Flash Flood in California, August 2, 2003

INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
205 PM PDT SAT AUG 2 2003

CONVECTION WAS CONTINUING THIS AFTERNOON...HOWEVER STRONGER DYNAMICS
WERE MOVING EAST INTO THE SIERRA AS ELONGATED VORT AXIS APPROACHES
THE SJ VALLEY. THUNDERSTORMS HAVE PRODUCED IMPRESSIVE PRECIP TOTALS
IN SEVERAL LOCATIONS...AND A PUBLIC INFORMATION STATEMENT WAS ISSUED
THIS MORNING TO SUMMARIZE SOME 24 HOUR AMOUNTS. REFER TO PNSHNX /WMO
HEADER NOUS46 KHNX/...OR THE CLIMATOLOGY SECTION OF THE NWS HANFORD
OFFICE WEBSITE...FOR DETAILS.

OTHERWISE WITH UPSTREAM DEFORMATION ZONE STILL APPROACHING THE COAST
...AND WITH X-SECTIONS PROJECTING WEAK H7-H5 UVM EARLY THIS EVE...
WILL KEEP POPS UNTIL VORT AND DEF AXIS SHIFT EAST OF THE CWA AROUND
06Z. WITH 18Z KEDW RAOB ALSO SHOWING PWS STILL IN EXCESS OF ONE INCH
...WILL ALSO MAINTAIN FLASH FLOOD WATCH FOR SIERRA ZONES FROM
YOSEMITE TO KINGS CANYON...AND FOR THE ADJACENT FOOTHILLS.

FLOW ALOFT HAS BEGUN VEERING SW THIS AFTERNOON...AND WILL STRENGTHEN
OVERNIGHT AS UPPER LOW MOVES E-NE FROM 34N/135W. SW FLOW WILL
PREVAIL THRU TUES AS LOW LIFTS SLOWLY NE TOWARD THE CA/OR COAST.
PROJECTED TEMPS ALOFT/THICKNESSES WILL SUPPORT SURFACE MAXES NEAR
SEASONAL LEVELS ACROSS THE HIGHER ELEVS. HOWEVER TEMPS SHOULD FALL
BELOW SEASONAL NORMALS IN THE SJ VALLEY AND ADJACENT FOOTHILLS AS
STRENGTHENING ONSHORE GRADS SUPPORT A GOOD MARINE INTRUSION INTO THE
VALLEY. GRADS SHOULD ALSO SUPPORT BREEZY TO WINDY CONDITIONS IN THE
KERN MTNS/DESERTS.

IN THE EXTENDED PERIOD...WED THRU SAT...MEDIUM RANGE MODELS IN GOOD
AGREEMENT AND POSITION CENTER OF CLOSED LOW OFF THE PAC NW COAST ON
DAY 4 AND 5 WITH ELONGATED TROUGH EXTENDING SOUTHWARD ALONG 135W.
MEANWHILE...UPPER LEVEL RIDGE AXIS SITUATED ALONG THE CONTINENTAL
DIVIDE. HEALTHY ONSHORE GRADIENTS WED THRU THU WILL BRING COOL MARINE
ENFORCEMENTS INTO THE SJ VLY AS BRISK WINDS BLOW THRU PACHECO PASS
AND COTTONWOOD PASS ON THE WEST SIDE. GUSTY WEST WINDS LIKELY TO
OCCUR BELOW THE KERN CO MTN PASSES AS WELL. AFTER THURSDAY...THE GFS
MODEL FORECASTS THE UPPER LEVEL RIDGE TO BUILD WESTWARD INTO CA.
WITH MODEST RISES IN HEIGHTS...THICKNESSES...AND 850 MB TEMPS
FORECAST BY THE GFS MODEL DURING THE FRI-SAT TIME PERIOD...EXPECT A
DECENT WARMUP BY THE END OF THE WORK WEEK WITH A CONTINUED UPWARD
TREND OF TEMPERATURES SATURDAY...ESP OVER THE HIER TERRAIN AND
DESERT.

.HNX...FLASH FLOOD WATCH FOR THE SOUTHERN SIERRA NEVADA FROM
       YOSEMITE TO KINGS CANYON UNTIL 900 PM.
    ...FLASH FLOOD WATCH FOR THE MARIPOSA...MADERA...AND
       FRESNO COUNTY FOOTHILLS UNTIL 900 PM.

JSN/DURFEE

CAZ089>099-031230-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
405 PM PDT SAT AUG 2 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL CALIFORNIA
INTERIOR.

.DAY ONE...TODAY

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE SOUTHERN
SIERRA NEVADA THIS EVENING. THUNDERSTORMS WILL CONTAIN HEAVY RAIN...
GUSTY WINDS...AND FREQUENT LIGHTNING. A FLASH FLOOD WATCH IS IN
EFFECT FOR THE SOUTHERN SIERRA NEVADA FROM YOSEMITE TO THE KERN
COUNTY LINE...AND ADJACENT FOOTHILLS...UNTIL 900 PM. REFER TO FFAHNX
/WGUS66 KHNX/ AND FLSHNX /WGUS86 KHNX/ FOR DETAILS.

THERE IS ALSO A SLIGHT CHANCE OF EVENING THUNDERSTORMS IN THE CENTRAL
AND SOUTHERN SAN JOAQUIN VALLEY...AS WELL AS THE KERN COUNTY
MOUNTAINS AND DESERTS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE.

JSN