Weather Service Report


947 
FXUS65 KMSO 312042
AFDMSO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
242 PM MDT TUE MAR 31 2015

.DISCUSSION...A STRONG COLD FRONT WILL MOVE ACROSS SOUTHWEST
MONTANA AND LEMHI COUNTY LATE THIS AFTERNOON AND EVENING AND
PRODUCE STRONG GUSTY WINDS. DEERLODGE TO ANACONDA, BUTTE, SALMON
AND GILMORE SUMMIT SHOULD SEE THE STRONGEST WINDS AND LOCALLY UP
TO 40-50 MPH...BUT MOSTLY 35-40 MPH. GUSTY SOUTHWEST WINDS WILL
PEAK OVER FLATHEAD LAKE EARLY THIS EVENING WITH LOCAL ROUGH WAVE
CONDITIONS. 

BEHIND THE COLD FRONT, SCATTERED SHOWERS WILL PERSIST THROUGH MUCH
OF THE EVENING, ESPECIALLY FROM THE BITTERROOTS AND MISSION
MOUNTAINS TO THE CONTINENTAL DIVIDE. THE SHOWERS FROM THE CAMAS
PRAIRIE TO OROFINO SHOULD QUICKLY DECREASE AND MOSTLY END EARLY
THIS EVENING. 

AS THE MAIN UPPER LEVEL WEATHER SYSTEM SHIFTS OVER SOUTHWEST
MONTANA THIS EVENING, THE SHOWERS SHOULD FURTHER ENHANCE WITH A
PERIOD OF LIGHT TO MODERATE SNOW IN THE TERRAIN. LOST TRAIL PASS
SHOULD BE THE SITE THAT IS MOST UNDER THIS AREA OF SNOW AND THUS
WINTER TRAVEL CONDITIONS WILL QUICKLY DEVELOP. IN ADDITION, THE
INITIALLY WET ROADS SHOULD QUICKLY BECOME SLUSHY AND THEN FREEZE
AS TEMPERATURES FALL WELL BELOW FREEZING ON LOST TRAIL PASS THIS
EVENING. SOME OF THE SNOW SHOWERS MAY ALSO IMPACT BANNOCK PASS,
GEORGETOWN LAKE AND AS FAR EAST AS HOMESTAKE PASS, BUT THE
AMOUNTS AND IMPACT SHOULD BE LESS.

AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL SETTLE OVER THE
NORTHERN ROCKIES WEDNESDAY AND PERSIST INTO THURSDAY. THIS SHOULD
TRANSLATE INTO MAINLY DAY TIME SHOWERS, WITH MANY AREAS SEEING
SOME GRAUPEL OR LIGHT SNOW MIXED, EVEN DOWN TO THE LOWER VALLEY
FLOORS OF WESTERN MONTANA AND CAMAS PRAIRIE OF NORTH CENTRAL
IDAHO.

COOL AND SHOWERY WEATHER WILL CONTINUE FRIDAY THROUGH EARLY NEXT
WEEK, ALTHOUGH NICE CONDITIONS WILL OCCUR BETWEEN SYSTEMS. IT WILL
BE DIFFICULT TO TIME MINOR DISTURBANCES. ONE TIME PERIOD THAT
DOES STAND OUT IS LATE EASTER INTO MONDAY AS FORECAST MODELS
CONTINUE TO TREND TOWARD A STRONGER DISTURBANCE. ALTHOUGH
CONFIDENCE IS NOT HIGH, THE POTENTIAL EXIST FOR MOUNTAIN PASS SNOW
AND POSSIBLY EVEN SNOWFALL ACROSS SOME LOWER VALLEYS. ALSO,
TEMPERATURES WILL REMAIN BELOW NORMAL WITH MORNING LOWS ESPECIALLY
CHILLY THUS CONTINUING THE THREAT TO SENSITIVE VEGETATION.

&&

.AVIATION...A STRONG COLD FRONT IS MOVING ACROSS WESTERN MONTANA
INTO EARLY THIS EVENING. KMSO AND KGPI ARE ALREADY BEING IMPACTED
BY A FEW SHOWERS AND INCREASED WINDS MID AFTERNOON. AS THE COLD
FRONT SHIFTS ACROSS SOUTHWEST MONTANA AND LEMHI COUNTY LATE THIS
AFTERNOON AND EARLY EVENING, IT WILL STRENGTHEN AND PRODUCE EVEN
STRONGER WINDS. KBTM AND KSMN SHOULD SEE A SIGNIFICANT WIND SHIFT
TO NORTHWEST WINDS AND GUSTS 40-45 KNOTS. THE SHOWERS SHOULD
FURTHER ENHANCE OVER THE SOUTHERN BITTERROOTS, SAPPHIRES, AND
NORTHERN LEMHI COUNTY THIS EVENING WITH MOUNTAIN OBSCURATIONS
LIKELY. ELSEWHERE, SCATTERED MOUNTAIN OBSCURATIONS DUE TO SNOW
SHOWERS WILL CONTINUE INTO THE EVENING.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT BUTTE/BLACKFOOT REGION.

     LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FLATHEAD/MISSION 
     VALLEYS.

ID...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM MDT 
     WEDNESDAY FOR LOST TRAIL PASS IN THE EASTERN LEMHI COUNTY.

     WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT EASTERN LEMHI COUNTY.

&&

$$

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