Severe Thunderstorm Warning 18, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
250 PM PDT SAT AUG 16 2003

.SYNOPSIS...A LOW PRESSURE SYSTEM MOVING INTO ARIZONA WILL COMBINE
WITH A MOIST AND UNSTABLE AIR MASS TO PRODUCE SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF THE REGION TODAY.  THE LOW WILL BEGIN
TO MOVE NORTHEAST SUNDAY WITH SOMEWHAT DRIER AIR MOVING IN FROM THE
WEST.
&&

.SHORT TERM...AIRMASS ACROSS THE EASTERN PORTION OF THE FORECAST
AREA STILL MOIST AND UNSTABLE. SATELLITE SHOWS PRECIPITABLE WATER
VALUES BETWEEN 1 AND 1.5 INCHES WITH LIFTED INDICES -1 TO -3. ONLY
PROBLEM HAS BEEN LACK OF A KICKER. THUNDERSTORMS FORMED ACROSS
NORTHERN NYE COUNTY AND ARE NOW MOVING SOUTH. THIS AREA/LINE OF
STORMS WILL MOVE SOUTH AT LEAST THROUGH LINCOLN COUNTY DURING THE
AFTERNOON AND PERHAPS FARTHER SOUTH THIS EVENING. EVEN IF THESE
STORMS DIE OFF...OUTFLOW MAY PROVIDE SOME LIFT SOUTH SO WILL HOLD
ONTO THE FLASH FLOOD WATCH THROUGH 1000 PM FOR THE EASTERN ZONES.
WILL ALSO HAVE TO INCLUDE A CHANCE OF THUNDERSTORMS THIS EVENING
OVER THE SIERRA. MODELS DIFFER FOR MONDAY THROUGH TUESDAY WITH GFS
PUSHING THE MOISTURE AND INSTABILITY FARTHER EAST THAN THE ETA WHICH
KEEPS MOISTURE AND INSTABILITY BACK OVER CLARK COUNTY INTO SAN
BERNARDINO COUNTY. NEITHER MODEL SEEMS CORRECT AND WILL GENERALLY GO
WITH SOME SORT OF COMPROMISE AND LEAVE A SLIGHT CHANCE OF
THUNDERSTORMS IN MOHAVE COUNTY MONDAY AND TUESDAY
AFTERNOONS/EVENINGS.

&&

.LONG TERM...WEDNESDAY THROUGH FRIDAY SHOULD SEE DRYING UNDER
SOUTHWEST FLOW. HOWEVER...THE GFS WANTS TO HINT AT RETURN FLOW UP
THE COLORADO RIVER VALLEY FROM THURSDAY ON. MOISTURE DOES NOT APPEAR
TO MAKE IT INTO OUR AREA UNTIL SATURDAY AND THAT IS A STRETCH. HAVE
INTRODUCED SLIGHT CHANCE POPS IN MOHAVE LINCOLN AND NORTHERN NYE
COUNTY FOR SATURDAY. HAVE ALSO LOWER TEMPERATURES A BIT DAY 7 TO
REFLECT INCREASED MOISTURE.

&&

.LAS...A FLASH FLOOD WATCH CONTINUES FOR LINCOLN AND EASTERN CLARK
COUNTIES IN NEVADA AND MOHAVE COUNTY IN ARIZONA UNTIL 1000 PM.
&&

HARRISON/JACQUES

AZZ001>003-036-CAZ026>029-NVZ013>022-171300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
555 AM PDT SAT AUG 16 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST CALIFORNIA/SOUTHERN
NEVADA/NORTHWEST ARIZONA

.DAY ONE...TODAY
A LOW PRESSURE SYSTEM MOVING EAST INTO ARIZONA TODAY WILL COMBINE
WITH A MOIST AND UNSTABLE AIR MASS TO PRODUCE SCATTERED
THUNDERSTORMS...WITH HEAVY RAIN POSSIBLE SOUTHERN NEVADA AND
NORTHWEST ARIZONA. A FLASH FLOOD WATCH IS IN EFFECT FOR LINCOLN AND
EASTERN CLARK COUNTIES IN NEVADA AND MOHAVE COUNTY ARIZONA FROM NOON
UNTIL 10 PM.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
SCATTERED SHOWERS AND THUNDERSTORMS WILL DIMINISH OVER MUCH OF
SOUTHERN NEVADA WITH THE BEST CHANCE REMAINING OVER NORTHWEST
ARIZONA SUNDAY AS A LOW PRESSURE SYSTEM MOVES INTO UTAH. THE THREAT
OF HEAVY RAIN WITH SOME STORMS MAY STILL EXIST ACROSS NORTHWEST
ARIZONA. DRIER FLOW WILL SPREAD OVER THE REGION MONDAY THROUGH
THURSDAY FOR A DIMINISHING THREAT OF THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN ACTIVATION IS NOT ANTICIPATED BUT WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO
STANDARD OPERATING PROCEDURES.