579
FXUS65 KTFX 081817
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1217 PM MDT TUE SEP 8 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SCATTERED SHOWERS WILL CONTINUE THROUGH THE AFTERNOON ALONG THE
ROCKY MOUNTAIN FRONT AND ACROSS THE HI-LINE.
- WARMER AND DRIER ON WEDNESDAY AND THURSDAY.
- COOLER AND WETTER CONDITIONS RETURN ON FRIDAY AND LAST THROUGH
THE WEEKEND.
DISCUSSION
/ISSUED 543 AM MDT TUE SEP 8 2026/
- METEOROLOGICAL OVERVIEW:
A SHORTWAVE TROUGH WILL MAKE ITS WAY ACROSS THE REGION THROUGH THE
DAY CONTINUING THE CHANCES FOR SHOWERS ALONG THE ROCKY MOUNTAIN
FRONT AND ACROSS THE HI-LINE. THERE IS A CHANCE FOR SOME ISOLATED TO
SCATTERED THUNDERSTORMS THIS AFTERNOON, ALTHOUGH THE THREAT FOR
SEVERE WEATHER IS LOW.
BY WEDNESDAY, UPPER-LEVEL FLOW BECOMES A BIT MORE ZONAL TO
NORTHWESTERLY, ALLOWING FOR TEMPERATURES TO WARM UP. THIS EFFECT IS
BRIEFLY ENHANCED ON THURSDAY AS WEAK TRANSIENT RIDGING MOVES THROUGH
WHICH WILL ALLOW FOR LOWER ELEVATION LOCATIONS TO REACH THE UPPER
70S TO MID 80S.
THE NEXT SYSTEM IS EXPECTED TO ARRIVE THURSDAY EVENING INTO FRIDAY
WITH COOLER AND WETTER CONDITIONS EXPECTED TO LAST THROUGH THE
WEEKEND.
- FORECAST CONFIDENCE & SCENARIOS:
SCATTERED SHOWERS WILL CONTINUE, PRIMARILY ALONG THE ROCKY MOUNTAIN
FRONT AND ACROSS THE HI-LINE THROUGH THE REST OF THE MORNING WITH
ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE THIS AFTERNOON. THESE
STORMS ARE NOT EXPECTED TO BE SEVERE BUT THEY MAY PRODUCE LOCALLY
HEAVY RAIN WHICH MAY CONTINUE SOME OF THE FLOODING CONCERNS FOR
AREAS THAT HAVE ALREADY RECEIVED A LOT OF RAIN.
WITH REGARDS TO THE SYSTEM THIS WEEKEND, THERE IS A CHANCE FOR
MOUNTAIN SNOW, PRIMARILY ABOVE 7000 FEET. CONFIDENCE IN AMOUNTS
ABOVE 4 INCHES IS LOW BUT THERE IS CURRENTLY A 60% CHANCE FOR AT
LEAST 2 INCHES OF SNOW IN THE MOUNTAINS SUNDAY MORNING. THE MAIN
CONCERN WILL BE FOR THOSE RECREATING IN THE BACKCOUNTRY WHERE
DIFFICULT CONDITIONS ARE EXPECTED FRIDAY THROUGH SUNDAY.
-THOR
AVIATION
08/18Z TAF PERIOD
RAIN SHOWERS WILL CONTINUE OVER NORTH-CENTRAL MT THROUGH THIS
AFTERNOON, DISSIPATING AROUND 21Z FOR KCTB AND 01Z FOR KHVR. THERE
IS A CHANCE OF WEAK THUNDERSTORMS OVER KBZN FROM 22Z TO 01Z. NEAR
ANY SHOWERS AND WEAK THUNDERSTORMS, MOUNTAIN OBSCURATION IS
POSSIBLE. VFR CONDITIONS WILL PREVAIL THROUGHOUT THIS TAF PERIOD
WITH THE EXCEPTION OF KHVR, WHICH COULD SEE MVFR VISBILITIES
THROUGH 01Z.
FOR KGTF: WHILE VFR CONDITIONS WILL PREVAIL THROUGHOUT THIS TAF
PERIOD, CLOUD DECKS WILL REMAIN LOW THROUGH THE AFTERNOON, BEFORE
BEGINNING TO LIFT AROUND 00Z. THE RAIN SHIELD WILL REMAIN NORTH OF
THE TERMINAL, BUT SOME LIGHT SHOWERS IN THE VICINITY ARE
POSSIBLE. DUE TO THE STRONG WESTERLY COMPONENT OF THE WIND, THERE
IS HIGH CONFIDENCE OF THE CROSS-WIND THRESHOLD BEING EXCEEDED
THROUGH 02Z, AT WHICH A SOUTHWESTERLY WIND SHIFT WILL CREATE A
LESS THAN 10% CHANCE OF THE CROSS-WIND THRESHOLD BEING EXCEEDED.
-DZOMBA
HYDROLOGY
AN AREAL FLOOD WATCH WILL CONTINUE FOR THE EAST SIDE OF GLACIER
PARK, BROWNING, CUT BANK AND SHELBY AREAS INTO TUESDAY. PERIODS OF
STEADY RAIN CONTINUE TO AFFECT THIS AREA, WITH MOST LOCATIONS
RECEIVING BETWEEN 2 AND 3 INCHES OF RAINFALL ALREADY IN THIS AREA.
AN ADDITIONAL INCH OF RAINFALL IS POSSIBLE THROUGH TUESDAY MORNING.
THUS SOME MINOR FLOOD IMPACTS COULD DEVELOP LATER TODAY OR INTO
TUESDAY MORNING. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 63 43 76 53 / 70 10 0 0
CTB 60 43 69 50 / 90 0 0 0
HLN 68 42 77 49 / 10 0 0 0
BZN 68 38 78 44 / 20 0 0 0
WYS 63 29 69 31 / 0 0 0 0
DLN 68 39 77 45 / 0 0 0 0
HVR 63 42 75 48 / 90 30 0 0
LWT 65 41 74 50 / 30 10 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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