706
FXUS65 KMSO 192021
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
121 PM MST WED FEB 19 2025
DISCUSSION
KEY MESSAGES:
- WIDESPREAD LIGHT TO MODERATE SNOW THIS AFTERNOON INTO THURSDAY
MORNING
- A WARMER AND WET PERIOD IS EXPECTED LATE THIS WEEKEND INTO
EARLY NEXT WEEK LEADING TO PONDING AND LOCALIZED MINOR FLOODING
THE NEXT DISTURBANCE HAS ALREADY PUSHED INTO NORTH CENTRAL IDAHO
CAUSING WIDESPREAD PRECIPITATION. THE LATEST CAMERAS ARE SHOWING
ACCUMULATING SNOW ACROSS THE CAMAS PRAIRIE AND ON TO OF WHITEBIRD
GRADE. THIS SNOW WILL STEADILY PUSH ACROSS THE REMAINDER OF THE
NORTHERN ROCKIES THIS AFTERNOON AND OVERNIGHT TONIGHT. THE
COMBINATION OF FREEZE UP OF WET ROAD WAYS TONIGHT ALONG WITH THE
POTENTIAL OF A COUPLE INCHES OF NEW SNOW ACCUMULATION WILL CREATE
HAZARDOUS ROAD CONDITIONS, SO NUMEROUS WINTER WEATHER ADVISORIES
HAVE BEEN ISSUED.
A LOW AMPLITUDE RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION
ON FRIDAY GIVING A MOMENTARY REDUCTION IN PRECIPITATION. THEN ON
SATURDAY ANOTHER WEAK DISTURBANCE WILL CAUSE SCATTERED SHOWERS
ACROSS THE NORTHERN ROCKIES. SNOW LEVELS WILL START TO RISE ON
SATURDAY LIMITED SNOW TO THE HIGHER TERRAIN WHILE THE VALLEYS
RECEIVE A WINTRY MIX.
THE MODELS ARE PROJECTING AN ATMOSPHERIC RIVER MOVING INTO THE
REGION ON SUNDAY AND LASTING INTO MONDAY. SNOW LEVELS WILL BE
RISING TO ABOVE 5000 FEET WITH WIDESPREAD PRECIPITATION.
CLEARWATER COUNTY ALONG WITH AREAS NEAR THE MONTANA/IDAHO BORDER
HAVE THE POTENTIAL OF RECEIVING A SIGNIFICANT AMOUNT OF
PRECIPITATION (80% CHANCE OF MORE THAN 1 INCHES OF RAIN IN 48HRS).
ANOTHER ASPECT OF THIS TIME FRAME WILL BE MOST VALLEYS'
TEMPERATURES STAYING ABOVE FREEZING SATURDAY NIGHT INTO TUESDAY
WITH THE THE LOWER VALLEYS OF NORTH CENTRAL IDAHO HAVING A GREATER
THAN 70% CHANCE FOR SUNDAY NIGHT MINIMUM TEMPERATURES BEING ABOVE
40 DEGREES. THE COMBINATION OF WARM TEMPERATURES ALONG WITH
WIDESPREAD RAIN COULD LEAD TO THE RAPID MELT OF LOW ELEVATION SNOW
CAUSING PONDING IN POOR DRAINAGE AREAS, LOCALIZED MINOR FLOODING
AND ICE BREAK-UPS ON SMALL CREEKS AND STREAMS. CONTINUE TO TAKE
PRECAUTIONS THIS WEEK BY CLEARING SNOW WHERE YOU CAN.
A DISTURBANCE IS EXPECTED TO IMPACT THE NORTHERN ROCKIES BY MID
NEXT WEEK WHICH WILL BRING MORE PRECIPITATION TO THE REGION. THE
AMOUNT OF COOLING ASSOCIATED WITH THIS FEATURE IS UNCERTAIN, SO
SNOW LEVELS HAVE THE POTENTIAL TO REMAIN RELATIVELY HIGH FOR THIS
TIME OF YEAR.
AVIATION
A WARM FRONT WILL CONTINUE TO SPREAD LIGHT TO MODERATE
SNOWFALL ACROSS NORTH-CENTRAL IDAHO THROUGH THIS EVENING, AND
EVENTUALLY FOR ALL ELEVATIONS IN WESTERN MONTANA BY 20/0000Z THIS
AFTERNOON. THE ONSET OF SNOWFALL FOR AVIATION SITES KGPI, KMSO
AND KHRF, IS EXPECTED BY 20/0000Z, THAT MAY BRING VISIBILITY DOWN
TO AROUND 1SM AND LOW CEILINGS THROUGH AROUND 20/1000Z THURSDAY
MORNING. KBTM CAN EXPECT SIMILAR CONDITIONS TO BEGIN SLIGHTLY
LATER AT 20/0200Z AND CONTINUE UNTIL SUNRISE. ACCUMULATIONS ARE
EXPECTED TO REMAIN RELATIVELY LIGHT, AT OR SLIGHTLY ABOVE 2
INCHES BY 20/1200Z.
MSO WATCHES/WARNINGS/ADVISORIES
MT... WINTER WEATHER ADVISORY UNTIL 8 AM MST THURSDAY FOR
BITTERROOT/SAPPHIRE MOUNTAINS...BUTTE/BLACKFOOT REGION...
FLATHEAD/MISSION VALLEYS...KOOTENAI/CABINET REGION...LOWER
CLARK FORK REGION...MISSOULA/BITTERROOT VALLEYS...
POTOMAC/SEELEY LAKE REGION...WEST GLACIER REGION.
ID...WINTER WEATHER ADVISORY UNTIL 7 AM PST THURSDAY FOR NORTHERN
CLEARWATER MOUNTAINS...GRANGEVILLE REGION...SOUTHERN CLEARWATER
MOUNTAINS.
WINTER WEATHER ADVISORY UNTIL 8 AM MST THURSDAY FOR EASTERN
LEMHI COUNTY...WESTERN LEMHI COUNTY.
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