Winter Storm Warning 5, NWS Pocatello, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
306 PM MST FRI MAR 24 2006

.SHORT TERM...STRONG SHORT WAVE 40N 135W WILL ENTER OREGON EARLY
SATURDAY. WARM FRONTAL BAND INITIALLY EXTENDS INTO NORTHERN NEVADA
BUT NEW SURFACE LOW GENERATES SOUTHEAST OREGON AND LIFTS
NORTHEAST. COLD FRONT CROSS CENTRAL MOUNTAINS AROUND 300 PM AND
THE UPPER SNAKE RIVER VALLEY 700 TO 800 PM SATURDAY EVENING. SNOW
LEVELS 7500 FEET OR HIGHER AHEAD OF FRONT FALL RAPIDLY TO VALLEY
FLOORS AS FRONT PASSES. WITH CONVECTIVE POTENTIAL AND SLIGHT
CHANCE OF THUNDERSTORMS VALLEYS COULD SEE 1 TO 3 INCHES SNOW WITH
FRONTAL PASSAGE. SOUTHWEST FLOW AND QPF .5 TO .8 INCH FOCUSED ON
ZONE 31 AND 18 FROM SATURDAY MORNING TO SUNDAY MORNING. THEREFORE
HEAVY SNOW WARNING FOR MOUNTAINS ISSUED. JET ADVANCES ACROSS
NEVADA AND UTAH SATURDAY NIGHT AND SUNDAY IN LESS THAN FAVORABLE
POSITION FOR STRONGEST WINDS TO CATCH FORECAST AREA.
STILL...SURFACE PRESSURE GRADIENT AND COLD ADVECTION ALOFT
SUFFICIENT FOR WINDS TO REACH ADVISORY LEVELS IN THE LOWER SNAKE
RIVER PLAIN AND EASTERN MAGIC VALLEY EARLY SUNDAY. MODELS VERY
SOME WITH SNOW AMOUNTS THE EASTERN HIGHLANDS. COULD BE AT LEAST 8
TO 10 INCHES ABOVE 7000 FEET LATE SATURDAY NIGHT THROUGH SUNDAY
NIGHT. RS

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...A RIDGE OF HIGH PRESSURE
WILL KEEP CONDITIONS MILD AND DRY ACROSS EASTERN IDAHO THROUGH EARLY
WEDNESDAY.  MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT
THAT A TROUGH OF LOW PRESSURE WILL MIGRATE THROUGH JUST SOUTH OF
IDAHO THROUGH NORTHERN NV/UT LATE WEDNESDAY INTO THURSDAY.  THIS
TRAJECTORY IS A MOIST PATTERN FOR EASTERN IDAHO...AND THE GENERAL
AGREEMENT BETWEEN FCST MODELS HAS INCREASED FORECASTER CONFIDENCE
THAT A DECENT PRECIPITATION EVENT WILL OCCUR DURING THAT PERIOD.
BEYOND THURSDAY AN ACTIVE ZONAL PATTERN WILL CONTINUE THROUGH WEEKS
END. CANTIN

&&

.AVIATION...VFR CONDITIONS WILL BE PREVALENT OVERNIGHT...WITH A
NOTABLE EXCEPTION AT KSUN AND WESTERN PORTIONS OF TWEB ROUTE 345
AFTER 09Z.  AS MOIST SOUTHERLY FLOW INCREASES CONDITIONS WILL
DETERIORATE TO IFR OR WORSE NEAR KSUN...WHILE SHOWER ACTIVITY WILL
PROMOTE MVFR CEILINGS FROM TWIN FALLS TO BOISE.  A COLD FRONT WILL
BRING WIDESPREAD MVFR/IFR CONDITIONS TO ALL TAF SITES AND TWEB
ROUTES LATE SATURDAY AFTERNOON (AFTER 00Z).  CANTIN

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
HEAVY SNOW WARNING FROM 6 AM SATURDAY TO 6 AM MST SUNDAY FOR
IDZ018-IDZ031.

&&

99/99

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE POCATELLO ID
430 AM MST FRI MAR 24 2006

IDZ017>025-031-032-251500-
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-
430 AM MST FRI MAR 24 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH FRIDAY

A PACIFIC STORM IS EXPECTED TO SPREAD VALLEY RAIN AND MOUNTAIN SNOW
THROUGH CENTRAL AND EASTERN IDAHO SATURDAY AND SATURDAY NIGHT.
MODERATE TO HEAVY MOUNTAIN SNOW IS POSSIBLE WITH THIS STORM ACROSS
THE CENTRAL MOUNTAINS ABOVE 6500 FEET. AS A RESULT...A WINTER STORM
WATCH HAS BEEN POSTED FOR PORTIONS OF THE CENTRAL MOUNTAINS. SNOW
LEVELS WILL FALL TO THE VALLEY FLOOR ACROSS THE SNAKE AND MAGIC
VALLEY SATURDAY EVENING BEHIND THE FRONT. A QUICK INCH OR TWO IS
POSSIBLE IN THE SNAKE VALLEY BEFORE ENDING EARLY SUNDAY MORNING.

.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.