Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 281105 CCA
AFDHNX

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
305 AM PST SAT FEB 28 2015

.SYNOPSIS...
A PAIR OF STORM SYSTEMS TRACKING SOUTH INTO CENTRAL CALIFORNIA WILL
BRING COOL...WET WEATHER TO MUCH OF THE REGION THROUGH THE WEEKEND
AND INTO EARLY NEXT WEEK.

&&

.DISCUSSION...
SATELLITE LOOPS SHOW THE UPPER-LEVEL LOW OVER THE CALIFORNIA/OREGON
BORDER THIS MORNING AS IT CONTINUES TO SINK SOUTH TOWARD CENTRAL
CALIFORNIA. THE SCATTERED CONVECTION OF FRIDAY EVENING HAS TAPERED
OFF TO ISOLATED SHOWERS...AND DID GET ONE REPORT OF SMALL HAIL NEAR
BASS LAKE AROUND 10Z /0200 PST/.

THE LOW IS FORECAST TO DEEPEN AS IT REACHES THE MONTEREY BAY AREA
THIS AFTERNOON. EXPECT ANOTHER ROUND OF CONVECTION TO FIRE UP OVER
THE CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY WITH OROGRAPHIC FORCING
OVER THE TEMBLORS AND DIABLO RANGE...WITH THE CIRCULATION AROUND
THE LOW PUSHING CELLS EASTWARD ACROSS THE VALLEY FLOOR TOWARD THE
FOOTHILLS. WHILE MODEL QPF IS GENERALLY LIGHT...COULD SEE LOCALLY
HEAVY AMOUNTS UNDER THUNDERSTORMS. /ONE THUNDERSTORM THAT MOVED OVER
PORTERVILLE FRIDAY EVENING DROPPED 0.08 INCH OF RAIN IN 20 MINUTES./

CONCERNING THUNDERSTORMS...THE 06Z NAM-12 HAS WIDESPREAD SURFACE-
COMPUTED CAPES OF 200-400 JOULES/KG NORTH OF KERN COUNTY BY 21Z
/1300 PST/ THIS AFTERNOON...WITH SURFACE-COMPUTED SURFACE LIFTED
INDICES OF 0 TO -2. THERE IS ONE AREA WITH A CAPER OF 300
JOULES/KG AND LIFTED INDEX OF -3 OVER THE DIABLO RANGE WEST OF
COALINGA...AND THE NAM-12 MAY BE PICKING UP ON OROGRAPHIC FORCING
AS THE FLOW LIFTS OVER THE MOUNTAINS. 500-MB TEMPERATURES NORTH OF
KERN COUNTY ARE FORECAST TO BE -23 TO -28 C...AND 850-MB THETA-E
IS FORECAST TO BE 296 TO 301 K. WITH THESE PARAMETERS...DO NOT
EXPECT SEVERE THUNDERSTORMS. PEA-SIZE HAIL IS LIKELY WITH THESE
STORMS...AND CANNOT RULE OUT A FUNNEL CLOUD.

ONE CONCERN THIS MORNING IS THE START TIME OFF THE WINTER WEATHER
ADVISORY FOR THE KERN COUNTY MOUNTAINS...WHICH WAS ISSUED MAINLY FOR
THE IMPACT OF SNOW ON THE GRAPEVINE AND TEHACHAPI PASS. AT THIS TIME
ONLY LIGHT SNOW IS EXPECTED AT THE TOPS OF THE PASSES BEFORE 00Z
SUNDAY /1600 PST THIS AFTERNOON/...BUT SLIGHT CHANGES IN TIMING OR
THE TRAJECTORY OF THE LOW COULD BRING HEAVIER SNOW EARLIER IN THE
DAY. WITH THE LOW FORECAST TO BE OVER POINT CONCEPTION BY 06Z SUNDAY
/2200 PST TONIGHT/...WRAP-AROUND PRECIPITATION WILL BE LIFTED OVER
THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND WILL HAVE A
BETTER CHANCE TO BRING SIGNIFICANT SNOW TO THE GRAPEVINE AND THE
SAN EMIGDIO MOUNTAINS INCLUDING FRAZIER PARK AND PINE MOUNTAIN
CLUB.

A SECOND LOW IS DROPPING DOWN THE COAST FOLLOWING A SIMILAR
TRAJECTORY TO THE FIRST SYSTEM. THIS LATER LOW IS FORECAST TO BE
OVER THE MONTEREY BAY AREA AROUND 00Z TUESDAY /1600 PST MONDAY/ AND
WILL BRING ANOTHER ROUND OF RAIN AND MOUNTAIN SNOW TO THE REGION.
THIS SYSTEM IS FORECAST TO MOVE OVER THE LOWER COLORADO RIVER BY 00Z
WEDNESDAY...ENDING THE PRECIPITATION OVER THE CENTRAL CALIFORNIA
INTERIOR.

AN AMPLIFYING UPPER-LEVEL EAST-PACIFIC RIDGE IS FORECAST TO BUILD
INTO CALIFORNIA TUESDAY NIGHT/WEDNESDAY. AS THE RIDGE MOVES OVER THE
SAN JOAQUIN VALLEY...COULD SEE PATCHY FOG DEVELOP AS THE INVERSION
FORMS OVER THE VALLEY FLOOR. THIS IS NOT UNEXPECTED AS HISTORICALLY
THE TULE FOG SEASON CAN RUN INTO THE FIRST WEEK OF MARCH.

&&

.AVIATION...OVER THE SOUTHERN SIERRA NEVADA...WIDESPREAD IFR AND
MOUNTAIN OBSCURATIONS IN SHOWERS. AREAS OF MVFR CEILINGS CAN BE
EXPECTED IN THE SIERRA FOOTHILLS AND ALONG THE NORTH FACING SLOPES
OF THE TEHACHAPI MOUNTAINS. LOCAL MVFR IS POSSIBLE IN HEAVIER
SHOWERS IN THE SAN JOAQUIN VALLEY. ADDITIONALLY...WIND GUSTS OF 30
KNOTS OR GREATER WILL OCCUR IN THE KERN COUNTY MOUNTAINS AND DESERT
THROUGH 06Z SUNDAY. VFR CONDITIONS CAN BE EXPECTED ELSEWHERE OVER
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 02-28       79:1926     51:1971     59:1986     28:1962
KFAT 03-01       79:1975     50:1951     59:1986     28:1888
KFAT 03-02       82:1921     48:1976     57:1986     26:1953

KBFL 02-28       81:1926     49:1945     56:1968     22:1893
KBFL 03-01       86:2009     48:1919     59:1920     26:1907
KBFL 03-02       87:1926     50:1919     57:2009     28:1907

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING ABOVE 4000
FEET FOR THE SOUTHERN SIERRA NEVADA FROM YOSEMITE NATIONAL PARK TO
THE KERN COUNTY LINE /CAZ096-097/.

WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM PST
MONDAY FOR THE KERN COUNTY MOUNTAINS /CAZ095/.

WIND ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR THE KERN COUNTY
MOUNTAINS AND DESERT AND THE INDIAN WELLS VALLEY /CAZ095-098-099/.

&&

$$

PUBLIC...SANGER
AVN/FW...DCH
SYNOPSIS...SANGER

WEATHER.GOV/HANFORD


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