Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 222036
AFDMSO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
236 PM MDT MON SEP 22 2014

...NEAR RECORD HIGH TEMPERATURES WEDNESDAY AND POSSIBLY THURSDAY...

.DISCUSSION...A WEAK WEATHER DISTURBANCE WILL BRUSH NORTH CENTRAL
IDAHO TONIGHT AND MAINLY NORTHWEST MONTANA TUESDAY. THIS WILL
SUPPORT MORE INSTABILITY AND POSSIBLY A FEW LIGHT SHOWERS.

HIGH PRESSURE IS EXPECTED TO STRENGTHEN WEDNESDAY AND FURTHER
WARM THE AIR MASS. AT THE SAME TIME, A STRONGER SOUTHWEST FLOW IS
EXPECTED TO DEVELOP. THE RESULTANT WINDS WILL HELP MIX THE LOWER
ATMOSPHERE AND PUSH VALLEY TEMPERATURES TO THE FULL POTENTIAL
(DESPITE THE SHORTER DAYS OF LATE SEPTEMBER). A FEW AREAS COULD
REACH OR EXCEED RECORD AFTERNOON TEMPERATURES WEDNESDAY,
ESPECIALLY IN WESTERN MONTANA VALLEYS. TEMPERATURES SHOULD WARM TO
15 TO 25 DEGREES ABOVE NORMAL. IN ADDITION TO THE HOT SEPTEMBER
TEMPERATURES, BREEZY CONDITIONS SHOULD DEVELOP WEDNESDAY AND MAY
IMPACT AREA LAKES WITH INCREASING WAVES/ROUGH CHOP.

A WEAKENING COLD FRONT SHOULD SHIFT ACROSS NORTH CENTRAL IDAHO AND
INTO WESTERN MONTANA THURSDAY. THE FRONT SHOULD DELIVER A LITTLE
COOLER AIR TO GRANGEVILLE, OROFINO AND NORTHWEST MONTANA THURSDAY.
HOWEVER, IT APPEARS TEMPERATURES SHOULD AGAIN APPROACH OR EXCEED
RECORD HIGHS IN SOUTHWEST MONTANA FROM ABOUT MISSOULA SOUTH AND
EAST TO THE DIVIDE AS WELL AS LEMHI COUNTY. WINDS SHOULD AGAIN
PICK UP THURSDAY, WITH THE BIGGEST IMPACT TO AREA LAKES.

ADDITIONAL COOL AIR SHOULD SHIFT ACROSS THE NORTHERN ROCKIES LATE
THURSDAY INTO FRIDAY. UNDER A MORE SOUTHERLY FLOW ALOFT, THE AIR
MASS SHOULD GRADUALLY MOISTEN AND EVENTUALLY PRODUCE, AT LEAST, A
FEW SHOWERS.

THERE IS STILL QUITE A BIT OF UNCERTAINTY FOR SATURDAY AND SUNDAY.
MODELS ARE VERY DIVERGENT REGARDING THE DEPTH, SPEED, AND LOCATION
OF THE APPROACHING UPPER TROUGH OF LOW PRESSURE. HOWEVER, THERE IS
MORE CONSISTENCY REGARDING ADDITIONAL SHOWERS AND COOLER
CONDITIONS. THE AMOUNT OF PRECIPITATION IS THE BIGGEST QUESTION.

&&

.AVIATION...A WEAK WEATHER DISTURBANCE WILL MOVE OVER NORTH
CENTRAL IDAHO TONIGHT BRINGING A SLIGHT CHANCE OF RAIN IN THE
VICINITY OF KSMN. WINDS WILL BE BREEZY AND COULD GUST INTO THE 15
TO 20 MPH RANGE UNTIL THIS EVENING. THE DISTURBANCE WILL THEN
MOVE ACROSS NORTHWEST MONTANA INTO TUESDAY. THE ATMOSPHERE SHOULD
MOISTEN SUFFICIENTLY TO SUPPORT A FEW SHOWERS, WITH KGPI AS THE
MOST IMPACTED TERMINAL.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&

$$



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