729
FXUS65 KTFX 221042
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
442 AM MDT MON JUN 22 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- BELOW NORMAL TEMPERATURES TODAY WILL MODERATE FROM TUESDAY
THROUGH FRIDAY, WITH THE WARMEST DAYS OF THE UPCOMING WEEK
OCCURRING ON THURSDAY AND FRIDAY.
- OUTSIDE OF TUESDAY AND WEDNESDAY THEIR WILL BE DAILY CHANCES
FOR PRECIPITATION, MOST NOTABLY FROM THURSDAY THROUGH THE
UPCOMING WEEKEND.
- STRONG AND GUSTY WINDS ARE POSSIBLE ON FRIDAY ACROSS SOUTHWEST
MONTANA.
- A COOL AND WET WEEKEND IS POSSIBLE ACROSS ALL OF THE NORTHERN
ROCKIES.
DISCUSSION
/ISSUED 1206 AM MDT MON JUN 22 2026/
- METEOROLOGICAL OVERVIEW:
MOIST AND UNSTABLE NORTHWEST FLOW ALOFT WILL HELP TO MAINTAIN
SHOWERS, THUNDERSTORMS, AND BELOW NORMAL TEMPERATURES ACROSS
SOUTHWEST THROUGH NORTH CENTRAL MONTANA TODAY, WITH PRECIPITATION
COVERAGE GRADUALLY WANING THROUGH THE EVENING HOURS TONIGHT AS THE
UPPER LEVEL FLOW BACKS TO THE WEST AS UPPER LEVEL RIDGING BEGINS TO
BUILD AND SLIDE EAST OVER THE NORTHERN ROCKIES. THIS UPPER LEVEL
RIDGE WILL BRING MODERATING TEMPERATURES FROM TUESDAY THROUGH
FRIDAY, WITH THURSDAY OR FRIDAY BEING THE WARMEST DAYS OF THE
UPCOMING WEEK AS WARM AIR SURGES NORTH OF AN APPROACHING UPPER LEVEL
TROUGH. WHILE MOST AREAS WILL REMAIN DRY ON TUESDAY AND WEDNESDAY AS
THE UPPER LEVEL RIDGE AXIS MOVES OVERHEAD AN ISOLATED SHOWER OR
THUNDERSTORM CAN'T BE RULED OUT, MAINLY OVER THE HIGHER TERRAIN. BY
THURSDAY AND FRIDAY PACIFIC MOISTURE WILL BEGIN TO STREAM NORTHEAST
AND OVER THE NORTHERN ROCKIES AS THE UPPER LEVEL FLOW BACKS TO THE
SOUTHWEST, WHICH WILL HELP TO SUPPORT SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS ACROSS SOUTHWEST THROUGH NORTH CENTRAL MONTANA. A
FEW OF THE THUNDERSTORMS ON THURSDAY AND FRIDAY COULD BE ON THE
STRONGER SIDE AS BOTH INSTABILITY AND SHEAR INCREASE ACROSS THE
REGION. AS THE UPPER LEVEL TROUGH SWINGS EAST AND OVER THE NORTHERN
ROCKIES THIS UPCOMING WEEKEND PRECIPITATION WILL BECOME MORE
WIDESPREAD, WITH TEMPERATURES FALLING BELOW TO WELL BELOW NORMAL. -
MOLDAN
- FORECAST CONFIDENCE & SCENARIOS:
STRONG AND GUSTY WINDS ON FRIDAY...
CLIMATE ANOMALY INDICATORS SUCH AS THE ECMWF EFIS AND NAEFS ARE
INDICATING THE POTENTIAL FOR A CLIMATOLOGICALLY UNUSUAL, WITH
RESPECT TO LATE JUNE CLIMATOLOGY, WIND EVENT ACROSS SOUTHWEST
MONTANA. H700 WINDS OF 20-40KTS FROM THE SOUTH TO SOUTHWEST PER
NAEFS ANALYSIS COMBINED WITH THE SOUTH-NORTH VALLEY ORIENTATION
AND/OR DEEP MIXING WILL SUPPORT STRONG SURFACE WINDS ACROSS ALL
ELEVATIONS SOUTH OF THE I-90 CORRIDOR FROM THE LATE MORNING THROUGH
EARL EVENING HOURS ON FRIDAY, ESPECIALLY WITHIN THE THE MADISON AND
BEAVERHEAD VALLEYS. BUFKIT SOUNDING FOR THESE RESPECTIVE VALLEYS
SHOWS AFTERNOON MIXING HEIGHTS OF BETWEEN 5000-10,000FT AGL, WHICH
WILL SUPPORT HIGHER END MOMENTUM TRANSFER TO THE SURFACE, WHICH
COMBINED WITH THE EFFECTS OF TERRAIN FUNNELING WILL HELP TO ENHANCE
SURFACE WIND SPEEDS/GUSTS. LATEST NBM5.0 PROBABILITIES WITH RESPECT
TO WIND SPEEDS OF 30 MPH OR GREATER FOR AREAS SOUTH OF THE I-90
CORRIDOR RANGE FROM A 40-60% CHANCE ACROSS MOST AREAS, WITH A 5-15%
CHANCE THAT SUSTAINED WIND SPEEDS REACH 40 MPH WITHIN THE DILLON,
ENNIS, AND NORRIS HILL AREAS. ADDITIONALLY, LATEST NBM5.0
PROBABILITIES WITH RESPECT TO WIND GUSTS OF 50 MPH OR GREATER FOR
MOST AREAS SOUTH OF THE I-90 CORRIDOR RANGE FROM A 20-60% CHANCE,
WITH A 5-10% CHANCE THAT GUSTS EXCEED 60 MPH WITHIN THE BEAVERHEAD
AND MADISON VALLEYS. THIS POTENTIAL STRONG WIND EVENT WILL NEED TO
BE MONITORED GIVEN THE INCREASED SUMMER TRAFFIC ACROSS THE AREA AS
STRONG CROSS WINDS WILL POSE A THREAT TO THOSE OPERATING HIGH
PROFILE VEHICLES.
WET AND COOL CONDITIONS THIS WEEKEND...
CLUSTER ANALYSIS IS FAVORING AND ANOMALIES UPPER LEVEL TROUGH DIGGING
IN OVER THE NORTHERN ROCKIES OVER THE PERIOD, WITH THE MAIN MODE OF
UNCERTAINTY BEING THE POSITION AND/OR TIMING OF THE TROUGH AS IT
MOVES OVER THE REGION. THIS POSITION AND/OR TIMING UNCERTAINTY WILL
ULTIMATELY IMPACT WHERE AND WHEN THE HEAVIEST PRECIPITATION FALLS,
BUT LATEST NBM5.0 PROBABILITIES SUPPORT A 40-80% CHANCE FOR 48HR
(6AM SATURDAY THROUGH 6AM MONDAY) RAINFALL AMOUNTS TO EXCEED 0.5"
ACROSS ALL OF SOUTHWEST THROUGH NORTH CENTRAL MONTANA, WITH A 20-40%
CHANCE THAT AMOUNTS EXCEED 1" ACROSS MOST AREAS OUTSIDE OF THE
GLACIER NATIONAL PARK, LITTLE BELTS, AND MADISON/GALLATIN RANGE
AREAS WHERE THERE IS A 40-70% CHANCE OF EXCEEDING 1". WHILE BELOW
NORMAL TEMPERATURES ARE LIKELY TO OCCUR ON BOTH SATURDAY AND SUNDAY
BENEATH THIS UPPER LEVEL TROUGH THERE IS A 30-50% CHANCE THAT HIGHS
ON SUNDAY WILL FAIL TO REACH 60 DEGREES, WITH EVEN A 10-30% CHANCE
THAT THE HIGHER ELEVATIONS OF CONTINENTAL DIVIDE FAIL TO REACH 32
DEGREES. - MOLDAN
AVIATION
22/12Z TAF PERIOD
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE ACROSS PORTIONS OF SOUTHWEST THROUGH NORTH CENTRAL
MONTANA THROUGH 03-06Z TUESDAY, WITH THE HIGHEST COVERAGE OF
PRECIPITATION OCCURRING ALONG AND SOUTH OF THE MONTANA HWY 200
AND NORTH OF THE US HWY 12 CORRIDOR. A FEW OF THE THUNDERSTORMS
NEAR THE KLWT TERMINAL COULD BECOME STRONG AND PRODUCE GUSTY WINDS
AND HAIL, ESPECIALLY BETWEEN 18-24Z THIS AFTERNOON. OUTSIDE OF
THE KBZN, KEKS, KWYS, AND KHLN TERMINALS WHERE VFR CONDITIONS ARE
EXPECTED THROUGHOUT THE NEXT 24 HOURS IFR/MVFR/LOW-VFR CONDITIONS
WILL OCCUR THROUGH 04-07Z TUESDAY AT THE REMAINING TERMINALS.
MOUNTAINS NORTH OF THE I-90 CORRIDOR WILL BE OBSCURED THROUGH
03-09Z TUESDAY. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 64 41 70 47 / 40 20 0 0
CTB 58 37 68 45 / 30 0 0 0
HLN 69 43 74 49 / 30 20 0 0
BZN 73 40 75 45 / 20 20 0 0
WYS 71 33 72 36 / 0 0 0 0
DLN 75 40 75 43 / 0 0 0 0
HVR 66 44 70 45 / 40 20 0 0
LWT 62 38 66 43 / 80 20 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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