Severe Thunderstorm Warning 109, NWS Salt Lake City, UT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
439 PM MDT FRI OCT 6 2006

.SYNOPSIS...A LOW PRESSURE SYSTEM WILL LIFT NORTHEAST THROUGH THE
GREAT BASIN THIS EVENING THROUGH EARLY SATURDAY...USHERING A
DRIER AIRMASS IN BEHIND IT. MOISTURE RETURNS TO SOUTHERN UTAH
BEGINNING LATE SUNDAY AHEAD OF A LOW THAT WILL FORM OVER SOUTHERN
CALIFORNIA.

&&

.DISCUSSION...PRECIPITATION OVER UTAH HAS FORMED IN TWO DISTINCT
BANDS THIS AFTERNOON...ONE OVER WESTERN UTAH AND EASTERN NEVADA
THAT IS MOVING TO THE NORTHEAST TOWARD THE WASATCH FRONT AND ONE
OVER EASTERN UTAH AND WESTERN COLORADO. THESE SHOWERS HAVE
PRODUCED COPIOUS AMOUNTS OF RAIN IN MANY LOCATIONS...PARTICULARLY
OVER EAST CENTRAL AND SOUTHEASTERN UTAH WHERE SOME 2-3 INCH RAIN
TOTALS HAVE BEEN REPORTED.

ISOLATED THUNDERSTORMS HAVE FORMED IN THESE AREAS OF
SHOWERS...MOSTLY OVER WESTERN AND SOUTH CENTRAL UTAH...BUT SO FAR
NO SEVERE WEATHER HAS BEEN REPORTED. HAVE CANCELLED THE SEVERE
THUNDERSTORM WATCH FOR THE WESTERNMOST UTAH COUNTIES WHERE STORMS
ARE WEAKENING AND MOVING TO THE NORTHEAST AS THE AIRMASS BECOMES
MORE STABLE. HOWEVER...THE POTENTIAL FOR SEVERE WEATHER STILL
EXISTS IN SOUTH CENTRAL AND SOUTHEASTERN UTAH WHERE DEEPER
MOISTURE AND BETTER INSTABILITY REMAINS IN PLACE. THE WATCH
REMAINS IN EFFECT FOR THOSE AREAS UNTIL 8 PM.

THE LOW THAT WAS OVER CALIFORNIA THIS MORNING IS NOW CENTERED
NEAR THE CALIFORNIA/NEVADA/ARIZONA TRIPLE POINT AND SHOULD REACH
SOUTHWESTERN UTAH BY EARLY THIS EVENING. MOST OF THE STORM SYSTEM
WILL MOVE THROUGH THE STATE AS AN OPEN WAVE TONIGHT AND EARLY
TOMORROW...AND A COOLER AND DRIER AIRMASS SHOULD MOVE IN BEHIND
IT. PRECIPITATION SHOULD END OVER SOUTHERN UTAH SATURDAY
MORNING...BUT LINGERING MOISTURE COULD KEEP SHOWERS AND
THUNDERSTORMS GOING OVER NORTHERN UTAH THROUGH SATURDAY
AFTERNOON.

SUNDAY SHOULD BE FAIRLY DRY ACROSS THE STATE...THOUGH MOISTURE
WILL BEGIN TO INCREASE ONCE AGAIN OVER SOUTHERN UTAH AS THE
REMAINING PIECE OF THE TROUGH CLOSES OFF OVER SOUTHERN
CALIFORNIA. LATEST MODELS PREDICT THE LOW WILL STAY PUT ON MONDAY
BEFORE MOVING ACROSS ARIZONA ON TUESDAY. PREVIOUS RUNS OF THE GFS
INDICATED THAT A SHORTWAVE WOULD MOVE THROUGH NORTHWESTERN UTAH
DURING THIS PERIOD...BUT THE 18Z RUN HAS BACKED OFF ON THIS
SOLUTION. ADDITIONALLY...BACK DOOR COLD FRONT THAT WAS FORECAST
TO MOVE THROUGH NORTHEASTERN UTAH ON WEDNESDAY IN PREVIOUS RUNS
NOW STAYS EAST OF THE STATE. OBVIOUSLY...THERE IS LITTLE MODEL
RUN-TO- RUN CONSISTENCY IN THE EXTENDED SO FORECAST CONFIDENCE
DURING THIS PERIOD REMAINS LOW.

&&

.HYDROLOGY...DEEP LAYER MOISTURE REMAINS OVER MOST OF THE
AREA...THOUGH DRYING IS BEGINNING TO OCCUR IN SOUTHWEST UTAH AS
THE LOW PRESSURE SYSTEM OVER CALIFORNIA APPROACHES THE AREA.
WIDESPREAD AND OCCASIONALLY HEAVY RAINFALL HAS PRODUCED 2-3 INCH
RAIN TOTALS OVER SOME SOUTHEASTERN UTAH LOCATIONS. THIS HAS
RESULTED IN FLASH FLOODING IN SOME LOCATIONS...AND SOME
ADDITIONAL FLOODING IS POSSIBLE THROUGH THIS EVENING. THE FLASH
FLOOD WATCH FOR SOUTHEASTERN AND EAST CENTRAL UTAH LOCATIONS
REMAINS IN EFFECT UNTIL 9 PM. OVER NORTHERN UTAH...OCCASIONAL
HEAVY RAIN HAS THE POTENTIAL TO PRODUCE DEBRIS FLOWS AT SEVERAL
BURN AREAS AND A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 6 AM
SATURDAY TO ADDRESS THIS CONCERN. PRECIPITATION WILL TAPER OFF
LATE TONIGHT/EARLY SUNDAY MORNING AS THE LOW MOVES NORTHEASTWARD
THROUGH THE STATE. HOWEVER...RAIN COULD LINGER OVER NORTHERN UTAH
UNTIL SATURDAY AFTERNOON.

&&

.AVIATION...AVIATION CONDITIONS WILL BEGIN TO DETERIORATE SHORTLY AS
A SIGNIFICANT BAND OF RAIN MOVES NORTHEAST OUT OF WEST CENTRAL UTAH.
CEILINGS AT 7000 FEET CURRENTLY WILL DROP WITHIN THE NEXT TWO HOURS
WITH A 70 PERCENT CHANCE OF MVFR CONDITIONS OCCURRING BETWEEN 00Z
AND 04Z IN RAIN. CEILINGS SHOULD SLOWLY IMPROVE THROUGH 07Z TO 7000
FEET AND THEN BEGIN TO DISSIPATE. COLD FRONT SHOULD ARRIVE BETWEEN
16Z AND 18Z SATURDAY.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...FLASH FLOOD WATCH UNTIL 9 PM FRIDAY FOR UTZ010-012-013-017<021.

     SEVERE THUNDERSTORM WATCH UNTIL 8 PM FRIDAY FOR UTZ012<014-UTZ017-
     018-020.

     FLASH FLOOD WATCH UNTIL 6 AM SATURDAY FOR UTZ002-UTZ003-UTZ007.

WY...NONE.

&&

TRAPHAGAN/HALL

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
449 PM MDT FRI OCT 6 2006

UTZ010>021-071300-
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-WASATCH PLATEAU/BOOK CLIFFS-WEST CENTRAL UTAH-WESTERN
UINTA BASIN-
449 PM MDT FRI OCT 6 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHERN TWO-THIRDS OF
UTAH.

.DAY ONE...TODAY AND TONIGHT

A VERY MOIST AND UNSTABLE AIRMASS OVER UTAH WILL FUEL NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING. A LOW PRESSURE SYSTEM
MOVING NORTHEAST INTO SOUTHERN UTAH LATER BY THIS EVENING WILL
PRODUCE STRONG THUNDERSTORMS...WITH HEAVY RAIN AND HAIL..INTO THE
EVENING HOURS. THE EXPECTED HEAVY RAINFALL COULD CREATE FLASH
FLOODING...ESPECIALLY IN SLOT CANYONS OR IN AREAS THAT HAVE ALREADY
RECEIVED HEAVY RAIN SINCE YESTERDAY. A FLASH FLOOD WATCH IS IN EFFECT
FOR MUCH OF SOUTHERN AND EASTERN UTAH THROUGH 900 PM MDT THIS
EVENING. CHECK THE LATEST SLCFFASLC FOR DETAILS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SATURDAY WILL SEE DRIER CONDITIONS SPREAD ACROSS SOUTHERN UTAH. THE
THREAT OF SHOWERS AND THUNDERSTORMS WILL RETURN SUNDAY...AND
CONTINUE INTO THE MIDDLE OF NEXT WEEK. HIGH PRESSURE ALOFT WILL
BRING AN END TO SHOWERS AND STORMS BY THE END OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

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

UTZ001>009-WYZ021-071300-
CACHE VALLEY/UTAH PORTION-GREAT SALT LAKE DESERT AND MOUNTAINS-
NORTHERN WASATCH FRONT-SALT LAKE AND TOOELE VALLEYS-
SOUTHERN WASATCH FRONT-SOUTHWEST WYOMING-WASATCH MOUNTAIN VALLEYS-
WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-
WESTERN UINTA MOUNTAINS-
449 PM MDT FRI OCT 6 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHERN UTAH AND EXTREME
SOUTHWEST WYOMING.

.DAY ONE...TODAY AND TONIGHT

WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED ACROSS THE
AREA THIS EVENING AND OVERNIGHT. HEAVY RAINS AND HAIL FROM STRONG
THUNDERSTORMS ARE EXPECTED THIS EVENING AS A LOW PRESSURE
SYSTEM LIFTS NORTHEAST ACROSS NORTHERN UTAH. THERE IS THE
POTENTIAL FOR DEBRIS FLOWS TO FORM IN BURN AREAS...AND A FLASH
FLOOD WATCH REMAINS IN EFFECT UNTIL 6 AM TOMORROW. SEE THE LATEST
SLCFFASLC FOR DETAILS. MINOR FLOODING MAY ALSO DEVELOP FROM THE
STRONG STORMS...ESPECIALLY IN THE URBAN AREAS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SHOWERS AND THUNDERSTORMS WILL LINGERING INTO SATURDAY...THEN END
MOST AREAS SATURDAY NIGHT OR EARLY SUNDAY. SHOWERS AND STORMS COULD
RETURN FOR THE FIRST HALF OF NEXT WEEK AS A NEW LOW PRESSURE SYSTEM
SETTLES INTO THE GREAT BASIN. HIGH PRESSURE ALOFT WILL RETURN LATE IN
THE WEEK...BRINGING AN END TO THE PRECIPITATION FOR NORTHERN UTAH
AND SOUTHWEST WYOMING.

.SPOTTER INFORMATION STATEMENT...

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
107 PM MDT FRI OCT 06 2006

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

1000 AM     FLASH FLOOD      CAPITOL REEF NP         38.28N 111.20W
10/06/2006                   WAYNE              UT   LAW ENFORCEMENT

            HWY 24 UNDCERCUT...ONE LANE WASHED OUT. WATER RUNNING
            OVER ROADWAY EAST OF PARK. GRAND WASH IS FLOODED AS WELL.
            RAINFALL TOTAL IN CAPITOL REEF NP 2.78 INCHES

&&

BAS