Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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000
FXUS66 KHNX 170945
AFDHNX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
245 AM PDT WED SEP 17 2014

.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL GIVE WAY TO AN APPROACHING LOW
PRESSURE SYSTEM. TEMPERATURES WILL FALL TO NEAR NORMAL TODAY...AND
TO BELOW NORMAL FOR THE LATTER PART OF THE WEEK. THERE WILL BE A
SLIGHT CHANCE OF MOUNTAIN AND DESERT THUNDERSTORMS TODAY THROUGH
FRIDAY.

&&

.DISCUSSION...
DESPITE SATELLITE LOOPS SHOWING A WELL-MIXED MARINE LAYER ALONG THE
COAST TUESDAY MORNING...THE PUSH OF MARINE AIR UP THE SAN JOAQUIN
VALLEY TUESDAY KEPT CENTRAL AND SOUTH VALLEY HIGH TEMPERATURES IN
THE MID TO UPPER 90S /EXCEPT FOR COALINGA AT 101/.

THUNDERSTORMS DEVELOPED OVER SOUTHERN CALIFORNIA AND CAME CLOSE TO
THE KERN COUNTY BORDERS WITH LOS ANGELES AND SAN BERNARDINO
COUNTIES...BUT LIGHTNING WAS NOT REPORTED WITHIN KERN COUNTY.
OUTFLOW WINDS FROM COLLAPSING THUNDERSTORMS DID...HOWEVER...TRIGGER
A FEW SHOWERS OVER THE SOUTHEASTERN KERN COUNTY DESERT.

THE REMNANT LOW FROM FORMER HURRICANE ODILE...NEAR THE ARIZONA-
MEXICO BORDER...UNDERCUT THE RIDGE AND ALLOWED THE UPPER-LEVEL
TROUGH TO DROP INTO THE NORTHERN HALF OF CALIFORNIA. THIS TROUGH
WILL PROVIDE SYNOPTIC COOLING FOR THE REGION TODAY...WITH HIGH
TEMPERATURES A FEW DEGREES COOLER THAN TUESDAY.

THE TROUGH WILL CONTINUE TO DROP SLOWLY SOUTHWARD THROUGH THE REST
OF THE WEEK. THE MODELS STILL FORECAST A LOW TO CLOSE IN THE BASE OF
THE TROUGH...BUT NOW PUSH THE LOW SOUTHWEST INTO THE PACIFIC FRIDAY
RATHER THAN DROPPING IT TO OVER FRESNO.

THE FORECAST CONCERNS THE NEXT FEW DAYS WILL BE MOISTURE FROM ODILE
COMING UP FROM THE SOUTHEAST...AND MOISTURE ASSOCIATED WITH THE
TROUGH AS IT DROPS SOUTH INTO THE REGION.

THE NAM-12 HAS THE GREATEST LAYER RELATIVE HUMIDITIES OVER
SOUTHWESTERN SAN BERNARDINO COUNTY TODAY...STAYING SOUTH AND EAST OF
KERN COUNTY. EXPECT MOSTLY LIGHT SHOWERS THIS AFTERNOON AND
EVENING...ALTHOUGH WITH A TROPICAL AIRMASS ISOLATED HEAVIER RAINFALL
REMAINS A POSSIBILITY.

THE SOUTHWEST FLOW ALONG THE LEADING EDGE OF THE TROUGH IS FORECAST
TO BRING DRIER MID-LEVEL AIR INTO CENTRAL CALIFORNIA THURSDAY. THIS
WILL KEEP THE THREAT OF SHOWERS AND THUNDERSTORMS CONFINED TO THE
SOUTHERN SIERRA NEVADA. CHANCES FOR CONVECTION INCREASE FRIDAY
AFTERNOON AND EVENING AS THE LOW CLOSES OFF AND WRAPS MOISTURE OVER
THE SOUTHERN SIERRA NEVADA FROM THE SOUTHEAST. THIS WOULD TRIGGER
THUNDERSTORMS OVER THE EASTERN SLOPES OF THE SOUTHERN SIERRA NEVADA
WITH STORMS CARRIED WESTWARD OVER THE CREST AND POSSIBLY EVEN AS FAR
WEST AS THE SIERRA FOOTHILLS.

THE NAM-12 DOES BRING A NARROW BAND OF MID-LEVEL MOISTURE INTO THE
NORTHERN HALF OF THE FORECAST AREA THURSDAY AS THE COLD FRONT
ARRIVES. ALTHOUGH THE HIGHEST MOISTURE AMOUNTS ARE FORECAST TO
STAY NORTH OF FRESNO...AND MOSTLY NORTH OF MERCED...AN ISOLATED
SHOWER OR TWO OVER MERCED AND MARIPOSA COUNTIES CANNOT BE RULED
OUT DURING THE DAY THURSDAY.

ONE CHANGE IN THE MODELS SINCE TUESDAY MORNING IS THAT THE LATEST
RUNS NOW BRING THE CLOSED LOW EASTWARD INTO THE SAN JOAQUIN VALLEY
SATURDAY AFTERNOON AND EVENING. THIS WILL KEEP A THREAT OF
THUNDERSTORMS OVER THE SIERRA NEVADA HIGH COUNTY THROUGH THE WEEKEND.

TEMPERATURES ARE FORECAST TO COOL THROUGH THE END OF THE WEEK...WITH
850-MB TEMPERATURES OVER THE CENTRAL VALLEY FALLING INTO THE TEENS
CELSIUS BY THURSDAY AFTERNOON. CENTRAL AND SOUTHERN SAN JOAQUIN
VALLEY HIGHS THURSDAY WILL BE IN THE MID 80S TO AROUND 90...AND WILL
BE A DEGREE OR TWO COLDER FRIDAY. TEMPERATURES ARE THEN FORECAST TO
WARM A FEW DEGREES EACH DAY...REACHING THE MID TO UPPER 90S BY NEXT
TUESDAY.

THERE ARE SIGNIFICANT DIFFERENCES BETWEEN THE GFS AND THE ECMWF BY
THE MIDDLE OF NEXT WEEK. THE GFS HAS AN UPPER-LEVEL RIDGE OVER
CALIFORNIA...WHILE THE ECMWF HAS A TROUGH MOVING INTO THE PACIFIC
NORTHWEST AND NORTHERN CALIFORNIA. GIVEN THIS UNCERTAINTY...HAVE
GONE WITH PERSISTENCE FOR DAY 8 OF THE FORECAST PERIOD.

&&

.AVIATION...
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 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 09-17      105:1979     73:1950     74:1984     48:1965
KFAT 09-18      107:1913     67:1963     78:1984     48:1978
KFAT 09-19      105:1922     70:1989     75:1984     44:1978

KBFL 09-17      108:1913     74:1993     76:1979     45:1915
KBFL 09-18      104:1913     69:1967     73:1984     45:1908
KBFL 09-19      104:1939     69:1989     73:2009     39:1908

&&

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

&&

$$

PUBLIC...SANGER
AVN/FW...DS
SYNOPSIS...SANGER

WEATHER.GOV/HANFORD


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