Dense Fog in California, February 1 to 5, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
210 AM PST FRI FEB 1 2013

.SYNOPSIS...
LITTLE CHANGE IS EXPECTED AS HIGH PRESSURE WILL CONTINUE TO
DOMINATE THE LOCAL WEATHER INTO THE FIRST PART OF NEXT WEEK. PATCHY
NIGHT AND MORNING FOG IN THE SAN JOAQUIN VALLEY IS POSSIBLE THROUGH
THE WEEKEND.

&&

.DISCUSSION...
AT 09Z /0100 PST/ THIS MORNING...SATELLITE LOOPS INDICATED THAT THE
CENTRAL CALIFORNIA INTERIOR REMAINED UNDER THE INFLUENCE OF AN
UPPER-LEVEL EAST-PACIFIC RIDGE. TEMPERATURES THURSDAY WERE A BIT
WARMER THAN FORECAST...AND CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY
TEMPERATURES AT 09Z WERE AS MUCH AS 6 DEGREES WARMER THAN AT 09Z
THURSDAY...AND DEWPOINTS WERE UP AS MUCH AS 4 DEGREES. AS A
RESULT...EXPECT HIGH TEMPERATURES TODAY TO BE AT LEAST A COUPLE OF
DEGREES WARMER THAN THURSDAY.

THE MODELS FORECAST AN UPPER-LEVEL LOW TO DEVELOP SATURDAY WEST OF
BAJA CALIFORNIA AS AN EAST-PACIFIC TROUGH SPLITS. THIS LOW IS
FORECAST TO SPIN SOME UPPER-LEVEL MOISTURE INTO THE CENTRAL
CALIFORNIA INTERIOR FROM THE SOUTH...SO HAVE INCREASED SKY COVER
OVER THE WEEKEND BECAUSE OF THE INFLUX OF CIRRUS.

THE NORTHERN COMPONENT OF THE TROUGH IS FORECAST TO MOVE THROUGH THE
PACIFIC NORTHWEST OVER THE WEEKEND AS AN UPPER-LEVEL SHORT-WAVE. THIS
SHORT-WAVE WILL FLATTEN THE RIDGE...RESULTING IN MINOR COOLING SUNDAY
BEFORE THE RIDGE REBOUNDS MONDAY.

ANOTHER UPPER-LEVEL TROUGH WILL MOVE THROUGH NORTHERN CALIFORNIA
TUESDAY NIGHT AND WEDNESDAY. THIS TROUGH WILL WEAKEN THE RIDGE AND
BRING A SLIGHT CHANCE OF SNOW TO THE HIGHER ELEVATIONS OF THE
SOUTHERN SIERRA NEVADA. THIS WILL BE A PRECURSOR SYSTEM TO A
STRONGER TROUGH THAT WILL REACH CALIFORNIA NEXT THURSDAY.

ALTHOUGH THE LATEST MODEL RUNS HAVE DELAYED THE ARRIVAL OF THE MAIN
TROUGH A BIT...THEY STILL FORECAST THIS TO BE A COLD STORM WITH
850-MB TEMPERATURES OVER FRESNO FALLING AS MUCH AS 12 C FROM 18Z
/1000 PST/ THURSDAY TO 18Z FRIDAY. THE GFS AND ECMWF DO DIFFER A BIT
ON TIMING AND THE ECMWF DIGS THE PRECIPITATION FURTHER SOUTH...ACROSS
THE ENTIRE HANFORD WARNING/FORECAST AREA...THAN THE GFS /WHICH KEEPS
PRECIPITATION NORTH OF KERN COUNTY/. HOWEVER...THE CONSENSUS IS
DEVELOPING THAT THIS COULD BE A SIGNIFICANT PRECIPITATION EVENT WITH
RAINFALL AMOUNTS BETWEEN 0.25 AND 0.50 INCH ON PARTS OF THE SAN
JOAQUIN VALLEY FLOOR..AND POSSIBLY DROPPING SNOW ON THE PASSES
THROUGH THE KERN COUNTY MOUNTAINS FRIDAY.

NOTE...ALTHOUGH SATURDAY...FEBRUARY 2ND...IS GROUNDHOG DAY...WINTER
       WILL NOT END UNTIL 0402 PDT /1102Z/ ON MARCH 20TH.

&&

.AVIATION...
IN THE SAN JOAQUIN VALLEY...LOCAL IFR/LIFR DUE TO FOG UNTIL 16Z
TODAY AND AGAIN AFTER 08Z SATURDAY. OTHERWISE...VFR WITH AREAS
OF MVFR IN HAZE THROUGH 12Z SATURDAY.  VFR CONDITIONS CAN BE
EXPECTED ELSEWHERE ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH
12Z SATURDAY.

&&

.AIR QUALITY ISSUES...
ON FRIDAY FEBRUARY 1 2013...FIREPLACE/WOOD STOVE BURNING IS
PROHIBITED IN FRESNO...KERN AND KINGS COUNTIES.
FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG

&&

.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 02-01       73:1991     43:1939     54:1905     25:1950
KFAT 02-02       74:1928     44:1903     57:1907     26:1950
KFAT 02-03       77:2000     46:1989     50:1995     25:1957

KBFL 02-01       76:1928     45:1965     55:1963     24:1902
KBFL 02-02       80:1928     44:1971     61:1958     23:1893
KBFL 02-03       79:2009     48:1980     59:1973     25:1923

&&

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

&&

PUBLIC...SANGER
AVN/FW...DURFEE
SYNOPSIS...WP

WEATHER.GOV/HANFORD