Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 210244 AAA
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
312 PM PDT WED AUG 20 2014

.UPDATE...
UPDATED AIR QUALITY AND AVIATION SECTIONS.

&&

.SYNOPSIS...AN UPPER LEVEL LOW CENTERED JUST OFFSHORE THE SOUTHERN
CALIFORNIA COAST WILL MOVE INLAND ACROSS NORTHERN BAJA THURSDAY.
ISOLATED THUNDERSTORMS ARE POSSIBLE NEAR THE SIERRA CREST THURSDAY.
OTHERWISE...EXPECT DRY CONDITIONS AND NEAR NORMAL TEMPERATURES
FOR THE NEXT SEVERAL DAYS.

&&

.DISCUSSION...
UPPER LEVEL LOW CONTINUES TO ROTATE OVER THE CHANNEL ISLANDS WITH
AN AREA OF DIFLUENCE/JET MAX ENERGY ACROSS SOUTHERN CALIFORNIA.
OVER CENTRAL CALIFORNIA...A NORTHEAST TO EAST WIND FLOW ALOFT HAS
KEPT THE AREA CLEAR SO-FAR. YET...WITH DIURNAL HEATING THIS
AFTERNOON AND AN UPSLOPE FLOW ONE THE BACK SIDE OF THE SIERRA
NEVADA...MAY SEE SOME CONVECTION POPPING UP SHORTLY. SATELLITE
IMAGERY IS SHOWING VERY ISOLATED CONVECTION. IN ADDITION...RADAR
IS SHOWING SOME REFLECTIVITY NEAR MAMMOTH MOUNTAIN. YET...BECAUSE
THE RADAR RETURNS DO NOT CORRESPOND WITH THE CLOUDS...THE
REFLECTIVITY IS THAT OF CHAFF AND NOT PRECIP. HOWEVER...PRECIP
WILL BE POSSIBLE THIS AFTERNOON NEAR YOSEMITE...AS NOTED IN VERY
SHORT RANGE MESO-SCALE MODELS. TEMPERATURE-WISE...THE VERY WEAK
SURFACE PRESSURE GRADIENT HAS ALLOWED THE MARINE LAYER TO REACH
NEAR 3000 FEET MSL...AS SEEN ON THE FORT ORD PROFILER. THIS DEPTH
IS ALLOWING MARINE AIR TO FILTER INTO THE SAN JOAQUIN VALLEY AS
MANY LOCATIONS NORTH OF FRESNO COUNTY WERE STILL IN THE 80S AS OF
200 PM PDT.

THE SHORT TERM FORECAST CALLS  FOR THE UPPER  LOW TO PUSH FURTHER
SOUTHEAST  AND PLACING THE DISTRICT  UNDER A MORE  NORTHERLY FLOW
ALOFT.  THE OFFSHORE FLOW PATTERN WILL  SWITCH TO MORE ONSHORE ON
FRIDAY AND MAINTAIN AN ALMOST STEADY STATE IN TEMPERATURE THROUGH
THE END OF THE WEEK. THEREFORE...WHILE TEMPERATURES MAY REACH THE
MID 90S IN THE NEXT DAY OR TWO...THE VALLEY WILL REMAIN BELOW THE
CENTURY MARK. UPPER AIR MODEL ANALYSIS SHOWS A GENERALLY CYCLONIC
FLOW PATTERN FOR THE NEXT FOUR TO FIVE DAYS ACROSS CALIFORNIA. IN
ADDITION...MODELS SHOW AN INSIDE SLIDER ATTEMPTING TO PUSH THROUGH
THE WEST ON FRIDAY/SATURDAY. MODEL TREND HAS THE TROF PUSH THROUGH
MAINLY THE INTER-MOUNTAIN/GREAT BASIN AREA...BUT IS LEANING TOWARD
DROPPING CLOSER TO CENTRAL CALIFORNIA.  AT THIS POINT...WILL ONLY
INCREASE  THE CLOUD COVER  FOR  THE DAYS MENTIONED  ABOVE AND NOT
INTRODUCE PRECIP. YET...WINDS...WHICH ARE EXPECTED TO REMAIN LIGHT
FOR THE NEXT 48 HOURS MAY INCREASE SLIGHTLY DURING TROF PASSAGE.
HOWEVER...NAMDNG5 MODEL ANALYSIS DOES NOT REACH ADVISORY CRITERIA
DURING THE TROF PASSAGE EVENT.

BY NEXT WEDNESDAY...MODELS FINALLY SHOW A BUILDING RIDGE PATTERN
OVER THE WEST. THEREFORE...TEMPERATURES WHICH WILL SHOW LITTLE
CHANGE FOR UP TO FIVE DAYS...WILL BEGIN A WARMING TREND TOWARD
WEDNESDAY. MODELS ARE SHOWING SOME UNCERTAINTY ON THE DEVELOPMENT
OF THE RIDGE...BUT MODEL TREND ANALYSIS DOES LEAN TOWARD A RIDGE BY
THE MIDDLE OF NEXT WEEK. THEREFORE...MENTION 100 DEG-F READINGS
ACROSS THE SAN JOAQUIN VALLEY BY NEXT WEDNESDAY.

&&

.AVIATION...ISOLATED THUNDERSTORMS ARE POSSIBLE NEAR THE SIERRA
CREST AFTER 20Z THURSDAY. OTHERWISE...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 08-20      108:1919     76:1959     75:1986     54:1974
KFAT 08-21      108:1919     80:1968     76:1913     51:1959
KFAT 08-22      108:1897     81:1960     75:1995     50:1899

KBFL 08-20      112:1950     77:1959     79:1950     52:1912
KBFL 08-21      110:1919     80:1968     77:1982     51:1918
KBFL 08-22      109:1919     82:1983     78:2009     44:1903
&&

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

&&

$$

PUBLIC...MOLINA
AVN/FW...MENDENHALL
SYNOPSIS...PJ

WEATHER.GOV/HANFORD


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