509
FXUS65 KTFX 272203
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
403 PM MDT THU AUG 27 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THIS EVENING.
- FRIDAY THROUGH SUNDAY IT WILL BE BREEZY ACROSS THE AREA WHICH
WILL LEAD TO ELEVATED FIRE WEATHER CONDITIONS ACROSS NORTH-
CENTRAL MONTANA.
- TEMPERATURES WILL COOL DOWN THIS WEEKEND WITH SHOWERS AND
THUNDERSTORMS.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON THERE IS AN UPPER-LEVEL RIDGE OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. IT WILL BE HOT THIS AFTERNOON
ACROSS NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. AN UPPER-
LEVEL SHORTWAVE WILL MOVE THROUGH THE UPPER-LEVEL RIDGE AND BRING
SHOWERS AND THUNDERSTORMS TO THE AREA THIS AFTERNOON AND EVENING.
SEE THE FORECAST CONFIDENCE & SCENARIOS SECTION FOR DETAILS. ON
FRIDAY THE UPPER-LEVEL RIDGE BEGINS TO MOVE EAST AWAY FROM NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. AS A RESULT OF THE
SHORTWAVE THAT MOVED THROUGH IT WILL BE SLIGHTLY COOLER ACROSS THE
AREA ON FRIDAY. SHOWERS AND THUNDERSTORMS WILL LINGER THROUGH
MUCH OF THE DAY ON FRIDAY ACROSS SOUTHWESTERN MONTANA. DUE TO AN
INCREASING PRESSURE GRADIENT AND APPROACHING UPPER-LEVEL TROUGH IT
WILL BE BREEZY ACROSS NORTH-CENTRAL MONTANA ON FRIDAY.
ON SATURDAY AN UPPER-LEVEL TROUGH ASSOCIATED WITH A PACIFIC COLD
FRONT BEGINS TO MOVE THROUGH NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. THIS BRINGS COOLER TEMPERATURES TO THE AREA
WITH SHOWERS AND THUNDERSTORMS. IT WILL ALSO BE BREEZY ON
SATURDAY DUE TO A STRONG PRESSURE GRADIENT. ON SUNDAY THE UPPER-
LEVEL TROUGH MOVES OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA. THIS WILL COOL TEMPERATURES DOWN MORE TO WELL-BELOW
SEASONAL AVERAGES WITH ANOTHER DAY OF SHOWERS AND THUNDERSTORMS.
ON MONDAY AN UPPER-LEVEL RIDGE BUILDS BACK IN OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW TEMPERATURES
TO WARM BACK UP WITH MOSTLY DRY WEATHER. TUESDAY THROUGH WEDNESDAY
AN UPPER-LEVEL TROUGH WILL MOVE BACK OVER THE AREA WHICH WILL
BRING SHOWERS AND THUNDERSTORMS BACK TO THE AREA ON TUESDAY AND
WEDNESDAY. -IG
- FORECAST CONFIDENCE & SCENARIOS:
TODAY THE STORM PREDICTION CENTER (SPC) ISSUED A SLIGHT RISK (15%
CHANCE FOR WINDS GUSTS OF 58 MPH OR GREATER) FOR SEVERE
THUNDERSTORMS ACROSS NORTH-CENTRAL MONTANA BETWEEN I-90 AND US
HIGHWAY 2 WEST OF FERGUS AND BLAINE COUNTIES. ACROSS THE REST OF
NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA THE SPC ISSUED A
MARGINAL RISK (5% CHANCE FOR WIND GUSTS OF 58 MPH OR GREATER) FOR
SEVERE THUNDERSTORMS. THIS AFTERNOON THERE WILL BE DEEP
INVERTED-V SOUNDINGS WITH DCAPE VALUES IN EXCESS OF 1200 J/KG. THE
UNCERTAINTY WITH THESE STORMS THIS AFTERNOON AND EVENING IS HOW
THE CURRENT LINE OF STORMS MOVING THROUGH NORTH-CENTRAL MONTANA
WILL AFFECT THE ENVIRONMENT AND IF THERE WILL BE CLEARING THIS
AFTERNOON BEFORE THE NEXT ROUND OF STORMS MOVES IN TO MAXIMIZE THE
SEVERE POTENTIAL OF ANY STORMS THAT FORM. IF THERE IS SUFFICIENT
CLEARING THEN THE STRONGEST STORMS HAVE THE POTENTIAL TO PRODUCE
OUTFLOW BOUNDARIES THAT PRODUCE WIND GUSTS UP TO 75 MPH.
ON FRIDAY THERE IS A 15 - 30% CHANCE FOR THUNDER IN SOUTHWESTERN
MONTANA SOUTHEAST OF A BOZEMAN TO DILLON LINE WITH THE HIGHEST
CHANCES IN THE WEST YELLOWSTONE AREA. ON SATURDAY THERE IS A 25 -
40% CHANCE FOR THUNDER ALONG AND SOUTH OF THE MONTANA HIGHWAY 200
CORRIDOR BETWEEN LINCOLN AND LEWISTOWN. ON SATURDAY THERE IS
GREATER THAN A 60% CHANCE FOR A QUARTER INCH OF RAIN OR GREATER
ACROSS CENTRAL AND SOUTHWESTERN MONTANA EAST OF I-15. ON SUNDAY
ACROSS NORTH-CENTRAL MONTANA EAST OF I-15 THERE IS A 40 - 60%
CHANCE FOR A QUARTER INCH OF RAIN OR GREATER. ON SUNDAY THERE IS A
50 - 70% CHANCE FOR WIND GUSTS OF 40 MPH OR GREATER ACROSS MOST
OF NORTH-CENTRAL MONTANA. -IG
AVIATION
28/00Z TAF PERIOD
SHOWERS AND THUNDERSTORMS WILL AFFECT THE CWA THROUGH AT LEAST 06Z
FRI, BEFORE SLOWLY DIMINISHING OVERNIGHT. THE MAIN IMPACT WILL BE
LIGHTNING/STRONG WIND GUSTS. ON FRIDAY, EXPECT ANOTHER ROUND OF
SHOWERS/THUNDERSTORMS TO AFFECT THE CWA DURING THE
AFTERNOON/EVENING HOURS, WITH STORMS BEGINNING MOSTLY AFTER 20Z
FRI OVER FAR SOUTHWEST MT, MOVING TOWARDS CENTRAL MT BY 00Z SAT.
FOR KGTF : MAIN CONCERN WILL BE STRONG CONVECTIVE WIND GUSTS WITH
THUNDERSTORMS THIS EVENING. CURRENT THINKING IS SOME STORMS COULD
PRODUCE BETWEEN 40 AND 50 KNOT GUSTS WITH THE STORMS AS THEY MOVE
THROUGH. OVERALL, MOST OF THE STORMS / OUTFLOW WIND GUSTS SHOULD
EXIT THE GREAT FALLS AREA BY 5Z FRI. FOR NOW, THUNDERSTORMS ARE
EXPECTED TO REMAIN JUST SOUTH OF THE GREAT FALLS AIRPORT FOR
FRIDAY AFTERNOON/EVENING. BRUSDA
FIRE WEATHER
TODAY THERE WILL BE SHOWERS AND THUNDERSTORMS ACROSS NORTH-CENTRAL
MONTANA. ALL THUNDERSTORMS WILL PRODUCE FREQUENT LIGHTNING AMD
GUSTY WINDS (OUTFLOWS). ISOLATED THUNDERSTORMS WILL BE ON THE
DRIER SIDE. IT WILL ALSO BE HOT THIS AFTERNOON. THIS WILL LEAD TO
ELEVATED FIRE WEATHER CONDITIONS THIS AFTERNOON. ON FRIDAY
AFTERNOON IN GLACIER COUNTY THE HREF (HI-RES ENSEMBLE FORECAST)
AND THE NBM HAVE AROUND A 50% CHANCE FOR WIND SPEEDS OF 15 MPH OR
GREATER COMBINED WITH RELATIVE HUMIDITY LESS THAN 20% (RED FLAG
CRITERIA). GIVEN THOSE PROBABILITIES ARE ONLY FOR LESS THAN HALF
OF THE ZONE (FWZ 112) AND THAT THE HOT DRY WINDY INDEX IS BELOW
THE 75TH PERCENTILE, NO FIRE WEATHER PRODUCTS WILL BE ISSUED.
THERE WILL BE ELEVATED FIRE WEATHER CONDITIONS ACROSS NORTH-
CENTRAL MONTANA TOMORROW. IT WILL BE BREEZY THIS WEEKEND WITH
SHOWERS AND THUNDERSTORMS, BUT IT WILL BE COOLER WHICH WILL REDUCE
THE RISK FOR FIRE WEATHER CONCERNS. -IG
PRELIMINARY POINT TEMPS/POPS
GTF 58 86 59 77 / 40 10 20 60
CTB 55 82 51 73 / 30 0 0 30
HLN 54 82 54 76 / 40 20 30 80
BZN 53 79 51 76 / 40 40 50 70
WYS 45 70 42 65 / 40 70 90 90
DLN 53 78 50 76 / 30 30 50 70
HVR 60 90 58 83 / 40 10 10 10
LWT 57 83 55 76 / 40 20 30 50
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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