National Weather Service Text Product Display

Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
000
FXUS66 KHNX 010323
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
723 PM PST Tue Jan 31 2017

.SYNOPSIS...Dry weather will continue over the area through
Wednesday with night and morning fog in the San Joaquin Valley.
Wet weather will return to the region late Wednesday night and
continue through Friday night with breezy to locally windy
conditions.

&&

.DISCUSSION...Surface dew points remain in the mid to upper 40s
this evening. This combine with clear skies and light winds has
increased confidence in dense fog overnight. Visibilities have
already began to fall with 03Z surface analysis showing widespread
3 to 4 miles. Fresno is the hold out but its surface dew point
depression remains one of the largest across the valley.
Nevertheless, that will change as radiational cooling continues
over the next several hours.

A Dense Fog Advisory is in effect from 10 PM tonight to noon
tomorrow, with greatest confidence that fog will develop between
Highway 99 and I5. Still, another round of widespread dense fog is
likely in the morning. Adjust your travel plan and/or commute to
allow for slower driving due to reduced visibilities.

&&

.PREV DISCUSSION... /issued 310 PM PST Tue Jan 31 2017/

DISCUSSION...Dry upper ridge over CA is the prevailing weather
feature today. This has provided our area with another dry day and
unseasonably warm temperatures over the Southern Sierra Nevada
and adjacent foothills as well as over the Tehachapi Mountains.
Meanwhile inversion conditions and light winds prevailed over the
San Joaquin Valley overnight and this morning resulting in a
significant area of dense fog which persisted into the early
afternoon in some locations. Several multiple vehicle collisions
occurred today in the central San Joaquin Valley. The ridge is
progged to slowly weaken and move east tonight and Wednesday as
shortwave energy pushes through Norcal. IR imagery is indicating
some mid/high clouds poised to slip southward into central CA
tonight and along with the energy to our north may inhibit
widespread fog formations. However, patches of dense fog might
form overnight in the central and south San Joaquin Valley tonight
and adverse travel conditions are possible again late tonight and
Wednesday morning.

WV indicating a large upper low pressure center near 34N/143W
which is slowly tracking toward the CA coast. This system pulled a
shortwave northward today which is progged to push into Norcal by
Wednesday Night. Precipitation from this system is progged to
impact our northern areas by late Wednesday Night and push
southward during the day Thursday. This system does contain some
tropical moisture so snow levels will be fairly high for early
February, between 6000 and 7000 feet on Thursday morning rising
to 7000 to 8000 feet during the day Thursday afternoon then lower
to around 6000 feet by late Friday. QPF progs are indicating 1.5
to 3 inches of liquid precipitation for the Southern Sierra
Nevada from Yosemite Park to Kings Canyon Wednesday night through
Friday evening and half an inch to 1.5 inches of liquid
precipitation south of Kings Canyon. Have issued a Winter Storm
Warning above 6000 feet for the Southern Sierra Nevada from Kings
Canyon Northward and a Winter Weather Advisory for the Southern
Sierra Nevada in Tulare County as significant to heavy snowfall
will likely adversely impact travel over the higher Sierras. The
low is progged to cross Norcal by Friday Night with diminishing
showers across our area.

The medium range models and their ensemble means are indicating a
shortwave ridge building inland into Socal on Saturday with
shortwave energy streaming to our north across Norcal over the
weekend. Our area should remain dry on Saturday through Sunday
except for a few showers in or northernmost areas. Daytime
temepratures will be near normal while overnight lows will be
above normal as a result of mid/high clouds from a Pacific
moisture fetch being pulled up from a large upper low near
Vancouver Island. This large low will move inland Sunday Night
and Monday and push some shortwave energy through central CA
Sunday Night and Monday. Have raised POPs and sky cover for this
time frame as a result as confidence has improved that our area
will see another round of precipitation early next week. An upper
ridge is then progged to amplify off the CA coast next Tuesday
with a northwest flow ahead of it providing for unsettled
conditions across our area until the ridge pushes inland toward
the middle of next week.

&&

.AVIATION...
In the San Joaquin Valley...widespread MVFR visibilities in haze
through 04Z Wednesday...then areas of LIFR visibilities and ceilings
in fog developing through 19Z Wednesday. VFR conditions will prevail
elsewhere across the central California interior through 00Z
Thursday.

&&

.AIR QUALITY ISSUES...
On Wednesday February 1 2017... Unhealthy for sensitive groups in
Fresno... Kern... Kings and Tulare Counties. Fireplace/Wood Stove
Burning Status is: No Burning Unless Registered in Fresno...
Kern... Kings... Madera... Merced and Tulare Counties. Further
information is available at Valleyair.org

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
Winter Weather Advisory from 4 AM Thursday to 10 PM PST Friday
CAZ097.

Winter Storm Warning from 4 AM Thursday to 10 PM PST Friday
ABOVE 6000 FEET FOR THE CAZ096.

Dense Fog Advisory until noon PST Wednesday CAZ089>092.

&&

$$

public...Meadows
avn/fw...DCH
prev discussion...DS

weather.gov/hanford
National Weather Service Regional Headquarters
