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000
FXUS65 KPIH 011635
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
935 AM MST SUN DEC 1 2013

.SHORT TERM...TODAY THROUGH WEDNESDAY. A QUICK UPDATE THIS MORNING
AS THE LATEST 12Z NAM MODEL WAS SHOWING A MOVE TOWARD THE POTENTIAL
FOR A MUCH STRONG WIND EVENT MONDAY AFTERNOON ACCOMPANYING THE
FRONTAL PASSAGE. HAVE OPTED AT THIS TIME TO ISSUE A HIGH WIND WATCH
FOR MONDAY FOR THE VALLEY ZONES...WITH THE IDEA THAT WE WILL
CERTAINLY SEE ADVISORY LEVEL WINDS IN ZONES 17/20/21 AND 22
POTENTIALLY SPIKING UP INTO WARNING CRITERIA WITH THE FRONTAL
PASSAGE SOMETIME BETWEEN 2 PM AND 6 PM MST. WE WILL BE ABLE TO HONE
IN ON THAT ITEM TONIGHT/MONDAY. SEE PREVIOUS DISCUSSION BELOW. HUSTON

WV IMAGERY THIS MORNING SHOWING UPPER LOW IN THE GULF OF ALASKA
BEGINNING TO SAG SOUTHEASTWARD. ATMOSPHERIC RIVER IS GETTING
CHANNELED BETWEEN THE LOW AND THE UPPER RIDGE AROUND 150W WITH
STRONG MOISTURE TRANSPORT PENETRATING INLAND INTO THE PACIFIC
NORTHWEST. NAEFS ENSEMBLE MEAN IVT LENDS CONFIDENCE TO A WET
FORECAST AS IT CONTINUES WITH A +4 STANDARD ANOMALY OVER MUCH OF
IDAHO. HAVE KEPT WITH FAIRLY HEAVY SNOW AMOUNTS IN THE CENTRAL
MOUNTAINS AND EASTERN HIGHLANDS WITH TOTAL ACCUMULATION OF UP TO 20
INCHES POSSIBLE. THUS WILL KEEP CURRENT HEADLINES IN PLACE. THE
ATMOSPHERIC RIVER SHIFTS SOUTHWARD LATE MONDAY AS A COLD FRONT
APPROACHES FROM THE NORTH. THE 700MB FLOW AHEAD OF THE FRONT IS
AROUND 50KTS ACROSS THE SNAKE PLAIN. GUSTY WINDS CAN BE EXPECTED
DURING THE DAY MONDAY AND INTO MONDAY NIGHT.

BEHIND THE FRONT...EXPECT LINGERING SNOWSHOWERS ESPECIALLY OVER THE
SOUTHERN HIGHLANDS WHERE THE UPSLOPE COMPONENT IS MOST FAVORABLE.
TUESDAY AND WEDNESDAY LOOK TO BE MUCH COOLER AS MODELS DEPICT HIGH
AMPLITUDE UPPER RIDGE INTO ALASKA WITH A NORTHERLY UPPER FLOW OVER
IDAHO.  HINSBERGER

.LONG TERM...WEDNESDAY THROUGH SATURDAY. SHARP HIGH PRESSURE RIDGE
NEAR 140W EXTENDING INTO ALASKA WITH COLD NORTHERLY WINDS DOWN
STREAM OVER SOUTHEAST IDAHO. THIS PATTERN PERSISTS PERHAPS AS FAR
OUT AS NEXT SUNDAY MORNING. COLD AIR APPEARS TO ORIGINATE AS FAR
AWAY AS THE EAST SIBERIAN SEA AND ARCTIC CIRCLE...DESCENDING THROUGH
THE NORTHWEST TERRITORIES. MODELS ARE SHOWING CONSISTENCY...AND
700MB WINDS LOOK FAVORABLE TO PUSH THIS AIR THROUGH THE MOUNTAIN
PASSES INTO THE UPPER SNAKE PLAIN. HAVE LOWERED BOTH HIGH AND LOW
TEMPERATURES WEDNESDAY THROUGH FRIDAY. KEPT SOME LOW POPS IN FOR
LIGHT SNOW EACH DAY...AS THE AIR IS RATHER COLD. TEMPERATURES WILL
BE THE BIG STORY. WEDNESDAY MORNING...NORTHERLY SURFACE WINDS NEAR
10 MPH AND MORNING LOWS NEAR ZERO IN THE UPPER SNAKE PLAIN WILL
SUPPORT EXTREME WIND CHILLS OF 15 TO 25 BELOW ZERO. THURSDAY MORNING
SHOULD BE THE COLDEST...SOME ZERO TO MINUS 10F AIR
TEMPERATURES...NOT WIND CHILLS...POSSIBLE. THE TRADE OFF COULD BE
NORTH WINDS SLIGHTLY LIGHTER AND REDUCING THE WIND CHILL THREAT.
THERE IS SOME MODEL SUPPORT FOR TEMPERATURES TO BE SEVERAL DEGREES
COLDER THAN CURRENTLY FORECAST...AND IF WE HAVE GOOD FRESH WHITE
SNOW COVER THAT IS POSSIBLE. RS
&&

.AVIATION...MVFR CEILINGS WILL BE THE GENERAL RULE AT ALL TAF SITES
TODAY THROUGH MONDAY. A DISTURBANCE EMBEDDED IN THE WESTERLY FLOW
ALOFT WILL CROSS KSUN MID DAY...THE SNAKE PLAIN BETWEEN 21Z AND 03Z
THIS AFTERNOON. LIGHT RAIN AND OR SNOW IS POSSIBLE AT KSUN 15-22Z
AND AT KIDA AND KPIH 21-03Z. SNOW LEVELS WILL BE NEAR 5800 FT MSL AT
KBYI SLOPING TO 5300 FT MSL TOWARDS THE MONTANA BORDER. MOUNTAINS
WILL BE OBSCURED AS THE STORM SYSTEM MOVES SLOWLY SOUTH...CROSSING
INTO UTAH BY 03/06Z. BREEZY WEST TO SOUTHWEST WINDS 20 TO 30 MPH
18-02Z TODAY...AND AGAIN MONDAY. POST FRONTAL WINDS NORTHERLY AT
KIDA 03/02Z AND KPIH 03/03Z. RS
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT MST MONDAY
NIGHT ABOVE 6000 FEET FOR THE IDZ032.

WINTER STORM WARNING FROM NOON TODAY TO 6 AM MST TUESDAY ABOVE
6000 FEET FOR THE IDZ019-023.

WINTER STORM WARNING FROM NOON TODAY TO MIDNIGHT MST MONDAY
NIGHT ABOVE 6000 FEET FOR THE IDZ031.

WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM MST TUESDAY
ABOVE 6000 FEET FOR THE IDZ025.

WINTER STORM WARNING FROM NOON TODAY TO MIDNIGHT MST MONDAY
NIGHT IDZ018.

HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING
IDZ017-020-021.
&&

$$