Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 192135
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
235 PM PDT SAT APR 19 2014

.SYNOPSIS...
FAIR SKIES AND WARM TEMPS THROUGH EASTER WEEKEND AS WEAK HIGH
PRESSURE PREVAILS. A FRONTAL SYSTEM ON TUESDAY WILL LOWER TEMPS
SIGNIFICANTLY AND ALSO PRODUCE A CHANCE OF LIGHT PRECIPITATION TO THE
NORTHERN FORECAST AREA.

&&

.DISCUSSION...
AT 2120Z /1420 PDT/...CONDITIONS WERE MUCH QUIETER THAN AT 21Z
FRIDAY... AND NEITHER NWS DOPPLER RADAR NOR LIGHTNING DATA INDICATED
ANY THUNDERSTORMS OVER THE SOUTHERN SIERRA NEVADA. ALSO AT 20Z
TODAY...TEMPERATURES ACROSS THE CENTRAL AND SOUTHERN SAN JOAQUIN
VALLEY WERE MOSTLY IN THE UPPER 70S TO MID 80S...AND WERE UP 2-4
DEGREES OVER 20Z FRIDAY. DESPITE THE WARMER TEMPERATURES...THE
MODELS HAD INDICATED THAT THERE WOULD BE LESS OMEGA /AN INDICATOR OF
LIFT IN THE ATMOSPHERE/ AND THIS WOULD RESULT IN GREATER STABILITY.
STILL CANNOT RULE OUT LATE AFTERNOON AND EARLY EVENING CONVECTION
OVER THE SOUTHERN SIERRA NEVADA HIGH COUNTRY...BUT EXPECT THIS WOULD
NOT BE AS WIDESPREAD OR STRONG AS FRIDAY/S THUNDERSTORMS. DID SCALE
BACK POPS FOR LATE THIS AFTERNOON AND EVENING...AND REMOVED MENTION
OF THUNDERSTORMS AFTER 03Z SUNDAY /2000 PDT THIS EVENING/.

THE MODELS ARE IN GOOD AGREEMENT WITH THE UPPER-LEVEL RIDGE
BUILDING INTO CALIFORNIA TONIGHT AS FRIDAY/S LOW MOVES INTO NEW
MEXICO. BY 00Z MONDAY /1700 PDT SUNDAY/...THE 500-MB 5760-METER
HEIGHT LINE IS FORECAST TO BE AS FAR NORTH AS THE CENTRAL SACRAMENTO
VALLEY...WITH THE 5820-METER HEIGHT LINE ALONG THE SOUTHERN
CALIFORNIA COAST. THESE HEIGHTS ARE NOT CONDUCIVE FOR PRECIPITATION
SO HAVE REMOVED MENTION OF THUNDERSTORMS FROM THE SOUTHERN SIERRA
NEVADA HIGH COUNTRY ON SUNDAY AND SUNDAY NIGHT.

THE GLOBAL-COMPOSITE WATER-VAPOR LOOP SHOWS THE NEXT UPPER-LEVEL LOW
LIFTING TO THE NORTHEAST OVER THE RIDGE...AND IS NOW JUST WEST OF
THE QUEEN CHARLOTTE ISLANDS. YET ANOTHER LOW...WHICH FORMED SOUTH OF
THE WESTERN TIP OF THE ALEUTIANS FRIDAY...HAD MOVED EASTWARD TO NEAR
46N/148W THIS AFTERNOON...WEST OF OREGON. THE TROUGH ASSOCIATED WITH
THE LOW WILL BRING THE NEXT CHANCE OF PRECIPITATION TO THE WFO
HANFORD WARNING/FORECAST AREA /CWFA/ MONDAY NIGHT AND TUESDAY.

THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH A SHARP DROP IN
850-MB TEMPERATURES OVER FRESNO TUESDAY MORNING...FALLING FROM
AROUND 16 C AT 00Z TUESDAY /1700 PDT MONDAY/ TO AROUND 4 C BY 00Z
WEDNESDAY /1100 PDT TUESDAY/...EXCEPT FOR THE NAM-12 WHICH DROPS THE
TEMPERATURE DOWN TO 2 C. THE SNOW LEVEL WILL FALL FROM AROUND 8000
FEET MONDAY NIGHT TO AROUND 5000 FEET NEAR YOSEMITE TUESDAY
NIGHT...RISING TO AROUND 7000 FEET IN THE TEHACHAPI MOUNTAINS.

THE COLD AIRMASS ALSO WILL BRING AN ABRUPT COOLING TO CENTRAL
CALIFORNIA...WITH CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY HIGHS
DROPPING FROM THE MID 80S TO AROUND 90 MONDAY TO THE LOWER TO MID
70S TUESDAY AND WEDNESDAY.

FOR THE SECOND CONSECUTIVE DAY...THE 12Z ECMWF HAS A STORM TOTAL QPF
OF UP TO A HALF INCH OVER THE SOUTHERN SIERRA NEVADA FROM THIS
STORM. THE 12Z GFS HAS A MORE NORTHERLY STORM TRACK...WITH THE
HEAVIEST PRECIPITATION NORTH OF THE WFO HANFORD COUNTY WARNING/
FORECAST AREA. THE HIGHEST QPF OVER THE SOUTHERN SIERRA NEVADA FROM
THE GFS IS ONLY AROUND A QUARTER OF AN INCH.

THE MAIN IMPACT OF THIS STORM WILL BE GUSTY WINDS OVER THE WEST SIDE
OF THE SAN JOAQUIN VALLEY AND ACROSS THE MOUNTAINS AND DESERTS OF
KERN COUNTY AS THE COLD FRONT PUSHES THROUGH. DEPENDING ON HOW MUCH
RAIN FALLS AHEAD OF THE FRONT...BLOWING DUST COULD BE A CONCERN.

ANOTHER RIDGE IS FORECAST TO BUILD INTO CALIFORNIA FOR NEXT
THURSDAY...BRINGING ANOTHER ROUND OF DRY AND WARMER WEATHER. HIGH
TEMPERATURES NEXT THURSDAY ARE FORECAST TO RECOVER TO NEAR NORMAL.
CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY HIGHS NEXT FRIDAY ARE
FORECAST TO WARM INTO THE UPPER 70S TO MID 80S...A FEW DEGREES ABOVE
THE NORMAL FOR LATE APRIL.

THE ECMWF BRINGS A LATE-WEEK UPPER-LEVEL TROUGH TO THE CALIFORNIA
COAST FRIDAY AND OVER CENTRAL CALIFORNIA FRIDAY NIGHT. THE GFS
BRINGS ITS TROUGH INTO CALIFORNIA DURING THE DAY SATURDAY. HAVE NOT
MADE ANY CHANGES TO THE FORECAST FOR DAYS 6-7 DUE TO THESE MODEL
DIFFERENCES.

&&

.AVIATION...
LOCAL MOUNTAIN OBSCURATIONS OVER THE SOUTHERN SIERRA NEVADA WITH
SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH 03Z SUNDAY. OTHERWISE...
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 HIGH.

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 04-19       93:2009     54:1967     64:1938     35:1955
KFAT 04-20       96:2009     53:1957     62:1989     36:1896
KFAT 04-21       98:2009     50:1900     64:2012     36:1968

KBFL 04-19       98:1910     54:1967     62:1938     38:1996
KBFL 04-20       98:1906     59:2007     64:1939     36:1904
KBFL 04-21       99:2009     57:2010     64:2009     33:1904

&&

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

&&

$$

PUBLIC...SANGER
AVN...SANGER
FW...MV
SYNOPSIS...WP

WEATHER.GOV/HANFORD





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