Area Forecast Discussion
Issued by NWS Pocatello, ID

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000
FXUS65 KPIH 260926
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
326 AM MDT SUN APR 26 2015

.SHORT TERM...TODAY THROUGH TUESDAY AFTERNOON. IT SEEMS THE BEST
WAY TO DESCRIBE TODAY`S WEATHER IS MESSY. THE SYSTEM CONTINUES TO
SPLIT AS IT IS MOVING EAST. DRIER AIR IS ALREADY WORKING INTO THE
WESTERN FRINGE OF OUR FORECAST AREA. MEANWHILE...A PRETTY
PERSISTENT BAND OF RAIN AND SNOW EXTENDS FROM AROUND CHALLIS TO
POCATELLO TO NEAR MALAD. AT THE SAME TIME...RAIN AND SNOW IS
INCREASING TO THE EAST OF THE BAND. SNOW IS FALLING DOWN TO
6000-6500FT. WE WILL LIKELY SEE SOME OF THE HIGHER PASSES...LIKE
WE`VE ALREADY SEEN AT WILLOW CREEK SUMMIT...GETTING SNOW AT TIMES.
HOWEVER...THE IMPACTS FOR MOST OF THEM WILL BE MINIMAL EXCEPT FOR
WILLOW CREEK AND HEADING OVER TETON PASS. THOSE TWO PASSES WILL
EVENTUALLY SEE IMPROVING CONDITIONS LATER THIS MORNING. AS THE DAY
WEARS ON...WE WILL SEE A GRADUAL SHIFT TO THE EASTERN HIGHLANDS WITH
THE FOCUS FOR PRECIPITATION. SNOW LEVELS WILL BOUNCE BACK TO
6500-7500FT BY AFTERNOON. IT DOES APPEAR THAT WE WILL SEE SOME
INSTABILITY SHOWERS ACROSS PORTIONS OF THE CENTRAL MOUNTAINS AND
SNAKE PLAIN. THE GFS AND THE HRRR ARE ACTUALLY TRYING TO DEPICT
THE POTENTIAL FOR A CONVERGENCE BAND...POSSIBLY AS FAR SOUTH AS
CRATERS TO AROUND FORT HALL. THAT IS SOMETHING THAT WILL NEED TO
BE MONITORED CLOSELY. BREEZY CONDITIONS WILL DEVELOP IN TWO
SEPARATE LOCATIONS TODAY. THE FIRST WILL BE ACROSS THE UPPER PLAIN
AND HIGHLANDS AS NORTHERLY WINDS KICK IN. THE MAGIC VALLEY AND
SOUTH-CENTRAL HIGHLANDS IS THE OTHER...AND WILL LIKELY SEE THE
STRONGEST WINDS. SUSTAINED WINDS OF 20-30 MPH ARE FORECAST WITH
30-35 MPH IN ISOLATED SPOTS. THIS IS TOO LOW FOR A WIND
ADVISORY...BUT IF ENOUGH PLOWING IS ONGOING THERE COULD BE SOME
BLOWING DUST IN AREAS THAT SAW LITTLE TO NO RAINFALL.

MONDAY AND TUESDAY WILL BE DRIER AND MUCH WARMER WITH HIGH
PRESSURE BUILDING ACROSS THE WEST. BY TUESDAY...HIGHS WILL BE WELL
INTO THE 70S FOR THE VALLEYS AND 50S/60S IN THE MOUNTAINS. KEYES

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY NIGHT. BOTH GFS AND ECMWF
IN AGREEMENT WITH THE UPPER RIDGE MOVING OFF TO THE EAST AND A
STRONG UPPER TROF MOVING INTO THE PAC NW BY WED MORN. THE TROF THEN
PASSES THRU ID ON THU. MOISTURE APPEARS TO BE LIMITED WITH THIS
SYSTEM. THIS WILL RESULT IN A FEW SHOWERS IN THE CENTRAL MTNS WED
AFTN AS THE INCREASING SW FLOW INTERACTS WITH THE TERRAIN. PRECIP
INCREASES IN COVERAGE ACROSS THE CENTRAL MTNS AND INTO THE UPPER
SNAKE HIGHLANDS WED NIGHT AS THE UPPER TROF APPROACHES. BY THU...A
COLD FRONT PASSES THRU PUSHING MOST OF THE PRECIP OUT OF THE AREA
EXCEPT FOR LINGERING SHOWERS IN THE EASTERN HIGHLANDS. STRONG WEST
TO SW WINDS ALONG WITH COOLER TEMPS ON THU. THE ECMWF IS A LITTLE
SLOWER WITH THIS SYSTEM...SO PRECIP IS A LITTLE MORE WIDESPREAD THAN
THE MOSTLY DRY GFS. NOW THE PICTURE GETS MUDDY. THE GFS DEVELOPS A
BROAD RIDGE OVER THE PAC NW ON FRI...WHILE THE ECMWF DOES JUST THE
OPPOSITE WITH A BROAD TROF. THE GFS MAINTAINS A DRY FCST THRU SUN
WITH A DOMINANT RIDGE...WHILE THE ECMWF DEVELOPS A CLOSED LOW OVER
WA. THE ECMWF SUGGESTS A WET SUN AND SUNDAY NIGHT...WHILE THE GFS IS
DRY. WILL CARRY LOW CHC FOR SHOWERS OVER THE EASTERN HIGHLANDS SUN
AND SUN NIGHT AND LEAVE THE REST OF THE FCST AREA DRY UNTIL THE
PICTURE BECOMES CLEARER. HEDGES

&&

.AVIATION...SHOWERS WILL MOVE OUT OF THE AREA LATER THIS MORN...WITH
IMPROVING CIGS BY AFTN. SW WINDS WILL BR RATHER STRONG TODAY ACROSS
THE SNAKE RIVER PLAIN. WINDS WILL SETTLE DOWN BY EVE. HEDGES

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$



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