Flash Flood in Arizona, August 1, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
405 PM PDT MON AUG 1 2005

.SYNOPSIS...WESTERLY FLOW ALOFT WILL BRING TEMPORARY DRYING TO
EASTERN CALIFORNIA AND WESTERN NEVADA BUT MOIST UNSTABLE AIR WILL
CONTINUE TO SUPPORT AFTERNOON THUNDERSTORMS FROM EASTERN NEVADA TO
NORTHWEST ARIZONA.
&&

.SHORT TERM...CONVECTION SEEMS TO BE INHIBITED BY MID-LAYER CAP AND
PERHAPS TO SOME EXTENT BY LARGE SCALE SINKING IN THE WAKE OF MCV
THAT MOVED NORTH FROM MOHAVE COUNTY INTO SW UTAH. ETA AND GFS ARE
BOTH SUGGESTING INTRUSION OF A MORE DRY STABLE AIRMASS FROM THE WEST
TOMORROW BUT LOW LEVEL MOISTURE IS STILL PLENTIFUL FROM LINCOLN
COUNTY SWWD TO SAN BERNARDINO. SO WILL PROBABLY SEE ANOTHER BREAK
TOMORROW FOR INYO COUNTY CA AND ESMERALDA COUNTY NV...WHILE THE
REMINDER OF THE FORECAST AREA REMAINS UNDER A THREAT OF AT LEAST
ISOLATED THUNDERSTORMS. WITH SLIGHTLY LESS BUOYANCY AND NO FOCUSING
MECHANISM THE ACTION WILL PROBABLY NOT BE WIDESPREAD BUT ANY
INDIVIDUAL STORM COULD STILL PRODUCE SIGNIFICANT RAINFALL IN THIS
MOISTURE RICH AIR MASS.

.LONG TERM...BY THURSDAY PROGS INDICATE SUBTROPICAL RIDGE WILL
EXPAND AND PRODUCE A RETURN TO MOIST SOUTHEAST FLOW ALOFT. IN
ADDITION...LARGE SUBTROPICAL CYCLONE NEAR BROWNSVILLE IS EXPECTED TO
DRIFT WESTWARD ACROSS THE MEXICAN PLATEAU NEXT COUPLE DAYS. THAT
WILL BEAR WATCHING IN TERMS OF POTENTIAL FOR GENERATING ORGANIZED
CONVECTION OVER THE SIERRA MADRE AND SUBSEQUENT REINFORCING SURGE
COME THURSDAY OR FRIDAY. EITHER WAY IT LOOKS AN UPWARD TREND FROM A
LOW GRADE MONSOON SET-UP TOMORROW AND WEDNESDAY TO A SOMEWHAT MORE
ACTIVE PATTERN THURSDAY AND FRIDAY.

.AVIATION...TAF ADEQUATELY COVERS ALL EXPECTED WEATHER AT KLAS.
PRIMARY IMPACT ON FLOW CONTROL BY THUNDERSTORMS WILL BE OVER THE
MORMON NESA CORRIDOR. OTHER AREAS APPEAR TO BE RELATIVELY FREE OF
ANY WEATHER THAT WOULD CREATE CONGESTION.

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

RUNK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
917 AM PDT MON AUG 1 2005

AZZ001>003-036-CAZ026>029-NVZ014>022-021700-
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-
917 AM PDT MON AUG 1 2005

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

.DAY ONE...MONDAY.

THE MONSOON PATTERN REMAINS IN PLACE TODAY. SCATTERED THUNDERSTORMS
ARE EXPECTED THIS AFTERNOON AND EVENING...ESPECIALLY EAST OF A LINE
FROM BARSTOW CALIFORNIA TO RACHEL NEVADA. SOME OF THE STORMS WILL
LIKELY PRODUCE ISOLATED SEVERE HAIL...DAMAGING WINDS...AND FLASH
FLOODING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THE MONSOON PATTERN IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEK.
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.

MORGAN