Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 05/19/07

AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
115 PM PDT THU MAY 17 2007 .SYNOPSIS... ONSHORE FLOW AND THE MARINE LAYER WILL CONTINUE LOW CLOUDS AND PATCHY FOG WEST OF THE MOUNTAINS DURING THE NIGHTS AND MORNINGS WITH PARTIAL AFTERNOON CLEARING NEAR THE COAST THROUGH THE WEEKEND. HIGH PRESSURE WILL BRING A LITTLE WARMING AND LESS MARINE LAYER CLOUDINESS EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... HIGH PRESSURE WILL CONTINUE TO BUILD OVER AREA THROUGH THE EVENING HOURS THEN WEAKEN OVERNIGHT. BASED ON DEWPOINTS GREATER THAN 50 DEG...MARINE LAYER DEPTH HAD LOWERED TO AROUND 2600 FEET BY NOON AND EXPECTED TO CONTINUE TO LOWER TO AROUND 2000 FEET BY THIS EVENING THEN SLOWLY DEEPEN OVERNIGHT...DUE TO REDEVELOPING COASTAL EDDY AND LESSENING SUBSIDENCE ALOFT AS ANOTHER WEAK UPPER TROUGH MOVES TOWARDS CALIFORNIA COAST. LOW LEVEL MOISTURE...BELOW 750 FEET...IS EXPECTED TO SURGE UP FROM GULF OF CALIFORNIA AND INTO COACHELLA VALLEY AGAIN TONIGHT DUE TO PREVAILING SOUTHEAST WINDS...OTHERWISE CONTINUED DRY DESERT AND MOUNTAINS THROUGH FRIDAY. THE UPPER TROUGH MOVING OVER SOUTHWEST CALIFORNIA FRIDAY BECOMES QUASI-STATIONARY THROUGH THE WEEKEND DUE TO THE STRONG RIDGE TO THE EAST. A LOW MOVING INLAND ACROSS PACIFIC NORTHWEST REGION FINALLY SHOVES THE DOWNSTREAM RIDGE EASTWARD ON SUNDAY...ALLOWING THE TROUGH TO MOVE EAST OF AREA MONDAY. KEPT MARINE LAYER DEPTH AROUND 2500 FEET THROUGH WEEKEND. HIGH PRESSURE RIDGE BUILDING ALONG 130 WEST LONGITUDE MONDAY AND SHIFTING SLOWLY EASTWARD THROUGH THURSDAY SHOULD BRING WARMING AND DRYING TREND FOR MOST OF SOUTHWEST CALIFORNIA EXCEPT COASTAL AREAS. && .AVIATION... 171830Z...LATEST MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH HAD LOWERED TO AROUND 2500 FEET SINCE THIS MORNING. THE MARINE LAYER SHOULD LOWER TO AROUND 2000 FEET BY TONIGHT. STRATUS...WITH BASES AROUND 1800 FEET MSL...HAS PULLED BACK TO NEAR THE COAST. EXPECT MOST COASTAL AIRPORTS TO SCATTER OUT BY EARLY AFTERNOON. STRATUS WILL PUSH BACK INLAND DURING THE EVENING REACHING THE INLAND VALLEY AREAS INCLUDING NEAR KONT BY MIDNIGHT. WITH THE LOWERING OF THE MARINE LAYER DEPTH THROUGH TONIGHT...EXPECT BASES TO LOWER TO AROUND 1500 FEET MSL TONIGHT. EARLIER CLEARING IS EXPECTED ON FRIDAY. ABOVE THE MARINE LAYER...CONTINUED VFR CONDITIONS THROUGH FRIDAY WITH A MOSTLY CLEAR SKY AND UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC/FIRE WEATHER...BALFOUR AVIATION/MARINE.......HORTON
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
805 AM PDT THU MAY 17 2007 .SYNOPSIS... ONSHORE FLOW AND THE MARINE LAYER WILL CONTINUE LOW CLOUDS AND PATCHY FOG WEST OF THE MOUNTAINS DURING THE NIGHTS AND MORNINGS WITH PARTIAL AFTERNOON CLEARING NEAR THE COAST THROUGH THE WEEKEND. HIGH PRESSURE WILL BRING A LITTLE WARMING AND LESS MARINE LAYER CLOUDINESS EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... HIGH PRESSURE REBUILDING TODAY. MARINE LAYER DEPTH AROUND 3000 FEET THIS MORNING WITH STRATUS LAYER ABOUT 1000 FEET THICK. INVERSION WILL BE STRENGTHENING AND LOWERING TODAY DUE TO SUBSIDENCE ALOFT. STRONGER ONSHORE PRESSURE GRADIENTS THIS AFTERNOON WILL INCREASE MOISTURE ADVECTION. EXPECT STRATUS BREAK UP/BURN OFF AROUND 0930 PDT INLAND VALLEYS AND BETWEEN 1230-1330 PDT COAST. MARINE LAYER EXPECTED TO LOWER TO AROUND 2000 FEET BY THIS EVENING THEN SLOWLY DEEPEN OVERNIGHT AS COASTAL EDDY REDEVELOPS AND ANOTHER WEAK UPPER TROUGH MOVES TOWARDS CALIFORNIA COAST. THIS TROUGH FORECAST TO BECOME NEGATIVE TILT ON FRIDAY AS IT MOVES OVER SOUTHWEST CALIFORNIA AND UNDERCUTS STRONG RIDGE TO THE EAST...SIMILAR TO YESTERDAYS SCENARIO. THUS ESTIMATE MARINE LAYER DEPTH WILL BE AROUND 3500 FEET BY FRIDAY NIGHT/SATURDAY MORNING. OVER THE MOUNTAINS AND DESERTS WEAK SOUTHEAST FLOW TO PREVAIL THROUGH FRIDAY. LOW LEVEL MOISTURE...BELOW 600 FEET...HAS MOVED UP FROM GULF OF CALIFORNIA AND INTO COACHELLA VALLEY...BOTH PALM SPRING AND THERMAL WERE REPORTING HAZE THIS MORNING...OTHERWISE AIR MASS IS DRY AND STABLE. ANOTHER WEAK AND SLIGHTLY DEEPER SURGE IS ADVERTISED FOR LATE TONIGHT/FRIDAY MORNING. FOR THE WEEKEND...THE UPPER TROUGH REMAINS OVER THE AREA BUT BECOME POSITIVELY TILTED AS LOW MOVES INLAND ACROSS PACIFIC NORTHWEST REGION AND SHOVES DOWNSTREAM RIDGE EASTWARD. MARINE LAYER EXPECTED TO REMAIN FAIRLY DEEP...AROUND 3500 FEET THROUGH WEEKEND. MAIN CHANGE WILL BE WIND FLOW ACROSS DESERTS AND MOUNTAINS BECOMING WESTERLY. TROUGH PUSHES EAST OF AREA MONDAY AS HIGH PRESSURE RIDGE BUILDS ALONG 130 WEST LONGITUDE. RIDGE SHIFTING EASTWARD TUESDAY AND WEDNESDAY WITH THERMAL TROUGH DEVELOPING OVER INTERIOR CALIFORNIA. THIS SHOULD BRING WARMING AND DRYING FOR MOST OF SOUTHWEST CALIFORNIA EXCEPT COASTAL AREAS. OFFSHORE FLOW STILL ADVERTISED FOR TUESDAY BUT WEAKER AND OF SHORTER DURATION THAN EARLIER MODEL RUNS INDICATED. && .AVIATION... 171500Z...12Z NKX SOUNDING AS WELL AS TOP REPORTS AND MORNING MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH WAS AROUND 3000 FEET. MARINE LAYER DEPTH IS EXPECTED TO LOWER DURING THE DAY TO AROUND 2000 FEET. STRATUS...WITH BASES AROUND 1600 FEET MSL...SHOULD PULL BACK TO NEAR THE COAST BETWEEN 18Z AND 20Z. EXPECT A LITTLE BETTER CLEARING AT THE COASTAL AIRPORTS THIS AFTERNOON. STRATUS SHOULD PUSH BACK INLAND DURING THE EVENING REACHING THE INLAND VALLEY AREAS BEFORE MIDNIGHT. ABOVE THE MARINE LAYER...CONTINUED VFR WITH A MOSTLY CLEAR SKY AND UNRESTRICTED VISIBILITIES. .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC/FIRE WEATHER...BALFOUR AVIATION/MARINE.......HORTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
650 PM CDT FRI MAY 18 2007 .DISCUSSION FOR AFTERNOON GRIDS/ZONES... THE RIDGE OF HIGH PRESSURE THAT BROUGHT THE CHILLY WEATHER TO THE AREA THIS MORNING HAS BEGUN TO SINK SOUTHWARD INTO THE OHIO VALLEY REGION. GRADIENT BETWEEN THE DEPARTING HIGH AND A DEEPENING SURFACE LOW OVER THE WESTERN DAKOTAS WILL LEAD TO A STRENGTHENING SOUTHWESTERLY FLOW OVER THE NEXT 24 HOURS WHICH WILL HELP PROPEL TEMPERATURES UP TO AROUND 80F SATURDAY AFTERNOON. RELATIVELY SUBTLE SHORTWAVE EMERGING EAST OF THE ROCKIES OVER SASKATCHEWAN WILL ZIP EASTWARD ACROSS SOUTHERN CANADA AND BEGIN TO AMPLIFY SOUTH OF HUDSON`S BAY BY SATURDAY NIGHT INTO SUNDAY. AS THE SHORTWAVE RACES EASTWARD SURFACE LOW WILL TRACK QUICKLY EAST ALONG THE CANADIAN BORDER AND ALLOW A SURFACE FRONT TO "BACKDOOR" INTO THE AREA VERY LATE SATURDAY NIGHT/SUNDAY MORNING. THE COLD LAKE WILL HELP GIVE THE FRONT A BOOST SOUTH/SOUTHWESTWARD AND LEAD TO DRAMATICALLY COLDER CONDITIONS ALONG/NEAR THE LAKE SUNDAY. THE ADVANCING COLD AIRMASS AND SUBSEQUENT FORCING ALONG THE FRONT WILL BE QUITE SHALLOW WITH VIRTUALLY NO HEIGHT FALLS PROGGED IN THE MID/UPPER LEVELS. GIVEN THE SHALLOW NATURE OF THE FRONT/CONVERGENCE...LACK OF UPPER SUPPORT...AND UNFAVORABLE TIME OF DAY REALLY THINK THE CHANCE OF CONVECTION ALONG THE BOUNDARY IS PRETTY SLIM LATE SATURDAY NIGHT INTO SUNDAY MORNING. WOULDN`T BE SHOCKED WITH SOME HEATING/DESTABILIZATION SUNDAY AFTERNOON THAT SOME SCATTERED CONVECTION DEVELOP ALONG THE BOUNDARY OVER OUR WESTERN/SOUTHERN CWA...HOWEVER WEAK DEEP LAYER SHEAR WILL LEAD TO POOR STORM ORGANIZATION AND COVERAGE OF PRECIPITATION SHOULD REMAIN RATHER LOW. SURFACE RIDGE AXIS WILL THEN BEGIN TO SLIDE EASTWARD SUNDAY NIGHT INTO MONDAY ALLOWING WINDS TO VEER TO THE EAST THEN MORE SOUTH-SOUTHEAST. WILL PROBABLY SEE A SLIGHT EASTERLY COMPONENT TO THE GRADIENT ON MONDAY AFTERNOON...WHICH THE COLD LAKE WILL LIKELY TAKE ADVANTAGE OF AND KEEP TEMPERATURES MUCH COOLER ALONG THE IMMEDIATE ILLINOIS LAKE SHORE...PARTICULARLY THE NORTH SHORE. ELSEWHERE TEMPERATURES SHOULD HAVE NO PROBLEM REBOUNDING NICELY TO AROUND 80F. MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE LARGE SCALE PATTERN NEXT WEEK LEADING TO SLIGHTLY GREATER THAN AVERAGE FORECAST CONFIDENCE. VIGOROUS TROUGH IS EXPECTED TO DIVE INTO THE NORTHERN ROCKIES EARLY IN THE WEEK ALLOWING FOR UPPER RIDGE TO AMPLIFY OVER THE MISSISSIPPI VALLEY AND GREAT LAKES. AMPLIFYING RIDGE AND STRENGTHENING SOUTHERLY FLOW SHOULD PUSH TEMPS UP TO WELL ABOVE AVERAGE FOR THE FIRST HALF OF THE WEEK. WESTERN TROUGH IS EXPECTED TO REMAIN FAIRLY PROGRESSIVE AND MARCH STEADILY EASTWARD ACROSS THE NORTHERN TIER OF STATES DURING THE WEEK. AS UPPER TROUGH TRACKS EASTWARD ATTENDANT SURFACE LOW WILL MOVE ALONG THE CANADIAN BORDER DRAGGING A COLD FRONT ACROSS THE CWA LATE WEDNESDAY/WEDNESDAY NIGHT. SURFACE RIDGING ALONG THE GULF COAST EARLY IN THE WEEK WILL LIKELY LIMIT MOISTURE RETURN AND RESULTANT INSTABILITY TO SOME EXTENT...HOWEVER GIVEN THE EXPECTED SUBSTANTIAL HEIGHT FALLS WITH THE VIGOROUS TROUGH AND THE TIME OF YEAR MAINTAINED CHC OF THUNDERSTORMS MIDWEEK. IZZI && .AVIATION DISCUSSION FOR 00Z TAFS... 650 PM QUIET NIGHT AS SFC HIGH MOVES OFF TO THE EAST AND RETURN SW FLOW PERSISTS BUT DIES DOWN AS TEMPS COOL. TAMDAR SOUNDINGS SHOW AIRMASS QUITE DRY AND MOISTURE WILL BE SLOW TO RETURN ALTHOUGH THAT PROCESS WILL BEGIN IN NEXT 24HRS. FOR THE MOST PART CONTINUING SW WINDS THROUGH 24HRS WITH SOME GUSTS ON SAT. SKIES GENLY CLEAR. KL && .MARINE... 215 PM A RIDGE OF HIGH PRESSURE EXTENDS FROM SOUTHERN QUEBEC THROUGH THE LOWER MISSISSIPPI VALLEY. A COLD FRONT EXTENDS FROM LOW PRESSURE OVER EASTERN CANADA...THROUGH ONTARIO...TO ANOTHER LOW OVER NORTH DAKOTA. CURRENTLY...WINDS OVER LAKE MICHIGAN ARE SOUTHWESTERLY AT 5 TO 10 KNOTS OVER THE SOUTHERN HALF OF THE LAKE AND 10 TO 15 KNOTS OVER THE NORTHERN HALF. BY LATE SATURDAY EVENING...STRONG HIGH PRESSURE WILL BUILD SOUTHEAST INTO ONTARIO...FORCING THE COLD FRONT DOWN THE LAKE. OVERNIGHT SATURDAY NIGHT...WINDS WILL QUICKLY TURN NORTHERLY BEHIND THE FRONT...AND WINDS ARE EXPECTED TO INCREASE TO AROUND 25 TO 30KT BEHIND THE FRONT AS COLD AIR STREAMS DOWN THE LENGTH OF THE LAKE. WAVE HEIGHTS WILL INCREASE IN RESPONSE TO THE INCREASING WINDS...AND WILL BE ENHANCED FURTHER BY COLD AIR ASSOCIATED WITH THE BUILDING HIGH PRESSURE...DRIVING WAVES EVEN HIGHER. THE FRONT SHOULD STALL OUT OVER THE OHIO VALLEY ON MONDAY WHILE THE HIGH PRESSURE SHIFTS TO THE EAST...SETTING UP A PERIOD OF SOUTHEASTERLY WINDS OVER THE LAKE. AS LOW PRESSURE TROUGHING DEVELOPS OVER THE CENTRAL PLAINS BY MID WEEK AND THE HIGH PRESSURE MOVES INTO NEW ENGLAND...WINDS WILL GRADUALLY SHIFT MORE SOUTHERLY AND INCREASE IN SPEED IN RESPONSE TO A STRENGTHENING PRESSURE GRADIENT. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
730 PM EDT FRI MAY 18 2007 .UPDATE... ISSUED EARLY UPDATE BASED ON CONSISTENCY OF 18Z NAM/GFS SHOWING BAND OF H85-7 FGEN AT NOSE OF 35-40KT H85 WSW LLJ DVLPG WNW-ESE FM THE WRN ZNS TO THE BAY OF GREEN BAY. ALTHOUGH AIRMASS IS INITIALLY DRY/ STABLE PER RECENT TAMDAR SDNGS...EXPECT ENUF DESTABILIZATION FOR SCT SHRA/ISOLD ELEVATED TSRA EXCEPT OVER THE FAR ERN CWA...WHERE DRIER/ MORE STABLE AIRMASS IF FCST TO LINGER TOO FAR AWAY FM LLJ/FGEN/ ASSOCIATED MSTR CNVGC. GFS/NAM SHOW SSI DROPPING AS LO AS -2C DURING THE NGT OVER THE W/SCNTRL ALG THE AXIS OF BEST FGEN. SUSPECT CNVCTN NOW PUSHING INTO NW MN WL PROPAGATE ESE ALG THE AXIS OF BEST FGEN PARALLEL TO THE WI BORDER. ANY TSRA SHOULD REMAIN BLO SVR LIMITS WITH LIMITED EFFECTIVE H85-5 LYR BULK SHEAR ARND 20 KT AS WELL AS MARGINAL ELEVATED CAPE NO MORE THAN ABOUT 500 J/KG. KC .PREVIOUS DISCUSSION (ISSUED AT 430 PM EDT)... .SHORT TERM (TONIGHT AND SATURDAY)... ATTEMPTED TO GO WITH A SOLUTION CLOSER TO THE GFS WHEN COMPARED TO THE NAM FOR THIS PERIOD...AS THE NAM IS MORE OF AN OUTLIER. HOWEVER...AM HESITANT TO TOTALLY DISREGARD ITS BRINING OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS TO THE WESTERN HALF OF THE CWA IN OVERNIGHT TONIGHT. THIS IS SLIGHTLY EARLIER THAN OUR PREVIOUS FORECAST. MISSING OUT ON THE PRIME HEATING OF THE DAY...AS THE COLD FRONT SLIDES ACROSS SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON. THIS SHOULD ASSIST IN KEEPING MUCH OF THE THUNDERSTORM ACTIVITY OUT OF THE CWA. HAVE ADDED LIKELY POPS FOR NORTHERN THIRD OF THE FORECAST AREA DURING THE DAY WITH MODELS CONTINUING TO PIN POINT THIS AREA AS GETTING THE BEST CHANCE OF SIGNIFICANT PRECIPITATION. .LONG TERM...00Z SUN ONWARD...NAM SHOWING A 500 MB SHORTWAVE PUSHING INTO ERN ONTARIO WHICH WILL HELP PUSH A COLD FRONT THROUGH THE CWA 00Z SUN. THE 500 MB RIDGE AXIS IS ACROSS THE NORTHERN PLAINS AT THAT TIME. RIDGE AXIS WILL TRY TO PUSH EASTWARD...BUT PROBLEM IS THERE IS A CLOSED 500 MB LOW AND TROUGH ON THE EAST COAST WHICH WILL PREVENT MOVEMENT EASTWARD FOR A WHILE. NAM SHOWING LOW LEVEL MOISTURE ON I290-I295K SURFACES DECREASING SAT NIGHT LATE...SO DRIZZLE SHOULD COME TO AN END AS LOW LEVELS DRY OUT ON SUN. GFS AND NAM ARE NOW WARMER AT 850 MB FROM PREVIOUS RUNS AND COLDEST THEY GET IS 0C OVER THE FAR NORTHERN PART OF LAKE SUPERIOR. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. DID REMOVE POPS FROM THE EAST HALF ON MONDAY BASED ON WARM FRONT STAYING WELL TO THE WEST. AS WARM FRONT GETS CLOSER...KEPT CHANCE POPS IJN FOR MON NIGHT FOR ALL OF CWA WITH OVERRUNNING SCENARIO SETTING UP. WITH TEMPERATURES NOT AS COLD...WARMED TEMPERATURES UP A FEW DEGREES ON SUNDAY. FROST STILL LOOKS POSSIBLE SUN NIGHT...BUT NOT AS WIDESPREAD AS TEMPERATURES WILL AGAIN BE WARMER. WENT CLOSE TO ADJMEN FOR TEMPERATURES. IN THE EXTENDED...GFS...ECMWF AND CANADIAN ALL SHOW THE 500 MB PATTERN CONSISTS OF A TROUGH IN THE WEST HALF OF THE U.S. AND RIDGING OVER THE EAST HALF WITH TROUGHING OFF THE NEW ENGLAND COAST 00Z TUE. THE TROUGH PULLS FURTHER EAST INTO THE NORTHERN PLAINS 00Z WED AND 00Z THU AND CONTINUES TO AFFECT THE AREA 00Z FRI. LOOKS WARMER NOW THAT WARM FRONT PASSES THROUGH ON TUE AND STAY IN WARM SECTOR THROUGH WED AND WILL RAISE TEMPERATURES UP FOR THIS. WENT CLOSE TO ADJMEH FOR HIGHS DURING THIS PERIOD AND ALSO LOWS AS COULD BE A HUMID AND WARM SCENARIO SETTING UP FOR MID WEEK. WITH UPPER TROUGH DELAYED...SHOULD ALLOW FOR SOUTHERLY WINDS TO BRING IN MORE MOISTURE AND WARMER AIR NOW. WOULD NOT BE SURPRISED TO SEE SOME SEVERE WEATHER FOR WED AS COLD FRONT STARTS TO HEAD TOWARDS THE AREA. REMOVED POPS FOR ALL BUT THE FAR WEST AND NORTH FOR TUE AND TUE NIGHT AS WARM FRONT HAS MOVED THROUGH THEN AND NO LOW LEVEL CONVERGENCE TO FOCUS ANYTHING AND WOULD NOT BE SURPRISED IF ATMOSPHERE IS CAPPED AT THAT POINT. KEPT CHANCE POPS IN FOR MON NIGHT AS WARM FRONT NEARS AND THEN KEPT IN CHANCE POPS FOR WED THROUGH FRI WITH COLD FRONT MOVING THROUGH WED AND THU AND THEN COLD POOL ALOFT WITH TROUGH IN THE AREA FOR FRI. TEMPERATURES LOOK TO BE ABOVE NORMAL. && .AVIATION...DISCUSSION FOR 00Z TAFS...UPDATED AT 730 PM EDT EXPECT DRY/VFR CONDITIONS TO LINGER THIS EVNG WITH CAPPED...DRY AIRMASS STILL IN PLACE. DVLPG LLVL JET WL CAUSE DESTABILIZATION AFT MIDNGT ALG WITH A CHC OF -SHRA/SLGT CHC TSRA. BUT LINGERING LLVL DRYNESS SHOULD MAINTAIN VFR CONDITIONS. THAT WL CHG ON SAT WITH PASSAGE OF SHARP COLD FNT. VIGOROUS LLVL CAD BEHIND THIS BNDRY WL CAUSE DVLPMNT OF LO INVRN/IFR CIGS. SHRA/ELEVATED TSRA PSBL AS SHRTWV CROSSES THE FA. PCPN MOISTENING/UPSLOPE COOLING OFF LK SUP BEHIND THE FNT WL CAUSE LWR VSBYS AS WELL ON SAT. && .MARINE...DISCUSSION FOR 4 PM ISSUANCE...THE NEXT CHANGE WILL COME IN THE FORM OF SHIFTING WINDS ALONG AND BEHIND AN APPROACHING COLD FRONT. THERE IS STILL A GOOD POTENTIAL FOR 30KT WINDS IN WAKE OF THIS FRONT SATURDAY AS 25-30 KT WINDS MIX TO SURFACE. AS A RESULT...WAVES MAY TOP 10 FEET ON LAKE SUPERIOR SATURDAY NIGHT INTO SUNDAY MORNING. && .FIRE WEATHER...RELATIVE HUMIDITY VALUES HAVE PLUMMETED INTO THE MID AND LOWER 20 PERCENT RANGE EARLY THIS AFTERNOON. SOUTHERLY WINDS HAVE ALSO BEEN ABLE TO PICK UP TO MEASURE 12 TO 17 MPH SUSTAINED WITH SOME GUSTS AROUND 20 MPH. WITH SOME PRECIPITATION IN OUR RECENT PAST...ESPECIALLY ACROSS THE NORTHERN HALF OF THE REGION...FUELS ARE NOT AS TERRIBLY DRY ACROSS THE EXTREME SOUTHERN END OF THE AREA. OTHER THAN THE WIND SHIFT WITH THE COLD FRONT LATE SATURDAY MORNING...FIRE WEATHER CONCERNS WILL BE SETTLING DOWN AS COOLER MOIST AIR SETTLES IN. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/MARINE/FIRE WEATHER...KF LONG TERM...GM UPDATE/AVIATION...KC
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS MARQUETTE MI
306 AM EDT SAT MAY 19 2007 .UPDATE... ISSUED EARLY UPDATE BASED ON CONSISTENCY OF 18Z NAM/GFS SHOWING BAND OF H85-7 FGEN AT NOSE OF 35-40KT H85 WSW LLJ DVLPG WNW-ESE FM THE WRN ZNS TO THE BAY OF GREEN BAY. ALTHOUGH AIRMASS IS INITIALLY DRY/ STABLE PER RECENT TAMDAR SDNGS...EXPECT ENUF DESTABILIZATION FOR SCT SHRA/ISOLD ELEVATED TSRA EXCEPT OVER THE FAR ERN CWA...WHERE DRIER/ MORE STABLE AIRMASS IF FCST TO LINGER TOO FAR AWAY FM LLJ/FGEN/ ASSOCIATED MSTR CNVGC. GFS/NAM SHOW SSI DROPPING AS LO AS -2C DURING THE NGT OVER THE W/SCNTRL ALG THE AXIS OF BEST FGEN. SUSPECT CNVCTN NOW PUSHING INTO NW MN WL PROPAGATE ESE ALG THE AXIS OF BEST FGEN PARALLEL TO THE WI BORDER. ANY TSRA SHOULD REMAIN BLO SVR LIMITS WITH LIMITED EFFECTIVE H85-5 LYR BULK SHEAR ARND 20 KT AS WELL AS MARGINAL ELEVATED CAPE NO MORE THAN ABOUT 500 J/KG. KC .PREVIOUS DISCUSSION (ISSUED AT 430 PM EDT)... .SHORT TERM (TONIGHT AND SATURDAY)... ATTEMPTED TO GO WITH A SOLUTION CLOSER TO THE GFS WHEN COMPARED TO THE NAM FOR THIS PERIOD...AS THE NAM IS MORE OF AN OUTLIER. HOWEVER...AM HESITANT TO TOTALLY DISREGARD ITS BRINING OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS TO THE WESTERN HALF OF THE CWA IN OVERNIGHT TONIGHT. THIS IS SLIGHTLY EARLIER THAN OUR PREVIOUS FORECAST. MISSING OUT ON THE PRIME HEATING OF THE DAY...AS THE COLD FRONT SLIDES ACROSS SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON. THIS SHOULD ASSIST IN KEEPING MUCH OF THE THUNDERSTORM ACTIVITY OUT OF THE CWA. HAVE ADDED LIKELY POPS FOR NORTHERN THIRD OF THE FORECAST AREA DURING THE DAY WITH MODELS CONTINUING TO PIN POINT THIS AREA AS GETTING THE BEST CHANCE OF SIGNIFICANT PRECIPITATION. .LONG TERM...00Z SUN ONWARD...NAM SHOWING A 500 MB SHORTWAVE PUSHING INTO ERN ONTARIO WHICH WILL HELP PUSH A COLD FRONT THROUGH THE CWA 00Z SUN. THE 500 MB RIDGE AXIS IS ACROSS THE NORTHERN PLAINS AT THAT TIME. RIDGE AXIS WILL TRY TO PUSH EASTWARD...BUT PROBLEM IS THERE IS A CLOSED 500 MB LOW AND TROUGH ON THE EAST COAST WHICH WILL PREVENT MOVEMENT EASTWARD FOR A WHILE. NAM SHOWING LOW LEVEL MOISTURE ON I290-I295K SURFACES DECREASING SAT NIGHT LATE...SO DRIZZLE SHOULD COME TO AN END AS LOW LEVELS DRY OUT ON SUN. GFS AND NAM ARE NOW WARMER AT 850 MB FROM PREVIOUS RUNS AND COLDEST THEY GET IS 0C OVER THE FAR NORTHERN PART OF LAKE SUPERIOR. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. DID REMOVE POPS FROM THE EAST HALF ON MONDAY BASED ON WARM FRONT STAYING WELL TO THE WEST. AS WARM FRONT GETS CLOSER...KEPT CHANCE POPS IJN FOR MON NIGHT FOR ALL OF CWA WITH OVERRUNNING SCENARIO SETTING UP. WITH TEMPERATURES NOT AS COLD...WARMED TEMPERATURES UP A FEW DEGREES ON SUNDAY. FROST STILL LOOKS POSSIBLE SUN NIGHT...BUT NOT AS WIDESPREAD AS TEMPERATURES WILL AGAIN BE WARMER. WENT CLOSE TO ADJMEN FOR TEMPERATURES. IN THE EXTENDED...GFS...ECMWF AND CANADIAN ALL SHOW THE 500 MB PATTERN CONSISTS OF A TROUGH IN THE WEST HALF OF THE U.S. AND RIDGING OVER THE EAST HALF WITH TROUGHING OFF THE NEW ENGLAND COAST 00Z TUE. THE TROUGH PULLS FURTHER EAST INTO THE NORTHERN PLAINS 00Z WED AND 00Z THU AND CONTINUES TO AFFECT THE AREA 00Z FRI. LOOKS WARMER NOW THAT WARM FRONT PASSES THROUGH ON TUE AND STAY IN WARM SECTOR THROUGH WED AND WILL RAISE TEMPERATURES UP FOR THIS. WENT CLOSE TO ADJMEH FOR HIGHS DURING THIS PERIOD AND ALSO LOWS AS COULD BE A HUMID AND WARM SCENARIO SETTING UP FOR MID WEEK. WITH UPPER TROUGH DELAYED...SHOULD ALLOW FOR SOUTHERLY WINDS TO BRING IN MORE MOISTURE AND WARMER AIR NOW. WOULD NOT BE SURPRISED TO SEE SOME SEVERE WEATHER FOR WED AS COLD FRONT STARTS TO HEAD TOWARDS THE AREA. REMOVED POPS FOR ALL BUT THE FAR WEST AND NORTH FOR TUE AND TUE NIGHT AS WARM FRONT HAS MOVED THROUGH THEN AND NO LOW LEVEL CONVERGENCE TO FOCUS ANYTHING AND WOULD NOT BE SURPRISED IF ATMOSPHERE IS CAPPED AT THAT POINT. KEPT CHANCE POPS IN FOR MON NIGHT AS WARM FRONT NEARS AND THEN KEPT IN CHANCE POPS FOR WED THROUGH FRI WITH COLD FRONT MOVING THROUGH WED AND THU AND THEN COLD POOL ALOFT WITH TROUGH IN THE AREA FOR FRI. TEMPERATURES LOOK TO BE ABOVE NORMAL. && .AVIATION...DISCUSSION FOR 06Z TAFS...UPDATED AT 130 AM EDT EXPECT DRY/VFR CONDITIONS TO PREVAIL TNGT WITH DRY AIRMASS STILL IN PLACE. BETTER DESTABILIZATION WITH DVLPG LLVL JET OVERNGT NOW APPEARS WL REMAIN TO THE SW OF CMX-SAW...SO TOOK SHRA CHCS OUT THRU 11Z. THAT WL CHG ON SAT WITH PASSAGE OF SHARP COLD FNT. VIGOROUS LLVL CAD BEHIND THIS BNDRY WL CAUSE DVLPMNT OF LO INVRN/IFR CIGS. SHRA/ELEVATED TSRA PSBL AS SHRTWV CROSSES THE FA. PCPN MOISTENING/UPSLOPE COOLING OFF LK SUP BEHIND THE FNT WL CAUSE LWR VSBYS AS WELL ON SAT. SOME DRIER LLVL AIR WL LIKELY ARRIVE SAT EVNG OVER THE KEWEENAW FIRST...HELPING TO IMPROVE VSBYS SOMEWHAT. BUT PERSISTENT LO INVRN SHOULD SUPPORT IFR CIGS THRU 06Z. && .MARINE...DISCUSSION FOR 4 PM ISSUANCE...THE NEXT CHANGE WILL COME IN THE FORM OF SHIFTING WINDS ALONG AND BEHIND AN APPROACHING COLD FRONT. THERE IS STILL A GOOD POTENTIAL FOR 30KT WINDS IN WAKE OF THIS FRONT SATURDAY AS 25-30 KT WINDS MIX TO SURFACE. AS A RESULT...WAVES MAY TOP 10 FEET ON LAKE SUPERIOR SATURDAY NIGHT INTO SUNDAY MORNING. && .FIRE WEATHER...RELATIVE HUMIDITY VALUES HAVE PLUMMETED INTO THE MID AND LOWER 20 PERCENT RANGE EARLY THIS AFTERNOON. SOUTHERLY WINDS HAVE ALSO BEEN ABLE TO PICK UP TO MEASURE 12 TO 17 MPH SUSTAINED WITH SOME GUSTS AROUND 20 MPH. WITH SOME PRECIPITATION IN OUR RECENT PAST...ESPECIALLY ACROSS THE NORTHERN HALF OF THE REGION...FUELS ARE NOT AS TERRIBLY DRY ACROSS THE EXTREME SOUTHERN END OF THE AREA. OTHER THAN THE WIND SHIFT WITH THE COLD FRONT LATE SATURDAY MORNING...FIRE WEATHER CONCERNS WILL BE SETTLING DOWN AS COOLER MOIST AIR SETTLES IN. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/MARINE/FIRE WEATHER...KF LONG TERM...GM UPDATE/AVIATION...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1157 PM CDT FRI MAY 18 2007 .AVIATION.../06Z TAF ISSUANCE/ IMMEDIATE CONCERN IN THE TAFS IS LOW LEVEL WIND SHEAR. AVAILABLE PROFILERS AND TAMDAR DATA INDICATING WINDS OF 35 TO 45 KT BY 1500 FT FROM SOUTHWEST MN TOWARDS MSP. SURFACE WINDS HAVE BEEN OSCILLATING BUT ARE LOW ENOUGH TO CREATE MENTIONABLE SHEAR IN THE TAFS. LOW LEVEL JET IS EXPECTED TO SHIFT EAST AND WEAKEN BY 10Z OR SO. AS THE FRONT APPROACHES OVERNIGHT...SCATTERED CONVECTION IS EXPECTED TO DROP SOUTHWARD. A REDEVELOPMENT IS EXPECTED SATURDAY AFTERNOON FROM RWF TOWARDS MSP AND THE WI TAF SITES. AFTER FRONTAL PASSAGE AT TAF SITES WINDS WILL SHIFT QUICKLY TO THE NORTHWEST AND THEN NORTH NORTHEAST. && .PREV DISCUSSION... /ISSUED 929 PM CDT FRI MAY 18 2007/ UPDATE... CONVECTION ONGOING IN ND AND NW MN CONTINUES TO WORK EAST AND SLOWLY EXPAND SOUTH. PROFILERS AND 00Z RAOBS INDICATING LOW LEVEL JET HAS DEVELOPED AND POINTED INTO THE CURRENT ACTIVITY. STRONG THETA-E ADVECTION ON THIS JET SHOULD ALLOW SOME THUNDERSTORMS TO CONTINUE THROUGH TONIGHT...BUT DECREASING IN INTENSITY AND SLIGHTLY IN COVERAGE. ELEVATED CONVECTIVE INDICES BULLSEYE AND THICKNESSES SUPPORT STORMS TO PRIMARILY MOVE EAST THROUGH THE NEXT FEW HOURS THEN TURN MORE SOUTHWARD...ESPECIALLY OVER FAR EASTERN MN AND NW/WEST CENTRAL WI. EVIDENCE OF A CAP ON RADAR TRENDS AND RAOB DATA OVER WRN MN WILL MAKE IT INITIALLY DIFFICULT FOR SOME OF THE CURRENT CONVECTION NEAR THE FARGO/MOOREHEAD AREA TO EXPAND SOUTH. SO HAVE ONLY NUDGED POPS UP SLIGHTLY AND EXPANDED TO THE SOUTH SOME THROUGH DAYBREAK. LOW TEMPS LOOK RIGHT ON...WHICH THANKS TO DEBRIS CLOUDS AND SOUTHERLY WINDS WILL BE ABOUT TEN DEGREES ABOVE NORMAL. PREV DISCUSSION... /ISSUED 230 PM CDT FRI MAY 18 2007/ DISCUSSION... WEAK MID/UPPER LEVEL RIDGE WILL BUILD ACROSS THE UPPER MIDWEST THROUGH THE WEEKEND. A WEAK SFC COLD FRONT OVR EXTREME NORTHERN MN...WILL SINK SOUTH OVR SOUTHERN MN BY SATURDAY EVENING. RELATIVELY QUIET PERIOD IN REGARDS TO ANY CONVECTIVE ACTIVITY DEVELOPING DURING THE EVENING HOURS OR BEFORE MIDNIGHT. THE NEXT MID LEVEL WAVE OR INSTABILITY AXIS MOVES INTO CENTRAL MN BY NOON SATURDAY. THUS...WITH A WEAK SURFACE FRONTAL BOUNDARY IN THE AREA...KEPT THE PRECIP CHANCES GOING FOR OUR FAR NORTHERN PORTION OF THE CWA LATER TONIGHT...AND OVER THE SOUTHERN HALF DURING THE DAY ON SATURDAY. MEANWHILE...REX BLOCK OVER NORTH AMERICA...WILL SLOWLY BREAKDOWN ACROSS THE NORTHERN U.S. AS STRONGER LOW PRESSURE TROUGH PROGRESS INTO THE NORTHERN PLAINS BY EARLY NEXT WEEK. TIMING OF THIS SYSTEM WILL BE DIFFICULT...CURRENT MEDIUM AND LONG RANGE MODELS ARE IN DISAGREEMENT. THE GFS ENSEMBLE MEMBERS BEGIN TO DIFFER PASS 132 HOURS. THUS...THE OVERALL TREND IS SLOW DOWN THE SYSTEM MOVING THAT IS FORECAST NOW TO MOVE INTO THE UPPER GREAT LAKES LATE IN THE PERIOD. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
759 AM PDT SAT MAY 19 2007 .SYNOPSIS... THE MARINE LAYER AND AN INTERMITTENT COASTAL EDDY WILL CONTINUE NIGHT AND MORNING LOW CLOUDS WEST OF THE MOUNTAINS...LINGERING AT TIMES DURING THE AFTERNOONS NEAR THE COAST THROUGH MONDAY. TEMPERATURES WILL REMAIN A BIT BELOW NORMAL NEAR THE COAST...AND NEAR NORMAL OVER THE MOUNTAINS AND DESERTS. BUILDING HIGH PRESSURE ALOFT BY THE MIDDLE OF NEXT WEEK IS EXPECTED TO BRING MORE SUN AND WARMER DAYS THROUGH THE END OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... WEAK ONSHORE SURFACE PRESSURE GRADIENTS AND A WEAK EDDY CIRCULATION OVER THE BIGHT CONTINUE THIS MORNING. THE 12Z MIRAMAR SOUNDING SHOWED A 9 DEGREE C INVERSION BASED NEAR 2.3K FT AND WEAK S FLOW UP THROUGH 6K FT. THE STRATUS LAYER LOOKS ABOUT AS THICK AS YESTERDAY SO WITH THE EDDY AND THE STRONG INVERSION...CLEARING AT THE BEACHES SHOULD NOT BE EXPECTED. ELSEWHERE W OF THE MTNS PARTLY CLOUDY TO SUNNY TOWARD THE FOOTHILLS BY THIS AFTERNOON WITH MAX TEMPS SOMEWHAT BELOW AVERAGE. A WEAK...BAGGY UPPER-LEVEL TROUGH OVER THE AREA IS EXPECTED TO SUPPORT THE EDDY CIRCULATION OVER THE BIGHT THROUGH SUN AT LEAST. ON MON...A STRONGER TROUGH MOVES THROUGH THE PAC NW...INCREASING ONSHORE FLOW HERE AND BUILDING THE MARINE LAYER FURTHER. EXPECT IT TO PEAK BY TUE MORNING THEN BEGIN TO MIX OUT AS N FLOW AND BUILDING HIGH PRESSURE ALOFT BEGIN TO TAKE HOLD. THIS SHOULD ALLOW SOME WARMING AND MORE SUNSHINE BY THE SECOND HALF OF THE WEEK FOR CLOUD-WEARY COASTAL RESIDENTS...AND CATATONIC SNOW CONE AND SUNGLASS VENDORS. && .AVIATION... 191500Z...12Z NKX SOUNDING AS WELL AS MORNING MDCRS SOUNDINGS AND TOP REPORTS INDICATE THE MARINE LAYER DEPTH WAS AROUND 2500 FEET. ONLY MINOR CHANGES ARE EXPECTED IN THE MARINE LAYER DEPTH THROUGH SUNDAY. A COASTAL EDDY REMAINS IN PLACE CENTERED WEST OF SAN CLEMENTE ISLAND AND SHOULD CONTINUE THROUGH SUNDAY. STRATUS...BASES AROUND 1200 FEET MSL...SHOULD PULL BACK TO NEAR THE COAST BETWEEN 18 AND 20Z. COASTAL ORANGE COUNTY INCLUDING KSNA SHOULD SCATTER OUT DURING THIS PERIOD BUT COASTAL SAN DIEGO COUNTY INCLUDING KCRQ AND KSAN SHOULD GO TO BROKEN CONDITIONS WITH ONLY BRIEF SCATTERED PERIODS. STRATUS SHOULD PUSH BACK INLAND AFTER 00Z REACHING THE INLAND VALLEY AREAS BY MIDNIGHT. ABOVE THE MARINE LAYER...CONTINUED VFR CONDITIONS WITH A MOSTLY CLEAR SKY AND UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...JAD AVIATION...HORTON
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
353 AM PDT SAT MAY 19 2007 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...NLY GRADS HAVE INCREASED ACRS THE AREA...WITH GUSTY WINDS OCCURRING THIS MORNING ACRS THE MTNS...PARTICULARLY NEAR THE I5 CORRIDOR AND THRU THE SANTA YNEZ RANGE. WITH THE EXCEPTION OF OCNL GUSTS...WINDS WERE BELOW ADVISORY LEVELS. NLY GRADS HAVE KEPT SKIES CLEAR ACRS SLO AND SBA COUNTIES. S OF PT CONCEPTION...MARINE LAYER WAS AROUND 2000 FEET DEEP...AND EDDY CRCLN HAS CAUSED CLOUDS TO PUSH INTO CSTL AND MOST VLY AREAS OF L.A. COUNTY...WITH STRATUS BEGINNING TO PUSH INTO VTU COUNTY ATTM. CLOUDS MAY SQUEAK INTO SERN SBA COUNTY BY DAYBREAK...BUT SHOULD GET NO FARTHER THAN THAT. XPCT SKIES TO CLEAR BY LATE MORNING JUST ABOUT EVERYWHERE TODAY. TEMPS MAY BE UP A COUPLE OF DEGREES FROM FRI...BUT OVERALL SHOULD NOT BE TOO DIFFERENT. XPCT LITTLE CHANGE IN THE PATTERN THROUGH MONDAY. STRONG NLY GRADS WILL CAUSE GUSTY WINDS ACRS THE MTNS THROUGH SUN NIGHT...WITH THE STRONGEST WINDS LIKELY TONIGHT...POSSIBLY APCHG ADVISORY LEVELS. THERE WILL LIKELY BE SOME GUSTY WINDS THRU AND BELOW PASSES AND CANYONS OF THE SANTA YNEZ RANGE IN SRN SBA COUNTY THIS EVENING... AGAIN...CLOSE TO ADVISORY LEVELS...WITH SOMEWHAT LESS IN THE WAY OF WIND EXPECTED SUN NIGHT. NIGHT THRU MORNING LOW CLOUDS SHOULD STILL BE FAIRLY WDSPRD ACRS CSTL AND VLY AREAS OF L.A. AND VTU COUNTIES TONIGHT/SUN MORNING...AND AGAIN SUN NIGHT/MON MORNING AS EDDY CRCLNS SHOULD FORM EACH NIGHT. STRATUS MAY MAKE A RETURN TO THE CENTRAL CST SUN NIGHT/MONDAY AS NLY GRADS BEGIN TO WKN. DO NOT XPCT MUCH CHANGE IN TEMPS ON SUN...THEN THERE COULD BE A FEW DEGRES OF COOLING ON MON. THIS WILL BE ESPECIALLY TRUE ACRS THE MTNS AND DSRTS AS HGTS LOWER...BUT THE LATEST WRF SHOWS SOME COOLING IN CSTL AND VLY ZONES OF L.A. AND VTU COUNTIES THANKS TO A DECENTLY STRONG EDDY CRCLN SUN NIGHT/MON MORNING. .LONG TERM...HGTS BEGIN TO RISE ACRS THE AREA TUE AS AN UPR RIDGE BUILDING ACRS THE ERN PAC EDGES INTO THE W CST. ONSHORE GRADS WILL WEAKEN AS WELL. STILL XPCT NIGHT THRU MORNING LOW CLDS/FOG IN CSTL AND VLY AREAS...MOST WDSPRD S OF PT CONCEPTION...BUT MARINE LAYER SHOULD BEGIN TO SHRINK IN DEPTH. THERE SHOULD BE SOME WARMING IN MOST AREAS ON TUE. HGTS WILL CONT TO RISE ACRS THE AREA WED...AND ONSHR FLOW WILL BECOME VERY WK. THIS SHOULD ALLOW FOR WARMING IN MOST AREAS AWAY FROM THE IMDT CST WED...WITH TEMPS GENERALLY ABOVE NORMAL IN THE VLYS...MTNS AND DSRTS. LITTLE CHANGE IS EXPECTED THU...THEN SLIGHT COOLING IS POSSIBLE ON FRI W OF THE MTNS AS ONSHORE FLOW BEGINS TO INCREASE. && .AVIATION...19/1100Z LATEST AMDAR SOUNDINGS INDICATE MARINE INVERSION BASED AROUND 1800 FEET THIS MORNING ACROSS THE LAX BASIN. SATELLITE/SURFACE OBS SHOW STRATUS/FOG SURGING NORTHWARD ALONG THE SOCAL COAST THANKS TO EDDY CIRCULATION. SO...ALL COASTAL AND VALLEY TAF SITES SOUTH OF POINT CONCEPTION WILL START OFF WITH IFR/MVFR CONDS THIS MORNING. EXPECT THESE KFR/MVFR CONDS TO BURN OFF BY LATE MORNING...WITH VFR CONDS EXPECTED IN THE AFTERNOON EXCEPT FOR IMMEDIATE COASTAL AREAS WHERE SOME CLOUDS/VSBYS RESTRICTIONS COULD PERSIST. FOR TAF SITES NORTH OF POINT CONCEPTION...EXPECT VFR CONDS THROUGH THE AFTERNOON. FOR THIS EVENING AND OVERNIGHT...HAVE LEFT KSBP/KSMX CLEAR BUT CONFIDENCE IS NOT VERY HIGH IN THIS FORECAST...GIVEN STRATUS OFFSHORE OF SLO/WESTERN SBA COUNTY. FOR KLAX...IFR CIGS/MVFR VSBYS THROUGH 16Z...THEN MVFR CIGS/VSBYS THROUGH THE AFTERNOON. STRATUS COULD SCATTER OUT TEMPORARILY THIS AFTERNOON...BUT ONSHORE FLOW WILL CIGS BACK RATHER QUICKLY. MVFR CIGS/VSBYS THIS EVENING...WITH CIGS LOWERING TO IFR OVERNIGHT. TYPICAL SEA BREEZE WILL DEVELOP AROUND 17Z AND CONTINUE THROUGH 03Z. OVERALL...HIGH CONFIDENCE IN KLAX TAF. FOR KBUR...IFR CIGS/MVFR VSBYS THROUGH 16Z...THEN MVFR CONDS THROUGH MID AFTERNOON (22Z). VFR CONDS EXPECTED TO PERSIST THORUGH THE EVENING...THEN IFR CIGS/MVFR VSBYS REDEVELOPING AROUND 08Z. OVERALL HIGH CONFIDENCE IN KBUR TAF. $$ .LOX WATCHES/WARNINGS/ADVISORIES... GALE WARNING (SEE LAXCWFLOX). && $$ PUBLIC...BRUNO AVIATION...THOMPSON WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1043 AM CDT SAT MAY 19 2007 .UPDATE...REST OF TODAY COLD FRONT CONTINUES TO MOVE SOUTH AND IS THROUGH THE NORTHERN HALF OF THE STATE. STRONG LOW LEVEL CAA BEHIND THE FRONT WILL KEEPS HIGH TEMPS DOWN SEVERAL DEGREES FROM PREVIOUS FORECAST. TEMPS STRUGGLING THROUGH THE 30S AND 40S ACROSS MOST OF ND AND THIS AIR IS ADVECTING SOUTH. DROPPED HIGHS INTO THE MID 60S ACROSS NORTHERN CWA BUT THIS MAY EVEN BE TOO WARM. WILL MONITOR AND ISSUE ANOTHER UPDATE IF NEEDED. CLOUDS HANGING IN TOUGH AND EXPECT THEM TO PERSIST THROUGH MUCH OF THE AFTERNOON. TAMDAR SOUNDINGS USED TO HELP DETERMINE THICKNESS OF CLOUD COVER AND WHEN/IF WE ARE ABLE TO MIX THEM OUT. FRONT MOVING RATHER QUICKLY AND BECOMING LESS CONFIDENT OF EVEN SMALL CHANCE POPS ACROSS THE SOUTHERN CWA THIS AFTERNOON. 12Z HI RES NAM SHOWING ANY CONVECTION THAT DOES FIRE SHOULD BE CONFINED TO SOUTHERN SD...POSSIBLY AFFECTING THE ABR CWA COUNTIES NEAR THE I-90 CORRIDOR. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH MONDAY NIGHT SOME ISOLATED SHOWERS AND THUNDERSTORMS STILL TRACKING THROUGH THE NORTHERN CWA. STRONGEST ECHOES REMAIN ACROSS THE EXTREME NORTHEASTERN CWA NEAR ROBERTS...BIG STONE...AND TRAVERSE COUNTIES. ACTIVITY HAS FORMED ALONG AXIS OF THE SURFACE PRE-FRONTAL TROUGH ASSOCIATED WITH AN UPPER LEVEL WAVE CURRENTLY SLIDING INTO NORTHERN MINNESOTA. SFC COLD FRONT IS NOW STRETCHING FROM JUST SOUTH OF KFGF...WESTWARD ACROSS CENTRAL AND NORTHERN NORTH DAKOTA. THIS BOUNDARY WILL GRADUALLY SAG SOUTHWARD THIS MORNING...AND IS EXPECTED TO STALL FOR A BIT ACROSS NORTHERN SOUTH DAKOTA. BOUNDARY WILL THEN PUSH NORTHWARD TONIGHT AS A WARM FRONT IN ADVANCE OF THE NEXT SHORTWAVE TROUGH EXPECTED TO EJECT EASTWARD OUT OF THE NORTHERN ROCKIES. SOME INSTABILITY STILL PRESENT ACROSS MUCH OF THE EASTERN CWA...WITH SOME WEAK LIFT ADVERTISED SO DID KEEP A MENTION OF -TRW THROUGH THE EARLY MORNING HOURS WITH THE FRONTAL BOUNDARY PUSHING SOUTHWARD. OTHERWISE BETTER CHANCES FOR PRECIPITATION WILL COME THIS EVENING INTO TONIGHT AS LOW LEVEL LAPSE RATES STEEPEN IN ADVANCE OF THE APPROACHING WAVE. BEST CHANCE FOR -TRW TONIGHT WILL BE IN THE VICINITY OF THE WARM FRONT PUSHING NORTHWARD. BOUNDARY IS EXPECTED TO BE SITUATED ACROSS THE SOUTHERN HALF OF THE CWA LATE THIS AFTERNOON INTO THE EVENING...AND SHOULD PUSH NORTHWARD LATE TONIGHT ALLOWING FOR THE BETTER THUNDERSTORM THREAT TO TRANSLATE NORTHWARD THROUGH THE NIGHT AS WELL. PRECIPITATION/THUNDERSTORM THREAT CONTINUES INTO SUNDAY AND MONDAY AS A SERIES OF WEAK WAVES CONTINUE TO EJECT OUT OF THE PARENT TROUGH PUSHING THROUGH THE NORTHERN ROCKIES SUNDAY INTO MONDAY. AN ELONGATED AREA OF SURFACE LOW PRESSURE WILL MIGRATE SLOWLY FROM THE WESTERN HIGH PLAINS SUNDAY INTO THE CENTRAL/EASTERN DAKOTAS BY MONDAY INTO MONDAY NIGHT. MODEL SOUNDINGS ADVERTISE INSTABILITY VALUES TO CONTINUE TO INCREASE INTO MONDAY AND MONDAY NIGHT ACROSS MUCH OF THE CWA...WITH THE CWA BISECTED BY THE SURFACE TROUGH FROM NORTHEAST TO SOUTHWEST. 40-50KT LLJ WILL SEND GULF MOISTURE NORTHWARD...AND BECOME ORIENTED TOWARD THE EASTERN CWA MONDAY NIGHT. WITH THE STRONGEST SHORTWAVE AHEAD OF THE MAIN UPPER TROUGH TO PUSH THROUGH THE REGION MONDAY NIGHT...IN COMBINATION WITH THE SFC TROUGH...LLJ...HAVE CONTINUED WITH THE LIKELY MENTION OF -TRW THROUGHOUT THE ENTIRE CWA FOR MONDAY NIGHT. AS FOR TEMPERATURES...EXPECT NEAR NORMAL TO ABOVE AVERAGE TEMPERATURES ACROSS THE CWA...AS H85 TEMPS HOVER IN THE TEENS TO LOWER 20S THROUGHOUT MOST OF THE SHORT TERM. DO BEGIN TO SEE SOME COOLING TEMPERATURES ALOFT AS THE WESTERN CWA BECOMES SITUATED ON THE BACKSIDE OF THE SURFACE TROUGH BY LATER MONDAY INTO MONDAY NIGHT. .LONG TERM...TUESDAY THROUGH FRIDAY GOOD AGREEMENT AND CONSISTENCY WITH THE MODELS AND ENSEMBLES WITH THE BIG UPPER TROUGH/LOW TO COME ACROSS THE UPPER MIDWEST THROUGH THE TUESDAY-WEDNESDAY NIGHT TIME PERIOD. IT LOOKS LIKE TUESDAY WILL START OUT WITH A GOOD SURFACE FRONTAL ZONE EXTENDING FROM SOUTHWEST TO NORTHEAST ACROSS THE ABR CWA. DEPENDING ON WHERE THIS FRONT SETS UP ALONG WITH THE AMOUNT OF SUNSHINE...TEMPERATURES COULD END UP BEING QUITE A BIT WARMER ON TUESDAY TO THE EAST OF THE FRONT. OTHERWISE...IT APPEARS A SURFACE LOW PRESSURE AREA WILL TRACK FROM SOUTHWEST TO NORTHEAST ALONG THE FRONT TUESDAY THROUGH WEDNESDAY NIGHT. THERE WILL BE PLENTY OF MOISTURE AND INSTABILITY AVAILABLE. THUS...THE LOCATION OF THE HEAVIEST RAINFALL WILL DEPEND ON THE TRACK OF THE SURFACE LOW PRESSURE AREA AND FRONTAL BOUNDARY. AT ANY RATE...THE CHANCES OF RAINFALL LOOK GOOD ACROSS THE CWA FOR AT LEAST TUESDAY AND WEDNESDAY. MAY SEE WRAPAROUND RAIN INTO WEDNESDAY NIGHT...ESPECIALLY EAST IN THE CWA. IT SHOULD BE COOL AND CLOUDY FOR MOST OF THE CWA ON TUESDAY AND WEDNESDAY. THURSDAY AND FRIDAY WILL CONTINUE TO BE BELOW NORMAL FOR TEMPERATURES WITH NORTHWEST WINDS AND LOW THICKNESSES OVER THE AREA BEHIND THE EXITING SURFACE LOW PRESSURE AREA. && .AVIATION... COLD FRONT CONTINUES TO MOVE SOUTH ACROSS SOUTH DAKOTA AND IS THROUGH THE NORTHERN HALF OF THE STATE. IFR/MVFR BKN-OVC CIGS BEHIND THE FRONT ACROSS KMBG...KABR AND KATY TERMINALS THROUGH THE AFTERNOON. CIGS WILL GENERALLY IMPROVE TO MOSTLY MVFR LATE THIS AFTERNOON. ACROSS KPIR AND SOUTHERN PORTIONS OF TWEB ROUTES 256 AND 257 A SMALL CHANCE FOR ISO -TSRA BY THIS AFTERNOON. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...TT SHORT TERM...MA LONG TERM...DM AVIATION...TT
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
119 PM PDT SAT MAY 19 2007 .SYNOPSIS... THE MARINE LAYER AND AN INTERMITTENT COASTAL EDDY WILL CONTINUE NIGHT AND MORNING LOW CLOUDS WEST OF THE MOUNTAINS...LINGERING AT TIMES DURING THE AFTERNOONS NEAR THE COAST THROUGH MONDAY. TEMPERATURES WILL REMAIN A BIT BELOW NORMAL WEST OF THE MOUNTAINS... AND NEAR NORMAL OVER THE MOUNTAINS AND DESERTS. BUILDING HIGH PRESSURE ALOFT BY THE MIDDLE OF NEXT WEEK IS EXPECTED TO BRING MORE SUN AND WARMER DAYS THROUGH THE END OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... WEAK ONSHORE SURFACE PRESSURE GRADIENTS AND A WEAK EDDY CIRCULATION OVER THE BIGHT CONTINUE THIS AFTERNOON. THE STRATUS HAS CLEARED BACK TO THE COAST. SOME PARTIAL CLEARING ALONG THE COASTAL STRIP THIS AFTERNOON SHOULD QUICKLY FILL BACK IN WITH MARINE STRATUS DURING THE EVENING...AND THEN SPREAD WELL INLAND OVERNIGHT. A WEAK...BAGGY UPPER-LEVEL TROUGH OVER THE AREA IS EXPECTED TO SUPPORT THE EDDY CIRCULATION OVER THE BIGHT THROUGH SUN AT LEAST. ON MON...A STRONGER TROUGH MOVES THROUGH THE PAC NW...INCREASING ONSHORE FLOW HERE AND BUILDING THE MARINE LAYER FURTHER. EXPECT IT TO PEAK BY TUE MORNING THEN BEGIN TO MIX OUT AS N FLOW AND BUILDING HIGH PRESSURE ALOFT BEGIN TO TAKE HOLD. THIS SHOULD ALLOW SOME WARMING AND MORE SUNSHINE BY THE SECOND HALF OF THE WEEK. LOOKS LIKE THE WARMING COULD HOLD INTO THE FIRST PART OF THE MEMORIAL WEEKEND...BUT MEDIUM RANGE MODELS ARE HINTING AT ANOTHER COLD TROUGH DESCENDING OVER CA ON MON...WITH BELOW AVERAGE TEMPERATURES AGAIN THROUGH TUE. && .AVIATION... 191915Z...LATE MORNING MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH HAD LOWERED TO AROUND 2000 FEET SINCE THIS MORNING. STRATUS WITH BASES AROUND 1500 FEET MSL HAS PULLED BACK TO NEAR THE COAST BUT REMAINS OVERCAST AT KSAN AND KCRQ. EXPECT THESE TWO LOCATIONS TO GO TO BROKEN WITH A BRIEF SCATTERED PERIOD THIS AFTERNOON. STRATUS SHOULD PUSH BACK ONSHORE AFTER 01Z REACHING THE INLAND VALLEY AREAS BY MIDNIGHT. A WEAK COASTAL EDDY REMAINS IN PLACE NEAR SAN CLEMENTE ISLAND. THIS EDDY IS EXPECTED TO STRENGTHEN ON SUNDAY WHICH SHOULD RESULT IN SOME DEEPENING OF THE MARINE LAYER ON SUNDAY. A LITTLE SLOWER AND LATER CLEARING IS EXPECTED ON SUNDAY. ABOVE THE MARINE LAYER...CONTINUED VFR CONDITIONS WITH A MOSTLY CLEAR SKY AND UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...JAD AVIATION...HORTON
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1030 AM PDT SAT MAY 19 2007 .SHORT TERM...ONE ISSUE HAS ARISEN WITH THE FORECAST FOR A POSSIBLE UPDATE. LOW CLOUDS HAVE SUDDENLY CRASHED INTO THE CENTRAL COAST AND MORRO BAY NOW REPORTS ONE MILE VISIBILITY. WILL MAKE AN AMENDMENT TO THE CENTRAL COAST ZONES. OTHERWISE...NO CHANGES EXPECTED FOR THE CURRENT FORECAST PACKAGE. BOUNDARY LEVEL TEMPERATURES AND UPPER LEVEL SYNOPTIC FEATURES REMAIN RATHER STAGNANT THROUGH ABOUT MONDAY WITH NO REAL CLEAR CUT TRENDS. THE ONLY FEATURE OF SOME SIGNIFICANCE IS AN ONGOING INCREASE IN NORTHERLY PRESSURE GRADIENTS THAT WILL CREATE SOME GUSTY WINDS THROUGH PASSES AND CANYONS OF THE TRANSVERSE MOUNTAIN RANGES INTO TONIGHT. WIND SPEEDS ARE EXPECTED TO STAY BELOW WIND ADVISORY CRITERIA. THE MARINE LAYER IS ABOUT 800 FEET DEEP ON THE CENTRAL COAST...AND 2300 FEET DEEP SOUTH OF POINT CONCEPTION DUE TO THE INFLUENCE OF A RECURRING EDDY CIRCULATION. LITTLE CHANGE IS FORECAST IN THE BEHAVIOR OF THE MARINE LAYER CLOUDS...EXCEPT THAT THE LOW CLOUDS WILL BE REINTRODUCED TO THE CENTRAL COAST TONIGHT BASED ON THE LATEST TRENDS. .LONG TERM...FROM PREVIOUS DISCUSSION...HGTS BEGIN TO RISE ACRS THE AREA TUE AS AN UPR RIDGE BUILDING ACRS THE ERN PAC EDGES INTO THE W CST. ONSHORE GRADS WILL WEAKEN AS WELL. STILL XPCT NIGHT THRU MORNING LOW CLDS/FOG IN CSTL AND VLY AREAS...MOST WDSPRD S OF PT CONCEPTION...BUT MARINE LAYER SHOULD BEGIN TO SHRINK IN DEPTH. THERE SHOULD BE SOME WARMING IN MOST AREAS ON TUE. HGTS WILL CONT TO RISE ACRS THE AREA WED...AND ONSHR FLOW WILL BECOME VERY WK. THIS SHOULD ALLOW FOR WARMING IN MOST AREAS AWAY FROM THE IMDT CST WED...WITH TEMPS GENERALLY ABOVE NORMAL IN THE VLYS...MTNS AND DSRTS. LITTLE CHANGE IS EXPECTED THU...THEN SLIGHT COOLING IS POSSIBLE ON FRI W OF THE MTNS AS ONSHORE FLOW BEGINS TO INCREASE. && .AVIATION...19/1100Z LATEST AMDAR SOUNDINGS INDICATE MARINE INVERSION BASED AROUND 1800 FEET THIS MORNING ACROSS THE LAX BASIN. SATELLITE/SURFACE OBS SHOW STRATUS/FOG SURGING NORTHWARD ALONG THE SOCAL COAST THANKS TO EDDY CIRCULATION. SO...ALL COASTAL AND VALLEY TAF SITES SOUTH OF POINT CONCEPTION WILL START OFF WITH IFR/MVFR CONDS THIS MORNING. EXPECT THESE KFR/MVFR CONDS TO BURN OFF BY LATE MORNING...WITH VFR CONDS EXPECTED IN THE AFTERNOON EXCEPT FOR IMMEDIATE COASTAL AREAS WHERE SOME CLOUDS/VSBYS RESTRICTIONS COULD PERSIST. FOR TAF SITES NORTH OF POINT CONCEPTION...EXPECT VFR CONDS THROUGH THE AFTERNOON. FOR THIS EVENING AND OVERNIGHT...HAVE LEFT KSBP/KSMX CLEAR BUT CONFIDENCE IS NOT VERY HIGH IN THIS FORECAST...GIVEN STRATUS OFFSHORE OF SLO/WESTERN SBA COUNTY. FOR KLAX...IFR CIGS/MVFR VSBYS THROUGH 16Z...THEN MVFR CIGS/VSBYS THROUGH THE AFTERNOON. STRATUS COULD SCATTER OUT TEMPORARILY THIS AFTERNOON...BUT ONSHORE FLOW WILL CIGS BACK RATHER QUICKLY. MVFR CIGS/VSBYS THIS EVENING...WITH CIGS LOWERING TO IFR OVERNIGHT. TYPICAL SEA BREEZE WILL DEVELOP AROUND 17Z AND CONTINUE THROUGH 03Z. OVERALL...HIGH CONFIDENCE IN KLAX TAF. FOR KBUR...IFR CIGS/MVFR VSBYS THROUGH 16Z...THEN MVFR CONDS THROUGH MID AFTERNOON (22Z). VFR CONDS EXPECTED TO PERSIST THORUGH THE EVENING...THEN IFR CIGS/MVFR VSBYS REDEVELOPING AROUND 08Z. OVERALL HIGH CONFIDENCE IN KBUR TAF. $$ .LOX WATCHES/WARNINGS/ADVISORIES... GALE WARNING (SEE LAXCWFLOX). && $$ PUBLIC...SWEET/BRUNO AVIATION...THOMPSON WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
327 PM CDT SAT MAY 19 2007 .SYNOPSIS... AT THE SURFACE...LOW PRESSURE AND WEAK SFC BOUNDARY FRONT NEAR BASSETT TO NORTH OF THEDFORD TO SOUTHEAST OF ALLIANCE IS CURRENTLY MAIN FOCUS FOR CONVECTION. NAM INDICATES SLOW MOVEMENT TO SOUTHEAST INTO EARLY EVENING. OTHER SCATTERED STORM FIRING OFF FRONT RANGE WITH SOME DEVELOPMENT SOON EXPECTED IN TRI STATE AREA. && .DISCUSSION... BEST ORGANIZED ACTIVITY IN BROWN AND ROCK COUNTY AT 2115Z WITH CONGESTING CU FIELDS TRAILING TO THE WEST. 0-6KM SHEAR IS WEAK AT 15-20 KTS...THUS BRIEF HEAVY RAIN...PEA HAIL AND GUSTY WINDS TO 50 MPH ARE EXPECTED. ISOLATED SEVERE STILL A CONCERN FOR ROTATING STORMS ALONG BOUNDARY INTO EARLY EVENING. SFC FRONT WILL LIFT NORTH FOR SUNDAY THEN BY MONDAY...CYCLOGENESIS IN ERN CO WILL DEVELOP FRONT ACROSS FORECAST AREA. BEST AREAL COVERAGE OF THUNDERSTORMS WILL BE MONDAY AFTERNOON/OVERNIGHT AHEAD OF UPPER TROUGH. THIS FCST PKG LEANED TOWARD FASTER NAM/SREF SOLUTION REGARDING POPS/WINDS TEMPS INTO TUESDAY. GFS LOOKS TOO SLOW...EVEN IN COMPARISON TO 12Z ECMWF. BEST SEVERE THREAT TO BE MONDAY AFTERNOON/NIGHT...AS 0-6KM SHEAR OF 30-40 KTS JUST NW OF SFC FRONT. THUS INCREASED TO LIKELY POPS MUCH OF NCTRL. && .AVIATION... GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH THE NEXT 24 HOURS OR SO AS THUNDERSTORM BASES SHOULD REMAIN AOA 5KFT AGL. HOWEVER AS PAST FEW NIGHTS...WIND GUSTS NEAR THESE STORMS COULD REACH OR EXCEED 50KT AS THEY COLLAPSE OR PRODUCE AN OUTFLOW BOUNDARY AND IN TURN REDUCED VISIBILITIES DUE TO BLOWING DUST...BOTH HAZARDOUS TO LIGHT AIRCRAFT. WEAKER WINDS ALOFT SHOULD ALSO PROHIBIT THE LLWS SEEN THE PAST FEW MORNINGS. MOISTURE AND BOUNDARIES WILL PERSIST ACROSS THE LBF TWEB ROUTES AGAIN SUNDAY AFTERNOON AND ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE AGAIN. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ KAR/13