Flash Flood Warning 40, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1010 AM PDT WED AUG 3 2005

.SYNOPSIS...HIGH PRESSURE TO THE EAST OF THE SOUTHERN GREAT BASIN
AND MOHAVE DESERT WILL CONTINUE TO KEEP MOIST AND UNSTABLE
CONDITIONS ACROSS THE REGION. THIS WILL RESULT IN SCATTERED
AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE AREA INTO THE END OF
THE WEEK.
&&

.UPDATE...THUNDERSTORMS FROM LAST NIGHTS STORMS PRODUCED A FAIRLY
WIDE AREA OF DEBRIS CLOUDS OVER MOHAVE/EASTERN SAN BERNARDINO/CLARK
COUNTIES THIS MORNING. CLOUDS DISSIPATING ATTM...HOWEVER INITIAL
HEATING TEMPERED THUS WILL LIKELY DELAY ONSET OF THUNDERSTORMS UNTIL
LATER IN THE AFTERNOON THIS AREA. DRY LINE STILL SEEN ON WATER VAPOR
FROM CENTRAL SAN BERNARDINO COUNTY/SOUTHERN NYE AND THEN ACROSS
CENTRAL LINCOLN COUNTY AND WILL LIKELY BE FOCUS FOR INITIAL
CONVECTION. ONCE AGAIN WILL NEED TO WATCH OUTFLOW BOUNDARIES AFTER
CONVECTION STARTS AND MONITOR THROUGH THE DAY. OVERALL CURRENT
FORECAST ON TRACK...THUS NO NEED FOR UPDATES ATTM.
&&

.AVIATION...TAF ADEQUATELY COVERS ALL EXPECTED WEATHER AT KLAS.
THUNDERSTORMS WILL ONCE AGAIN FORM THIS AFTERNOON ACROSS MAINLY THE
PEACH SPRING/MORMON MESA CORRIDOR AND THEN ACROSS DAGGETT APPROACH
DURING THE LATE AFTERNOON/EVENING. POSSIBLE ACTIVITY IN THE KLAS
VALLEY WITH OUTFLOW BOUNDARIES MAY CAUSE ERRATIC WINDS THROUGH 06Z.
&&

.PREV DISCUSSION...347 AM PDT...SEVERAL THINGS HAPPENED OVERNIGHT
ALONG THE SOUTHWESTERN CWA. TWO COLLIDING OUTFLOW BOUNDARIES FROM
EARLIER CONVECTION SET OFF SCATTERED THUNDERSTORMS OVER CLARK COUNTY
FROM HENDERSON EAST THROUGH THE LAKE MEAD RECREATION AREA. THIS
PRODUCED A SPECTACULAR LIGHTNING SHOW AND HEAVY RAIN THAT CAUSED
SOME MINOR FLOODING IN HENDERSON/BOULDER CITY AND THE LAKE MEAD AREA
WHERE UPWARDS OF .75 INCHES FELL. FURTHER SOUTH...A LARGE MCS FORMED
OVER SOUTHCENTRAL ARIZONA AND MOVED TO THE NORTHWEST PRODUCING
STRONG WIND GUSTS AND HEAVY RAIN IN THE LAKE HAVASU AREA. AS OF 3
AM...SCATTERED THUNDERSTORMS ARE STILL FIRING IN EXTREME SOUTHERN
CLARK...EASTERN SAN BERNARDINO AND WESTERN MOHAVE COUNTIES.

THE EXTENSIVE CLOUD COVER GENERATED BY THE LINGERING THUNDERSTORM
ACTIVITY WILL SUPPRESS TEMPERATURES FOR A WHILE TODAY FOR AREAS
MAINLY SOUTH AND EAST OF THE LAS VEGAS VALLEY. ANOTHER CONCERN TODAY
WILL BE WHERE BOUNDARIES FROM THE MCS AND OTHER CONVECTION END UP.
THIS COULD PROVIDE A MECHANISM FOR STORMS FIRING TODAY. ON THE
LARGER SCALE...A SHORTWAVE MOVING ACROSS THE NORTHERN U.S. WILL
SUPPRESS AND WEAKEN THE HIGH PRESSURE AREA THAT HAS BEEN DOMINANT
OVER THE FOUR CORNERS REGION FOR THE PAST SEVERAL DAYS. AS THIS
TROUGH MOVES EAST...THE HIGH ELONGATES AND STRETCHES ACROSS THE
SOUTHWESTERN HALF OF THE COUNTRY THROUGH THURSDAY. IT EVENTUALLY
RE-ESTABLISHES ITSELF OVER NEVADA BY THE WEEKEND AND STRENGTHENS.
MODELS CONTINUE TO SHOW A MOIST AND UNSTABLE AIRMASS ACROSS THE
SOUTHERN HALF OF THE CWA THROUGH THE NEXT SEVEN DAYS AND WILL LIKELY
SEE ISOLATED TO SCATTERED THUNDERSTORMS EACH AFTERNOON IN THIS
REGION. THE WESTERN PARTS OF THE FORECAST AREA SHOULD REMAIN ON THE
DRY SIDE THROUGH THURSDAY BUT AS THE HIGH SETTLES OVER WESTCENTRAL
NEVADA BY THE WEEKEND...THE MOISTURE AND INSTABILITY COULD RETURN TO
THIS AREA.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
.NV...NONE.
.AZ...NONE.
.CA...NONE.
&&

JENSEN/SALMEN

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE LAS VEGAS NV
846 AM PDT WED AUG 3 2005

AZZ001>003-036-CAZ026>029-NVZ014>022-041540-
DEATH VALLEY NATIONAL PARK CA-ESMERALDA AND CENTRAL NYE COUNTY NV-
LAKE HAVASU AND FORT MOHAVE AZ-LAKE MEAD NATIONAL RECREATION AREA AZ-
LAKE MEAD NATIONAL RECREATION AREA NV-LAS VEGAS VALLEY NV-
LINCOLN COUNTY NV-NORTHEAST CLARK COUNTY NV-NORTHWEST DESERTS AZ-
NORTHWEST PLATEAU AZ-
OWENS VALLEY AND ADJACENT EASTERN SIERRA SLOPES CA-
SAN BERNARDINO COUNTY DESERTS CA-SAN BERNARDINO COUNTY-
UPPER COLORADO RIVER VALLEY CA-SHEEP RANGE NV-
SOUTHERN CLARK COUNTY NV-SPRING MOUNTAINS-RED ROCK CANYON NV-
WESTERN CLARK AND SOUTHERN NYE COUNTY NV-
846 AM PDT WED AUG 3 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
CALIFORNIA...SOUTHERN NEVADA AND NORTHWEST ARIZONA.

.DAY ONE...WEDNESDAY.

THE MONSOON PATTERN REMAINS IN PLACE TODAY. SCATTERED THUNDERSTORMS
ARE EXPECTED THIS AFTERNOON AND EVENING...MAINLY SOUTH AND EAST OF A
LINE FROM CENTRAL SAN BERNARDINO COUNTY CALIFORNIA...TO DESERT ROCK
NEVADA AND THEN TO NORTHERN LINCOLN COUNTY. SOME OF THE STORMS WILL
LIKELY PRODUCE SMALL HAIL...STRONG WINDS...AND LOCALIZED HEAVY
RAIN...WHICH COULD RESULT IN FLASH FLOODING.

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

THE MONSOON PATTERN IS EXPECTED TO REMAIN IN PLACE THROUGH THE
WEEKEND. SCATTERED THUNDERSTORMS CAN BE EXPECTED EACH AFTERNOON AND
EVENING...WITH ISOLATED SEVERE WEATHER AND FLASH FLOODING POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.