Severe Thunderstorm Warning 65, NWS Salt Lake City, UT

000 
WWUS55 KSLC 112201
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
400 PM MDT THU AUG 11 2005

UTC013-112210-
/O.EXP.KSLC.SV.W.0065.000000T0000Z-050811T2200Z/
DUCHESNE UT-
400 PM MDT THU AUG 11 2005

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL DUCHESNE COUNTY
EXPIRED AT 400 PM MDT...

THIS THUNDERSTORM HAS MOVED INTO UINTAH COUNTY.


$$

AOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
308 PM MDT THU AUG 11 2005

.SYNOPSIS...DRIER AIR WILL SPREAD ACROSS NORTHERN UTAH THROUGH
SATURDAY. A VERY MOIST AIRMASS WILL REMAIN IN PLACE ACROSS FAR
SOUTHERN UTAH INTO THE WEEKEND.

&&

.DISCUSSION...THUNDERSTORMS FIRING UP IN THE NORMAL MOUNTAIN AREAS
FROM THE UINTAS TO BOULDER MOUNTAIN. CELLS IN THE NORTH DEALING
WITH DRY AIR ENTRAINMENT AS PRECIPITABLE WATER DECREASES...HOWEVER
SHORT WAVE TROF ON WATER VAPOR STILL ON TRACK TO CROSS THE NORTH AND
INSTABILITY SUFFICIENT FOR SOME ACTIVITY WHICH COULD CONTINUE ALONG
THE IDAHO BORDER WELL INTO THE EVENING. ELSEWHERE IN THE NORTH CELLS
SHOULD DIMINISH QUICKLY WITH THE SHORT WAVE PASSAGE AND LOSS OF
HEATING EARLY THIS EVENING. SOUTHWEST UTAH HAS SEEN FULL SUNSHINE
BUT CONVECTION IS SLOW TO FORM. WATER VAPOR DEPICTS SQUEEZING OF
MOISTURE IN THIS REGION AND WEAK VORT MAX FROM SOUTHERN NEVADA TO
DRIFT INTO THIS REGION THIS EVENING. OUTFLOWS FROM TERRAIN DRIVEN
CELLS AND WEAK DYNAMICS SHOULD ACT ON THE OBSERVED LARGE CAPE VALUES
OVER THIS REGION...ALLOWING ACTIVITY TO INCREASE IN COVERAGE AND
INTENSITY NEXT SEVERAL HOURS. THUNDERSTORMS SHOULD CONTINUE WELL
INTO THE EVENING AND EVEN OVERNIGHT IN THE FAR SOUTH UNDER A LIGHT
NORTHERLY FLOW. THREAT FOR LOCALLY HEAVY RAIN STILL EXISTS IN THE
SOUTH BUT UNCERTAIN IF COVERAGE WILL BE GREAT ENOUGH FOR A FLASH
FLOOD WATCH AREA.

DRYING CONTINUES IN FRIDAY AS THE WESTERLIES PRESS SOUTH AND
ADDITIONAL SHORT WAVES FROM THE PACNW APPROACH. SHORT WAVE DIGS INTO
IDAHO AND ANOTHER JET MAX CROSSES THE NORTH ON SATURDAY. THIS COOLS
THE NORTH A LITTLE INTO SATURDAY AND MOISTURE IS SUPPRESSED
FURTHER SOUTH. ISOLATED ACTIVITY IN THE NORTHEAST REGIONS POSSIBLE
AS JUST ENOUGH MOISTURE REMAINS ALONG WITH THE NEXT SHORT WAVE TROF
FOR LATE FRIDAY. UPPER TROF AXIS IN THE NORTHERN ROCKIES SHIFTS EAST
OF UTAH ON SATURDAY FOR LITTLE CHANCE FOR ANY CONVECTION IN THE
NORTH. IN THE FAR SOUTH MOISTURE REMAINS IN PLACE AND POSSIBILITY
FOR DYNAMICS AND WEAK FLOW TO PRODUCE STRONG CELLS NEAR THE ARIZONA
BORDER.

THERE ARE DIFFERENCES WITH THE NAM AND GFS RUNS...BUT LITTLE GENERAL
CHANGE IN THE PATTERN IS NOTED ON SUNDAY. THE NAM IS MUCH FURTHER
SOUTH WITH THE WEST COAST UPPER LOW AND THE GFS EJECTED A STRONG
VORT MAX INTO SOUTHERN UTAH ON SUNDAY. 12Z GFS AND ECMWF RUN WOULD
SUGGEST A GOOD SURGE OF MOISTURE AND DYNAMICS WITH AN UPPER LOW FROM
THE WEST COAST LIFTING INTO UTAH FOR ACTIVE CONVECTIVE DAYS MONDAY
AND TUESDAY...THEN SIGNIFICANT DRYING MID NEXT WEEK. THE SURGE OF
MOISTURE WOULD SEEP IN THE WESTERN AREAS AS SOON AS SUNDAY AFTERNOON
OR SUNDAY NIGHT. WE TRENDED THE FORECAST FOR THIS IDEA WITH HIGHEST
CHANCES FOR MONDAY AND TUESDAY.

&&

.HYDRO...FLASH FLOOD POTENTIAL WILL BE MAIN ISSUE THIS EVENING.
CELLS IN THE SOUTH WILL BE SLOW MOVING OFF OF THE TERRAIN AND SHOULD
INCREASE IN COVERAGE THIS EVENING WITH NUMEROUS OUTFLOWS AND SOME
DYNAMICS MOVING IN FROM NEVADA TO ADD TO THE MIX. CONCERN WILL BE
SOUTHERN UTAH AGAIN AND SPECIFICALLY THE SOUTHWEST PORTION INTO THE
EVENING HOURS.

&&

.AVIATION...NONE. SEE SLCTAFSLC.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.

&&

TARDY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
600 AM MDT THU AUG 11 2005

UTZ012>021-121300-
CASTLE COUNTRY-CENTRAL AND SOUTHWEST MOUNTAINS-
GLEN CANYON RECREATION AREA/LAKE POWELL-HENRY MOUNTAINS-
SAN RAFAEL SWELL-SANPETE/SEVIER VALLEYS-SOUTH CENTRAL UTAH-
SOUTHWEST UTAH-UTAHS DIXIE AND ZION NATIONAL PARK-WEST CENTRAL UTAH-
600 AM MDT THU AUG 11 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHWESTERN HALF OF UTAH

.DAY ONE... TODAY

SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTHERN
AND CENTRAL UTAH TODAY. LOCAL HEAVY RAIN IS POSSIBLE WITH THESE
STORMS. SHOWERS AND THUNDERSTORMS WILL PERSIST INTO TONIGHT THEN
DIMINISH AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY

SCATTERED SHOWERS AND THUNDERSTORMS WITH THE POTENTIAL FOR HEAVY
RAIN WILL OCCUR ACROSS MAINLY SOUTHERN UTAH THROUGH THE REMAINDER OF
THE WEEK.

SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.