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FXUS65 KMSO 232048
AFDMSO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
ISSUED BY NATIONAL WEATHER SERVICE GREAT FALLS MT
248 PM MDT THU MAY 23 2013

.DISCUSSION...WESTERN MONTANA AND NORTH CENTRAL IDAHO ARE
CURRENTLY IN BETWEEN WEATHER FEATURES THIS AFTERNOON, WHICH HAS
ALLOWED US A BRIEF RESPITE FROM PRECIPITATION. THIS WILL BE SHORT
LIVED HOWEVER AS ANOTHER WAVE OF ENERGY IS EXPECTED TO ROTATE
AROUND THE LOW PRESSURE SYSTEM CURRENTLY SITTING IN THE PACIFIC
NORTHWEST. THIS WAVE HAS AN IMPRESSIVE AMOUNT OF LIFT ASSOCIATED
WITH IT AND THUS ANOTHER ROUND OF POTENTIALLY HEAVY WET SNOW IS
EXPECTED LATE THIS AFTERNOON THROUGH FRIDAY MORNING. THE LOCATIONS
WITH THE GREATEST LIKELIHOOD OF SEEING IMPACTFUL SNOW THIS EVENING
INCLUDE SOUTHWEST MONTANA (BUTTE, GEORGETOWN LAKE, ANACONDA,
MACDONALD PASS AND HOMESTAKE PASS), AND LEMHI COUNTY (LOST TRAIL
PASS, SALMON, GILMORE SUMMIT). LOCATIONS FURTHER NORTH ALONG THE
CONTINENTAL DIVIDE (WEST GLACIER, SWAN LAKE, CONDON, SEELEY LAKE)
WILL LIKELY SEE MORE SNOW DEVELOP OVERNIGHT INTO THE EARLY MORNING
HOURS. THE MAIN IMPACT FROM THIS NEXT ROUND OF SNOW WILL BE
SLUSHY/SLICK ROADWAYS, BREAKAGE OF TREE LIMBS WHICH HAVE ALREADY
BEEN WEAKENED BY TODAY`S SNOW, AND PERIODS OF VERY LOW VISIBILITY
DUE TO CONVECTIVE SHOWERS BRINGING SHORT LIVED PERIODS OF INTENSE
SNOWFALL. ADDITIONAL POWER OUTAGES ARE POSSIBLE. VARIOUS WINTER
WEATHER PRODUCTS WILL REMAIN IN EFFECT THROUGH FRIDAY MORNING.

THIS NEXT WAVE OF ENERGY WILL EXIT THE REGION TOMORROW MORNING,
BRINGING A SOMEWHAT DRIER PERIOD FOR THE MORNING. THIS WILL BE
AGAIN, SHORT-LIVED HOWEVER AS YET ANOTHER WAVE OF ENERGY ROTATES
AROUND THE LOW PRESSURE SYSTEM BRINGING ENHANCED SHOWERS ACROSS
ALL OF WESTERN MONTANA AND NORTH CENTRAL IDAHO. THE MAIN FOCUS OF
THESE SHOWERS DOES APPEAR TO BE ACROSS NORTHWEST MONTANA WHERE
ANOTHER ROUND OF SNOW SHOWERS IS POSSIBLE. FORECAST MODELS DO
INDICATE SNOW LEVELS BEGINNING TO RISE DURING THIS TIME SO
ACCUMULATING SNOW SHOULD NOT BE AS IMPACTFUL AS THE LATEST WAVES
MOVING THROUGH THE REGION.

FOR THE HOLIDAY WEEKEND IT DOES APPEAR CONDITIONS WILL MODERATE
SLIGHTLY BACK TOWARDS MORE NORMAL CONDITIONS FOR THIS TIME OF
YEAR. THE THREAT OF PRECIPITATION WILL BE ON THE DECLINE ALTHOUGH
THEIR COULD BE SOME LINGERING SHOWERS?PARTICULARLY IN THE
AFTERNOONS. TEMPERATURES WILL RISE BACK TO NEAR NORMAL FOR THIS
TIME OF YEAR.

BY MONDAY ANOTHER TROUGH OF LOW PRESSURE IS EXPECTED TO PUMP
MOISTURE AND ENERGY BACK INTO THE REGION BRINGING PRECIPITATION
BACK INTO THE FORECAST. THIS COULD TRANSLATE INTO THUNDERSTORMS
ACROSS THE REGION BY TUESDAY AND WEDNESDAY.

&&

.AVIATION...THE LATEST SURGE OF MOISTURE AND DYNAMICS WILL BE
SWEEPING NORTHWARDS INTO CANADA THIS AFTERNOON. CONDITIONS WILL
ONLY IMPROVE TEMPORARILY AS YET ANOTHER SPOKE OF ENERGY POWERED BY
A STRONG JET STREAK WILL MOVE INTO LEMHI COUNTY AND SOUTHWEST
MONTANA LATER THIS AFTERNOON. KSMN AND KBTM WILL BE MOST IMPACTED
WITH LOW CEILINGS AND LIMITED VISIBILITIES THROUGH MUCH OF THE
NIGHT. THE CONTINENTAL DIVIDE WILL BE OBSCURED ALL THE WAY TO THE
CANADIAN BORDER. THE IDAHO PANHANDLE AND FAR NORTHWEST CORNER OF
MONTANA WILL SEE IMPROVED CONDITIONS THROUGH MUCH OF THE NIGHT, IN
RELATIVE COMPARISON TO LOCATIONS TO THE EAST. WHILE CONDITIONS ARE
EXPECTED TO IMPROVE FOR FRIDAY, THE ATMOSPHERE WILL BE MOIST AND
UNSTABLE ENOUGH FOR CLOUD AND SHOWER DEVELOPMENT BY AFTERNOON.

&&

NOTE: FLOOD WATCHES...WARNINGS AND ADVISORIES WILL NOT BE LISTED BELOW.

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING UNTIL 9 AM MDT FRIDAY BUTTE/BLACKFOOT
     REGION.

     WINTER WEATHER ADVISORY UNTIL 9 AM MDT FRIDAY
     BITTERROOT/SAPPHIRE MOUNTAINS.

     WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM MDT
     FRIDAY POTOMAC/SEELEY LAKE REGION...WEST GLACIER REGION.

ID...WINTER WEATHER ADVISORY UNTIL 9 AM MDT FRIDAY EASTERN LEMHI
     COUNTY.

&&

$$