Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 181042
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
342 AM PDT THU SEP 18 2014

.SYNOPSIS... AN APPROACHING LOW PRESSURE SYSTEM WILL LOWER
TEMPERATURES TO NEAR NORMAL TODAY AND FRIDAY. TEMPERATURES WILL RISE
ABOVE SEASONAL NORMALS BY SATURDAY. THERE WILL BE A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE HIGHER SIERRAS THROUGH
SUNDAY.

&&

.DISCUSSION...MAIN FEATURE OF CONCERN THIS MORNING IS A FAIRLY
STRONG UPPER TROUGH APPROACHING THE CA COAST. WV IMAGERY AND GOES
HIGH DENSITY WINDS ARE INDICATING AN UPPER LOW PRESSURE CENTER
CURRENTLY SITUATED NEAR 41N/127W WHICH IS TAKING AIM AT THE
NORCAL COAST. RH PROGS ARE INDICATING THAT THIS SYSTEM WILL NOT
HAVE MUCH MOISTURE ASSOCIATED WITH IT AS IT PUSHES THROUGH
CENTRAL CA LATER TODAY AND TONIGHT. HOWEVER...IT WILL PROVIDE FOR
A VERY NOTICABLE COOLING TREND TODAY AS TEMPERATURES ARE EXPECTED
TO LOWER TO NEAR SEASONAL NORMALS TODAY IN RESPONSE TO LOWERING
HEIGHTS AND THICKNESSES. ANY PRECIPITATION ASSOCIATED WITH THIS
SYSTEM TODAY WILL LIKELY BE CONFINED TO THE YOSEMITE PARK AREA
WHERE THERE WILL BE MARGINAL INSTABILITY AND CAPE FOR CONVECTION
TO TAKE PLACE THIS AFTERNOON AS PER THE 00Z AND 06Z WRF RUNS. THE
HIGH RESOLUTION WRF IS INDICATING THE POTENTIAL FOR ANOTHER BRIEF
PERIOD OF BREEZY TO LOCALLY WINDY CONDITIONS AGAIN TONIGHT ALONG
THE WEST SIDE OF THE SAN JOAQUIN VALLEY AND OVER THE PASSES OF
THE KERN COUNTY MOUNTAINS AND DESERTS.

THE TROUGH IS PROGGED TO MOVE EAST OF THE REGION ON FRIDAY...BUT
THE UPPER LOW IS PROGGED TO BREAK OFF AND FORM A CUT OFF LOW OFF
THE CENTRAL CA COAST AND DROP SLOWLY SOUTHWARD THROUGH FRIDAY
NIGHT AND REMAIN STATIONARY OFF THE SOCAL COAST ON SATURDAY. THE
LOW IS THEN PROGGED TO LIFT SLOWLY NORTHEAST AND CROSS OUR AREA
BY SUNDAY. THE PROXIMITY OF THIS UPPER LOW WILL MAINTAIN ENOUGH
INSTABILITY OVER THE AREA FOR A SLIGHT CHANCE OF THUNDERSTORMS
EACH DAY OVER THE SOUTHERN SIERRA NEVADA...MAINLY ALONG THE
CREST. AT THIS TIME THIS SYSTEM IS NOT EXPECTED TO HAVE SUFFICIENT
MOISTURE FOR PRECIPITATION ELSEWHERE IN OUR CWFA...BUT IF ANY
TROPICAL MOISTURE BECOMES ENTRAINED IN THE UPPER LOW ON SATRUDAY
WHILE IT IS OFF THE SOCAL COAST...THE POTENTIAL MAY EXIST FOR
SOME SPRINKLES OR LIGHT SHOWERS NEARLY ANYWHERE IN OUR CWFA ON
SATURDAY NIGHT AND SUNDAY. TEMPERATURES ARE PROGGED TO REMAIN NEAR
SEASONAL NORMALS ON FRIDAY THEN RISE SLIGHTLY OVER THE WEEKEND AS
NOTICABLE RISES IN MID LEVEL TEMPERATURES ARE ANTICIPATED.

THE MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT IN EJECTING THE
UPPER LOW WELL TO THE NORTHEAST OF OUR AREA BY MONDAY AS A DRY
UPPER RIDGE PUSHES INLAND. THE RIDGE IS PROGGED TO AMPLIFY OVER
THE GREAT BASIN THROUGH WEDNESDAY WHICH WILL LEAVE OUR AREA UNDER
A DRY SOUTHWEST FLOW BETWEEN THE GREAT BASIN RIDGE AND ANOTHER
UPPER TROUGH THAT WILL IMPACT OUR AREA TOWARD THE END OF THE
PERIOD. AS A RESULT...TEMPERATURES WILL RISE UPWARD TO WELL ABOVE
SEASONAL NORMALS AGAIN FOR MONDAY THROUGH WEDNESDAY. THE MODELS
ARE IN DISAGREEMENT WITH THEIR HANDLING OF THE NEXT TROUGH AS IT
MOVES INLAND NEXT THURSDAY. THE ECWMF IS MUCH DEEPER WITH IT AND
IF IT WERE TO PAN OUT A SHARP COOLING TREND WOULD TAKE PLACE
TOWARD THE END OF NEXT WEEK ALONG WITH SHOWERY CONDITIONS.
HOWEVER...THE GFS IS NOT AS DEEP WITH THE TROUGH AND ARE NOT AS
PRONOUNCED WITH THE COOLING TREND ADVERTISED BY THE ECWMF AND
KEEP ANY PRECIPITATION ASSOCIATED WITH IT TO THE NORTH OF OUR
AREA.

&&

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

&&

.AIR QUALITY ISSUES...NONE.

&&

.CERTAINTY...

THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS MEDIUM.
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 09-18      107:1913     67:1963     78:1984     48:1978
KFAT 09-19      105:1922     70:1989     75:1984     44:1978
KFAT 09-20      104:1939     73:2007     73:1939     46:1978

KBFL 09-18      104:1913     69:1967     73:1984     45:1908
KBFL 09-19      104:1939     69:1989     73:2009     39:1908
KBFL 09-20      104:1899     73:2007     70:1974     38:1908
&&

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

&&

$$

PUBLIC...DS
AVN/FW...DCH
SYNOPSIS...DS

WEATHER.GOV/HANFORD


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