121
FXUS65 KTFX 300603
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1203 AM MDT SUN AUG 30 2026
KEY MESSAGES
- GUSTY WEST WINDS DEVELOP FROM THE LATE MORNING THROUGH EVENING
HOURS.
- SOME MINOR SNOW ACCUMULATIONS ARE EXPECTED ABOVE 6500 FEET
ACROSS GLACIER NATIONAL PARK.
- HIGH TEMPERATURES TODAY WILL BE 10 TO 15 DEGREES BELOW NORMAL.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
SHOWERS AND THUNDERSTORMS WILL GRADUALLY EXIT TO THE EAST OF THE
NORTHERN ROCKIES THROUGH THE LATE MORNING AND AFTERNOON HOURS, WITH
INCREASING WESTERLY WINDS REPLACING THE DEPARTING PRECIPITATION FOR
THE REMAINDER OF THE DAY. HIGH TEMPERATURES IN WAKE A PACIFIC COLD
FRONT WILL ONLY RISE INTO THE MID-50S TO NEAR 70 DEGREES TODAY,
WHICH IS 10 TO 15 DEGREES BELOW NORMAL. FALLING SNOW LEVELS ALONG
THE CONTINENTAL DIVIDE, SPECIFICALLY THE GLACIER NATIONAL PARK
REGION, IS EXPECTED TO LEAD TO SOME MINOR SNOWFALL ACCUMULATIONS
PRIOR TO PRECIPITATION ENDING.
QUASI-ZONAL FLOW TO BEGIN THE WORK WEEK WILL BACK TO THE SOUTHWEST
THROUGH THE DAY ON TUESDAY AS UPPER LEVEL TROUGHING DIGS SOUTH ALONG
THE WESTERN SEABOARD. THIS TROUGH WILL DEEPEN THROUGH THE MIDDLE OF
THE WORK WEEK WHILE SLOWLY DRIFTING EAST OVER THE WESTERN CONUS,
WHICH WILL PLACE THE NORTHERN ROCKIES BENEATH SOUTHWEST TO SOUTHERLY
FLOW THROUGH THE REMAINDER OF THE FORECAST PERIOD. PACIFIC MOISTURE
STREAMING NORTHEAST TO NORTH WITHIN THIS FLOW WILL SUPPORT DAILY
CHANCES FOR SHOWERS AND STORMS FROM TUESDAY THROUGH THE UPCOMING
WEEK, ESPECIALLY OVER THE MOUNTAINS OF SOUTHWEST MONTANA AND ALONG
THE CONTINENTAL DIVIDE. TEMPERATURES WILL SEE-SAW BETWEEN 5 DEGREES
ABOVE TO BELOW NORMAL THROUGH THE UPCOMING WORK WEEK WITHIN THIS
PATTERN, WITH PERIODS OF GUSTY SOUTH WINDS DEVELOPING IN THE NORTH-
SOUTH ORIENTATED VALLEYS OF SOUTHWEST MONTANA AS THE UPPER LEVEL
FLOW BECOMES MORE SOUTHERLY IN NATURE. - MOLDAN
- FORECAST CONFIDENCE & SCENARIOS:
GUSTY WINDS THROUGH THE DAY TODAY...
CONFIDENCE REMAINS HIGH THAT GUSTY WEST WINDS WILL DEVELOP ACROSS
ALL OF SOUTHWEST THROUGH NORTH CENTRAL MONTANA TODAY, MOST NOTABLY
FROM THE LATE MORNING THROUGH EVENING HOURS. THERE IS HIGH
CONFIDENCE THAT FREQUENT WIND GUSTS OF BETWEEN 30-40 MPH WILL OCCUR
ACROSS THE REGION THROUGH THIS TIMEFRAME, WITH THE STRONGEST WINDS
OCCURRING ALONG THE ROCKY MOUNTAIN FRONT WEST OF THE I-15 CORRIDOR
AND ALONG THE MONTANA HWY 200/US HWY 87 CORRIDORS BETWEEN GREAT
FALLS AND LEWISTOWN. ONE NOTABLE CHANGE FROM THE PAST 48 HOURS HAS
BEEN A NORTHWARD SHIFT IN THE STRONGEST H850-700 WINDS, WHICH ARE
NOW PROG'D TO RESIDE BETWEEN THE MONTANA HWY 200 AND US HWY 2
CORRIDORS. THIS NORTHWARD SHIFT FROM THE PAST 48 HOURS, WHICH HAD
BEEN SHOWING THE CORE OF STRONGEST WINDS RESIDING OVER THE MONTANA
HWY 200 CORRIDOR, HAS RESULTED IN AN INCREASE (ALBEIT STILL LOW) IN
PROBABILITIES FOR WIND GUSTS TO EXCEED 55 MPH ALONG THE US HWY 2
CORRIDOR. IT IS NOT OUT OF THE REALM OF POSSIBILITY THAT A FEW WIND
PRONE LOCATIONS ACROSS GLACIER COUNTY AND IN LEE OF THE SWEET GRASS
HILLS WILL REACH OR EXCEED HIGH WIND CRITERIA TODAY; HOWEVER, GIVEN
THAT THESE OCCURRENCES WILL BE FAR AND FEW BETWEEN WE WILL CONTINUE
TO HOLD OFF ON ISSUING ANY HIGH WIND WARNINGS. NONE-THE-LESS, THOSE
TRAVELING IN HIGH PROFILE VEHICLES SHOULD BE PREPARED FOR STRONG
CROSS WINDS.
LISTED BELOW ARE THE NBM5.0 PROBABILITIES FOR WIND GUSTS TO EXCEED
35, 45, AND 55 MPH FOR SELECT LOCATIONS ACROSS NORTH CENTRAL,
CENTRAL, AND SOUTHWEST MONTANA.
SUNDAY'S WIND GUSTS PROBABILITIES
LOCATION > 35 MPH | > 45 MPH | > 55 MPH
BROWNING 100% | 85% | 20%
CUT BANK 100% | 85% | 25%
HAVRE 95% | 50% | 10%
GREAT FALLS 95% | 50% | <5%
LEWISTOWN 65% | 5% | 0%
HELENA 80% | 15% | <5%
BOZEMAN 40% | 5% | <5%
DILLON 60% | 5% | 0%
ENNIS 50% | 5% | 0%
WEST YELLOWSTONE 75% | <5% | 0%
ACCUMULATING SNOW IN THE MOUNTAINS OF GLACIER NATIONAL PARK...
CONFIDENCE IN MINOR SNOWFALL ACCUMULATIONS HAS INCREASED FOR THE
MOUNTAINS OF GLACIER NATIONAL PARK, MAINLY FOR THOSE ELEVATIONS
ABOVE 6500FT. MODEL GUIDANCE HAS SETTLED IN ON BETTER TIMING OF
PRECIPITATION MOVING ACROSS THE PARK AS SNOW LEVEL FALL, WITH THIS
OVERLAP BETWEEN BOTH PRECIPITATION AND "LOW" SNOW LEVELS PROMOTING
SOME MINOR ACCUMULATIONS OF UP TO 1-2" FOR THE HIGHER PEAKS. THOSE
LOOKING TO RECREATE IN THE BACKCOUNTRY OF GLACIER NATIONAL PARK ABOVE
6500FT SHOULD BE PREPARED FOR WET AND RAW CONDITIONS, ALONG WITH THE
POTENTIAL FOR SLIPPERY TRAIL CONDITIONS. - MOLDAN
AVIATION
30/06Z TAF PERIOD
SHOWERS AND THUNDERSTORMS WILL LINGER THROUGHOUT THE MAJORITY OF
THE CWA DURING THE FIRST FEW HOURS OF THIS TAF PERIOD, BEGINNING
TO DISSIPATE AROUND 14Z. WESTERLY WINDS WILL INCREASE IN THE LATE
MORNING/EARLY AFTERNOON, WITH MOST TERMINALS SEEING GUSTS BETWEEN
25-30 KTS. KGTF, KCTB AND KHVR WILL SEE GUSTS AROUND 35-40 KTS.
THESE WINDS WILL LAST INTO THE EVENING, BEFORE BEGINNING TO
DISSIPATE AROUND 01Z. VFR CONDITIONS WILL PREVAIL THROUGHOUT THIS
TAF PERIOD, WITH MVFR CONDITIONS AND MOUNTAIN OBSCURATION
POSSIBLE DUE TO A PASSING SHOWER OR THUNDERSTORM.
FOR KGTF: THUNDERSTORMS WILL CONTINUE TO IMPACT KGTF THROUGH 09Z,
BEFORE TRANSITIONING TO LIGHT RAIN SHOWERS. THE RAIN SHOWERS WILL
DISSIPATE AND SOUTHWESTERLY WINDS WILL BEGIN TO INCREASE AROUND
14Z, WITH A SUSTAINED WIND AROUND 20 KTS AND GUSTS AROUND 35 KTS.
THE WINDS WILL LAST INTO THE EVENING, BEGINNING TO DISSIPATE
AROUND 01Z. DUE TO THE SOUTHWESTERLY COMPONENT OF THESE WINDS,
THERE IS A LESS THAN 10% CHANCE OF A CROSS-WIND EXCEEDING 15 KTS
OUTSIDE OF A THUNDERSTORM. -DZOMBA
PRELIMINARY POINT TEMPS/POPS
GTF 67 47 78 49 / 30 0 0 0
CTB 61 45 74 47 / 20 10 0 0
HLN 69 44 78 49 / 30 0 0 0
BZN 70 40 77 45 / 70 0 0 0
WYS 62 30 70 35 / 70 0 0 20
DLN 70 39 79 44 / 30 0 0 0
HVR 69 49 77 50 / 50 10 0 0
LWT 66 44 75 48 / 70 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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