876
FXUS65 KTFX 242003
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
203 PM MDT SUN MAY 24 2026
KEY MESSAGES
- WARM, BREEZY AND MOSTLY DRY CONDITIONS FOR MUCH OF THE REGION
TODAY, WITH SOME ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE IN
SOUTHWEST MT THIS AFTERNOON.
- MONDAY THROUGH FRIDAY WILL SEE DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON AND EVENING HOURS. SOME OF
THESE STORMS COULD BE STRONG TO SEVERE.
- WARM TEMPERATURES WILL CONTINUE THROUGH TUESDAY, WITH A BRIEF
COOL DOWN WEDNESDAY AND THURSDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
DUE TO ZONAL FLOW ALOFT, TODAY WILL BE WARM, BREEZY AND MOSTLY
DRY ACROSS THE REGION, WITH THE EXCEPTION OF A FEW SHOWERS AND
WEAK THUNDERSTORMS POSSIBLE IN SOUTHWEST MT THIS AFTERNOON.
TOMORROW, AN UPPER-LEVEL TROUGH BEGINS TO MOVE INLAND FROM THE
WEST COAST, BRINGING WIDESPREAD CHANCES FOR SHOWERS AND
THUNDERSTORMS. THE UPPER LEVEL TROUGH WILL TRANSITION THE ZONAL
FLOW TO SOUTHWESTERLY FLOW, ADVECTING WARM AIR INTO MONTANA. THIS
WARM AIR ADVECTION, COMBINED WITH UPPER LEVEL RIDGING TO THE EAST,
WILL MAKE FOR THE WARMEST DAY OF THE WEEK FOR MOST OF THE REGION,
WITH HIGHS IN THE 80S TO LOW 90S. THE WARM TEMPERATURES WILL LAST
THROUGH TUESDAY, BEFORE A COLD FRONT TUESDAY NIGHT WILL BRING A
BRIEF COOL DOWN WEDNESDAY AND THURSDAY.
ON TUESDAY, THE AXIS OF THE UPPER LEVEL TROUGH MOVES SOUTHEAST
DOWN WESTERN OREGON AND AND NORTHERN CALIFORNIA, RESULTING IN
SOUTHEASTERLY FLOW INTO THE REGION. THE TROUGH SETTLES INTO A SPIN
OVER CALIFORNIA AND NEVADA WEDNESDAY AND THURSDAY, CREATING A
SHIFT TO A MORE STEEP SOUTHERLY FLOW. ON FRIDAY, THE TROUGH BEGINS
TO BREAK DOWN AND THE AXIS MOVES NORTHEAST TOWARDS MONTANA,
PUTTING THE REGION BACK INTO SOUTHEASTERLY FLOW.
WITH THE DAILY INFLUENCE OF THIS TROUGH SPINNING TO THE SOUTHWEST
OF MONTANA COMES AN USHERING OF MOIST AND UNSTABLE AIR INTO THE
REGION EACH DAY. COMBINED WITH THE WARM AFTERNOON TEMPERATURES,
THERE IS A DAILY CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THE
REST OF THE APPROACHING WORK WEEK. SOME OF THESE STORMS COULD BE
STRONG TO SEVERE, DEPENDING ON THE POSITION OF THE TROUGH AND THE
TIMING OF THE MOISTURE EACH DAY. SEE THE "FORECAST CONFIDENCE &
SCENARIOS" SECTION FOR MORE DETAILS. -DZOMBA
- FORECAST CONFIDENCE & SCENARIOS:
MONDAY THUNDERSTORMS:
OVERALL, THESE SHOWERS AND THUNDERSTORMS LOOK RELATIVELY MILD
COMPARED TO WHAT IS EXPECTED LATER IN THE WEEK. WITH CAPE
GENERALLY EXPECTED TO STAY BELOW 1000 J/KG, THERE IS NOT A LOT TO
WORK WITH. SOME ISOLATED INSTANCES OF STRONG, GUSTY WINDS ARE
CERTAINLY POSSIBLE ACROSS SOUTHWEST MONTANA BUT NOTHING REACHING
THE LEVEL OF CONCERN COMPARED TO WHAT ARRIVES LATER IN THE WEEK.
TUESDAY THUNDERSTORMS:
ONE OF THE LIMITING FACTORS ON TUESDAY WILL BE MOISTURE. THE 00Z
RUN OF THE GFS HAS CONTINUED THE TREND OF PUSHING BACK THE TIMING
FOR WHEN THE MOIST AIR GETS PULLED UP INTO CENTRAL MONTANA. THE
EURO STILL HAS DEWPOINTS GETTING CLOSE TO 50 DEGREES STARTING AT
AROUND 6 PM. EITHER WAY, THE TREND IS THAT THE MOIST AIR IS NOT
EXPECTED TO ARRIVE UNTIL MUCH LATER IN THE DAY THAN WHAT WOULD
NORMALLY BE FAVORABLE FOR SEVERE WEATHER.
THIS NOT TO SAY THAT SEVERE WEATHER IS NOT POSSIBLE. WITH HIGHS
ACROSS THE NORTHERN PLAINS IN THE MID 80S TO MID 90S, THERE IS
STILL A POTENTIAL FOR ISOLATED, STRONG, DIURNALLY-DRIVEN
CONVECTION. BECAUSE MOISTURE IS GOING TO BE LACKING, ESPECIALLY IN
THE EARLY AFTERNOON HOURS, THE MAIN CONCERN WILL BE DRY
DOWNBURSTS WHICH COULD PRODUCE ISOLATED INSTANCES OF STRONG WINDS.
ALL THINGS CONSIDERED, THE TIMING OF THE MOISTURE WILL DETERMINE
THE DYNAMICS OF THE AFTERNOON. IF THE MOISTURE IS ABLE TO ARRIVE
EARLIER IN THE DAY, THE CHANCES FOR STRONGER CONVECTION INCREASES.
HOWEVER, IF THE CURRENT TREND OF THE GFS PUSHES THE ARRIVAL
FURTHER INTO THE EVENING/OVERNIGHT HOURS, THEN THE THREAT LESSENS
SIGNIFICANTLY. DESPITE ONLY BEING A COUPLE DAYS OUT, THERE IS
STILL UNCERTAINTY AS TO HOW TUESDAY WILL PLAY OUT.
THROUGH FRIDAY.
WEDNESDAY THUNDERSTORMS:
BY WEDNESDAY, MOIST AIR IS EXPECTED TO FILTER INTO CENTRAL AND
NORTH- CENTRAL MONTANA WITH THE LATEST EURO PUSHING AFTERNOON
DEWPOINTS INTO THE LOW TO MID 60S ACROSS THE NORTHERN PLAINS. THE
CURRENT AREAS OF CONCERN ARE FOCUSED MORE ON CENTRAL MONTANA,
PARTICULARLY AROUND JUDITH BASIN, FERGUS, CHOUTEAU, HILL, AND
BLAINE COUNTIES. THE LATEST MODEL RUNS CONTINUE TO SHOW A MODEST
1000-1500 J/KG CAPE ACROSS THE REGION. THE LIMITING FACTOR ON
WEDNESDAY WILL BE HOW WARM TEMPERATURES GET. RIGHT NOW, EAST OF A
LINE BETWEEN HAVRE AND LEWISTOWN, HIGHS IN THE UPPER 70S TO MID
80S ARE EXPECTED, WITH LOCATIONS TO THE WEST OF THAT LINE ONLY
REACHING THE LOW TO MID 70S. WIDESPREAD CLOUD COVER THROUGHOUT THE
DAY IS POSSIBLE, WHICH COULD FURTHER LIMIT AFTERNOON INSTABILITY.
SIMPLY PUT, IT IS NOT UNREASONABLE FOR A COUPLE OF THE STORMS ON
WEDNESDAY TO BE NEAR-SEVERE OR SEVERE. HOWEVER, RIGHT NOW THERE IS
TOO MUCH UNCERTAINTY IN THE MORNING SETUP TO MAKE ANY
DETERMINISTIC CALLS ON HOW WIDESPREAD OR SIGNIFICANT THE THREAT
WILL BE.
THURSDAY AND FRIDAY THUNDERSTORMS:
WHILE THERE IS STILL A BIT OF UNCERTAINTY AS TO EXACTLY HOW THIS
UPPER LEVEL TROUGH WILL SET UP ACROSS THE WESTERN CONUS, THERE IS
INCREASING CONFIDENCE WITH THE LATEST MODEL RUNS THAT BOTH
THURSDAY AND FRIDAY WILL BE WIDESPREAD THUNDERSTORM DAYS. AS OF
NOW, THE EURO IS A LOT MORE GENEROUS WITH CAPE THAN THE GFS ON
BOTH DAYS. THE CANADIAN OPTED MORE FOR A CONFINED AREA OF HIGHER
CAPE ACROSS THE CENTRAL THIRD OF THE CWA ON THURSDAY, ROUGHLY
BETWEEN GREAT FALLS AND BOZEMAN. ON FRIDAY, THE CANADIAN SHOWS
HIGHER CAPE VALUES IN THE NORTHERN HALF OF THE CWA. -THOR AND
DZOMBA
AVIATION
24/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. THERE WILL BE
ISOLATED THUNDERSTORMS THROUGH 03Z OVER SOUTHWEST MT, MOSTLY SOUTH
OF A DILLON TO BIG SKY LINE. THUNDERSTORMS WILL ALSO REDEVELOP
AFTER 21Z ON MONDAY OVER SOUTHWEST MT AND ALONG THE DIVIDE FROM
DILLON NORTHWARD TO THE HELENA AREA. MOUNTAINS/PASSES WILL BE
OBSCURED AT TIMES OVER SOUTHWEST MT BY PASSING
SHOWERS/THUNDERSTORMS. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 48 88 56 88 / 0 0 10 50
CTB 45 84 52 84 / 0 0 10 50
HLN 47 85 51 84 / 0 10 20 40
BZN 44 85 48 83 / 0 10 30 60
WYS 36 78 39 75 / 10 0 10 60
DLN 43 81 46 79 / 0 20 30 40
HVR 49 91 58 96 / 0 0 10 10
LWT 46 84 53 88 / 0 0 0 10
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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