Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 201040
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
340 AM PDT SAT SEP 20 2014

.SYNOPSIS...
SLIGHT WARMING TODAY. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS OVER THE SOUTHERN SIERRA NEVADA THIS WEEKEND AND A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE SOUTHERN
TEHACHAPI MOUNTAINS TODAY AS A WEATHER SYSTEM MOVES THROUGH. WEAK
UPPER RIDGE WILL RETURN WITH DRY CONDITIONS AND WARMER TEMPS EARLY
NEXT WEEK.

&&

.DISCUSSION...
A RIDGE OF HIGH PRESSURE NOW DOMINATING THE REGION WITH FEW MID
LEVEL CLOUDS SHOWING THE FLOW ALOFT IN A OFFSHORE DIRECTION. THIS
OFFSHORE FLOW IS ALSO BEING SUPPORTED BY THE WEAK LOW JUST OFF THE
CENTRAL CALIFORNIA COAST. THE UPPER LOW WILL ALSO SUPPORT A
SOUTHEASTERLY FLOW OVER THE DESERT SOUTHWEST WHICH WILL ALLOW FOR
A NORTHERLY SURGE OF SUBTROPICAL MOISTURE INTO THE REGION. THIS
INFLUX OF MOISTURE...WHILE MOSTLY EAST OF THE DISTRICT...WILL
INCREASE THE POTENTIAL THREAT OF AFTERNOON THUNDERSTORMS OVER THE
SIERRA NEVADA CREST. IN ADDITION...BLENDED TOTAL PRECIP WATER
IMAGERY SHOWING THE ONE INCH LINE MOVING THROUGH ARIZONA AND
ROTATING TOWARD SOUTHERN NEVADA. THEREFORE...UNCERTAINTY IS LOW
FOR THE THREAT OF THUNDERSTORMS AND WILL MENTION CHANCE LEVEL
PROBABILITIES.

THE RIDGE WILL ALSO ALLOW TEMPERATURES TO START A WARMING TREND
FOR SEVERAL DAYS. MODELS PROGGING THE RIDGE TO AMPLIFY DURING THE
WEEKEND BEFORE SHIFTING EAST AND OVER THE MIDWEST TOWARD MIDWEEK.
BY MONDAY...THE UPPER LOW MOVES TOWARD THE INTER-MOUNTAIN WEST
WITH THE FLOW ALOFT BECOMING ONSHORE. THIS CHANGE IN THE FLOW
ALOFT WILL DIMINISH THE THREAT OF THUNDERSTORM ACTIVITY OVER THE
SIERRA NEVADA AND BEGIN MODERATING THE WARMING TEMPERATURES. BY
MIDWEEK...ON AROUND WEDNESDAY...THE WEATHER WILL TRANSITION TO A
COOLER AND POSSIBLY CLOUDY PATTERN AS A STORM DROPS TOWARD THE
PACIFIC NORTHWEST FROM THE GULF OF ALASKA. MODELS PROG THE STORM/S
ASSOCIATED COLD FRONT TO ENTER NORTHERN CALIFORNIA ON LATE
WEDNESDAY AND APPROACH THE DISTRICT NEAR THURSDAY.

CURRENTLY...MODELS ARE PROGGING THE STORM TO AFFECT THE PACIFIC
NORTHWEST AND NORTHERN CALIFORNIA WITH THE TAIL END MOVING THROUGH
MERCED COUNTY AND YOSEMITE. WHILE NO MENTION OF PRECIP WILL BE
PLACED OVER MERCED COUNTY...OROGRAPHIC FLOW WILL SUPPORT AT LEAST
SLIGHT CHANCE PROB OF PRECIP OVER THE YOSEMITE AREA LATER IN THE
WEEK. OTHERWISE...CLOUD COVER WILL BE THE MAIN INFLUENCE FROM THE
TROUGH...COLD FRONT...PASSAGE. HOWEVER...TEMPERATURE WILL SEE GOOD
COOLING FROM THE FRONTAL PASSAGE AS VALUES DROP INTO THE LOWER 80S
BY NEXT WEEKEND.

&&

.AVIATION...
A CHANCE OF THUNDERSTORMS WILL EXIST OVER THE SOUTHERN SIERRA NEVADA
CREST AND A SLIGHT CHANCE OVER THE SOUTHERN END OF THE TEHACHAPI
RANGE FROM 18Z TODAY THROUGH 06Z SUNDAY. MVFR IS POSSIBLE IN SMOKE
ALONG THE SOUTH END AND EAST SIDE OF THE SAN JOAQUIN VALLEY.
OTHERWISE...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 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 09-20      104:1939     73:2007     73:1939     46:1978
KFAT 09-21      102:1949     72:1945     74:1983     42:1968
KFAT 09-22      104:1949     67:1923     72:1999     41:1968

KBFL 09-20      104:1899     73:2007     70:1974     38:1908
KBFL 09-21      105:2003     74:1945     73:1983     37:1908
KBFL 09-22      105:2003     70:1923     74:1949     40:1908

&&

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

&&

$$

PUBLIC...MOLINA
AVN/FW...JDB
SYNOPSIS...BSO

WEATHER.GOV/HANFORD



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