Severe Thunderstorm Warning 14, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
944 AM PDT SUN AUG 15 2004

.SYNOPSIS...THE AIR OVER THE SOUTHERN GREAT BASIN AND MOJAVE DESERT
WILL CONTINUE TO BE MOIST AND UNSTABLE FOR THE NEXT SEVERAL DAYS.
SCATTERED THUNDERSTORMS WILL AGAIN FORM IN THE AFTERNOON AND EVENING
HOURS THROUGHOUT THE AREA TODAY. SOME OF THE THUNDERSTORMS COULD
PRODUCE LOCALLY HEAVY RAIN. TEMPERATURES FOR THE NEXT FEW DAYS WILL
BE BELOW NORMAL DUE TO CLOUDS AND HIGHER HUMIDITIES.
&&

.UPDATE...ISSUED FLOOD WATCH UNTIL 9 PM FOR INYO...SAN
BERNARDINO...AND EXTREME SOUTHWEST MOHAVE COUNTIES. UPDATED ZONES
ALREADY OUT.
&&

.PREV DISCUSSION...
255 AM PDT SUN AUG 15 2004

.SHORT TERM...A COUPLE OF CLUSTERS OR CONVECTION PERSIST STILL IN
SOUTHERN NYE AND NORTHERN MOHAVE COUNTIES THIS MORNING. FAIRLY
CONFIDENT THAT THUNDERSTORMS WILL BE WIDE SPREAD AGAIN TODAY AND
THIS EVENING AS ATMOSPHERE REMAINS MOIST AND UNSTABLE. BIGGEST
UNCERTAINTY IN TODAYS FORECAST DEALS WITH PRECIPITATION CHANCES AND
FLASH FLOODING POTENTIAL...PARTICULARLY IN SAN BERNARDINO COUNTY.
NUMEROUS TOOLS POINT TO THE EASTERN TWO THIRDS OF THE COUNTY BEING
PRIME FOR THUNDERSTORM DEVELOPMENT. THE ETA IN PARTICULAR SHOWS LI S
OF -2 TO -4 THERE LATE IN THE AFTERNOON ALONG WITH SOME VERY HIGH
CAPES AND A THETA RIDGE OVER THIS AREA. WHAT MAKES ME THINK TWICE
ABOUT PUTTING IN HIGH POPS AND A FLASH FLOOD WATCH IN THIS AREA IS
THE SATELLITE PICTURES SHOWING DRY AIR MOVING IN FORM THE WEST.
GRANTED THERE WILL STILL BE LOW LEVEL MOISTURE LET THERE...BUT
WITHOUT THE DEEP MOISTURE DEPTH I THINK THE PW WILL BE TOO LOW TO
WARRANT A WATCH NOW. WILL PUNT AND LEAVE IT THE DAY SHIFT TO DECIDE.
WEAK TROUGHINESS WILL SETTLE OVER CENTRAL NEVADA WITH A NORTH SOUTH
AXIS ORIENTATION. THIS SHOULD LEAD TO A HERNIATED ATMOSPHERE WHERE
CONVECTION WILL POP THROUGH ANY WEAKNESS THAT CAN BE FOUND NEAR THIS
TROUGH. ETA AND GFS SIMILAR IN DEPICTING TROUGH THE NEXT TWO DAYS.
HAVE KEPT PREVIOUS FORECAST OF POPS MAINLY OVER EASTERN 2/3S OF CWA
AS SOME DRYING WILL CONTINUE OVER THE WEST. AS CLOUDS PRECIPITATION
AND RH HAVE KEPT TEMPS BELOW NORMAL I HAVE A SLOW WARMING TREND IN
THE FORECAST AS THESE PARAMETERS LESSEN.

.LONG TERM...WEAK UPPER TROUGH PROGGED TO START MOVING EAST OF THE
AREA WEDNESDAY WITH WEAK HIGH PRESSURE DEVELOPING THURSDAY. NOT MUCH
FLOW TO SCOUR OUT MOISTURE AND GFS LEAVES QUITE A BIT OF MOISTURE
AND INSTABILITY OVER THE FORECAST AREA. WILL BROAD BRUSH SLIGHT
CHANCE OF THUNDERSTORMS FOR MOST ZONES AND CHANCE POPS IN SOME
MOUNTAIN ZONES. A MORE SOUTHWESTERLY FLOW WILL HELP REDUCE MOISTURE
AND INSTABILITY FRIDAY AND SATURDAY WITH ANY CHANCE OF THUNDERSTORMS
LIMITED TO THE NORTH...FROM ESMERALDA COUNTY ACROSS TO NORTHERN
LINCOLN COUNTY.

.AVIATION...TAF ADEQUATELY COVERS ALL SIGNIFICANT WEATHER EXPECTED
AT KLAS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
.NV...NONE.
.AZ...FLOOD WATCH AZZ002 UNTIL 9 PM.
.CA...FLOOD WATCH CAZ026>029 UNTIL 9 PM.
&&

MORGAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
1000 AM PDT SUN AUG 15 2004

AZZ002-CAZ026>029-161700-
DEATH VALLEY NATIONAL PARK-LAKE HAVASU AND FORT MOJAVE-
OWENS VALLEY AND ADJACENT EASTERN SIERRA SLOPES-
SAN BERNARDINO COUNTY DESERTS-SAN BERNARDINO COUNTY-
UPPER COLORADO RIVER VALLEY-
1000 AM PDT (1000 AM MST) SUN AUG 15 2004

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

.DAY ONE...TODAY.

A FLOOD WATCH FOR FLASH FLOODING IS IN EFFECT UNTIL 9 PM THIS
EVENING. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON AND EVENING...WITH HEAVY RAIN AND FLASH
FLOODING POSSIBLE. A SEVERE STORM OR TWO CANNOT BE RULED OUT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED EACH DAY. ISOLATED SEVERE STORMS AND FLASH FLOODING CANNOT
BE RULED OUT.

AZZ001-003-036-NVZ014>022-161700-
ESMERALDA AND CENTRAL NYE COUNTY-LAKE MEAD NATIONAL RECREATION AREA-
LAS VEGAS VALLEY-LINCOLN COUNTY-NORTHEAST CLARK COUNTY-
NORTHWEST DESERTS-NORTHWEST PLATEAU-SHEEP RANGE-
SOUTHERN CLARK COUNTY-SPRING MOUNTAINS-RED ROCK CANYON-
WESTERN CLARK AND SOUTHERN NYE COUNTY-
1000 AM PDT (1000 AM MST) SUN AUG 15 2004

.DAY ONE...TODAY.

SCATTERED THUNDERSTORMS WILL CONTINUE THROUGH THIS AFTERNOON AND
EVENING. ISOLATED SEVERE STORMS AND FLASH FLOODING CANNOT BE RULED
OUT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED EACH DAY. ISOLATED SEVERE STORMS AND FLASH FLOODING CANNOT
BE RULED OUT.

MORGAN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
819 AM PDT SUN AUG 15 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0415 AM     FLASH FLOOD      DEATH VALLEY            36.30N 116.41W
08/15/2004                   INYO               CA   NATL PARK SVC

            HIGHWAY 190 CLOSED...ROAD TO SCOTTYS CASTLE WASHED
            OUT...DAMAGE ON DAYLIGHT PASS TO BEATTY. TIME OF EVENT
            ESTIMATED.

&&

MORGAN