Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 090819
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
219 AM MDT TUE SEP 9 2014

.DISCUSSION...UPPER TROUGH OVER THE PAC NW WILL CONTINUE PUSHING
THROUGH THE STATE TODAY. EXPECT TO SEE SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS OUR EASTERN HIGHLANDS THROUGH THIS EVENING. AT
THE SURFACE...A COLD FRONT WILL MOVE THROUGH PRODUCING SOUTHWEST
WINDS WITH GUSTS 35 TO 40 MPH ACROSS THE SNAKE PLAIN. THIS IS ENOUGH
TO PRODUCE ROUGH CHOPPY WATERS ON AMERICAN FALLS RESERVOIR. THUS A
LAKE WIND ADVISORY HAS BEEN ISSUED FOR THIS AFTERNOON.

WE WILL BEGIN TO TRANSITION INTO A DRIER NORTHWESTERLY FLOW AFTER
THE UPPER TROUGH PASSES LATER THIS AFTERNOON. MODELS THOUGH ARE
SUGGESTING A SECONDARY TROUGH WILL DROP IN OUT OF CANADA AND CLIP
THE ISLAND PARK AREA WITH SOME MOISTURE. ADDITIONALLY...MODELS ARE
SHOWING A GREAT DEAL OF UNCERTAINTY WITH TEMPERATURES ON ACCOUNT OF
THE SECONDARY TROUGH. THE COOLEST TEMPS WILL BE THURS NIGHT TO
FRIDAY MORNING WITH TEMPERATURES DROPPING TO THE FREEZING MARK IN
THE UPPER SNAKE PLAIN. IF THE CANADIAN AIR HAS A STRONG ENOUGH
PUSH...IT MAY SPILL ACROSS THE DIVIDE AND DROP OUR TEMPERATURES EVEN
LOWER. THIS WILL BE THE FORECAST CHALLENGE FOR THE WEEK.  HINSBERGER
&&

.AVIATION...AN UPPER TROUGH AXIS WAS GRADUALLY WORKING EAST THROUGH
NORTH IDAHO/ERN OREGON EARLY THIS MORNING. MODELS SUGGEST THAT THE
AXIS WILL SWING THROUGH THE WYOMING BORDER REGION AROUND
MID-AFTERNOON. ANTICIPATING ISOLATED CONVECTION TO CONTINUE ACROSS
THE SRN HIGHLANDS AHEAD OF THE TROUGH PASSAGE TODAY WITH NO
CONVECTIVE IMPACTS ON SNAKE RIVER PLAIN TERMINALS. THE PASSING
TROUGH WILL BRING SOME WIND HOWEVER...WITH STRONG GUSTY WSW WINDS
ANTICIPATED THROUGHOUT THE SNAKE RIVER PLAIN BY MID-AFTERNOON AND
CONTINUING INTO THE EARLY EVENING HOURS. HUSTON
&&

.FIRE WEATHER...UPPER TROUGH AXIS OVER NORTH IDAHO/ERN OREGON EARLY
THIS MORNING WILL PROGRESS EAST THROUGH THE WYOMING BORDER REGION BY
MID-AFTERNOON. ISOLATED THUNDERSTORMS WILL SPREAD EAST ACROSS THE
SOUTHERN/CARIBOU HIGHLANDS AHEAD OF THE TROUGH TODAY AND END BY
LATE AFTERNOON. STRONG GUSTY WEST WINDS (ALBEIT LIGHTER THAN
PREVIOUS PROGS) WILL OVERSPREAD THE REGION THIS AFTERNOON AND
CONTINUE INTO THE EARLY EVENING HOURS BEFORE DECOUPLING.
NON-CRITICAL FUEL CONDITIONS HAVE QUELLED ANY RED FLAG HIGHLIGHTS
FOR NOW. A BACK-DOOR FRONT WILL EASE INTO THE MONTANA DIVIDE REGION
THIS AFTERNOON HELPING TO SUPPORT ISOLATED CONVECTION IN THAT REGION
THROUGH THE EVENING. A SECONDARY TROUGH IS EXPECTED TO ROTATE
THROUGH THE NRN ROCKIES THURSDAY BRINGING A SLIGHT RISK OF SHOWERS
TO THE DIVIDE REGION AND A FAIRLY DECENT NORTHERLY PUSH OF COOLER
AIR SPILLING OVER THE DIVIDE INTO THE SNAKE RIVER PLAIN.
TEMPERATURES WILL GRADUALLY RECOVER THROUGH THE WEEKEND AS A RIDGE
BUILDS OVER THE AREA. THE MODELS SUGGEST A WEAK LOW WILL
ADVANCE OVER THE SHALLOW RIDGE SOMETIME MONDAY/TUESDAY BRINGING A
SLIGHT CHANCE OF SHOWERS TO THE CNTRL MOUNTAINS. HUSTON
&&

.PIH WATCHES/WARNINGS/ADVISORIES...LAKE WIND ADVISORY FROM 3 PM
THIS AFTERNOON TO 8 PM MDT THIS EVENING IDZ021.
&&

$$




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