416
FXUS65 KTFX 060948
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
348 AM MDT WED AUG 6 2025
KEY MESSAGES
- A COLD FRONT WILL BRING BREEZY TO WINDY CONDITIONS AND A
COUPLE ROUNDS OF SHOWERS AND THUNDERSTORMS TONIGHT THROUGH
THURSDAY EVENING, SOME STORMS MAY BE STRONG TO SEVERE.
- TEMPERATURES COOL AS MUCH AS 10 TO 20 DEGREES BELOW AVERAGE
ON FRIDAY WITH MORE BREEZY TO WINDY CONDITIONS AND MORE PERIODS
OF SHOWERS AND EMBEDDED THUNDERSTORMS.
- A WARMING AND DRYING TREND IS EXPECTED FOR THE WEEKEND INTO
EARLY NEXT WEEK, BUT A FEW FAST MOVING WEATHER SYSTEMS MAY BRING
BRIEF COOL DOWNS AND SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
HIGH AND MID- LEVEL CLOUDINESS WILL CONTINUE TO INCREASE IN
ADVANCE OF AN APPROACHING PACIFIC TROUGH AND ATTENDANT COLD FRONT.
AN INITIAL AREA OF SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
WEST AND SOUTHWEST MONTANA THIS EVENING AND THEN SPREAD EAST
NORTHEASTWARD DURING THE OVERNIGHT HOURS. LOCALIZED GUSTY WINDS
WILL BE THE PRIMARY CONCERN WITH COLD AIR ADVECTION AND 30 TO 50
KT MID- LEVEL FLOW ALOFT. BRIEF DOWNPOURS AND EVEN SOME HAIL MAY
BECOME MORE COMMON AS THE STORMS MOVE OVER CENTRAL/NORTH-CENTRAL
AREAS EAST OF I15 WHERE PWAT VALUES INCREASE TO THE 0.75 TO 1 INCH
MARK. LOW ML CAPE (300 - 800 J/KG) IS DEFINITELY A CONFOUNDING
FACTOR GOING AGAINST SOME OF THE MORE AGGRESSIVE CAMS, BUT A FEW
STRONG TO SEVERE STORMS CAN'T BE RULED OUT, ESPECIALLY FOR AREAS
SOUTH AND EAST OF A GREAT FALLS TO HAVRE LINE.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE EXPECTED AGAIN
THURSDAY AFTERNOON AND EVENING AS THE MAIN TROUGH AXIS MOVES
CLOSER TO THE NORTHERN ROCKIES. ONCE AGAIN, ML CAPE LOOKS TO BE IN
QUESTION WITH SOME DETERMINISTIC HOLDING BACK ON HIGHER NUMBERS.
AREAS EAST OF A HELENA TO HAVRE LINE ARE EXPECTED TO HAVE THE
HIGHEST ML CAPE (500 TO 1,500 J/KG) TO COMPLIMENT BULK SHEAR
MOSTLY IN THE THE 30 TO 50 KTS. STRONG GUSTY WINDS, LARGE HAIL,
AND BRIEF HEAVY DOWNPOURS WILL BE TO PRIMARY CONCERNS THURSDAY
AFTERNOON AND EVENING. WITH CONTINUED STRONGER FLOW ALOFT, THERE
WILL ALSO BE GENERAL BREEZY TO WINDY CONDITIONS THURSDAY THROUGH
SATURDAY, ESPECIALLY ALONG THE ROCKY MOUNTAIN FRONT AND FOR
SOUTHWESTERN LOCATIONS SOUTH OF I90.
THE COLD CORE OF THE TROUGH WILL MOVE DIRECTLY OVER CENTRAL AND
SOUTHWEST MONTANA ON FRIDAY, WITH H500 TEMPERATURES 2 TO 3
STANDARD DEVIATIONS BELOW CLIMATOLOGY. SOME OF THE HIGH MOUNTAIN
PEAKS MAY SEE A TOUGH OF LIGHT SNOW OR FLURRIES FRIDAY MORNING,
ESPECIALLY OVER THE CENTRAL ISLAND RANGES. AFTERNOON HIGHS WILL
NOT ECLIPSE THE 60S AND 70S FOR MOST LOCATIONS AND THERE WILL BE
CONTINUED PERIOD OF SHOWERS AND ISOLATED THUNDERSTORMS, MOSTLY
OVER NORTH-CENTRAL MONTANA.
MOST ENSEMBLES FAVOR A NORTHWESTERLY FLOW ALOFT MOVING IN FOR THE
WEEKEND IN THE WAKE OF THE DEPARTING TROUGH; HOWEVER,
DISCREPANCIES REMAIN IN THE DEPTH AND TIMING OF THE SHORTWAVES
PASSING THROUGH IT. OVERALL, THERE WILL BE A SHIFT TO RIDGING
ALOFT AND AT LEAST NEAR TO ABOVE NORMAL TEMPERATURES BY MID- NEXT
WEEK, BUT THE WARMING AND DRYING TREND MAY BE BRIEFLY INTERRUPTED
BY BRIEF COOL DOWNS AND CHANCES FOR SHOWERS AND THUNDERSTORMS THIS
WEEKEND INTO EARLY NEXT WEEK. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
STRONG TO SEVERE THUNDERSTORMS TONIGHT THROUGH THURSDAY
EVENING...
A COUPLE WAVES OF SHOWERS AND THUNDERSTORMS WILL PASS THROUGH THE
REGION TONIGHT AND ON THURSDAY. SOME CAMS HAVE RAMPED UP THE
COVERAGE AND INTENSITY OF STORMS FOR TONIGHT, NAMELY THE NAM AND
THE HRW NSSL. GIVEN THE COLD AIR ADVECTION AND THE STRONGER FLOW
ALOFT, IT'S NOT OUT OF THE QUESTION FOR A FEW STRONG TO SEVERE
STORMS TO DEVELOP. CENTRAL AND NORTH-CENTRAL AREAS WILL BE MOST
SUSCEPTIBLE TO HIGHER END WIND GUSTS, BUT THE LATEST HREF ONLY
GIVES AROUND A 10% CHANCE FOR GUSTS EXCEEDING 35 MPH. AS MENTIONED
EARLY THE RICHEST MOISTURE AND CAPE WILL GENERALLY BE EAST OF A
GREAT FALLS TO HAVRE LINE WHERE INSTANCES OF HAIL AND BRIEF
DOWNPOURS MAY OCCUR WITH THE STRONGEST STORMS.
THE SECOND ROUND OF STORMS WILL BE THURSDAY AFTERNOON AND
EVENING, CENTRAL/NORTH-CENTRAL MONTANA AND SOUTHWESTERN AREAS
NORTH OF I90 WILL SEE THE GREATEST COVERAGE. AREAS EAST OF A
HELENA TO HAVRE LINE WILL BE MOST SUSCEPTIBLE TO STRONG WIND
GUSTS, LARGE HAIL, AND HEAVY DOWNPOURS IN ADDITION TO LIGHTNING.
FLOODING IS GENERALLY NOT EXPECTED, BUT BURN SCARS THAT HAPPEN GET
STRONGER CELLS OVERHEAD WILL NEED TO BE MONITORED FOR POTENTIAL
FLOODING CONCERNS.
GUSTY WINDS, AND CONTINUED SHOWERS AND THUNDERSTORMS LATE
THURSDAY THROUGH SATURDAY...
BREEZY TO WINDY CONDITIONS WILL ACCOMPANY THIS SYSTEM THURSDAY
THROUGH SATURDAY. THE STRONGEST WINDS WILL BE OVER SOUTHERN
MADISON AND GALLATIN COUNTIES LATE THURSDAY INTO FRIDAY WHEN THERE
WILL BE A 30 TO 60% CHANCE FOR GUSTS EXCEEDING 45 MPH. THE WINDS
MOVE NORTHWARD INTO CENTRAL/NORTH-CENTRAL MONTANA ON FRIDAY AND
SATURDAY. AREAS ALONG THE NORTHERN ROCKY MOUNTAIN FRONT WILL SEE
THE STRONGEST WINDS DURING THIS PERIOD WITH PROBABILITIES FOR 45
MPH GUSTS OR HIGHER RUNNING BETWEEN 30 AND 60%.
CENTRAL AND NORTH-CENTRAL AREAS WILL SEE THE MOST RAIN WITH A 30
TO 50% CHANCE FOR HALF INCH RAIN TOTALS EAST OF A GREAT FALLS TO
HAVRE LINE FOR THE 48 HR PERIOD ENDING AT 6 AM SATURDAY MORNING.
TEMPERATURES WILL BE COLD ENOUGH FOR SOME LIGHT SNOW OR A FEW
FLURRIES OVER THE HIGHER MOUNTAIN PEAKS FRIDAY MORNING, MOSTLY
OVER THE CENTRAL ISLAND RANGES. - RCG
AVIATION
06/12Z TAF PERIOD
RIDGING ALOFT WILL PROVIDE WIDESPREAD VFR CONDITIONS THROUGH
WEDNESDAY AFTERNOON WHILE HIGH AND MID-LEVEL CLOUDS INCREASE FROM
THE WEST. SOUTHWESTERLY FLOW ALOFT THEN BECOMES ESTABLISHED OVER THE
NORTHERN ROCKIES AFTER 07/00Z. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER WESTERN AND SOUTHWESTERN MONTANA
BEFORE MOVING EAST NORTHEASTWARD INTO THE PLAINS AND VALLEYS DURING
THE LATER EVENING AND OVERNIGHT HOURS. GUSTY AND ERRATIC WINDS AND
LIGHTNING WILL BE THE PRIMARY HAZARD CONCERNS. - RCG
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 86 57 79 51 / 0 40 40 50
CTB 79 54 71 49 / 0 30 20 20
HLN 87 57 79 49 / 10 30 60 60
BZN 89 52 84 46 / 0 30 40 60
WYS 82 43 77 37 / 0 10 20 40
DLN 85 51 79 44 / 10 10 30 30
HVR 88 58 82 52 / 0 60 40 40
LWT 83 53 77 47 / 10 70 50 80
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page