021
FXUS65 KTFX 250604
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1204 AM MDT TUE AUG 25 2026
KEY MESSAGES
- DAILY CHANCES FOR THUNDERSTORMS IN SOUTHWEST MONTANA SPREADING
INTO CENTRAL MONTANA BY THURSDAY.
- TEMPERATURES WILL GRADUALLY WARM WITH THURSDAY EXPECTED TO BE
THE HOTTEST DAY OF THE WEEK BEFORE A COLD FRONT BRINGS COOLER
TEMPERATURES TO THE REGION.
- COOLER AND BREEZIER CONDITIONS ARE EXPECTED TO LAST THROUGH THE
WEEKEND.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
UPPER-LEVEL RIDGING WILL CONTINUE TO BUILD OVER THE REGION WITH
GRADUALLY INCREASING SURFACE TEMPERATURES THROUGH THE MIDDLE OF
THE WEEK. WITH THE POSITION OF THE RIDGE AXIS, SOUTHWESTERLY FLOW
ALOFT WILL MAINTAIN ENOUGH OF AN INFLUX OF MONSOONAL MOISTURE TO
KEEP UP DAILY CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS,
PARTICULARLY IN SOUTHWEST MONTANA. AS THE RIDGE STARTS TO MOVE
EASTWARD WEDNESDAY INTO THURSDAY, THE COVERAGE FOR THUNDERSTORM
ACTIVITY IS EXPECTED TO BECOME MORE WIDESPREAD INTO CENTRAL
MONTANA WITH A CHANCE FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS
POSSIBLE PARTICULARLY ON THURSDAY AS AN UPPER-LEVEL TROUGH STARTS
TO PUSH INTO THE REGION. THIS TROUGH WILL CONTINUE TO MAKE ITS WAY
ACROSS MONTANA THROUGH THE WEEKEND BRINGING COOL AND BREEZY
CONDITIONS TO THE STATE AND DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. WHILE SOME UNCERTAINTY IN THE EXTENDED PATTERN
REMAINS, THERE ARE HINTS THAT A COOLER AND POTENTIALLY MORE ACTIVE
PATTERN MAY START TO SET UP HEADING INTO NEXT WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
THUNDERSTORM AND PRECIPITATION CHANCES:
THERE WILL BE DAILY CHANCES FOR THUNDERSTORMS ACROSS SOUTHWEST
MONTANA TUESDAY THROUGH THURSDAY THAT WILL SLOWLY SPREAD NORTH AS
THE WEEK CONTINUES. LOOKING AT MODEL SOUNDINGS, THERE ARE DEEP
INVERTED-V PROFILES WHICH INCREASES CONFIDENCE IN THESE
THUNDERSTORMS BEING ON THE DRIER SIDE. THIS MEANS THE MAIN THREATS
WILL BE LIGHTNING AND GUSTY/ERRATIC WINDS WHICH WILL PROVIDE
LITTLE RELIEF TO THE CURRENT FIRE SITUATION. FOR MORE ON THE
EXPECTED FIRE WEATHER CONCERNS, SEE THE FIRE WEATHER SECTION.
AS THE THUNDERSTORM POTENTIAL SPREADS INTO CENTRAL MONTANA, THERE
IS STILL AN EXPECTATION THAT MOST OF THESE THUNDERSTORMS WILL BE
ON THE DRIER SIDE WITH A HINT THAT SOME ISOLATED STRONG TO SEVERE
WEATHER IS POSSIBLE THURSDAY AFTERNOON. CURRENT MODEL RUNS
INDICATED AROUND 1000-1500 J/KG CAPE WITH AROUND 20-35KTS OF BULK
SHEAR. THERE IS STILL A BIT OF UNCERTAINTY WITH WHERE THE GREATEST
THREAT FOR SEVERE WEATHER WILL BE BUT THE MAIN CONCERN WITH ANY
THUNDERSTORM THAT DEVELOPS WILL BE STRONG WIND GUSTS.
EXTENDED FORECAST:
THERE IS DECENT AGREEMENT AMONGST THE MODELS ON A STRONG UPPER-LEVEL
TROUGH MOVING THROUGH THIS WEEKEND WHICH WILL BRING COOLER AND
BREEZY CONDITIONS TO THE REGION. LOOKING TOWARDS NEXT WEEK, THERE
IS AN INTERESTING POTENTIAL WITH CLUSTER GUIDANCE HINTING TOWARDS
POTENTIALLY MULTIPLE TROUGHS MOVING THROUGH THE AREA. IT IS FAR
TOO EARLY TO PIN DOWN THE FINER DETAILS OF WHAT IS TO OCCUR BUT
THERE IS HOPE OF FALL-LIKE CONDITIONS ON THE MORE DISTANCE
HORIZON.
-THOR
AVIATION
25/06Z TAF PERIOD
WEAK SHORTWAVES WILL UNDERCUT A BUILDING RIDGE ALOFT AND BRING
INCREASED MID- AND HIGHER LEVEL CLOUDINESS AND A FEW ISOLATED
SHOWERS AND THUNDERSTORMS TONIGHT INTO TUESDAY. CONVECTIVE
ACTIVITY CURRENTLY ALONG THE MT/ID BORDER WILL SLOWLY EXPAND
NORTHWARD DURING THE OVERNIGHT HOURS INTO TUESDAY MORNING, BUT
WILL GENERALLY STAY SOUTH THE US HIGHWAY 12 CORRIDOR. ADDITIONAL
SHOWERS AND STORMS WILL INITIATE WITH AFTERNOON INSTABILITY OVER
ROUGHLY THE SAME LOCATIONS BETWEEN 25/18 AND 26/06Z. BRIEF GUSTY
WINDS UP TO 30 KTS AND ISOLATED LIGHTNING WILL BE THE PRIMARY
IMPACTS WITH THIS ACTIVITY, BUT THERE'S A 30% CHANCE OR LESS FOR
FOR IMPACTS AT THE SOUTHWEST TERMINALS. OTHERWISE, SURFACE WINDS
WILL MOSTLY BE EASTERLY OVER THE PLAINS AND VARIABLE IN SOUTHWEST
MT. ONCE AGAIN, WILDFIRE SMOKE WILL COMPROMISE SLANTWISE
VISIBILITY UPON ASCENT/DESCENT.
FOR KGTF: WINDS WILL BE EAST TO NORTHEAST FOR MUCH OF THE PERIOD,
WITH GUSTS MOSTLY LESS THAN 15 KTS. THERE IS CURRENTLY LESS THAN
A 20% CHANCE FOR CROSSWINDS OVER 15 KTS. VFR CONDITIONS WILL
PREVAIL, BUT WILDFIRE SMOKE WILL COMPROMISE SLANTWISE VISIBILITY
UPON ASCENT/DESCENT. - RCG
FIRE WEATHER
THROUGH WEDNESDAY, THERE ARE ONLY MARGINAL CONCERNS FOR ELEVATED
FIRE WEATHER WITH TEMPERATURES GRADUALLY WARMING AND WINDS GENERALLY
EXPECTED TO BE ON THE CALMER SIDE. THE ONLY WILD CARD THAT COULD
POTENTIALLY CREATE DIFFICULT CONDITIONS WILL BE THE DAILY CHANCES
FOR DRY THUNDERSTORMS. THE PRIMARY FOCUS ON TUESDAY WILL BE
SOUTHWEST MONTANA WITH THE THREAT FOR DRY THUNDERSTORMS SPREADING
INTO PORTIONS OF CENTRAL MONTANA BY WEDNESDAY. WITH THIS BEING THE
ONLY MODE OF CONCERN FOR FIRE WEATHER, NO PRODUCTS WILL BE ISSUED AT
THIS TIME. BUT GIVEN HOW DRY THE FUELS ARE FOLKS SHOULD CONTINUE TO
TAKE ALL MEASURES TO PREVENT SPARKS FROM OCCURRING.
THURSDAY CURRENTLY LOOKS THE MOST CONCERNING FOR POTENTIAL ELEVATED
FIRE WEATHER CONDITIONS. GUSTY CONDITIONS IN SOUTHWEST AND PORTIONS
OF CENTRAL MONTANA, COMBINED WITH A MORE ROBUST CHANCE FOR DRY
THUNDERSTORMS, AND TEMPERATURES RANGING FROM THE UPPER 80S TO MID
90S COULD MAKE THINGS DIFFICULT FOR ONGOING FIRE OPERATIONS. RIGHT
NOW THE HDWI IS ONLY HIGHLIGHTING THE PROBABILITY OF EXCEEDING THE
75TH PERCENTILE WITH ABOUT A 20% CHANCE FOR SOME LOCATIONS TO EXCEED
THE 90TH PERCENTILE. SO AT THIS TIME, CRITICAL FIRE WEATHER
CONDITIONS ARE NOT EXPECTED. BUT THIS WILL NEED TO BE MONITORED
CLOSELY AS THE WILD CARD OF DRY THUNDERSTORM COVERAGE AND INTENSITY
MAY ACT AS A NUDGE FACTOR TOWARDS MORE CRITICAL CONDITIONS.
-THOR
PRELIMINARY POINT TEMPS/POPS
GTF 78 52 82 53 / 0 0 0 0
CTB 76 48 78 49 / 0 0 0 0
HLN 85 53 85 54 / 0 0 10 10
BZN 83 49 83 50 / 0 0 10 20
WYS 80 41 79 40 / 10 20 40 40
DLN 85 49 84 49 / 0 0 20 20
HVR 80 51 82 52 / 0 0 0 0
LWT 76 48 81 50 / 0 0 10 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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