Flash Flood Warning 22, NWS Las Vegas, NV

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
300 PM PDT FRI JUL 24 1998

SYNOPSIS...MONSOONAL MOISTURE THAT HAS BEEN ACROSS THE MOJAVE DESERT
AND SOUTHERN GREAT BASIN WILL GRADUALLY DIMINISH OVER THE WEEKEND.
THIS WILL RESULT IN A DECREASING THREAT OF THUNDERSTORMS AND A SLIGHT
WARMING TREND.

DISCUSSION...THUNDERSTORMS DEVELOPING ON SCHEDULE MAINLY N OF TPH-
LAS-IGM LINE. CELLS BECOMING MOST NUMEROUS ACROSS ESMERALDA...NRN NYE
AND NRN LINCOLN COUNTY IN ADVANCE OF SHORTWAVE SEEN ON WATER VAPOR
IMAGERY MOVING N NEAR CA/NV BORDER. THIS AREA LIKELY HAS THE BEST
CHANCE FOR ORGANIZED THUNDERSTORMS AND WITH OUTFLOW BOUNDARY
INTERACTION WILL LIKELY SEE ADDITIONAL STORMS FIRE TO THE S. WILL
CONTINUE FLASH FLOOD WATCH ZONES 13/14/15. ISOLATED THUNDERSTORMS
VICINITY CLARK CO NV DEVELOPING BOTH OVER THE MOUNTAINS AND ON VALLEY
CONVERGENCE ZONE NOTED IN ALERT GAGE WIND DATA (SEE LAS WEB SITE FOR
DOCUMENTATION). STORMS TO MOVE THROUGH PARTS OF LAS VALLEY AS THEY
CONTINUE TO DEVELOP AND MOVE NE.  ELSEWHERE...DRY TONGUE BEHIND
SHORTWAVE EVIDENT OVER SRN CA AND SW AZ WITH SUBSIDENCE HELPING TO
CAP AND/OR STABILIZE ATMOSPHERE.

IN GENERAL USING A BLEND OF MODELS FOR FORECAST WITH MID/UPPER LEVEL
RIDGE OVER NW MEXICO HANDLED VERY DIFFERENTLY DEPENDING ON THE MODEL.
AVN/NGM BUILD CENTER OF HIGH INTO NRN BAJA/SRN CA PRODUCING A DEEP NW
FLOW ALOFT. BOTH MODELS ALSO QUICKLY DRY OUT ATMOSPHERE AS A RESULT.
PREFER SLOWER MORE MODEST DRYING ON ETA AS LOW LEVEL MOISTURE NOT
LIKELY TO BE SCOURED OUT. GENERALLY FORECASTING A CONTINUED
DECREASING TREND IN THUNDERSTORMS WITH HIGHEST CHANCES ACROSS SOUTH
CENTRAL NV ZONES AS DEEPER MOISTURE REMAINS IN PLACE.  WITH SLOW
DRYING TEMPERATURES WILL REBOUND BUT AGAIN NOT AS QUICKLY AS NGM/AVN
MOS GUIDANCE SUGGESTS. FOR SRN NV EXTENDED...CONTINUING A LOW END
MONSOON FORECAST WITH SLIGHT CHANCE AFT/EVE THUNDERSTORMS OVER
MOUNTAINS.  MRF NOTORIOUS FOR MISSING SW MONSOON MOISTURE AND
POSITION OF UPPER HIGH WOULD LEAVE THE DOOR OPEN FOR POSSIBLE
MOISTURE SURGES. LAS 2100. NEMETH

AZZ001>003-036-CAZ026>029-NVZ016>022-242245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1045 AM PDT (1045 AM MST) FRI JUL 24 1998

...ISOLATED THUNDERSTORMS EXPECTED ACROSS THE MOJAVE DESERT
TODAY....

MOISTURE HAS BEGUN TO DECREASE ACROSS THE MOJAVE DESERT SINCE
THURSDAY...REDUCING THE THREAT OF SCATTERED THUNDERSTORMS.
HOWEVER...ENOUGH MOISTURE REMAINS IN PLACE SO THAT ISOLATED SHOWERS
AND THUNDERSTORMS ARE STILL POSSIBLE THIS AFTERNOON AND EVENING.
ANY THUNDERSTORMS THAT DO FORM WILL BE CAPABLE OF PRODUCING LOCALLY
HEAVY RAIN AND STRONG WIND GUSTS.

BECAUSE THE THUNDERSTORMS ARE EXPECTED TO BE ISOLATED IN COVERAGE...A
FLASH FLOOD WATCH HAS NOT BEEN ISSUED FOR THE AREA.  THIS DOES NOT
MEAN THAT INDIVIDUAL STORMS WILL NOT PRODUCE HEAVY RAIN. RATHER...
THE POTENTIAL FOR WIDESPREAD FLASH FLOODING OVER THE GENERAL AREA IS
NOT AS HIGH AS THE PAST SEVERAL DAYS.

REMAIN ALERT FOR ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING...
ESPECIALLY IF YOU WILL BE CAMPING OR HIKING IN THE MOUNTAINS AND
CANYONS.

NEMETH