FXUS66 KHNX 221713
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
913 AM PST TUE DEC 22 2009
.SYNOPSIS...
THE LOW PRESSURE SYSTEM HAS MOVED TO THE EAST BUT COLD AIR BEHIND
THIS SYSTEM WILL MOVE OVER THE AREA TODAY. THE MAIN WEATHER
CONCERNS WILL BE HIGH WINDS IN THE KERN MOUNTAINS AND DESERTS
THIS AFTERNOON AND EVENING AND FREEZING TEMPERATURES IN THE SAN
JOAQUIN VALLEY TONIGHT AND WEDNESDAY NIGHT. OTHERWISE HIGH
PRESSURE WILL PREVAIL OVER THE DISTRICT WITH THE RETURN OF VALLEY
FOG BY CHRISTMAS EVE AND MORNING.
&&
.DISCUSSION...A LOW LEVEL CONVERGENCE AREA HAS CAUSED SHOWERS TO
DEVELOP ACROSS PARTS OF KERN AND TULARE COUNTIES THIS MORNING.
UPDATE ISSUED TO INCREASE CLOUDS OVER THE MTNS AND SOUTH END OF
THE VALLEY...AND PUT SOME SLIGHT CHANCE POPS THIS MORNING FOR THE
FOOTHILLS AND FAR SOUTH END OF THE VALLEY.
TWO PIECES OF ENERGY ARE SEEN IN WATER VAPOR PIX ON THE BACK SIDE
OF THE DEPARTING TROF. THE FIRST IS MOVING SOUTH ALONG THE SIERRA
NEAR TAHOE...THE SECOND IS ALONG THE WE/OR BORDER. THESE WILL CONT
TO BRING SOME INSTABILITY SNOW SHOWERS TO THE MTNS TODAY...AND THE
SECOND WILL REINFORCE COLDER AIR MOVING INTO CENTRAL CA.
&&
.PREV DISCUSSION... /ISSUED 310 AM PST TUE DEC 22 2009/
SYNOPSIS...
A FAST MOVING COLD FRONT WILL EXIT THE FORECAST AREA LATER THIS
MORNING AND IN ITS WAKE, STRONG WINDS WILL BUFFET THE KERN COUNTY
MOUNTAINS AND DESERT TODAY AND TONIGHT. HIGH PRESSURE WILL BUILD
INTO THE AREA TONIGHT BRINGING LIGHT WINDS. COLD AIR OVER CENTRAL
CALIFORNIA WILL SET THE STAGE FOR FREEZING TEMPERATURES IN THE SAN
JOAQUIN VALLEY AND VERY COLD MORNING LOWS IN THE KERN COUNTY
DESERT.
DISCUSSION...THINGS ARE REALLY MOVING FAST THIS MORNING AS THE
JET IS DRIVING THE COLD FRONT VERY QUICKLY TO THE SOUTHEAST. WITH
THE ARRIVAL OF THE JET DYNAMICS AND THE COLDER AIR ALOFT SOME
THUNDER HAS DEVELOPED ALTHOUGH IT HAS BEEN ISOLATED IN NATURE. AT
THE CURRENT SPEED OF MOVEMENT THE COLD FRONT WILL BE KNOCKING ON
KERN COUNTY IN THE NEXT 2-3 HOURS AND THE WINDS WILL LIKELY START
CRANKING UP BY SUNRISE. THE HIGH WIND WARNING TIMING LOOKS GOOD AS
I MOVED IT UP BY 5 HOURS FROM THE WATCH. FORECAST MODEL WINDS AT
700 MB ARE AT 75 KNOTS PER THE NAM12 MODEL AND I HAVEN'T SEEN
VALUES THIS HIGH BEFORE. WITH THE SUBTROPICAL JET EXITING TO THE
EAST OVER SOUTHERN CALIFORNIA AS THE POLAR JET INVADES FROM THE
NORTH AND SURFACE PRESSURE DIFFERENCES BETWEEN BAKERSFIELD AND
CHINA LAKE APPROACH 10 MILLIBARS BY MID DAY, THIS COULD INDEED BE
A NOTABLE WIND EVENT OVER THE KERN COUNTY MOUNTAINS AND
DESERT...HOLD ON TO YOUR HATS! IN THE SAN JOAQUIN VALLEY, THE COLD
FRONT HAS ALREADY PASSED THROUGH HANFORD AND VISALIA AND AS THE
POLAR JET NOSES IN FROM THE NORTH, WINDS WILL GET RATHER BRISK
FROM THE NORTHWEST. WILL NEED TO KEEP A CLOSE EYE ON THE WEST SIDE
MESONET STATIONS ALONG THE I-5 CORRIDOR FOR ANY POSSIBLE
ADVISORIES? ANYWAY WITH THE INCREASED SPEED OF THE FRONT, I HAVE
ENDED PRECIPITATION AREA WIDE BY LATE MORNING AND TRIMMED WAY BACK
ON THE MORNING POPS.
IN THE WAKE OF TODAY'S COLD SYSTEM, TONIGHT SHOULD GET COLD ENOUGH
FOR THE FREEZING CONDITIONS IN THE SAN JOAQUIN VALLEY TO REMAIN A
MAJOR CONCERN. ALONG THE EAST SIDE OF THE SJV THE BOUNDARY LAYER
SHOULD EASILY DECOUPLE BY LATE EVENING, THUS THE GREATEST THREAT
OF A PROLONGED FREEZE SHOULD BE HERE. OVER THE WEST SIDE, SOME
MIXING MAY HINDER THE SURFACE COOLING FOR MUCH OF THE NIGHT, THUS
A HARD FREEZE MAY BE MINIMIZED. WITH A COLD NORTHERLY FLOW ALOFT
CONTINUING ON WEDNESDAY, THE THREAT FOR A MORE UNIFORM FREEZE
APPEARS GREATER ON WEDNESDAY NIGHT.
OUT IN THE KERN COUNTY DESERTS SOME BONE CHILLING TEENS ARE
LIKELY ON WEDNESDAY NIGHT AS THE WINDS SUBSIDE AND A LIGHT
EASTERLY FLOW OFF THE GREAT BASIN PREVAILS.
CHRISTMAS EVE AND CHRISTMAS LOOK DRY AND COOL WITH A RIDGE OF HIGH
PRESSURE DOMINATING THE WEST COAST WITH NORTHERLY FLOW ALOFT.
&&
.AVIATION...
IFR CEILINGS WILL OCCUR IN THE FOOTHILLS AND MOUNTAINS TODAY WITH
SCATTERED SHOWERS. MVFR CONDITIONS ARE STILL POSSIBLE ALONG THE
NORTH AND WEST FACING SLOPES OF THE TEHACHAPI MOUNTAINS
TONIGHT...WITH CONDITIONS IMPROVING TO VFR IN THE SIERRA NEVADA
AND FOOTHILLS AFTER 02Z WEDNESDAY. ADDITIONALLY...VERY STRONG
WINDS WILL OCCUR THROUGH AND BELOW THE KERN COUNTY MOUNTAIN PASSES
UNTIL 06Z WEDNESDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL
ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 18Z WEDNESDAY.
&&
AIR QUALITY ISSUES...
NONE
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 10 PM PST THIS EVENING FOR CAZ095-098-
099.
FREEZE WATCH FROM THIS EVENING THROUGH WEDNESDAY MORNING FOR
CAZ089>092.
FREEZE WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR
CAZ089>092.
&&
$$
PUBLIC...BINGHAM
AVN/FW...BEAN
SYNOPSIS...BSO
WEATHER.GOV/HANFORD
