Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 050956
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
256 AM PDT WED AUG 5 2015

.SYNOPSIS...
LOOK FOR WARMING TEMPERATURES THROUGH THURSDAY...THEN A WEAK LOW
PRESSURE SYSTEM WILL BRING ANOTHER COOLDOWN FOR THE WEEKEND. A FEW
THUNDERSTORMS ARE EXPECTED OVER THE SIERRA THURSDAY NIGHT AND
FRIDAY...WHILE A RUMBLE OF THUNDER CAN NOT BE RULED OUT IN THE
VALLEY AS FAR SOUTH AS MERCED COUNTY.

&&

.DISCUSSION...
MOISTURE FROM TROPICAL STORM GUILLERMO STREAMED INTO CENTRAL
CALIFORNIA TUESDAY BRINGING CONSIDERABLE HIGH CLOUDINESS. THESE
CLOUDS...COMBINED WITH MARINE AIR THAT FILLED THE SAN JOAQUIN
VALLEY...RESULTED IN MUCH COOLER HIGH TEMPERATURES ACROSS THE
CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY THAN HAD BEEN FORECAST.
WHILE THE SOUTH END OF THE SAN JOAQUIN VALLEY SAW HIGHS IN THE LOWER
TO MID 90S...LOCATIONS ELSEWHERE IN THE VALLEY STRUGGLED TO REACH
THE MID 80S. MERCED ONLY REACHED 81 DEGREES...13 DEGREES BELOW
NORMAL. FRESNO/S HIGH OF 84 WAS ONLY ONE DEGREE WARMER THAN THE
RECORD LOW MAXIMUM TEMPERATURE FOR AUGUST 4TH OF 83 DEGREES...SET IN
1976.

THE WEATHER PATTERN THIS MORNING HAS AN UPPER-LEVEL SHORT-WAVE
MOVING THROUGH NORTHERN CALIFORNIA AND AN UPPER-LEVEL RIDGE CENTERED
OVER SOUTHERN ARIZONA. THIS PATTERN WILL KEEP THE SOUTHWEST FLOW
ALOFT IN PLACE OVER THE REGION. THE SHORT-WAVE BROUGHT LIGHT RAIN TO
THE NORTHERN SAN JOAQUIN VALLEY TUESDAY AFTERNOON...INCLUDING A
TRACE TO MERCED...BUT ADDITIONAL RAINFALL IS NOT EXPECTED.

A WAVE ROTATING AROUND THE RIDGE IS FORECAST TO MOVE THROUGH
SOUTHERN CALIFORNIA TONIGHT. AT THIS TIME MOISTURE OVER KERN COUNTY
APPEARS TOO LIMITED FOR ANY PRECIPITATION BUT THE PAST COUPLE OF
SYSTEMS PROVED STRONGER THAN THE MODELS HAD FORECAST SO WILL KEEP
AN EYE ON THE WAVE.

SATELLITE LOOPS SHOW THE BAND OF HIGH CLOUDS CONTINUING TO STREAM
ACROSS THE EASTERN PACIFIC INTO CALIFORNIA THIS MORNING. THESE
CLOUDS LIKELY WILL KEEP TEMPERATURES DOWN AGAIN TODAY...ESPECIALLY
IN THE PARTS OF THE SAN JOAQUIN VALLEY WHERE THE MARINE AIR POOLED
AND WILL BE SLOW TO MIX OUT. THE FORECASTED HIGHS OF UPPER 80S TO
LOWER 90S LOOKS ON TRACK.

500-MB HEIGHTS ARE FORECAST TO RISE THURSDAY AS THE TROUGH BEGINS TO
APPROACH THE COAST AND THE FLOW OVER CALIFORNIA BUCKLES SLIGHTLY. IF
THE MARINE AIR MIXES OUT...TEMPERATURES COULD APPROACH NORMAL VALUES.

THE FLOW ALOFT IS FORECAST TO BECOME MORE SOUTHERLY THURSDAY NIGHT
AS THE TROUGH COMES ONSHORE. THIS WILL ALLOW MONSOONAL MOISTURE
WRAPPING AROUND THE RIDGE TO MOVE INTO CALIFORNIA. WHILE THE NAM-12
HAS BACKED OFF SOME ON THE MOISTURE...THESE WILL BE ENOUGH DYNAMICS
AND MID-LEVEL MOISTURE FOR A FEW THUNDERSTORMS OVER THE SOUTHERN
SIERRA NEVADA THURSDAY NIGHT THROUGH FRIDAY NIGHT.

FOR THE WEEKEND...AN UPPER-LEVEL LOW IS FORECAST TO DROP OUT OF THE
GULF OF ALASKA AND REACH THE QUEEN CHARLOTTE ISLANDS. THIS LOW IS
FORECAST TO BRING ANOTHER TROUGH TO OFF THE CALIFORNIA COAST
BEGINNING SUNDAY.

WHILE THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT THROUGH 18Z
/1100 PDT/ SUNDAY...THEY BEGIN TO DIVERGE AFTER THIS POINT. THE
ECMWF IS THE MORE PROGRESSIVE OF THE TWO MODELS WITH AN UPPER-LEVEL
TROUGH OVER CALIFORNIA FOR THE MIDDLE OF NEXT WEEK WHILE THE GFS
CLOSES OFF THE TROUGH INTO AN EAST PACIFIC LOW THAT REMAINS WEST OF
CALIFORNIA FOR THE END OF THE FORECAST PERIOD.

&&

.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 08-05      110:1895     83:1957     79:1998     51:1950
KFAT 08-06      110:1902     78:1999     77:1998     54:1950
KFAT 08-07      112:1908     82:1999     78:1990     54:1975

KBFL 08-05      110:1998     85:1957     84:1909     52:1899
KBFL 08-06      110:1990     79:1999     85:1978     54:1903
KBFL 08-07      110:1905     81:1999     83:1978     56:1999

&&

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

&&

$$

PUBLIC...SANGER
AVN/FW...JEB
SYNOPSIS...JEB

WEATHER.GOV/HANFORD


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