Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 222130
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
230 PM PDT MON SEP 22 2014

.SYNOPSIS...
A WEAK UPPER RIDGE WILL RETURN WITH DRY CONDITIONS AND WARMER TEMPS
EARLY THIS WEEK. HOWEVER...A CHANGE IN THE WEATHER WILL OCCUR LATE
IN THE WEEK AS A PACIFIC STORM ENTERS THE REGION WITH COOLING AND
POSSIBLE PRECIP.

&&

.DISCUSSION...
SATELLITE LOOPS SHOW CLEAR SKIES ACROSS INTERIOR CENTRAL CALIFORNIA
THIS AFTERNOON AS AN UPPER-LEVEL RIDGE BUILDS INTO THE STATE. AT 20Z
/1300 PDT/...TEMPERATURES IN THE CENTRAL AND SOUTHERN SAN JOAQUIN
VALLEY RANGED FROM THE UPPER 70S TO MID 80S AND WERE MOSTLY WITHIN A
DEGREE OF PERSISTENCE. TEMPERATURES HAVE RECOVERED FROM THIS MORNING
WHEN THEY WERE RUNNING ABOUT 4 DEGREES DOWN FROM SUNDAY MORNING...
AND VALLEY HIGHS ARE ON TRACK TO REACH THE LOWER TO MID 90S TODAY.

FALL BEGINS THIS EVENING AT 0329Z TUESDAY /1929 PDT TONIGHT/...AND
WILL BE USHERED IN BY A COUPLE OF DAYS WITH ABOVE-NORMAL
TEMPERATURES. THE 12Z MODELS ARE IN GOOD AGREEMENT WITH 850-MB
TEMPERATURES OVER THE CENTRAL SAN JOAQUIN VALLEY WARMING BY ABOUT
ONE DEGREE CELSIUS THROUGH TUESDAY AFTERNOON AS THE RIDGE CONTINUES
TO BUILD OVER THE REGION. CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY
HIGHS TUESDAY AND WEDNESDAY ARE EXPECTED TO BE MOSTLY IN THE MID TO
UPPER 90S.

A SHARP CHANGE IN THE WEATHER WILL OCCUR THURSDAY AS A STRONG UPPER-
LEVEL TROUGH MOVES INTO THE STATE. IN ADDITION TO SYNOPTIC
COOLING... THE TROUGH WILL DEEPEN THE MARINE LAYER AND THE
DEVELOPMENT OF AN ONSHORE FLOW WILL BRING A SURGE OF COOLER AIR INTO
THE SAN JOAQUIN VALLEY. THE MODELS FORECAST A 12 C DROP FROM
WEDNESDAY AFTERNOON TO FRIDAY AFTERNOON...AND CENTRAL AND SOUTHERN
SAN JOAQUIN VALLEY HIGHS COULD DROP AS MUCH AS 14 DEGREES FROM
WEDNESDAY TO THURSDAY. TEMPERATURES WILL CONTINUE TO COOL FRIDAY AND
BOTTOM OUT IN THE LOWER TO MID 80S SATURDAY.

ONE WEATHER CONCERN WITH THE ARRIVAL OF THE TROUGH IS THE THREAT OF
GUSTY WINDS THROUGH AND BELOW THE PASSES AND CANYONS OF THE KERN
COUNTY MOUNTAINS. GUSTS LIKELY WILL REACH ADVISORY LEVELS /45 MPH OR
HIGHER/ AT TIMES...AND A HAZARDOUS WEATHER ADVISORY /SFOHWOHNX OR
FLUS46 KHNX/ HAS BEEN ISSUED FOR THESE WINDS.

THE SECOND CONCERN IS THE THREAT OF MOUNTAIN CONVECTION WITH THE
ARRIVAL OF THE TROUGH. ALTHOUGH THE SYSTEM CURRENTLY IS NOT FORECAST
TO HAVE A LOT OF MOISTURE...500-MB HEIGHTS ARE FORECAST TO FALL
BELOW 5720 METERS AS FAR SOUTH AS DELANO BY FRIDAY AFTERNOON AND
EVENING...WITH HEIGHTS OVER YOSEMITE NATIONAL PARK BELOW 5700
METERS. CONVECTION OVER THE SOUTHERN SIERRA NEVADA WILL BE POSSIBLE
THURSDAY THROUGH SUNDAY...WITH THE BEST CHANCE SATURDAY AS THE UPPER-
LEVEL LOW MOVES INTO THE GREAT BASIN AND WRAP-AROUND MOISTURE MOVES
ONTO THE EASTERN SLOPES OF THE SOUTHERN SIERRA NEVADA AND LIFTS
OROGRAPHICALLY INTO THE HIGH COUNTRY. THE EASTERLY FLOW ALOFT COULD
CAUSE THUNDERSTORMS OVER THE CREST TO DRIFT WESTWARD...POSSIBLY AS
FAR AS THE SIERRA FOOTHILLS OR EVEN INTO THE SAN JOAQUIN VALLEY.

ANOTHER UPPER-LEVEL RIDGE IS FORECAST TO BUILD ONTO THE PACIFIC
COAST BEGINNING SUNDAY AFTERNOON. 850-MB TEMPERATURES ARE FORECAST
BY BOTH THE GFS AND ECMWF TO WARM TO AROUND 20 C BY THE MIDDLE OF
NEXT WEEK...AND THE WARMEST PARTS OF THE CENTRAL AND SOUTHERN SAN
JOAQUIN VALLEY COULD SEE HIGHS AROUND 90 FOR THE START OF OCTOBER.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR
DURING THE NEXT 24 HOURS.

&&

.AIR QUALITY ISSUES...
NONE.

&&

.CERTAINTY...

THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.

THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.

&&

.CLIMATE...
             RECORDS
SITE DATE    HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR

KFAT 09-22      104:1949     67:1923     72:1999     41:1968
KFAT 09-23      105:1949     66:1904     70:2011     47:1968
KFAT 09-24      102:1899     62:1904     73:1939     46:1945

KBFL 09-22      105:2003     70:1923     74:1949     40:1908
KBFL 09-23      107:1943     71:1986     72:1949     31:1903
KBFL 09-24      103:1919     72:1920     74:2009     35:1908

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

PUBLIC...SANGER
AVN/FW...DCH
SYNOPSIS...WP

WEATHER.GOV/HANFORD


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