Hail and Damaging Wind in Utah, June 1 to 2, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
354 PM MDT MON JUN 1 2009

.SYNOPSIS...A RIDGE ACROSS THE REGION WILL GRADUALLY SHIFT EAST BY
MIDWEEK AND A SOUTHWESTERLY FLOW WILL DEVELOP. DRIER AIR WILL
SLOWLY SPREAD INTO THE REGION ON THIS FLOW.

&&

.DISCUSSION...THUNDERSTORMS HAVE BEEN WIDESPREAD AGAIN TODAY
ACROSS THE CWA...THOUGH THEY HAVE FORMED ALMOST EXCLUSIVELY
OVER THE HIGHER TERRAIN. FEW OF THESE STORMS HAVE BEEN ABLE TO
MOVE INTO VALLEY LOCATIONS...AS STORM MOTION HAS BEEN VERY SLOW AS
EXPECTED. INDIVIDUAL STORMS HAVE BEEN PULSE-LIKE AND SHORT-
LIVED...WITH VERY LITTLE ORGANIZATION OBSERVED IN THE LOW- SHEAR
ENVIRONMENT. SHOWERS ARE EXPECTED TO PERSIST INTO THE EVENING
HOURS BEFORE TAPERING OFF AROUND MIDNIGHT.

THE LARGE LOW PRESSURE SYSTEM SPINNING IN THE PACIFIC WILL BEGIN
SLOWLY MOVING EASTWARD TOMORROW...PUTTING THE CWA IN A WARM
ADVECTION SOUTHERLY FLOW FOR A FEW DAYS. THIS WILL ALSO HELP TO
ADVECT SOME DRIER AIR INTO SOUTHERN UTAH...PARTICULARLY IN THE
LOWER LEVELS OF THE ATMOSPHERE. THIS SHOULD DECREASE CONVECTIVE
ACTIVITY IN THE SOUTH...PERHAPS AS EARLY AS TOMORROW
AFTERNOON...THOUGH ISOLATED HIGH BASED CONVECTION WILL STILL BE
POSSIBLE THROUGH MOST OF THE FORECAST PERIOD.

MODELS ARE IN GOOD AGREEMENT IN THE EXTENDED...BRINGING THE LOW
FURTHER ONSHORE WEDNESDAY THROUGH FRIDAY. SOUTHWEST WINDS WILL BE
GUSTY AHEAD OF THIS SYSTEM...PARTICULARLY ON FRIDAY AFTERNOON...IF
THE CURRENT TIMING HOLDS. THERE IS ONLY A SLIGHT DIFFERENCE IN THE
TIMING OF THIS LOW BETWEEN THE ECMWF AND GFS...WITH THE GFS BEING
ABOUT 12 HOURS QUICKER...BRINGING THE 500MB COLD POOL DIRECTLY
OVER NORTHERN UTAH AROUND 12Z SATURDAY. THIS DISCREPANCY MADE HIGH
TEMPERATURES ON FRIDAY AFTERNOON ONE OF THE MOST UNCERTAIN PARTS
OF THE FORECAST...WITH THE EC PROMOTING SURFACE TEMPERATURES ABOUT
10 DEGREES FAHRENHEIT WARMER THAN THE FASTER GFS. CURRENT FORECAST
IS A COMPROMISE BETWEEN THOSE TWO SOLUTIONS...WITH A SLIGHT LEAN
TOWARD THE WARMER EC.

&&

.AVIATION...PREDOMINANT VFR CONDITIONS ARE EXPECTED THROUGH THE
PERIOD AT KSLC. WINDS ARE EXPECTED TO REMAIN FROM THE WEST-NORTHWEST
UNTIL A SOUTHERLY DRAINAGE WIND RE-DEVELOPS BETWEEN 03-04Z. THERE IS
A 30 PERCENT CHANCE THAT ADDITIONAL THUNDERSTORMS WILL DEVELOP IN
THE VICINITY OF THE TERMINAL THROUGH THIS EVENING...WITH THE MOST
LIKELY IMPACT BEING ERRATIC GUSTY WINDS.

&&

.FIRE WEATHER...HIGH PRESSURE OVER THE STATE IS WEAKENING...AND WILL
BEGIN MOVING TO THE EAST OVERNIGHT. MOISTURE UNDER THE RIDGE HAS
RESULTED IN YET ANOTHER DAY OF AFTERNOON SHOWERS AND THUNDERSTORMS.
DUE TO LIGHT WINDS...THESE STORMS ARE MOVING SLOWLY...INCREASING THE
CHANCE OF WETTING RAIN IN THOSE AREAS THAT THAT SEE THUNDERSTORMS.

THE MOISTURE THAT HAS BEEN RESPONSIBLE FOR THE AFTERNOON CONVECTION
OF THE PAST FEW DAYS WILL BEGIN TO DECREASE FROM THE SOUTH TOMORROW.
WHILE THUNDERSTORM DEVELOPMENT IS EXPECTED TO OCCUR AGAIN TOMORROW
AFTERNOON...ACTIVITY WILL START LATER AND BE LESS WIDESPREAD IN THE
SOUTHERN PART OF THE STATE AS THE DRIER AIR MOVES IN.

A STRONG LOW PRESSURE SYSTEM IS MOVING ONTO THE CALIFORNIA COAST.
AHEAD OF THIS SYSTEM...A STRONG...DRY SOUTHWEST FLOW WILL DEVELOP
TOMORROW AFTERNOON. THIS WILL BRING STRONG WINDS AND A RAPID DRYING
TREND TO THE AREA THAT WILL LAST THOUGH AT LEAST THURSDAY.

&&

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

&&

PUBLIC...SCHOENING
FIRE WEATHER...HOSENFELD
AVIATION...SEAMAN

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1046 AM MDT MON JUN 1 2009

UTZ001>016-019>021-517-518-WYZ021-021200-
CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT-
SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT-
GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS-
WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-
WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS-
WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL-
SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH-
UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH-
GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS-
SOUTHERN MOUNTAINS-SOUTHWEST WYOMING-
1046 AM MDT MON JUN 1 2009

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED
ACROSS THE OUTLOOK AREA ONCE AGAIN TODAY...WITH THE GREATEST
COVERAGE DURING THE AFTERNOON AND EVENING HOURS. A FEW OF THESE
STORMS WILL PRODUCE LOCALLY HEAVY RAIN...BRINGING A THREAT OF
ISOLATED FLASH FLOODING TO SLOT CANYONS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A DRYING TREND WILL BEGIN FROM THE SOUTHWEST ON TUESDAY WHILE THE
NORTH AND EAST REMAINS MOIST. THIS DRYING WILL SPREAD ACROSS MORE
OF THE OUTLOOK AREA WEDNESDAY THROUGH THURSDAY. GUSTY SOUTHWEST
WINDS WILL ACCOMPANY THIS DRIER AIR. ISOLATED HIGH BASED
THUNDERSTORMS COULD STILL OCCUR THROUGH THE END OF THE WEEK AND
INTO THE WEEKEND...WITH GUSTY WINDS POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

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

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
613 PM MDT MON JUN 1 2009

UTZ002-005-007-020045-
GREAT SALT LAKE DESERT AND MOUNTAINS UT-NORTHERN WASATCH FRONT
UT-WASATCH MOUNTAINS I-80 NORTH UT-
613 PM MDT MON JUN 1 2009

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN BOX ELDER COUNTY
UNTIL 645 PM MDT...

AT 610 PM MDT...STORM SPOTTERS REPORTED A STRONG THUNDERSTORM
PRODUCING PENNY SIZE HAIL IN TREMONTON. THIS STORM IS MOVING
NORTHEAST AT 10 MPH.

PENNY TO NICKEL SIZE HAIL IS EXPECTED WITH THIS STORM...ALONG WITH
FREQUENT DANGEROUS LIGHTNING.

* LOCATIONS IMPACTED INCLUDE...
   COLLINSTON...
   FIELDING AND PLYMOUTH...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

THIS STORM IS CAPABLE OF PRODUCING PENNY TO NICKEL SIZE HAIL. IF
THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY
BUILDING.