Severe Thunderstorm Warning 52, NWS Pocatello, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
214 PM MDT SUN AUG 31 2008

.DISCUSSION...WV SHOWS UPPER TROUGH HAS MADE LANDFALL WITH TROUGH
AXIS ROUGHLY THROUGH CENTER OF WASHINGTON/OREGON THIS AFTERNOON.
SFC COLD FRONT SPLIT THIS MORNING WITH FIRST WAVE ALREADY THROUGH
A SIGNIFICANT PORTION OF EASTERN IDAHO...CURRENTLY STALLED ON A
LINE FROM ROUGHLY KDIJ TO KPIH AND THEN SOUTHWEST INTO NEVADA.
SECOND PORTION OF FRONT HUNG UP IN CENTRAL MTNS COINCIDENT WITH
700MB TROUGH...WHERE LINE OF SHOWERS AND ISOLATED STORMS CONTINUES
THIS AFTERNOON. STRONGER STORMS ALREADY FIRING ALONG THE FRONT IN
NEVADA AND ARE BEGINNING TO MAKE NORTHWARD PROGRESS INTO SOUTHERN
IDAHO. GIVEN MOISTURE AND SHEAR PROFILES...BEST BET FOR STRONG TO
POTENTIALLY SEVERE THUNDERSTORMS THIS AFTERNOON IN EXTREME
SOUTHEAST CORNER AHEAD OF FRONT. STRONG WIND GUSTS AND HAIL THE
MAJOR THREATS. DEEP CONVECTION EXPECTED TO END WITH SUNSET. UPPER
TROUGH PUSHES EAST TONIGHT AND THROUGH THE DAY MONDAY. WILL EXPECT
SHOWERS ACROSS THE AREA UNDER INFLUENCE OF COLD POOL ALTHOUGH LACK
OF JET DYNAMICS AND MUCH DRIER AIR SHOULD PRECLUDE THUNDERSTORM
DEVELOPMENT. CAVEAT TO THE PRECIPITATION IS THAT BOTH THE NAM AND
THE GFS MAINTAIN DRY SLOT OVER THE SNAKE VALLEY THROUGH
MONDAY. WINDS STAY ELEVATED UNDER TIGHT SFC GRADIENT BEHIND THE
FRONT...WHICH WILL HELP KEEP OVERNIGHT LOWS RELATIVELY MILD
TONIGHT. STUCK CLOSE TO AVERAGE OF NAM/GFS NUMERICAL GUIDANCE.
HIGHS ON MONDAY WILL STRUGGLE...AND COULD BE LOWER THAN CURRENTLY
FCST GIVEN CURRENT TEMPS IN VALLEY. OVERNIGHT LOWS MONDAY NIGHT
COULD REACH NEAR FREEZING...AND WILL NEED TO BE WATCHED FOR
POTENTIAL FROST/FREEZE STATEMENT. OTHERWISE...UPPER LOW/TROUGH
DEPARTS MON NIGHT LEAVING BROAD COOL TROUGH OVER PACNW. MODELS
DROP WEAK WAVE THROUGH PANHANDLE SKIRTING THE MONTANA BORDER TUE
AND TUE NIGHT...BUT DOESNT APPEAR TO HOLD MUCH MOISTURE OTHER THAN
FOR A FEW MID LEVEL CLOUDS. AREA REMAINS UNDER THE INFLUENCE OF
THE COOL TROUGH THROUGH THE REMAINDER OF THE FCST...WITH MAINLY
DRY CONDITIONS AND COOLER THAN NORMAL TEMPS.  DMH

&&

.AVIATION...EXPECT THUNDERSTORMS AND RAIN SHOWERS AT ALL SNAKE PLAIN
TAF SITES THIS EVENING FROM BURLEY TO IDAHO FALLS.  THE COLD FRONT
APPEARS TO BE VERY NEAR POCATELLO AS IT HAS PROGRESSED EAST OF TWIN
FALLS AND BURLEY.  EXPECT MAINLY VFR CONDITIONS THROUGH MONDAY BUT
SOME OCCASIONAL MVFR CEILINGS OR VISIBILITIES MAY OCCUR UNDERNEATH A
HEAVY RAIN SHOWER OR THUNDERSTORM.  EXPECT GENERAL WINDS IN THE 10
TO 20 MPH RANGE THROUGH MONDAY AT BYI...IDA...AND PIH.
GK

&&

.FIRE WEATHER...AN UPPER LEVEL TROF CONTINUES TO PROGRESS EAST WITH A
COLD FRONT MOVING THROUGH EXTREME SOUTHEASTERN IDAHO AT PRESENT.  A
RED FLAG WARNING IS IN EFFECT UNTIL 8 PM FOR ZONES 412 AND 413 FOR
SCATTERED THUNDERSTORM ACTIVITY WITH DAMAGING WINDS AND HEAVY RAIN
POSSIBLE.  ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE
THE REMAINDER OF THE DISTRICT.  THE COLD FRONT CLEARS IDAHO TONIGHT
AND MUCH COLDER AND MOIST CONDITIONS WILL CONTINUE ON LABOR DAY.
GK

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR IDZ413.

&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE POCATELLO ID
557 AM MDT SUN AUG 31 2008

IDZ017>025-031-032-011030-
EASTERN MAGIC VALLEY-SAWTOOTH MOUNTAINS-UPPER SNAKE HIGHLANDS-
UPPER SNAKE RIVER PLAIN-LOWER SNAKE RIVER PLAIN-
SOUTH CENTRAL HIGHLANDS-CARIBOU HIGHLANDS-
CACHE VALLEY/IDAHO PORTION-WASATCH MOUNTAINS/IDAHO PORTION-
BIG AND LITTLE WOOD RIVER REGION-LOST RIVER/PAHSIMEROI-
557 AM MDT SUN AUG 31 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL CONTINUE TODAY AND TONIGHT ACROSS
PORTIONS OF EASTERN IDAHO. THE BEST CHANCE WILL BE IN THE HIGHER
ELEVATIONS. STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS
SOUTHEAST IDAHO...SOUTH AND EAST OF A LINE FROM MALAD TO POCATELLO
TO PALISADES RESERVOIR. LARGE HAIL AND DAMAGING WINDS ARE THE MAIN
THREATS. LOCALLY HEAVY RAINFALL IS POSSIBLE AS WELL...WITH A MORE
WIDESPREAD RAIN THREAT TONIGHT IN THE SOUTHEASTERN MOUNTAINS. AT
THIS TIME...NO FLOODING IS EXPECTED. THERE IS ENOUGH COVERAGE OF
THUNDERSTORMS IN THIS AREA FOR RED FLAG CONDITIONS TO BE MET.
THEREFORE A RED FLAG WARNING HAS BEEN ISSUED. PLEASE SEE RFWPIH FOR
MORE INFORMATION.

SNOW LEVELS WILL DROP TONIGHT ACROSS THE CENTRAL MOUNTAINS AND
SOUTHERN HIGHLANDS TO APPROXIMATELY 8000 TO 8500 FEET. LOCAL SNOW
ACCUMULATIONS UP TO 2 INCHES ARE FORECAST IN THE CENTRAL MOUNTAINS
ON THE HIGHER PEAKS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

RAIN AND MOUNTAIN SNOW SHOWERS WILL CONTINUE THROUGH MONDAY NIGHT.
SNOW LEVELS WILL DROP BY AFTERNOON TO APPROXIMATELY 7000 TO 7500
FEET. TOTAL ACCUMULATIONS OF 2 TO 4 INCHES ABOVE 8000 FEET IN THE
CENTRAL MOUNTAINS ARE FORECAST...WITH 1 TO 3 INCHES ACROSS THE
SOUTHERN AND EASTERN HIGHLANDS. MUCH COOLER TEMPERATURES AND GUSTY
WINDS WILL CREATE FALL LIKE WEATHER CONDITIONS ACROSS EASTERN
IDAHO. HIGH TEMPERATURES WILL RANGE FROM THE 30S IN THE HIGHER
ELEVATIONS TO NEAR 60 IN THE SNAKE PLAIN.

.SPOTTER INFORMATION STATEMENT...

WE ASK TRAINED SPOTTERS AND CITIZENS TO REPORT SIGNIFICANT
WEATHER CONDITIONS WHEN IT IS SAFE TO DO SO. THESE CONDITIONS MAY
INCLUDE HAIL...TORNADOES...STRONG WIND...DUST STORMS...SNOWFALL...
EXTREME COLD TEMPERATURES...FREEZING RAIN OR HEAVY RAIN...DENSE
FOG...AND FLOODING OR ICE JAMS. INFORMATION ABOUT THESE HAZARDOUS
CONDITIONS SHOULD BE CALLED INTO YOUR NATIONAL WEATHER SERVICE
OFFICE IN POCATELLO USING THE 1-800 SEVERE WEATHER HOTLINE...OR
208-233-0834.