Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 251033
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
333 AM PDT SAT OCT 25 2014

.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL BRING INCREASED CLOUDS ALONG WITH A
COOLING TREND AND STRONG WINDS TODAY. HIGH PRESSURE WILL BUILD
INLAND BY THE MIDDLE OF NEXT WEEK...BRINGING A RETURN TO WARMER
CONDITIONS.

&&

.DISCUSSION...
A CHANGE IN THE WEATHER IS QUICKLY APPROACHING THE DISTRICT TODAY
AS A COLD FRONT MOVES ONSHORE. CURRENTLY...THE COLD FRONT IS SOME
150 MILES OFFSHORE WITH THE ASSOCIATED CENTER OF THE LOW ABOUT 400
MILES NORTHWEST OF THE BAY AREA. IR SATELLITE AND REGIONAL DOPPLER
RADAR IMAGERY SHOWS THE PRECIP STILL OFFSHORE BUT DIRECTED AT THE
BAY AREA. SHORT RANGE MODELS...INCLUDING THE HRRR...SHOW PRECIP
ENTERING THE BAY AREA AT AROUND 5 AM PDT...AND SPREADING EASTWARD
DURING THE MORNING HOURS. CURRENT TIMING HAS LIGHT PRECIP ENTERING
THE CENTRAL CALIFORNIA INTERIOR JUST BEFORE NOON AND IN THE
YOSEMITE AREA BEFORE 4 PM PDT TODAY.

WHILE MODELS HAVE A VERY GOOD HANDLE ON THE PASSAGE OF THE COLD
FRONT THROUGH CENTRAL CALIFORNIA TODAY...THEY ALSO SHOW A
WEAKENINGCOLD FRONT AS IT PASSES. THEREFORE...PRECIPITATION
WHICH MAY ENTER THE MERCED/MADERA TO MARIPOSA COUNTY AREA AND INTO
YOSEMITE MAY NOT REACH THE SOUTHERN SAN JOAQUIN VALLEY. BLENDED
TOTAL PRECIP WATER ALONG WITH INTERGRATED WATER VAPOR TRANSPORT
SHOW THE BULK OF THE MOISTURE REMAINING WELL NORTH OF THE DISTRICT
DURING ITS PASSAGE. MODELS SHOW THE COLD FRONT FALLING APART
DURING ITS PASSAGE. YET...BEFORE FALLING
APART...WINDS...ESPECIALLY OVER THE SIERRA CREST WILL INCREASE FOR
BREEZY TO WINDY CONDITIONS IN THE AFTERNOON HOURS. IN ADDITION...
MODELS ARE STILL PROGGING A FIVE TO SIX DEG-C DROP IN 850MB TEMPS
TODAY...FROM THAT OF FRIDAY AFTERNOON...WHICH WILL TRANSLATE IN A
10 DEG-F DROP IN SURFACE TEMP/S THIS AFTERNOON. THEREFORE...WILL
NOT EXPECT VALLEY TEMPERATURE TO RISE BEYOND THE 70S THIS
AFTERNOON AS WE FEEL THE INFLUENCES OF THE COLD FRONT.

THIS STORM SYSTEM WILL BE SHORT LIVED AND IS EXPECTED TO EXIT THE
REGION BY MONDAY MORNING. THE STORM SYSTEM WILL BE REPLACED WITH A
WEAK RIDGE PATTERN WHICH WILL FEEL MORE LIKE A ZONAL FLOW PATTERN.
THEREFORE...WILL NOT EXPECT A SIGNIFICANT WARMING TREND DURING THE
MIDDLE PART OF THE WEEK. BY THE END OF THE WEEK...THE BIG ISSUE
WILL BE THE PASSAGE OF ANOTHER TROUGH MOVING THROUGH THE REGION.
ENSEMBLE MODELS SHOWING HIGH UNCERTAINTY WITH THE TIMING OF THE
TROUGH AND NOT THE AMPLITUDE. GFS MOD TREND EVEN SHOWING THE
TROUGH DEEPENING BEFORE ENTERING THE WEST COAST. THEREFORE...WHILE
EVEN THE RELATIVE MEASURE OF PREDICTABILITY REMAINS LOW AND NEAR
10 PERCENT OF OCCURRING...CONFIDENCE IN DEVELOPING A TROUGH
INCREASES AS SHOWN TO THE MOD-TREND. THEREFORE...WILL INTRODUCE
CLIMO PROB OF PRECIP FOR FRIDAY NIGHT /OCT.31/ AS THE POTENTIAL
EXIST FOR SOME PRECIP.

&&

.AVIATION...
STRONG WIND GUSTS IN EXCESS OF 50 KNOTS ACROSS THE SOUTHERN SIERRA
CREST. LOCAL MVFR CONDITIONS IN CLOUDS AND SHOWERS DEVELOPING ACROSS
THE SOUTHERN SIERRA AFTER 18Z SATURDAY. AREAS OF MVFR AND LOCAL IFR
CONDITIONS IN UPSLOPE CLOUDS AND SHOWERS ACROSS VALLEY FACING SLOPES
AFTER 06Z SUNDAY. VFR CONDITIONS WILL PREVAIL ELSEWHERE 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 10-25       91:1966     61:1998     62:1982     36:1971
KFAT 10-26       89:2003     57:2004     58:1927     35:1939
KFAT 10-27       89:2003     58:1896     61:1987     35:1970

KBFL 10-25       94:1917     62:1939     66:1982     35:1899
KBFL 10-26       92:2003     58:1996     61:1959     35:1939
KBFL 10-27       99:1906     56:2004     64:1987     34:1919
&&

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

&&

$$

PUBLIC...MOLINA
AVN/FW...DCH
SYNOPSIS...MOLINA

WEATHER.GOV/HANFORD



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