Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 042109
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
200 PM PDT WED MAY 4 2016

.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL BRING UNSETTLED WEATHER THROUGH THE
WEEKEND. THIS SYSTEM WILL BRING THE THREAT OF SHOWERS AND
THUNDERSTORMS TO MUCH OF THE REGION ALONG WITH COOLER TEMPERATURES.

&&

.DISCUSSION...A SLOW MOVING PACIFIC STORM SYSTEM WILL BRING
WELCOME RAIN AND HIGH SIERRA SNOW INTO DROUGHT-WEARY CENTRAL CA
DURING THE NEXT FEW DAYS. THE STORM IS CENTERED A FEW HUNDRED
MILES WEST OF POINT CONCEPTION ON CURRENT SATELLITE IMAGERY. A
SOUTHWESTERLY FLOW ALOFT HAS SO FAR BEEN TRANSPORTING MID AND HIGH
LEVEL MOISTURE INTO CA. THIS MOISTURE WILL DEEPEN WITH TIME AS
THE STORM DRIFTS CLOSER TO THE COAST DURING THE NEXT 24 HOURS.

IN THE MEANTIME...THE MODELS FORECAST IMPRESSIVE RISES OF
PRECIPITABLE H2O (1+ INCHES) OVER THE SJ VLY ALONG WITH INCREASING
LIFT AND JET DYNAMICS. IN FACT...A 300 MB JET MAX OF 100+ KNOTS IS
FORECAST TO NOSE INTO THE CWA THIS EVENING. THIS SUPPORTS AN
INCREASE IN WINDS THROUGH AND BELOW THE WEST SIDE MOUNTAIN PASSES.
IN TURN THIS WILL KICK UP SOME DUST IN SOME WEST SIDE LOCALITIES
EARLY TONIGHT WHILE OTHERWISE BRINGING A SHALLOW INTRUSION OF MARINE
AIR INTO MUCH OF THE REST OF THE SJ VLY. A WIND ADVISORY WAS ISSUED
ACCORDINGLY FOR THE WEST SIDE OF THE SJ VLY FOR THIS EVENING. UNTIL
MOISTURE IN THE LOWER LEVELS OF THE ATMOSPHERE INCREASES...MEASURABLE
PRECIPITATION WILL BE LIMITED TO THE HIGHEST ELEVATIONS OF THE CWA
TONIGHT.

SHOWER ACTIVITY WILL INCREASE SIGNIFICANTLY OVER THE CWA THURSDAY
AS THE OFFSHORE STORM NEARS THE CA COAST. CONVECTIVE PARAMETERS
SUPPORT THE DEVELOPMENT OF ISOLATED THUNDERSTORMS...A FEW WITH
HEAVY RAIN AND SMALL HAIL...THURSDAY AFTERNOON THROUGH THURSDAY
EVENING. CAPES OF 700-1200 JOULES/KG ARE FORECAST OVER MUCH OF THE
CWA DURING THIS TIME WITH LIFTED INDICES PROGGED AS LOW AS -4C
OVER THE SIERRA.

THE MODELS BRING THE CENTER OF THIS STORM INLAND OVER THE CWA
FRIDAY AND DO NOT EXIT THIS SYSTEM INTO NEVADA UNTIL SATURDAY
EVENING. DURING THIS TIME...THE WEATHER WILL REMAIN UNSETTLED
OVER THE ENTIRE CENTRAL CA INTERIOR WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. AFTERNOON TEMPERATURES FRIDAY AND
SATURDAY WILL BE UNSEASONABLY COOL...AVERAGING A GOOD 8 TO 15
DEGREES BELOW NORMAL IN MANY LOCATIONS.

THE WEATHER WILL BE SLOW TO IMPROVE THIS WEEKEND AS THE STORM
SYSTEM INCHES EASTWARD TO THE FOUR CORNERS REGION. MUCH OF THE
CWA WILL BE DEALING WITH A GOOD DEAL OF BACKWASH MOISTURE FROM
THIS STORM SYSTEM THROUGH MOTHERS DAY WITH RESIDUAL SHOWERS...
ESPECIALLY OVER THE MOUNTAINS. TEMPERATURES WILL CONTINUE TO
AVERAGE COOLER THAN NORMAL SUNDAY AS WELL.

A DRYING TREND AND A DAY TO DAY WARMUP WILL BEGIN MONDAY AND
CONTINUE THROUGH NEXT WEDNESDAY AS A RIDGE OF HIGH PRESSURE ALOFT
BUILDS IN FROM THE EASTERN PACIFIC. TEMPERATURES WILL RECOVER TO
SEASONABLE LEVELS IN MOST AREAS MONDAY THEN BOUNCE UPWARD BY A
FEW MORE DEGREES ON DAYS 6 AND 7. THE GFS IS HINTING THAT ANOTHER
STORM SYSTEM WILL DEVELOP OVER THE EASTERN PACIFIC LATER NEXT
WEEK. WHETHER OR NOT IT BRINGS WET WEATHER BACK INTO CENTRAL CA
REMAINS TO BE SEEN...SO STAY TUNED.

&&

.AVIATION...INCREASING AREAS OF MVFR AND LOCAL MOUNTAIN OBSCURING
IFR OVER THE SOUTHERN SIERRA NEVADA THRU 18Z THU. THEN MAINLY IFR
OVER THE SOUTHERN SIERRA NEVADA AFTER 18Z THU. INCREASING AREAS OF
MVFR OVER THE TEHACHAPI MOUNTAIN AFTER 18Z THU. ISOLATED
THUNDERSTORMS POSSIBLE THROUGHOUT THE CENTRAL CA INTERIOR AFTER 18Z
THU. OTHERWISE...VFR CONDITIONS WILL PREVAIL 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 HIGH.

CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP FOR ADDITIONAL INFORMATION
AN/OR TO PROVIDE FEEDBACK.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
CAZ089-091.

&&

$$

PUBLIC...DURFEE
AVN/FW...DS
SYNOPSIS...BSO

WEATHER.GOV/HANFORD


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