650
FXUS65 KTFX 280553
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1153 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.
UPDATE
/ISSUED 816 PM MDT THU AUG 27 2026/
EARLY EVENING UPDATE IS OUT. ISOLATED SEVERE STORMS CONTINUE. THE
SEVERE THUNDERSTORM WATCH WILL CONTINUE FOR A BIT. THE PLAN IS TO
EXPIRE THE WATCH BY 10 PM. AT THIS TIME, WE ARE NOT THINKING OF
EXTENDING THE WATCH UNLESS STORMS BECOME MORE WIDESPREAD SEVERE
OVER THE NEXT HOUR. THE AIRMASS IS COOLING, THUS THE INSTABILITY
IS DECREASING, ALONG WITH THE THREAT FOR SEVERE STORMS. AGAIN THE
MAIN IMPACT FROM ANY SEVERE STORMS THIS EVENING SHOULD BE
LIGHTNING AND STRONG WIND GUSTS.
LOOKING AHEAD, A SLOW COOLING TREND IS BEGINNING, WITH
TEMPERATURES NOTICEABLY COOLER BY SUNDAY. DAILY CHANCES FOR
SHOWERS/THUNDERSTORMS WILL CONTINUE, WITH THE BEST CHANCE FOR
STORMS OVER CENTRAL AND SOUTHWEST MT ON FRIDAY. BRUSDA
DISCUSSION
/ISSUED 816 PM MDT THU AUG 27 2026/
- 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
28/06Z TAF PERIOD
THUNDERSTORMS WILL LINGER IN THE FIRST FEW HOURS OF THIS TAF
PERIOD AROUND KHVR AND KLWT. RAIN SHOWERS WILL BEGIN IN SOUTHWEST
MT AROUND 12Z, MOVING IN A NORTHEAST FASHION THROUGH KWYS, KEKS
AND KBZN. THUNDERSTORM CHANCES RETURN AROUND 22Z IN CENTRAL MT,
WITH CONVECTIVE ACTIVITY INCREASING IN THE FOLLOWING HOURS IN
SOUTHWEST MT AND EAST OF KCTB. THE MAIN THREAT WITH THESE
THUNDERSTORMS WILL BE GUSTY, ERRATIC WINDS AND FREQUENT LIGHTNING.
OVERALL, VFR CONDITIONS WILL PREVAIL THROUGHOUT THIS TAF PERIOD,
ALTHOUGH MOUNTAIN OBSCURATION WILL OCCUR WITH PASSING SHOWERS AND
THUNDERSTORMS.
FOR KGTF: WINDS WILL BE AROUND 09KT FROM THE SOUTHWEST, BEFORE
BECOMING LIGHT AND VARIABLE AROUND 11Z. WHILE THERE IS A CHANCE
FOR THUNDERSTORM ACTIVITY STARTING AROUND 22Z, CONFIDENCE IN EXACT
TIMING AND LOCATION IS LOW AT THIS TIME, HENCE THE BROAD PROB30
GROUP. ANY THUNDERSTORM THAT DEVELOPS WILL BE CAPABLE OF PRODUCING
GUSTY, ERRATIC WINDS, BRIEF, HEAVY DOWNPOURS, AND FREQUENT
LIGHTNING. DUE TO THE PREDOMINATE SOUTHWEST DIRECTION OF THE WIND
DURING THIS TAF PERIOD, THERE IS A LESS THAN 10% CHANCE OF A
CROSS-WIND EXCEEDING 15 KT OUTSIDE OF A THUNDERSTORM. -DZOMBA
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 20 20 60
CTB 55 82 51 73 / 30 0 10 40
HLN 54 82 54 76 / 40 30 20 70
BZN 53 79 51 76 / 40 30 50 60
WYS 45 70 42 65 / 40 90 80 90
DLN 53 78 50 76 / 30 30 50 70
HVR 60 90 58 83 / 40 0 20 30
LWT 57 83 55 76 / 40 20 20 50
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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