Damaging Wind and Lightning Strikes in California, August 20, 2003

INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION...RETRANSMIT ONLY
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
200 PM PDT WED AUG 20 2003

KHNX 88D INDICATING CONVECTION BEGINNING NEAR THE SIERRA CREST. 18Z
MESO IS STRONGER WITH CAPES OVER THE MOUNTAINS AND KERN DESERTS THAN
PREVIOUS MODEL RUNS. INSTABILITY IS ALSO MORE PRONOUNCED WITH THE 18Z
MESO AS LI/S ACROSS THE MOUNTAINS AND KERN DESERTS ARE PROGGED TO BE
IN THE -1 TO -4 RANGE. THUNDERSTORMS HAVE ALREADY BEEN GOING ON FOR
THE PAST COUPLE OF HOURS OVER SOUTHERN SAN BERNARDINO COUNTY...AND WV
LOOP INDICATING ADDITIONAL MOISTURE IS ON IT/S WAY FROM THE
SOUTHEAST...SO WILL KEEP MENTION OF ISOLATED TO SCATTERED T-STORMS
ACROSS THE HIGHER ELEVATIONS FOR TONIGHT. THE OFFSHORE CUTOFF LOW
WHICH HAS BEEN OUR MAIN WEATHER FEATURE...HAS ACTUALLY BEEN
RETROGRADING TODAY...WHICH IS NOTHING NEW AS THE 12Z AND 18Z MESO...
AS WELL AS THE 12Z GFS...HAVE BEEN INDICATING THIS HAPPENING. THE LOW
IS EXPECTED TO MAKE AN EASTWARD TURN THURSDAY AS IT GETS SCOOPED UP
BY AN OPEN WAVE TROUGH WHICH WILL TURN THE UPPER FLOW OVER CENTRAL CA
TO THE SOUTH THEN TO THE SOUTHWEST. THE TIMING OF THIS TAKING PLACE
WILL BE CRITICAL IN TERMS OF CONVECTIVE DEVELOPMENT THURSDAY. AT THIS
TIME WITH CONFIDENCE LOW...WILL KEEP MENTION OF ISOLATED TO SCATTERED
POPS ACROSS THE ENTIRE CWFA THURSDAY...IN CASE OF A SLOWER TIMING.
TEMPERATURES THURSDAY WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF CLOUD
COVER THAT SPREADS ACROSS THE AREA. COMPROMISED BETWEEN MET AND MAV
TEMPERATURE GUIDANCE. AS THE TROUGH SWINGS BY ACROSS NORCAL FRIDAY...
EXPECT SURFACE P-GRADS TO STRENGTHEN ENOUGH TO ALLOW FOR SOME MARINE
AIR TO SPILL INTO THE SAN JOAQUIN VALLEY. MEANWHILE...HIGHER
ELEVATIONS WILL BEGIN TO WARM UP AS SKIES CLEAR OUT. HIGH PRESSURE IS
EXPECTED TO BUILD INTO CENTRAL CA FROM THE DESERTS SOUTHWEST FRIDAY
NIGHT AND SATURDAY FOR MOSTLY CLEAR SKIES AND A DRYING TREND.

IN THE EXTENDED-FORECAST PERIOD...SUNDAY THROUGH WEDNESDAY...THE
MEDIUM-RANGE MODELS ARE IN GENERAL AGREEMENT WITH A WEAK SHORT-WAVE
TROUGH MOVING INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK...ALTHOUGH
THERE ARE MINOR TIMING DIFFERENCES. THE TROUGH WILL HAVE LITTLE
IMPACT ON THE STRONG UPPER-LEVEL RIDGE OVER MUCH OF THE CONTINENTAL
UNITED STATES. 500-MB HEIGHTS ARE FORECAST TO REMAIN ABOVE 5880
METERS THROUGH THE PERIOD...WITH DRY WEATHER AND ABOVE-NORMAL HIGH
TEMPERATURES. BY MIDWEEK...THE GFS HAS A STRONGER SHORT-WAVE TROUGH
DROPPING OUT OF THE GULF OF ALASKA INTO THE PACIFIC NORTHWEST. THIS
TROUGH IS FORECAST TO WEAKEN THE RIDGE FOR THE LATTER HALF OF THE
WEEK.

THE GFS FORECASTS SOME HIGH-LEVEL MOISTURE TO WRAP AROUND THE RIDGE
INTO SOUTHERN CALIFORNIA BEGINNING TUESDAY...SO HAVE INCREASED CLOUD
COVER OVER THE MOUNTAINS AND DESERTS FOR SOME CIRRUS PER NEIGHBORING
OFFICES.

.HNX...NONE.

DS/SANGER

CAZ089>099-211230-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HANFORD CA
530 AM PDT WED AUG 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL CALIFORNIA
INTERIOR.

.DAY ONE...TODAY.

THERE IS A CHANCE OF THUNDERSTORMS IN THE AFTERNOON AND A SLIGHT
CHANCE IN THE EVENING FOR THE SIERRA NEVADA FROM YOSEMITE TO KINGS
CANYON...FOR THE TULARE COUNTY MOUNTAINS...FOR THE KERN COUNTY
MOUNTAINS AND THE SOUTHEASTERN KERN COUNTY DESERT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

A SLIGHT CHANCE OF THUNDERSTORMS ARE FORECAST...FOR THURSDAY FOR THE
SAN JOAQUIN VALLEY, THE FRESNO COUNTY AND TULARE COUNTY FOOTHILLS,
THE KERN COUNTY MOUNTAINS AND THE KERN COUNTY DESERT...THERE IS A
CHANCE FOR THUNDERSTORMS...FOR THURSDAY FOR THE SIERRA NEVADA FROM
YOSEMITE TO KINGS CANYON, THE TULARE COUNTY MOUNTAINS AND THE
SOUTHEASTERN KERN COUNTY DESERT.

.SPOTTER INFORMATION STATEMENT...

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