623
FXUS65 KTFX 240008
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
508 PM MST THU JAN 23 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- IT WILL BE WINDY THIS AFTERNOON AND EVENING ACROSS NORTH-
CENTRAL AND CENTRAL MONTANA WITH THE STRONGEST WINDS ALONG THE
ROCKY MOUNTAIN FRONT AND ADJACENT PLAINS ON THURSDAY.
- TONIGHT INTO EARLY FRIDAY MORNING A COLD FRONT WILL MOVE
THROUGH BRINGING WIDESPREAD SNOW AND COLDER TEMPERATURES FOR
THIS WEEKEND.
- EARLY NEXT WEEK TEMPERATURES WILL BEGIN TO WARM UP WITH DRY
CONDITIONS.
UPDATE
/ISSUED 422 PM MST THU JAN 23 2025/
THE HIGH WIND WARNING FOR THE EAST GLACIER PARK REGION, NORTHERN
HIGH PLAINS, AND EASTERN GLACIER, WESTERN TOOLE, AND CENTRAL PONDERA
COUNTIES HAS BEEN CANCELLED. WIND SPEEDS AND GUSTS HAVE FALLEN BELOW
WARNING CRITERIA LATE THIS AFTERNOON, BUT INFREQUENT WIND GUSTS IN
EXCESS OF 60 MPH ARE POSSIBLE ALONG AND WEST OF THE US HIGHWAY 89
CORRIDOR FROM DUPUYER NORTH TO THE CANADIAN BORDER. TRAVELERS ARE
STILL URGED TO EXERCISE CAUTION THROUGH THE EARLY EVENING HOURS DUE
TO THESE INFREQUENT GUSTS, ESPECIALLY IF OPERATING A HIGH-PROFILE
VEHICLE. - MOLDAN
DISCUSSION
/ISSUED 422 PM MST THU JAN 23 2025/
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS AN UPPER-LEVEL RIDGE OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA WHICH WILL BRIEFLY WARM UP
TEMPERATURES THIS AFTERNOON. DUE TO A STRONG SURFACE PRESSURE
GRADIENT THERE WILL BE STRONG WINDS THIS AFTERNOON THROUGH EARLY
THIS EVENING PRIMARILY ALONG THE ROCKY MOUNTAIN FRONT AND ADJACENT
PLAINS. DUE TO THE WINDS THERE WILL BE BLOWING SNOW THIS AFTERNOON
THROUGH THIS EVENING ACROSS NORTH-CENTRAL MONTANA WITH THE GREATEST
IMPACTS ALONG THE HIGHWAY 87/200 CORRIDOR. TONIGHT/EARLY FRIDAY
MORNING A COLD FRONT ASSOCIATED WITH AN UPPER-LEVEL TROUGH WILL MOVE
THROUGH. IT WILL BRING WIDESPREAD SNOW TO THE AREA AND COLDER
TEMPERATURES FOR FRIDAY AND SATURDAY. THERE WILL BE SNOWFALL RATES
IN EXCESS OF ONE HALF INCH PER HOUR WITH THE FRONTAL PASSAGE IN
NORTH-CENTRAL AND CENTRAL MONTANA LATE TONIGHT THROUGH EARLY FRIDAY
MORNING. LIGHT SNOW WILL CONTINUE ACROSS MUCH OF NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA DURING THE REST OF THE DAY ON
FRIDAY AFTER THE FRONTAL PASSAGE. ON FRIDAY AND SATURDAY THE UPPER-
LEVEL TROUGH REMAINS OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA. LIGHT SNOW WILL LINGER IN CENTRAL MONTANA ON SATURDAY
MORNING. ON SUNDAY AN UPPER-LEVEL RIDGE BEGINS TO BUILD IN OVER
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THE UPPER-LEVEL
RIDGE WILL REMAIN OVER THE AREA THROUGH AT LEAST NEXT THURSDAY. THIS
WILL GRADUALLY WARM UP TEMPERATURES AND DRY OUT NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA THROUGH AT LEAST NEXT THURSDAY.
EARLY NEXT WEEK IT WILL BE BREEZY AT TIMES TOO DUE TO A STRONG
SURFACE PRESSURE GRADIENT.
- FORECAST CONFIDENCE & SCENARIOS:
FOR THE SNOW TONIGHT THROUGH SATURDAY MORNING, THERE IS A 20 - 50%
CHANCE FOR 2 INCHES OF SNOW FOR LOWER-ELEVATION LOCATIONS ALONG THE
HIGHWAY 87/200 CORRIDOR SOUTH TO THE HELENA VALLEY. FOR THE REST OF
THE LOWER-ELEVATIONS OF NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA THERE IS A 20 - 50% CHANCE FOR AN INCH OF SNOW OR GREATER
FROM TONIGHT THROUGH SATURDAY MORNING. FOR THE MOUNTAINS OF CENTRAL
MONTANA THERE IS A 80% CHANCE FOR 6 INCHES OF SNOW OR GREATER FROM
TONIGHT THROUGH SATURDAY MORNING. FOR SNOWFALL RATES ASSOCIATED WITH
THE FRONTAL PASSAGE LATE TONIGHT THROUGH EARLY FRIDAY MORNING THERE
IS A 70% CHANCE OR GREATER FOR SNOWFALL RATES OF ONE HALF INCH PER
HOUR ACROSS MUCH OF NORTH-CENTRAL AND CENTRAL MONTANA. FROM THE
BEARS PAW MOUNTAINS SOUTHWEST TO THE LITTLE BELT MOUNTAINS THERE IS
A 70% CHANCE FOR SNOWFALL RATES OF ONE INCH PER HOUR LATE TONIGHT
INTO EARLY FRIDAY MORNING. AS A RESULT ACROSS MUCH OF NORTH-CENTRAL
AND CENTRAL MONTANA WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM
TONIGHT THROUGH FRIDAY NIGHT. THE WINTER WEATHER ADVISORY FOR THE
LITTLE BELT AND HIGHWOOD MOUNTAINS WAS UPGRADED TO A WINTER STORM
WARNING. SEE THE WATCHES/WARNINGS/ADVISORIES SECTION BELOW FOR
DETAILS.
FOR THE REST OF THE FORECAST PERIOD THERE IS HIGH CONFIDENCE THAT
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA WILL BE UNDER AN
UPPER-LEVEL RIDGE THROUGH AT LEAST NEXT THURSDAY. -IG
AVIATION
24/00Z TAF PERIOD
GUSTY WEST TO SOUTHWEST SURFACE WINDS ALONG WITH AREAS OF MOUNTAIN
WAVE TURBULENCE AND LOW LEVEL WIND SHEAR WILL DECREASE THIS
EVENING AS WESTERLY FLOW ALOFT TURNS NORTHWESTERLY WITH AN
INCOMING UPPER LEVEL TROUGH. A COLD FRONT MOVES SOUTH THROUGH THE
REGION OVERNIGHT SHIFTING SURFACE WINDS TO NW AND N, REACHING
KBZN FRIDAY MORNING. INITIALLY VFR CONDITIONS THIS EVENING WILL
DEGRADE TO MVFR AS SNOW DEVELOPS WITH THE APPROACH AND PASSAGE OF
THE COLD FRONT LATER TONIGHT WITH BRIEF IFR/LIFR POSSIBLE IN
EMBEDDED BANDS WITH HEAVIER SNOWFALL RATES. SNOW ENDS FROM NORTH
TO SOUTH ON FRIDAY WITH IMPROVING CONDITIONS BUT LIKELY SOME
LINGERING LOWER TO MID LEVEL CLOUDS AND MOUNTAIN OBSCURATION.
HOENISCH
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 21 28 13 25 / 90 40 40 0
CTB 16 26 7 24 / 80 10 10 0
HLN 18 28 10 23 / 80 70 30 0
BZN 13 26 2 19 / 30 80 10 0
WYS 0 21 -12 17 / 10 70 0 0
DLN 13 24 0 17 / 10 40 0 0
HVR 16 27 9 24 / 70 10 0 0
LWT 18 24 9 20 / 70 30 30 0
TFX WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 11 PM MST
FRIDAY FOR BEARS PAW MOUNTAINS AND SOUTHERN BLAINE-CASCADE
COUNTY BELOW 5000FT-FERGUS COUNTY BELOW 4500FT-JUDITH BASIN
COUNTY AND JUDITH GAP-WESTERN AND CENTRAL CHOUTEAU COUNTY.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 PM MST
FRIDAY FOR BIG BELT, BRIDGER AND CASTLE MOUNTAINS-ELKHORN AND
BOULDER MOUNTAINS-GATES OF THE MOUNTAINS-SNOWY AND JUDITH
MOUNTAINS-SOUTHERN ROCKY MOUNTAIN FRONT-UPPER BLACKFOOT AND
MACDONALD PASS.
WINTER STORM WARNING FROM 11 PM THIS EVENING TO 11 PM MST FRIDAY
FOR LITTLE BELT AND HIGHWOOD MOUNTAINS.
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