Severe Thunderstorm Warning 90, NWS Salt Lake City, UT

000 
WWUS55 KSLC 212146
SVSSLC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
344 PM MDT WED SEP 21 2005

UTC015-212154-
/O.EXP.KSLC.SV.W.0090.000000T0000Z-050921T2145Z/
EMERY UT-
344 PM MDT WED SEP 21 2005

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL EMERY COUNTY
EXPIRES AT 345 PM MDT...

THE SEVERE THUNDERSTORM THAT MOVED EAST THROUGH EMERY COUNTY HAS 
CROSSED THE COLORADO RIVER INTO GRAND COUNTY UTAH. 

LAT...LON 3886 11074 3864 11074 3876 11013 3925 11005

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
115 PM MDT WED SEP 21 2005

.SYNOPSIS...A MOIST PACIFIC STORM WILL CROSS THE INTERMOUNTAIN
REGION EARLY TONIGHT BRINGING UNSETTLED WEATHER. WEAK HIGH PRESSURE
WILL BE OVER THE AREA THURSDAY BEFORE AN UPPER LOW DEVELOPS ALONG
THE WEST COAST FOR THE UPCOMING WEEKEND.

&&

.DISCUSSION...UPPER LOW EVIDENT IN EARLY AFTERNOON WATER VAPOR
IMAGERY LIFTING NORTHEAST AND EVOLVING INTO OPEN WAVE ACROSS
NORTHERN NV/SOUTHERN ID. AXIS OF SUBTROPICAL MOISTURE EXTENDS
DOWNSTREAM OF THIS FEATURE ACROSS MUCH OF SOUTHERN AND EASTERN
UT...WHILE DRIER MID LEVEL AIR HAS OVERSPREAD THE WESTERN DESERTS.
DESPITE THIS DRIER AIR ALOFT...LOW LEVEL MOISTURE REMAINS IN PLACE
ACROSS THE FORECAST AREA WITH SURFACE DEW POINTS GENERALLY IN THE
MID TO UPPER 50S...AND PW VALUES (BOTH GOES DERIVED AND IPW SENSOR)
REMAIN IN THE .75 TO 1 INCH RANGE. SUNSHINE THIS AFTERNOON HAS
RESULTED IN SUFFICIENT SURFACE HEATING TO ALLOW FOR SURFACE
BASED LI VALUES IN THE -2 TO -4 RANGE ACROSS NORTHERN UT. CONVECTION
CONTINUES TO DEVELOP ACROSS NORTHEAST NV INTO FAR NORTHWEST UT AHEAD
OF APPROACHING TROUGH AXIS. AS LIFT ASSOCIATED WITH THIS TROUGH AXIS
INTERACTS WITH MOIST UNSTABLE AIRMASS EXPECT CONVECTION TO INCREASE
IN AREAL COVERAGE THROUGH THE REMAINDER OF THE AFTERNOON AND EARLY
EVENING HOURS. SHEAR PROFILES CONTINUE TO SUPPORT A THREAT FOR
ORGANIZED STRONG CONVECTION THROUGH AFTERNOON HOURS...THIS THREAT
WILL DIMINISH RAPIDLY THIS EVENING AS SHEAR PROFILES WEAKEN IN
PROXIMITY TO MID LEVEL TROUGH AXIS. EXPECT MAJORITY OF PRECIPITATION
TO EXIT FORECAST AREA BY 03Z AS MOISTURE AND DYNAMICS TRANSLATE
EAST.

EXTENDED MODELS CONTINUE TO ADVERTISE LONGWAVE TROUGH DEVELOPING
OVER THE UPCOMING WEEKEND...HOWEVER LATEST SOLUTIONS KEEP TROUGH
AXIS NEAR KSFO. THIS IS FURTHER WEST THAN WHAT HAD BEEN SUGGESTED A
COUPLE OF DAYS AGO...BUT MAKES MORE SENSE BASED ON RECENT TREND OF
UPPER LOWS TO DEVELOP ALONG/JUST OFF CA COAST AS OPPOSED TO OVER THE
INTERIOR WEST. LEAD SHORTWAVE PROGGED TO BRUSH NORTHERN UT
FRIDAY/FRIDAY NIGHT...WHICH WILL BRING A CHANCE OF PRECIPITATION TO
FAR NORTHERN UT. AS LOW DEVELOPS OFF COAST DEEP SOUTHERLY FLOW
EXPECTED TO SPREAD ACROSS FORECAST AREA. GFS DOES SUGGEST PLUME OF
MID LEVEL MOISTURE TO SPREAD NORTHWARD WITHIN THIS FLOW ACROSS
FORECAST AREA. AS A RESULT HAVE RETAINED SLIGHT CHANCE POPS OVER THE
WEEKEND. THIS TROUGH IS NOW FORECAST TO LIFT ACROSS THE REGION
TUESDAY...HOWEVER SUFFICIENT UNCERTAINTY REMAINS WITH TIMING OF THIS
FEATURE TO PRECLUDE INTRODUCING ANYTHING MORE THAN SLIGHT CHANCE
POPS AT THIS TIME.

&&

.AVIATION...ALTHOUGH ISOLATED CELLS DEVELOPING OVER THE WEST DESERTS
MAY IMPACT KSLC THROUGH 22Z...BEST THREAT FOR THUNDERSTORMS WILL BE
WITHIN THE 22-02Z TIMEFRAME ASSOCIATED WITH STORM SYSTEM CURRENTLY
MOVING INTO FAR NORTHWEST UT. CEILINGS WILL LIKELY FALL INTO THE
4000-5000FT RANGE ASSOCIATED WITH THESE STORMS. WIND SHIFT TO NW
EXPECTED TO ARRIVE BY 02Z. WEAK PRESSURE GRADIENT OVERNIGHT MAY
ALLOW SOUTHERLY DRAINAGE WINDS TO DEVELOP TOWARDS 10-12Z TIMEFRAME.

&&

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

&&

SEAMAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
615 AM MDT WED SEP 21 2005

UTZ001>021-WYZ021-221200-
CACHE VALLEY/UTAH PORTION-CASTLE COUNTRY-
CENTRAL AND SOUTHWEST MOUNTAINS-
GLEN CANYON RECREATION AREA/LAKE POWELL-
GREAT SALT LAKE DESERT AND MOUNTAINS-HENRY MOUNTAINS-
NORTHERN WASATCH FRONT-SALT LAKE AND TOOELE VALLEYS-SAN RAFAEL SWELL-
SANPETE/SEVIER VALLEYS-SOUTH CENTRAL UTAH-SOUTHERN WASATCH FRONT-
SOUTHWEST UTAH-SOUTHWEST WYOMING-UTAHS DIXIE AND ZION NATIONAL PARK-
WASATCH MOUNTAIN VALLEYS-WASATCH MOUNTAINS I-80 NORTH-
WASATCH MOUNTAINS SOUTH OF I-80-WASATCH PLATEAU/BOOK CLIFFS-
WEST CENTRAL UTAH-WESTERN UINTA BASIN-WESTERN UINTA MOUNTAINS-
615 AM MDT WED SEP 21 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO
THIRDS OF UTAH AND EXTREME SOUTHWEST WYOMING.

.DAY ONE...TODAY

NUMEROUS SHOWERS AND THUNDERSTORMS CAN BE EXPECTED TODAY.  AN
ISOLATED SEVERE THUNDERSTORM WILL BE POSSIBLE THIS AFTERNOON AND
EVENING...BUT WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED.  A FEW
STORMS MAY PRODUCE HEAVY RAINFALL.  THE SHOWERS AND STORMS
WILL BE TRIGGERED BY A VIGOROUS UPPER LEVEL DISTURBANCE MOVING ACROSS
THE REGION...COUPLED WITH A COLD FRONT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

BARJENBRUCH