Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 160519
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
919 PM PST Fri Dec 15 2017

.SYNOPSIS...A dry cold front will move southward through the
central California interior late tonight and be followed by
blustery, cooler weather Saturday. Another cold front will
move southward through the district Wednesday morning.
Otherwise, dry weather will prevail through the end of next
week.

&&

.DISCUSSION...
Extended the red flag warnings for the Sierra Nevada and the Kern
County Mountains through 7 PM Saturday. The humidity in Kern
County is expected to stay low through Saturday afternoon in many
places. In the Sierra Nevada, there will be some recovery
overnight as the cold front comes through. But winds are expected
to turn northeasterly again by Saturday afternoon, lowering
humidity once again into the single digits and teens at enough
places to be a concern, expecially with wind speeds increasing.


.PREVIOUS DISCUSSION...A couple of cold fronts will move
southward through the central California interior during the next
3 to 5 days. Unfortunately neither of them will bring the precip
that we so desperately need. In fact, the long range ensembles
depict a very bleak outlook for a return of wet weather over the
CWA through at least Christmas Day. If this trend continues,
December, 2017 will be one of the driest Decembers on record in
central California.

The first cold front shows up pretty well on infrared satellite
imagery this afternoon and is currently making inroads into
northern California. Until it sweeps southward through the CWA
late tonight, temperatures will stay relatively mild compared to
recent nights and a grimey haze will linger over much of the San
Joaquin Valley. With its passage, this front will bring little
more than a few snow flurries to the highest elevations of
Yosemite National Park. Otherwise, this generally dry cold front
will exit south and east of Kern county by daybreak. In its wake,
northwesterly winds will blow rather briskly over Merced county
and the western third of the San Joaquin Valley Saturday and may
gust up to 35 mph in some locations and kick up some dust. The
good news is that this cold front will finally scour out the crud
that has been plaguing the San Joaquin Valley for the past several
days. Otherwise, this weekend will be much cooler with high
temperatures closer to normal throughout the CWA. Saturday night
and Sunday night will be colder too, especially over the
mountains and desert. This will be a noticeable change over the
higher terrain where balmy temperatures and very low humidities
prevailed this week. Additionally, low clouds will bank up in the
wake of this cold front late tonight into Saturday along the north
facing slopes of the Tehachapi mountains.

An offshore flow will become re-established over the district
Saturday night and Sunday as a high pressure ridge over the
eastern Pacific builds back over central California. This ridge
will dominate the pattern through Tuesday and bring mostly clear
skies, slightly milder afternoon temperatures and seasonably
chilly nights during the early part of next week.

Meanwhile, the second cold front will approach the district from
the northwest Tuesday evening. Like its predecessor, this front
will be moisture-starved and bring little more than a few showers
to the higher elevations of the Sierra Wednesday. Otherwise, the
front will breeze through our CWA with little fanfare Wednesday
morning. The cold air mass that follows this second front will
likely pack more of a sting than tonight`s cold front, however.
Temperatures could plummet into the teens in the Kern county
desert Wednesday night and possibly as low as the lower to mid 20s
in the coldest locations of the San Joaquin Valley by daybreak
Thursday. Wednesday night will probably be the coldest night.
Toward the end of next week, the ridiculously resilient high
pressure ridge off the West coast is forecast to amplify while a
closed low develops over northern Baja. This will lead to another
potentially strong offshore wind event across southern California
from Thursday evening through Friday. Locally gusty east winds
could also blow through the canyons and passes of Kern county
during this time as well. Otherwise, temperatures will rebound a
bit by next Friday and there could be a return of haze and patchy
late night fog in the San Joaquin Valley as we head into Christmas
weekend.

&&

.AVIATION...
Widespread MVFR visibility in haze and mist will persist in the San
Joaquin Valley through 12z. MVFR in clouds along the foothills and
south end through 19z. Gusty winds to 35 mph along the west side of
the SJV, possible reduced visibility in blowing dust. Otherwise, VFR
conditions will prevail over the central CA interior during the next
24 hours.

&&

.AIR QUALITY ISSUES...
On Saturday December 16 2017... Fireplace/Wood Stove Burning
Status is: No Burning Unless Registered in Kern... Kings and
Tulare Counties. Further information is available at Valleyair.org

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is high.
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...
Red Flag Warning until 7 PM PST Saturday CAZ295>297.

Wind Advisory from 7 AM to 7 PM PST Saturday CAZ089>091.

&&

$$

public...Bean
avn/fw...JDB
prev discussion...Durfee
synopsis...Durfee

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