Severe Thunderstorm Warning 9, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1018 AM PDT FRI AUG 13 2004

.SYNOPSIS...MONSOON MOISTURE WILL REMAIN IN THE MOJAVE DESERT AND
SOUTHERN GREAT BASIN TODAY...FUELING SCATTERED THUNDERSTORMS
AND CONSIDERABLE CLOUD COVER WHICH WILL HOLD AFTERNOON TEMPERATURES
DOWN TO NEAR SEASONAL AVERAGES. WESTERLY FLOW WILL BEGIN TO PUSH THE
MOISTURE EAST OVER THE WEEKEND...WITH THUNDERSTORM CHANCES
DECREASING SLIGHTLY FROM WEST TO EAST. GENERALLY DRY WEATHER WILL
RETURN EARLY NEXT WEEK...WITH AFTERNOON HIGHS REMAINING CLOSE TO
SEASONAL AVERAGES.
&&

.UPDATE...MAY HAVE TO RECONSIDER PERSONAL NON-BELIEF IN
PARASKEVIDEKATRIAPHOBIA. WALKED IN TO FIND A DEAD RADAR AND
THUNDERSTORMS ALREADY UNDERWAY. FORTUNATELY...HAVE EXCELLENT VIEW OF
SAN BERNARDINO COUNTY FROM KEYX RADAR. SCATTERED STORMS STILL
ONGOING THERE WITH AT LEAST TWO MESOSCALE CIRCULATIONS EVIDENT IN
SATELLITE LOOPS. TEMPERATURE FORECAST PROBABLY CANNOT BE SALVAGED
TODAY AS MORE THAN ONE ZONE WILL HAVE CLOUDS AND/OR RAIN OVER PART
OF THE ZONE AND SUNSHINE OVER PART OF THE ZONE. WILL LOOK AGAIN
AFTER 18Z OBS COME IN TO SEE IF ANY IMPROVEMENT CAN BE MADE.
&&

.PREV DISCUSSION...
240 AM PDT FRI AUG 13 2004

.SHORT TERM...WEAK VORT CURRENTLY MOVING NORTHWARD INTO FAR SOUTHERN
NEVADA IS DRIVING RESIDUAL LIGHT SHOWERS IN THE IMMEDIATE LAS VEGAS
VICINITY. FLOW IS WEAK ENOUGH THAT THIS IMPULSE SHOULD CONTINUE TO
AFFECT THE NORTHERN AND EASTERN PORTIONS OF THE CWA BY AIDING
CONVECTION AGAIN THIS AFTERNOON. THE QUESTION MARK IN MY MIND IS
OVER SOUTHERN AND WESTERN SAN BERNARDINO COUNTY WHERE MOISTURE AND
INSTABILITY REMAIN...BUT SYNOPTIC SCALE LIFT DUE TO THE VORT CENTER
MAY NOT BE GREAT. HOWEVER 00 AND 06Z ETA CONTINUE TO SHOW UPPER
DIVERGENCE MOVING FROM THE SOUTHEAST PART OF THE CWA NORTH AND
WESTWARD TOMORROW AFTERNOON AND EVENING. THIS SHOULD HELP THE
CONVECTION IN THE SOUTHWEST. AS A RESULT I HAVE INCREASED POPS CWA
WIDE FOR FRIDAY AFTERNOON WITH LIKELY POPS IN THE NORTHEAST AND
CHANCE IN THE SOUTHWEST. MODELS SHOW INSTABILITY GETTING SHUNTED
EAST IN LATER PERIODS...AND WHILE FLOW IS NOT EXTREMELY STRONG TO
PUSH OUT LOW LEVEL MOISTURE...IT MAY BE ENOUGH TO LIMIT CONVECTION
IN THE WEST. AS A RESULT HAVE MORE OR LEFT PREVIOUS FORECAST ALONE
THERE.

.LONG TERM...00Z GFS CONTINUES WITH TREND OF SLOWLY DRYING THE CWA
OUT DURING THE LONG TERM. HOWEVER FLOW ALOFT IS FAIRLY WEAK AND
NECESSARY DRY SOUTHWEST FLOW STILL A QUESTION MARK DURING THE
MONDAY/TUESDAY/WEDNESDAY TIME FRAME. IN FACT GFS CONTINUES MOISTURE
OVER THE FAVORED LINCOLN/MOHAVE COUNTIES INTO THE MIDDLE OF NEXT
WEEK AND WITH UNCERTAINTY AND SOMEWHAT SUPPORT OF LESS DRYING FROM
UKMO/ECMWF/CANADIAN HAVE ADDED 20 PCT POPS BACK INTO TO GRIDS FOR
TUESDAY/WEDNESDAY OVER THE EASTERN AREAS. THURSDAY EVEN MORE
QUESTIONABLE THAN TUE/WED ALTHOUGH TREND IS FOR DRIER SOUTHWEST FLOW
TO MOVE OVER THE CWA THUS PUSHING MOISTURE TO THE EAST. HOWEVER FLOW
REMAINS LIGHT AND WILL INTRO 10 PCT POPS AGAIN OVER LINCOLN/MOHAVE
COUNTIES FOR THE AFTERNOON...BUT LEAVE MENTION OF CONVECTION OUT OF
THE ZONES FOR NOW. WILL ADJUST AS TIME PERIOD GETS CLOSER. COOLER
TEMPS DURING THE SHORT TERM SHOULD BEGIN TO WARM INTO THE LONG TERM
DUE TO LESS CLOUD COVER/MOISTURE...BUT OVERALL TEMPS SHOULD BE
AROUND NORMAL.

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

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

MORGAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
345 PM PDT THU AUG 12 2004

AZZ001-003-NVZ018-019-131700-
NORTHWEST DESERTS-NORTHWEST PLATEAU-SHEEP RANGE-SPRING MOUNTAINS-
RED ROCK CANYON-
345 PM PDT (345 PM MST) THU AUG 12 2004

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

.DAY ONE...TODAY.

SCATTERED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING.
LOCALLY HEAVY RAINFALL IS POSSIBLE...AND ISOLATED FLOODING MAY
OCCUR.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED AGAIN ON FRIDAY AND SATURDAY...WITH LOCALLY HEAVY RAIN
POSSIBLE EACH DAY. ONLY ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED ON SUNDAY. FOR MONDAY THROUGH WEDNESDAY...
THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

AZZ036-NVZ016-017-020-021-131700-
LAKE MEAD NATIONAL RECREATION AREA-LAS VEGAS VALLEY-
NORTHEAST CLARK COUNTY-WESTERN CLARK AND SOUTHERN NYE COUNTY-
345 PM PDT (345 PM MST) THU AUG 12 2004

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

.DAY ONE...TODAY.

ISOLATED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING.
LOCALLY HEAVY RAINFALL IS POSSIBLE...AND ISOLATED FLOODING MAY
OCCUR.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED AGAIN ON FRIDAY AND SATURDAY...WITH LOCALLY HEAVY RAIN
POSSIBLE EACH DAY. FOR SUNDAY THROUGH WEDNESDAY...THE PROBABILITY OF
WIDESPREAD HAZARDOUS WEATHER IS LOW.

AZZ002-CAZ028-029-NVZ022-131700-
LAKE HAVASU AND FORT MOJAVE-SAN BERNARDINO COUNTY DESERTS-
SAN BERNARDINO COUNTY-UPPER COLORADO RIVER VALLEY-
SOUTHERN CLARK COUNTY-
345 PM PDT (345 PM MST) THU AUG 12 2004

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

.DAY ONE...TODAY.

ISOLATED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING.
LOCALLY HEAVY RAINFALL IS POSSIBLE...AND ISOLATED FLOODING MAY
OCCUR. SOME STORMS WILL ALSO PRODUCE STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED AGAIN ON FRIDAY AND SATURDAY...WITH LOCALLY HEAVY RAIN
POSSIBLE EACH DAY. FOR SUNDAY THROUGH WEDNESDAY...THE PROBABILITY OF
WIDESPREAD HAZARDOUS WEATHER IS LOW.

NVZ014-015-131700-
ESMERALDA AND CENTRAL NYE COUNTY-LINCOLN COUNTY-
345 PM PDT THU AUG 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHERN NEVADA.

.DAY ONE...TODAY.

SCATTERED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND EVENING.
SEVERE WEATHER IS NOT EXPECTED...ALTHOUGH SOME STORMS MAY PRODUCE
LOCALLY GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED AGAIN ON FRIDAY AND SATURDAY...WITH LOCALLY HEAVY RAIN
POSSIBLE EACH DAY. FOR SUNDAY THROUGH WEDNESDAY...THE PROBABILITY OF
WIDESPREAD HAZARDOUS WEATHER IS LOW.

CAZ026-027-131700-
DEATH VALLEY NATIONAL PARK-
OWENS VALLEY AND ADJACENT EASTERN SIERRA SLOPES-
345 PM PDT THU AUG 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
CALIFORNIA.

.DAY ONE...TODAY.

ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON AND
EVENING. SEVERE WEATHER IS NOT EXPECTED...ALTHOUGH SOME STORMS MAY
PRODUCE LOCALLY GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS CAN BE
EXPECTED AGAIN FRIDAY AND SATURDAY. FOR SUNDAY THROUGH WEDNESDAY...
THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW.

MORGAN