GALE WARNING ON THE NORTH END OF THE LAKE TO EXPIRE AS OF 900 AM CDT. MEANWHILE...A HIGH PRESSURE AREA WILL BUILD SOUTH AND EAST ACROSS THE PLAINS STATES...TO THE MID MISSISSIPPI VALLEY THROUGH THURSDAY. ANOTHER COLD FRONT IS FORECAST TO DROP SOUTHWARD ACROSS LAKE MICHIGAN THURSDAY AFTERNOON AND EVENING AHEAD OF ANOTHER HIGH PRESSURE WHICH WILL BUILD SOUTHEASTWARD ACROSS THE NORTHERN PLAINS STATES. THIS REINFOCING PUSH OF COLD AIR IS NOT EXPECTED TO BE ACCOMPANIED BY WINDS AS STRONG AS THOSE EXPERIENCED THIS MORNING. SMALL CRAFT ADVISORIES FOR THE ILLINOIS AND INDIANA NEARSHORE WATERS ARE EXPECTED TO EXPIRE LATER THIS MORNING AS WINDS SUBSIDE. MERZLOCK && .LOT WATCHES/WARNINGS/ADVISORIES... IL...SMALL CRAFT ADVZY UNTIL 10AM COASTAL WATERS. IN...SMALL CRAFT ADVZY UNTIL 10AM COASTAL WATERS. LM...GALE WARNING FOR THE NORTH THIRD OF LAKE MICHIGAN TODAY && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
245 PM CDT WED JUL 11 2007 .DISCUSSION...EARLY MORNING GRIDS 245AM...OVERVIEW...TROUGHINESS OVER THE GREAT LAKES DURING REMAINDER OF THE WEEK WILL GIVE WAY TO EXPANDING UPPER RIDGE FROM THE WEST OVER THE WEEKEND. AIRMASS WILL BECOME WARMER AND MORE MOIST FROM SUNDAY ONWARD AS ORGANIZED SW FLOW RESUMES AND PERSISTS. ...DISCUSSION...WITH UPPER SHORT WAVE OVER ONTARIO MOVING ALONG A BROAD AREA OF NW WINDS IS USHERING IN COOLER AND DRIER AIRMASS TODAY. A TIGHTENING GRADIENT ALONG THE WESTERN FLANK OF THIS TROUGH OVER CENTRAL CANADA WILL SUPPORT A TRAILING SHEARED SHORT WAVE SLIDING SEWD INTO HIGH PLAINS LATER TODAY THEN ACROSS WESTERN AND SOUTHERN LAKES THURSDAY. MAIN BAROCLINICITY APPEARS TO BE SHAPING UP ACROSS IOWA AND NRN HALF OF ILL FOR THURSDAY AND EARLY THURSDAY NIGHT. MOISTURE AND INSTABILITY SOMEWHAT LIMITED SO ONLY SCTD SHOWERS AND PERHAPS AND ISOLD TSTM IS EXPECTED MAINLY THURSDAY AFTN AND INTO THE EVENING. BY FRIDAY A SECONDARY PUSH OF COOLER AIR IS EXPECTED. BY THE WEEKEND AIRMASS MODIFICATION SHOULD BEGIN UNDER A STRONG JULY SUN. BROADER UPPER AIR PATTERN CHANGES SHOW THE EASTERN US TROUGH WILL WEAKEN AND SLIDE EASTWARD BY THEN WITH UPPER RIDGE WHICH HAS PERSISTED OVER THE WEST MAKING A MOVE INTO THE CENTRAL STATES AND WESTERN LAKES. WHILE MODELS HAVE BEEN PRETTY UNIFORM IN THE FIRST 4 DAYS OF FCST THERE IS SOME ARGUMENT DEVELOPING OVER THE WEEKEND AND NEXT WEEK. MAIN BONE OF CONTENTION IS THE AMPLITUDE OF THE RIDGE AND LOCATION. ECMWF MAINTAINS A DEEPER TROUGH ALONG THE EAST COAST WHILE GFS IS MUCH FLATTER AND WOULD SUPPORT A MORE SUSTAINED WARMUP. GIVEN TIME OF YEAR AND PROXIMITY OF PLAINS HEAT AS WELL AS EXPECTED BROAD WSW FLOW REGIME SETTING UP A DEFINED WARMING TREND ALONG WITH HIGHER HUMIDITY IS LKLY FROM SUNDAY ONWARD. ANY LLJ RELATED CONVECTION SHOULD BE CONFINED TO THE NRN LAKES. AT THIS POINT CURRENT FCST PUSHING HIGHS TWD 90 BY MONDAY IS REASONABLE. IN SHORTER MORE PLEASANT TIME FRAME..ACARS SOUNDINGS FROM CENTRAL IOWA AND RFD SUGGEST HIGHS WILL PEAK IN THE UPPER 70S TODAY. CLOUDS WILL HOLD TEMPS ABOUT THE SAME THURSDAY THEN PERHAPS AN EVEN COOLER DAY BY A FEW DEG FOR FRIDAY AS 850MB TEMPS FCST TO DIP ANOTHER 3-4 DEG. AFTER THAT THE WARMING BEGINS. ONLY CHC POPS FOR THURSDAY AS MOISTURE IS LIMITED. KML && .AVIATION DISCUSSION REGARDING 06Z TAFS... 1235 AM CDT SFC ANALYSIS SHOWS COLD FRONT NOW OFF TO E OF TERMINAL AREA WITH WINDS AROUND TO WNW. THIS ALSO SHOWS DEW POINT FRONT RUNNING FROM NWRN IND-W CNTRL IL...ALSO CLEARING SEWD WITH MUCH DRIER AIR MASS MOVG IN FROM NW. BASED ON THIS AND CURRENT SATLT IMAGERY EXPECT VFR CONDITIONS THRU TAF PERIOD. WITH DRYING AIR MASS...VIS WILL BE UNRESTRICTED. HOWEVER...SOME DIURNAL CU EXPECTED TO FORM LATE THIS MRNG/ERLY AFTN AND CONTINUE INTO THIS EVENING. COVERAGE WILL BE SCT AOA 45 HND FT BASED ON FCST SOUNDINGS. COME OF THESE CU WILL LIKELY LIFT AND SPREAD INTO A HIGH BASED BKN STRATO CU DECK LATER IN THE AFTN BEFORE DSIPTG ARND SUNSET. WNWLY-NWLY SFC WINDS NR 15 KTS THIS MRNG WILL DMNSH AND BCM MORE WLY THRU THIS AFTN AS HI PRES AREA OVR PLAINS STAS DROPS SEWD...TO W AND S OF TERMINAL AREA. MERZLOCK && .MARINE DISCUSSION... 745 PM CDT THE LOW OVER LAKE SUPERIOR WILL INTENSIFY AND MOVE INTO HUDSON BAY TONIGHT. THE WIND HAS INCREASED TO GALE OVER NORTHERN LAKE MICHIGAN BECAUSE OF THE INCREASE SURFACE PRESSURE GRADIENT. WILL ISSUE A GALE WARNING THROUGH WEDNESDAY. THERE WERE NUMEROUS SHIP REPORTS AND SOME MARINE COASTAL STATIONS ARE REPORTING WIND UP TO 40 KNOTS. WE HAVE INCREASED THE WAVE FORECAST AS WELL. WE EXPECT THE WIND TO DIMINISH THURSDAY. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING FOR THE NORTH HALF OF LAKE MICHIGAN && $$
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
350 AM PDT FRI JUL 13 2007 ...UPDATED AVIATION DISCUSSION... .SHORT TERM (TODAY-SUN)... PLENTY OF CONTINUED WARMING ABOVE 1000 FT TODAY AS LATEST ACARS AND PROFILERS INDICATES MARINE LAYER DEPT NEAR 700 FT THIS MORNING. WARM AIR ABOVE INVERSION HAS HELPED TO STRENGTHEN THE INVERSION. UPPER LVL RIDGE OVER AZ/NV WILL PUSH WESTWARD AND KEEP SW FLOW ALOFT FROM UPPER LVL TROF IN THE EASTERN PAC TO THE NORTH. RISING HEIGHTS AND THICKNESS LVLS WILL MEAN THAT TEMPS WILL WARM UP NICELY ONCE AGAIN TODAY. IN FACT...PORTIONS OF THE ANTELOPE VALLEY SHOULD HEAT UP TO 104 DEGREES AND WARMEST PARTS OF THE SAN FERNANDO VALLEY SHOULD REACH NEAR 101 DEGREES THIS AFTERNOON. LATEST SATELLITE IMAGERY INDICATED LIMITED LOW CLOUD COVERAGE NEAR SAN DIEGO IMMEDIATE COAST. DOWNTOWN LOS ANGELES SHOULD WARM UP TO THE MID 80S THIS AFTERNOON. ALL FOUR COUNTIES WILL SEE A NICE WARM UP TODAY AND ONCE AGAIN TOMORROW. THE MARINE LAYER SHOULD REMAIN UNDER 1000 FT THROUGH SUNDAY. A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ARE STILL POSSIBLE SATURDAY AND ADDED SUNDAY AS WELL AS UPPER LVL FLOW WILL BE OUT OF THE SE TO S. ALTHOUGH MID LEVEL MOISTURE WILL REMAIN AT OR ABOVE 700 MB...SOME CONVECTIVE PARAMETERS SUCH AS K INDEX VALUES IN THE 30S AND LI VALUES JUST UNDER SUB ZERO OVER THE LA AND VTU COUNTY MOUNTAINS AND ANTELOPE VALLEY BOTH DAYS SHOULD WARRANT SLIGHT CHANCE POPS FOR THE WEEKEND. ADDED SBA COUNTY MOUNTAINS AS WELL TO STAY COORDINATED WITH HANFORD NWS. CONFIDENCE LEVEL IS LOW THAT THUNDERSTORMS WILL OCCUR AS EARLIER RUNS INDICATED A STRONG VORT MAX ROTATING AROUND THE HIGH FOR SAT. HOPEFULLY ENOUGH MOISTURE AND HOT TEMPS WILL HELP A FEW ISOLATED STORM DEVELOP. DRY LIGHTNING COULD BE OF CONCERN AS WELL FOR THE FIRE-FIGHTING COMMUNITY. SKIES SHOULD REMAIN CLEAR IN MOST AREAS EXCEPT LA/VTU/SBA COUNTY MOUNTAINS AND ANTELOPE VALLEY WILL HAVE SOME AFTERNOON PARTLY CLOUDY SKIES WITH CU BUILD-UPS LIKELY. TEMPS WILL REMAIN ABOVE NORMAL THROUGH SUNDAY. .LONG TERM...(MON-THU) BOTH GFS AND ECMWF ARE IN AGREEMENT THAT UPPER LVL RIDGE WILL BEGIN TO TRANSLATE TO THE EAST...WHILE BROAD UPPER LVL TROF DIGS FARTHER SOUTH. UPPER LVL FLOW WILL BEGIN TO TURN OUT OF THE SW BRINGING COOLER MORE STABLE AIR OVER THE REGION. THIS WILL DRY OUT ANY RESIDUAL MOISTURE OVER THE MOUNTAINS AND DESERTS AND BEGIN TO SEE TEMPS TREND COOLER THROUGH THE WEEK. AS TROF PUSHES FARTHER SOUTH AND SWINGS ACROSS SO CAL TUE THROUGH THU...HEIGHTS WILL LOWER TO 582 BY WED AND THU ACROSS THE SLO/SBA COUNTIES. THIS WILL TRANSLATE INTO TEMPS LOWERING TO THE 80S FOR MOST VALLEYS AND 60S TO 70S ALONG THE COASTAL PLAIN. THE ANTELOPE VALLEY WILL BE DOWN IN THE LOWER 90S AS WELL. EXPECT MARINE LAYER TO DEEPEN DRAMATICALLY ON TUE EVENING THROUGH THE PERIOD AND EXPECT GUSTY SOUTHWEST WINDS TO AFFECT THE ANTELOPE VALLEY DURING MID WEEK. && .AVIATION...13/1150Z. WEAK MARINE LAYER HAS BEEN ERODED...LEAVING ALL SITES CLEAR THIS MORNING. HIGH CONFIDENCE IN VFR EVERYWHERE THROUGH THE DAY...EXCEPT FOR A SLIGHT CHANCE OF IFR CIGS AT KSMX JUST BEFORE SUNRISE...AND POSSIBLY LOOKS MVFR HAZE AT KLAX. ABOVE NORMAL SEABREEZE EXPECTED ALONG THE COAST...SIMILAR TO THURSDAY. UNSURE OF TIMING FOR MARINE LAYER RETURN TONIGHT...IF AT ALL. KLAX...VFR THROUGH THE DAY...WITH A SLIGHT CHANCE OF MVFR HAZE AROUND SUNRISE. EXPECT USUAL AFTERNOON SEABREEZE NEAR 14 KT TODAY. FOR KBUR...HIGH CONFIDENCE IN VFR CONDS THROUGH THE DAY. $$ .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...KAPLAN AVIATION...MEIER WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
405 AM PDT FRI JUL 13 2007 .SYNOPSIS... INCREASING MID LEVEL MONSOONAL MOISTURE IN SOUTHEAST FLOW ALOFT WILL BRING A CHANCE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS THROUGH SATURDAY...DECREASING SUNDAY. DRIER SOUTHWEST FLOW ALOFT WILL RETURN FOR MONDAY THROUGH THURSDAY OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH SUNDAY)... EASTERLY WAVE...NOW CENTERED OVER NORTHWEST MEXICO...CONTINUES TO MOVE STEADILY WESTWARD WITH AN INVERTED TROUGH EXTENDING TO THE NORTH. THIS INVERTED TROUGH AND ASSOCIATED MOISTURE IS EXPECTED TO REACH SOUTHWEST CALIFORNIA THIS AFTERNOON WITH PW`S INCREASING ABOVE 1.25 INCHES FOR SOUTHERN SECTIONS AND MOISTENING IN THE 500 TO 600 MB LAYER. MODEL INSTABILITIES CONTINUE TO BE MARGINAL. GIVEN THE INCREASE IN MOISTURE AT THE TIME OF PEAK HEATING...SLIGHT CHANCE OF THUNDERSTORMS FOR THE MOUNTAINS APPEARS REASONABLE. SOME OF THESE COULD MOVE WEST OF THE MOUNTAINS IN THE LATE AFTERNOON AND EARLY EVENING...THE COMBINED EFFECTS OF THE SOUTH SOUTHEASTERLY STEERING LEVEL FLOW AND THE WEAK DYNAMICS PROVIDED BY THE INVERTED TROUGH. PW`S FOR SATURDAY ARE SLIGHTLY HIGHER...BUT WITH WEAKER DYNAMICS. SLIGHT CHANCE POPS AGAIN LOOK REASONABLE. PW`S ARE HIGH ENOUGH TO SUPPORT SOME RAINFALL...BUT LOWER LEVELS REMAIN FAIRLY DRY...MORE FAVORABLE FOR STRONG GUSTY SURFACE WINDS THAN FLOODING RAINFALL. AFTERNOON THUNDERSTORMS FOR SUNDAY CAN`T BE RULED OUT FROM RESIDUAL MID LEVEL MOISTURE...THOUGH MOISTURE SHOULD BE DECREASING. NAM IS DOING A DECENT JOB IN SHOWING PATCHIER STRATUS COVERAGE THIS MORNING...THEN GRADUALLY GREATER COVERAGE THE NEXT TWO NIGHTS. INLAND TEMPERATURES WILL SLOWLY WARM THROUGH SATURDAY...THEN SLOWLY COOL SUNDAY. && .LONG TERM (MONDAY THROUGH THURSDAY)... A WEAK TROUGH OF LOW PRESSURE TO THE NORTHWEST WILL BRING DRYING...SLOW COOLING THROUGH WEDNESDAY...AND A SLOWLY DEEPENING MARINE LAYER. BY NEXT WEEKEND...ECMWF/GFS SHOW SOME WARMING WITH SOME POTENTIAL FOR A MORE SUBSTANTIAL INFLUX OF MONSOONAL MOISTURE. HOWEVER...WITH LOW PRESSURE REMAINING JUST OFF THE WEST COAST... DRIER AIR WILL REMAIN NOT VERY FAR AWAY TO THE NORTHWEST. && .AVIATION... 131045Z...LATE EVENING MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH WAS AROUND 1500 FEET NEAR KSAN AND AROUND 500 FEET NEAR KLAX. ONLY MINOR CHANGES IN THE MARINE LAYER DEPTH IS EXPECTED TODAY. STRATUS WAS HAVING A HARD TIME FORMING ALONG THE COAST BUT EXPECT SOME DEVELOPMENT ALONG THE COAST BEFORE SUNRISE. STRATUS WITH BASES AROUND 1000 FEET MSL COULD BRING CEILINGS TO SOME OF THE COASTAL AIRPORTS SUCH AS KSAN AND KCRQ BY SUNRISE AS WELL. STRATUS SHOULD CLEAR OUT WITHIN 1 OR 2 HOURS AFTER SUNRISE. STRATUS SHOULD RETURN TO PORTIONS OF THE COAST THIS EVENING AND PUSH LOCALLY INLAND AFTER MIDNIGHT. ABOVE THE MARINE LAYER INCLUDING THE MOUNTAINS AND DESERTS...VFR CONDITIONS SHOULD CONTINUE WITH SCATTERED CIRRUS ABOVE FL300 AND UNRESTRICTED VISIBILITIES. SOME MID AND HIGH LEVEL MOISTURE MOVING IN FROM THE SOUTHEAST MAY BRING ISOLATED THUNDERSTORMS TO THE MOUNTAINS AND DESERT AREAS THIS AFTERNOON AND EVENING BUT CONFIDENCE IS LOW AT THIS TIME. IF ANY CONVECTION DEVELOPS...BASES SHOULD BE AROUND 10000 MSL WITH TOPS TO FL400. HORTON && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...MARTIN AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS UPTON NY
1053 AM EDT FRI JUL 13 2007 .SYNOPSIS...A WEAK COLD FRONT WILL APPROACH THE REGION LATE TODAY AND DISSIPATE AS IT MOVES OFFSHORE TONIGHT. HIGH PRESSURE BRIEFLY RETURNS FOR SATURDAY INTO SATURDAY NIGHT...THEN A LOW PRESSURE SYSTEM MOVING ACROSS SOUTHERN CANADA WILL DRAG ANOTHER COLD FRONT CLOSER TO THE AREA LATE SATURDAY NIGHT AND SUNDAY. THIS FRONT WILL MOVE JUST OFFSHORE SUNDAY NIGHT...THEN RETURN BACK NORTH AS A WARM FRONT ON MONDAY. UNSETTLED WEATHER WILL PREVAIL NEXT WEEK AS SEVERAL WEAK FRONTAL BOUNDARIES WILL SLIDE THROUGH THE REGION...WHILE THE BERMUDA HIGH REMAINS PARKED WELL OFFSHORE. && .NEAR TERM /THROUGH TONIGHT/...HAVE ADDED SLIGHT CHANCE POP TO INLAND SECTIONS FOR THIS AFTERNOON INTO EARLY THIS EVENING AS APPROACHING COLD FRONT MAY MANAGE TO SPARK A FEW SHOWERS...MAYBE A THUNDERSTORM. 06Z NAM/12Z RUC BOTH INDICATE POTENTIAL FOR BROKEN LINE OF WIDELY SCATTERED CONVECTION AHEAD OF THE FRONT...AS MID LEVEL SHORTWAVE EVIDENT ON GOES WV IMAGERY OVER W PA/E OH AND ENTRANCE REGION OF UPPER JET TO THE NORTH PROVIDING SOME FORCING. SOME MOISTURE POOLING SHOULD ALSO TAKE PLACE AHEAD OF THE FRONT...WITH 850 MB DEWPOINTS INCREASING TO +8C OR +9C AND SOME BOUNDARY LAYER MOISTURE CONVERGENCE. ALY 12Z SOUNDING ALSO SHOWS STEEP LAPSE RATES UP TO 600 MB WITH ONLY WEAK CAPPING ABOVE THAT...WHILE OKX SOUNDING SHOWS STRONGER MID LEVEL CAP CLOSER TO THE COAST...BOTH WELL MODELED ESPECIALLY BY NAM. WOULD EXPECT ANY SHOWERS/TSTMS THAT DEVELOP TO PRODUCE GUSTY WINDS GIVEN DRY AIR BELOW THE LCL /INVERTED V APPEARANCE TO FORECAST SOUNDINGS/ AND SOME MID LEVEL DRYING NOTED ON ALY SOUNDING. ACTIVITY SHOULD QUICKLY FADE AROUND SUNSET WITH LOSS OF HEATING. MORNING SOUNDINGS SUPPORT EARLIER FORECAST MAX TEMPS. SW FLOW AND WARM ADVECTION WILL ALLOW TEMPS TO WARM UP 3-5 DEGREES FROM THU READINGS...ALTHOUGH AN ONSHORE COMPONENT WILL KEEP COASTAL SECTIONS FROM GETTING TOO WARM. EXPECT LOW-MID 80S FOR MOST AREAS...WITH THE WARMEST SPOTS IN NE NJ AND NYC REACHING THE UPPER 80S. && .SHORT TERM /SATURDAY THROUGH SUNDAY/...THE WEAK FRONT WILL WASH OUT ACROSS THE AREA TONIGHT. INCREASED CLOUDINESS AND HIGHER DEWPOINTS WILL KEEP TEMPS A BIT MILDER...MOSTLY IN THE 60S...BUT SOME UPPER 50S WILL STILL BE OBSERVED INLAND. THE AREA WILL BE UNDER SSW FLOW ON SAT...BETWEEN THE BERMUDA HIGH OFFSHORE AND LOW PRESSURE MOVING ACROSS CENTRAL ONTARIO. THE NEXT COLD FRONT WILL BE WELL BACK TO THE WEST ACROSS THE GREAT LAKES... SO EXPECT A DRY AND SEASONABLE DAY. MORE SOUTHERLY WIND DIRECTION RATHER THAN THE SW WINDS OF TODAY WILL KEEP TEMPS A TOUCH COOLER...MOSTLY UPPER 70S TO LOWER 80S...WITH SOME MID 80S IN NE NJ AND NYC. THE FRONT MOVES CLOSE ENOUGH BY LATE SAT NIGHT TO WARRANT SLIGHT CHANCE POPS. SOME DISCREPANCIES BETWEEN THE MODELS AS TO THE SPEED OF THE FRONTAL ADVANCE ON SUN...WITH THE GFS FASTER...THE NAM SLOWER AND THE GGEM IN BETWEEN. WENT WITH A MIDDLE SCENARIO CLOSE TO THE GGEM AT THIS POINT...SLIGHT CHANCE POPS IN THE MORNING INCREASING TO CHANCE IN THE AFTERNOON. MODELS ARE FCSTING VERY STRONG MID LEVEL WIND FIELD ACROSS SOUTHERN NEW ENGLAND SUN AFTERNOON...WITH 0-6 KM SHEAR VECTORS OF 50-60 KT ACROSS THE FCST AREA BY 00Z MON. THIS COULD BE A HIGH SHEAR AND LOW CAPE EVENT THOUGH...AS MARGINAL LAPSE RATES/LOW LEVEL MOISTURE ALONG WITH POSSIBLE LIMITED INSOLATION DUE TO CLOUDINESS COULD LIMIT INSTABILITY. DUE TO THE UNCERTAINTY REGARDING AVAILABLE INSTABILITY...WILL NOT INCLUDE ENHANCED TSTM WORDING AT THIS TIME. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 00Z GFS SIMILAR TO PREVIOUS THINKING WITH THE FCST FOR NEXT WEEK. STILL EXPECTING UNSETTLED WEATHER THROUGH THE PERIOD AS THE VERY PERSISTENT UPPER TROF REMAINS ACROSS THE NORTHEAST AND A SERIES OF FRONTAL BOUNDARIES SLIDE THROUGH THE REGION. THE FIRST FRONT WILL PUSH JUST SOUTH OF THE AREA SUNDAY NIGHT...THEN RETURN BACK NORTH AS A WARM FRONT ON MON. SW FLOW WILL PUSH TEMPERATURES BACK INTO THE UPPER 80S TO NEAR 90 MON AND TUE. ANOTHER FRONT WILL APPROACH TUE NIGHT...THEN WILL BECOME NEARLY STATIONARY OVER THE AREA. SEVERAL WAVES OF LOW PRES WILL DEVELOP ON THIS BOUNDARY...KEEPING CHANCE POPS IN THE FCST THROUGH THE PERIOD. AFTER A BRIEF WARM-UP ON MON/TUE WITH HIGHS IN THE UPPER 80S TO NEAR 90...TEMPERATURES WILL DROP BACK CLOSER TO NORMAL FOR THE MIDDLE OF THE WEEK. HIGHS WILL GENERALLY BE IN THE MID 80S AT INLAND LOCATIONS...LOW 80S CLOSER TO COASTAL LOCATIONS. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/...VFR CONDITIONS AT ALL THE TERMINALS THROUGH 12Z SATURDAY. AC AND CIRRUS MOVING EAST ATTM. SOME UPSTREAM CLOUDINESS SEEN AT SIMILAR LEVELS. MORE AC AND CIRRUS POSSIBLE AGAIN LATE TODAY AND THIS EVENING WITH THE APPROACH OF WEAK FRONT OR TROUGH. WEST WINDS AROUND 5 TO 10 KT WILL INCREASE THIS MORNING. WITH HEATING...INVERSION WILL BREAK AND ACARS SOUNDINGS SUGGEST A SLIGHT TURN TO THE WEST/NORTHWEST WITH AROUND 16 TO 19 KTS TO MIX DOWN. I EXPECT WEST/SOUTHWEST BY AFTERNOON WITH THE APPROACH OF THE AFOREMENTIONED WEAK COLD FRONT...OR SURFACE TROUGH. JFK...ISP...BDR...AND GON MAY GO AROUND CLOSER TO SEAS BREEZE DIRECTIONS AFTER 17Z. A FEW SHOWERS...MAYBE A TSTM...COULD DEVELOP OVER INLAND SECTIONS THIS AFTERNOON INTO EARLY THIS EVENING...MAINLY OF CONCERN TO KSWF BUT POSSIBLY GETTING TO WITHIN VICINITY OF KHPN/KBDR/KGON. POINT PROBABILITY IS TOO LOW FOR INCLUSION IN TAF ATTM...WILL MONITOR AND AMEND IF NECESSARY AS SITUATION UNFOLDS. OUTLOOK FROM 12Z SATURDAY THROUGH TUESDAY...VFR CONDITIONS EXPECTED SATURDAY AS HIGH PRESSURE BUILDS IN. A COLD FRONTAL PASSAGE ON SUN AND TUE MAY HELP TO FOCUS SCT CONVECTION...PRODUCING BRIEF SUB-VFR CONDITIONS. && .MARINE...SW WINDS ANTICIPATED AHEAD OF NEXT WEAK FRONT TODAY AS HIGH PRESSURE SITS WELL TO THE EAST. LOCAL SEA BREEZES WILL INFLUENCE THE NEAR SHORE WATERS AND BAYS. FRONT PASSES THROUGH TONIGHT...AND OCEAN WATERS COULD SEE A BRIEF GUST TO 25 KT RIGHT AFTER FROPA. DURATION OF THESE STRONGER GUSTS NOT EXPECTED TO BE LONG ENOUGH TO WARRANT SCA. AN APPROACHING COLD FRONT ON SATURDAY WILL INCREASE S TO SW FLOW. BY SUNDAY...NEAR SCA WINDS OF 20 TO 25 KT COULD BE ACHIEVED ALONG WITH 5 FT SEAS ON THE OCEAN. YET ANOTHER COLD FRONT IS PRESENTLY EXPECTED TO TRAVERSE THE REGION TUESDAY. OTHERWISE...SOUTHWESTERLY WIND FLOW TO PREVAIL THROUGH A GOOD PORTION OF NEXT WEEK. LITTLE CHANCE FOR SHOWERS WITH THE INITIAL FRONT LATE TODAY AND TONIGHT. BETTER CHANCE WITH NEXT FRONT SUNDAY. UNSETTLED WEATHER CONTINUES ACROSS THE WATERS WITH PRESENCE OF UPPER TROUGH AND SURFACE FRONT THROUGH MID WEEK. && .HYDROLOGY...MAINLY DRY WX EXPECTED THROUGH SAT EVENING...THEN SCATTERED MOSTLY LIGHT RAINFALL POSSIBLE LATE SAT NIGHT THROUGH TUESDAY. THERE IS SOME POTENTIAL FOR MORE SIGNIFICANT AND WIDESPREAD RAINFALL SUN AFTERNOON/EVENING AS A COLD FRONT MOVES THROUGH THE AREA...BUT AT THIS TIME DO NOT EXPECT ANY MAJOR HYDROLOGIC PROBLEMS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...BG/CJ NEAR TERM...BG/CJ SHORT TERM...CJ LONG TERM...CJ/MPS AVIATION...PW MARINE...BG/PW HYDROLOGY...CJ
AREA FORECAST DISCUSSION
NWS UPTON NY
714 AM EDT FRI JUL 13 2007 .SYNOPSIS... A WEAK COLD FRONT WILL APPROACH THE REGION LATE TODAY AND DISSIPATE AS IT MOVES OFFSHORE TONIGHT...WITH NO PRECIPITATION EXPECTED. HIGH PRESSURE BRIEFLY RETURNS FOR SATURDAY INTO SATURDAY NIGHT...THEN A LOW PRESSURE SYSTEM MOVING ACROSS SOUTHERN CANADA WILL DRAG ANOTHER COLD FRONT CLOSER TO THE AREA LATE SATURDAY NIGHT AND SUNDAY. THIS FRONT WILL MOVE JUST OFFSHORE SUNDAY NIGHT...THEN RETURN BACK NORTH AS A WARM FRONT ON MONDAY. UNSETTLED WEATHER WILL PREVAIL NEXT WEEK AS SEVERAL WEAK FRONTAL BOUNDARIES WILL SLIDE THROUGH THE REGION...WHILE THE BERMUDA HIGH REMAINS PARKED WELL OFFSHORE. && .NEAR TERM /THROUGH TONIGHT/... FAIRLY VIGOROUS SHORTWAVE MOVING INTO WRN PA AS OF 06Z HAS SPARKED SOME SCT SHOWER/TSTM ACTIVITY ACROSS UPSTATE NY EARLY THIS MORNING...WITH AREAS OF MID LEVEL CLOUDINESS EXTENDING SOUTHWARD ACROSS PA AND INTO THE DELMARVA. THIS INITIAL SHORTWAVE WILL MOVE NE ACROSS NRN NY AND INTO NEW ENGLAND TODAY...AND SHOULD TAKE THE ASSOCIATED PRECIP ALONG WITH IT WITH DRY CONDITIONS PREVAILING ACROSS THE FCST AREA. WILL HAVE TO KEEP AN EYE ON THE MID LEVEL CLOUDS FURTHER SOUTH...WHICH MAY BRING A FLY INTO THE OINTMENT OF AN OTHERWISE MOSTLY SUNNY FCST FOR THIS MORNING. DO EXPECT SOME INCREASE OF CLOUDS ACROSS WRN SECTIONS THIS AFTERNOON AS A WEAK COLD FRONT APPROACHES...BUT STILL NO PRECIP AS THE LOW LEVELS WILL REMAIN RATHER DRY AND STABLE. SW FLOW AND WARM ADVECTION WILL ALLOW TEMPS TO WARM UP 3-5 DEGREES FROM THU READINGS...ALTHOUGH AN ONSHORE COMPONENT WILL KEEP COASTAL SECTIONS FROM GETTING TOO WARM. EXPECT LOW-MID 80S FOR MOST AREAS...WITH THE WARMEST SPOTS IN NE NJ AND NYC REACHING THE UPPER 80S. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE WEAK FRONT WILL WASH OUT ACROSS THE AREA TONIGHT. DO NOT EXPECT ANY PRECIP WITH THIS FEATURE...AS SFC/UPPER FORCING IS VERY WEAK AND THE LOW LEVELS WILL STILL BE RELATIVELY DRY AND STABLE. INCREASED CLOUDINESS AND HIGHER DEWPOINTS WILL KEEP TEMPS A BIT MILDER...MOSTLY IN THE 60S...BUT SOME UPPER 50S WILL STILL BE OBSERVED INLAND. THE AREA WILL BE UNDER SSW FLOW ON SAT...BETWEEN THE BERMUDA HIGH OFFSHORE AND LOW PRESSURE MOVING ACROSS CENTRAL ONTARIO. THE NEXT COLD FRONT WILL BE WELL BACK TO THE WEST ACROSS THE GREAT LAKES... SO EXPECT A DRY AND SEASONABLE DAY. MORE SOUTHERLY WIND DIRECTION RATHER THAN THE SW WINDS OF TODAY WILL KEEP TEMPS A TOUCH COOLER...MOSTLY UPPER 70S TO LOWER 80S...WITH SOME MID 80S IN NE NJ AND NYC. THE FRONT MOVES CLOSE ENOUGH BY LATE SAT NIGHT TO WARRANT SLIGHT CHANCE POPS. SOME DISCREPANCIES BETWEEN THE MODELS AS TO THE SPEED OF THE FRONTAL ADVANCE ON SUN...WITH THE GFS FASTER...THE NAM SLOWER AND THE GGEM IN BETWEEN. WENT WITH A MIDDLE SCENARIO CLOSE TO THE GGEM AT THIS POINT...SLIGHT CHANCE POPS IN THE MORNING INCREASING TO CHANCE IN THE AFTERNOON. MODELS ARE FCSTING VERY STRONG MID LEVEL WIND FIELD ACROSS SOUTHERN NEW ENGLAND SUN AFTERNOON...WITH 0-6 KM SHEAR VECTORS OF 50-60 KT ACROSS THE FCST AREA BY 00Z MON. THIS COULD BE A HIGH SHEAR AND LOW CAPE EVENT THOUGH...AS MARGINAL LAPSE RATES/LOW LEVEL MOISTURE ALONG WITH POSSIBLE LIMITED INSOLATION DUE TO CLOUDINESS COULD LIMIT INSTABILITY. DUE TO THE UNCERTAINTY REGARDING AVAILABLE INSTABILITY...WILL NOT INCLUDE ENHANCED TSTM WORDING AT THIS TIME. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... 00Z GFS SIMILAR TO PREVIOUS THINKING WITH THE FCST FOR NEXT WEEK. STILL EXPECTING UNSETTLED WEATHER THROUGH THE PERIOD AS THE VERY PERSISTENT UPPER TROF REMAINS ACROSS THE NORTHEAST AND A SERIES OF FRONTAL BOUNDARIES SLIDE THROUGH THE REGION. THE FIRST FRONT WILL PUSH JUST SOUTH OF THE AREA SUNDAY NIGHT...THEN RETURN BACK NORTH AS A WARM FRONT ON MON. SW FLOW WILL PUSH TEMPERATURES BACK INTO THE UPPER 80S TO NEAR 90 MON AND TUE. ANOTHER FRONT WILL APPROACH TUE NIGHT...THEN WILL BECOME NEARLY STATIONARY OVER THE AREA. SEVERAL WAVES OF LOW PRES WILL DEVELOP ON THIS BOUNDARY...KEEPING CHANCE POPS IN THE FCST THROUGH THE PERIOD. AFTER A BRIEF WARM-UP ON MON/TUE WITH HIGHS IN THE UPPER 80S TO NEAR 90...TEMPERATURES WILL DROP BACK CLOSER TO NORMAL FOR THE MIDDLE OF THE WEEK. HIGHS WILL GENERALLY BE IN THE MID 80S AT INLAND LOCATIONS...LOW 80S CLOSER TO COASTAL LOCATIONS. && .AVIATION /11Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS AT ALL THE TERMINALS THROUGH 12Z SATURDAY. AC AND CIRRUS MOVING EAST ATTM. SOME UPSTREAM CLOUDINESS SEEN AT SIMILAR LEVELS. MORE AC AND CIRRUS POSSIBLE AGAIN LATE TODAY AND THIS EVENING WITH THE APPROACH OF WEAK FRONT OR TROUGH. WEST WINDS AROUND 5 TO 10 KT WILL INCREASE THIS MORNING. WITH HEATING...INVERSION WILL BREAK AND ACARS SOUNDINGS SUGGEST A SLIGHT TURN TO THE WEST/NORTHWEST WITH AROUND 16 TO 19 KTS TO MIX DOWN. I EXPECT WEST/SOUTHWEST BY AFTERNOON WITH THE APPROACH OF THE AFOREMENTIONED WEAK COLD FRONT...OR SURFACE TROUGH. JFK...ISP...BDR...AND GON MAY GO AROUND CLOSER TO SEAS BREEZE DIRECTIONS AFTER 17Z. OUTLOOK FROM 12Z SATURDAY THROUGH TUESDAY...VFR CONDITIONS EXPECTED SATURDAY AS HIGH PRESSURE BUILDS IN. A COLD FRONTAL PASSAGE ON SUN AND TUE MAY HELP TO FOCUS SCT CONVECTION...PRODUCING BRIEF SUB-VFR CONDITIONS. && .MARINE... SW WINDS ANTICIPATED AHEAD OF NEXT WEAK FRONT TODAY AS HIGH PRESSURE SITS WELL TO THE EAST. LOCAL SEA BREEZES WILL INFLUENCE THE NEAR SHORE WATERS AND BAYS. AN APPROACHING COLD FRONT ON SATURDAY WILL INCREASE S TO SW FLOW. BY SUNDAY...NEAR SCA WINDS OF 20 TO 25 KT COULD BE ACHIEVED ALONG WITH 5 FT SEAS ON THE OCEAN. YET ANOTHER COLD FRONT IS PRESENTLY EXPECTED TO TRAVERSE THE REGION TUESDAY. OTHERWISE...SOUTHWESTERLY WIND FLOW TO PREVAIL THROUGH A GOOD PORTION OF NEXT WEEK. LITTLE CHANCE FOR SHOWERS WITH THE INITIAL FRONT LATE TODAY AND TONIGHT. BETTER CHANCE WITH NEXT FRONT SUNDAY. UNSETTLED WEATHER CONTINUES ACROSS THE WATERS WITH PRESENCE OF UPPER TROUGH AND SURFACE FRONT THROUGH MID WEEK. && .HYDROLOGY... DRY WX EXPECTED THROUGH SAT EVENING...THEN SCATTERED MOSTLY LIGHT RAINFALL AMOUNTS WILL BE POSSIBLE LATE SAT NIGHT THROUGH TUESDAY. THERE IS SOME POTENTIAL FOR MORE SIGNIFICANT AND WIDESPREAD RAINFALL SUN AFTERNOON/EVENING AS A COLD FRONT MOVES THROUGH THE AREA... BUT AT THIS TIME DO NOT EXPECT ANY MAJOR HYDROLOGIC PROBLEMS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...CJ NEAR TERM...CJ SHORT TERM...CJ LONG TERM...CJ/MPS AVIATION...PW MARINE...PW HYDROLOGY...CJ
AREA FORECAST DISCUSSION
NWS MISSOULA MT
222 PM MDT FRI JUL 13 2007 ...CONTINUED VERY HOT WITH INCREASED THUNDERSTORM ACTIVITY... .DISCUSSION...THE VERY HOT PATTERN WILL CONTINUE THROUGH THE WEEKEND WITH HIGH TEMPERATURE RECORDS LIKELY FALLING IN MANY LOCATIONS. A CHANGE THOUGH...FOR MOST AREAS ANYWAY...IS THAT WE WILL GET INTO A MORE CONVECTIVE PATTERN DURING THIS TIME AS WELL. AREAS TO THE SOUTH SUCH AS SOUTHERN IDAHO AND LEMHI COUNTIES AS WELL AS FAR SOUTHWEST MONTANA HAVE ALREADY HAD ISOLATED STORMS THE PAST COUPLE NIGHTS. HOWEVER...BEGINNING LATER TONIGHT...MOISTURE AND INSTABILITY WILL INCREASE OVER THE REMAINDER OF THE NORTHERN ROCKIES. THIS WILL GIVE RISE TO PREDOMINANTLY AFTERNOON AND EVENING THUNDERSTORMS...ALTHOUGH WITH PERSISTENT INSTABILITY...A FEW STORMS MAY LINGER THROUGH THE NIGHT TIME PERIODS. THE STORMS WILL LIKELY HAVE A MIXTURE OF BRIEF STRONG WIND GUSTS AND MODERATE TO HEAVY RAIN SHOWERS. EVEN WITH SOME RAIN...FREQUENT LIGHTNING WILL CAUSE INCREASING WILDFIRE CONCERNS. SUNDAY NIGHT THROUGH WEDNESDAY. THE INTENSE...RECORD HEAT WILL CONTINUE THROUGH AT LEAST MID WEEK AS THE UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE REGION. TEMPERATURES IN VALLEY LOCATIONS WILL HOVER WITHIN A FEW DEGREES OF THE CENTURY MARK (ON EITHER SIDE) DURING THE AFTERNOONS. IN ADDITION TO THE HEAT WAVE...AFTERNOON THUNDERSTORMS ARE EXPECTED TO FIRE UP MAINLY OVER THE MOUNTAINOUS TERRAIN. ANTICIPATED MODEL CONVECTIVE TEMPERATURES SUGGEST THAT THUNDERSTORM DEVELOPMENT SHOULD BEGIN DURING THE LATE AFTERNOON HOURS (AROUND PEAK HEATING)...EXCEPT ON TUESDAY WHEN EARLY AFTERNOON INITIATION COULD HELP SHAVE A FEW DEGREES OFF OF THE AFTERNOON HIGH TEMPERATURES. GIVEN THE VERY DRY AIR IN THE LOWER LEVELS...GUSTY WINDS COULD DEVELOP NEAR THUNDERSTORMS AS THEY COLLAPSE. LIGHTNING STRIKES WILL LIKELY LEAD TO NEW FIRE STARTS. WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...OVERNIGHT WEDNESDAY WILL BE ACTIVE WITH CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED OVER NORTHWEST MONTANA AND NORTH CENTRAL IDAHO. UPPER LEVEL FLOW WILL BE FROM THE SOUTH WITH MODELS INDICATING GOOD LIFT AND MOISTURE AVAILABLE. THIS ACTIVITY IS ASSOCIATED WITH A WEAK COLD FRONT AND UPPER LEVEL JET MOVING OVER THE AREA. THE FRONT WILL PUSH IN ON THURSDAY AND WILL FINALLY BEGIN TO PROVIDE SOME RELIEF FROM THE HOT TEMPERATURES THE PAST COUPLE OF WEEKS. HOWEVER THEY WILL STILL REMAIN A LITTLE BIT ABOVE NORMAL FOR THIS TIME OF YEAR WITH HIGHS HOVERING AROUND 90 DEGREES. WE WILL BEGIN TO DRY OUT THURSDAY NIGHT AND FRIDAY WITH A SLIGHT WARM UP IN STORE FOR THE EARLY PART OF THE WEEKEND. && .AVIATION...SHOWERS AND THUNDERSTORMS ARE DEVELOPING IN THE VICINITY OF KBTM AND KSMN AT THIS TIME. WINDS MAY BECOME GUSTY NEAR THESE AREAS OF CONVECTION AND AIRCRAFT IN THESE AREAS SHOULD BE AWARE OF ENCOUNTERING TURBULENCE...SEE APPROPRIATE TAFS AND TWEBS. && .FIRE WEATHER...STORMS ARE BEGINNING TO APPROACH NORTH CENTRAL IDAHO THIS AFTERNOON...AND EXPECT THESE TO EXPAND TO SCATTERED COVERAGE OVER THAT AREA DURING THE EVENING. UNFORTUNATELY THESE ARE PRODUCING MORE LIGHTNING THAN RAIN. THE LOLO AND KOOTENAI FOLKS SHOULD KEEP AN EYE ON RADAR LATER THIS EVENING AS SOME OF THESE STORMS SHOULD HANG TOGETHER AND MOVE INTO THAT AREA. THINK THEY WILL BE ISOLATED BY THAT TIME...THOUGH...AND FOR NOW HAVE LEFT YOU OUT OF THE RED FLAG. LOOKS LIKE SOUTHWEST AND WEST CENTRAL MONTANA WILL SEE THE MOST THUNDERSTORM ACTIVITY SATURDAY...AND HAVE ISSUED A WATCH FOR THAT AREA. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR BITTERROOT-DEERLODGE/WEST BEAVERHEAD-EAST BEAVERHEAD-EAST LOLO. ID...RED FLAG WARNING FROM 5 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING FOR CLEARWATER/NEZ PERCE-PALOUSE/HELLS CANYON. && $$ SHORT TERM...WHITMORE/LOEFFELBEIN LONG TERM....HENRY/FOSTER AVIATION...FOSTER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
325 PM CDT FRI JUL 13 2007 .SYNOPSIS... DISORGANIZED FRONTAL STRUCTURAL AND ENHANCED CU FIELD STRETCHES FROM KDGW TO KCDR...KVTN AND THEN SHARPLY SOUTH THROUGH KLBF AND KMCK. ASSOCIATED ENHANCED CU FIELD IS POTENTIAL AREA FOR TSTM DEVELOPMENT THIS AFTN AND EVENING. WEAK UA DISTURBANCE IS OVER SERN MT AND TRANSLATING SWD. SHEAR IS NOT AS DEEPLY LAYERED AS IT WAS YESTERDAY SUGGESTING LESS POTENTIAL FOR SEVERE WEATHER. && .DISCUSSION... INCLUDED ISOLATED STORMS LATE THIS AFTN AND TONIGHT FOR 1500 TO 2500 CAPE...MODEST SHEAR AND NO CIN. THE NAM12 AND TO A LESSER EXTENT THE GFS INDICATE ISOLATED AFTN OR EVENING TSTMS SUNDAY AND MONDAY. ACTIVITY APPEARS TO BE DIURNALLY FORCED. OTHERWISE THE FCST IS DRY WITH A SIGNIFICANT WARMING TREND THIS WEEKEND AND CONTINUING THROUGH FRIDAY. THE ATM IS EXPECTED TO REMAIN CAPPED AT 14 TO 15C AT H7 AND H5 TEMPS WARM TO -5C BY MIDWEEK. THUS THE ATM WILL GRADUALLY BECOME QUASI BAROTROPIC OR SUBTROPICAL IN NATURE. ALL DATA SUPPORTS VERY WARM WEATHER SUNDAY THROUGH FRIDAY. THE ONLY QUESTION IS HOW WARM. THE UPPER LEVEL RIDGE IS FCST TO BUILD DIRECTLY OVER NEB NEXT WEEK. THIS WOULD PRODUCE THE DEEPEST VERTICAL MIXING AND WARMEST TEMPS FARTHER NORTH ACROSS THE DAKOTAS. THUS THE FCST FOR NEB IS FOR VERY WARM BUT NOT RECORD OR NEAR RECORD WARM TEMPS. TEMPS SATURDAY THROUGH MONDAY ARE A BLEND OF THE NAM12 TEMPS AND GUIDANCE. THE NAM12 WAS COOLER THAN THE GUIDANCE SATURDAY AND SUNDAY BUT WARMER MONDAY. MAX TEMPS WERE GRADUALLY RAMPED UP TO THE UPPER 90S TO 100 BY MONDAY. THEREAFTER THE FCST TEMPS CLOSELY FOLLOW THE HPC GRIDS WHICH CALL FOR 90S FOR THE REST OF THE WEEK. NO SIGNIFICANT RAINFALL IS EXPECTED NEXT WEEK AND CONDITIONS COULD GRADUALLY DRY OUT SO THAT PERHAPS NEAR 100F WOULD BE COMMON BY THE END OF THE WEEK BUT THIS IS SOMEWHAT SPECULATIVE AT THIS POINT. LATER FCSTS COULD VERY WELL BE AIMING FOR THIS MARK. IN FACT THE MEDIUM RANGE FCST INDICATES THE UPPER LEVEL RIDGE REMAINS PARKED OVER THE CNTL AND NRN PLAINS THROUGH SUNDAY 10 DAYS OUT AND THE 14 DAY FCST IS FOR THIS RIDGE TO REMAIN NEARLY STATIONARY WITH ABOVE NORMAL TEMPS. THUS ALL INDICATIONS ARE AN EXTENDED PERIOD OF ABOVE NORMAL TEMPERATURES AND BELOW NORMAL RAINFALL IS ABOUT TO BEGIN. && .AVIATION... ISOLATED TO SCATTERED CONVECTION WILL BE PRESENT IN THE VCNTY OF WESTERN 098...264 AND 274 TWEB ROUTES THROUGH THE LATE EVENING HOURS. HAIL AND GUSTY WINDS WILL BE A THREAT TO LIGHT AIRCRAFT NEAR THESE ROUTES AND SHOULD BE AVOIDED. OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED...ALTHOUGH MVFR CONDITIONS WITH LIGHT FOG NEAR 3 MILES MAY BE POSSIBLE ALONG THE PLATTE RIVER VALLEY NEAR SUNRISE. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ CDC