842
FXUS65 KTFX 071109
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
509 AM MDT TUE APR 7 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- WINDY TODAY, WITH TEMPERATURES FALLING BEHIND A COLD FRONT.
- COOLER TEMPERATURES LINGER INTO WEDNESDAY, BUT TREND WARMER
TOWARD THE WEEKEND.
- SHOWERS AND A FEW THUNDERSTORMS THIS WEEKEND, MAINLY NEAR
TERRAIN.
DISCUSSION
/ISSUED 1152 PM MDT MON APR 6 2026/
- METEOROLOGICAL OVERVIEW:
A STRONG UPPER LEVEL DISTURBANCE CONTINUES TO PROGRESS EAST
SOUTHEASTWARD FROM BC, HEADING TOWARD SOUTHERN AB/SK BY THIS
AFTERNOON. STRONG ZONAL FLOW ALOFT ON THE SOUTHERN PERIPHERY OF THIS
UPPER DISTURBANCE WILL RESULT IN A PERIOD OF STRONG WINDS, INITIALLY
ALONG THE ROCKY MOUNTAIN FRONT EARLY THIS MORNING. DAYTIME MIXING
WILL BEGIN TO MIX THE STRONGER WINDS ALOFT TO THE SURFACE ACROSS THE
REMAINDER OF THE REGION MID TO LATE-MORNING. AS THE CORE OF THE
UPPER DISTURBANCE PROGRESSES EASTWARD, COLDER AIR SINKING SOUTHWARD
FROM CANADA WILL UNDERCUT THE WARMER AIRMASS THROUGH THE AFTERNOON,
SLOWLY DIMINISHING THE SPATIAL EXTEND OF THE STRONGEST WINDS ACROSS
THE REGION.
DAYTIME MIXING DIMINISHES BY THE EVENING, WHICH WILL BE THE ENDING
POINT FOR THE STRONG WINDS FOR MOST AREAS. A SECOND WAVE OF STRONGER
MID-LEVEL WINDS MOVES ACROSS AREAS EAST OF US-87 EARLY WEDNESDAY
MORNING. AREAS SOUTHEAST OF TERRAIN EAST OF US-87 WILL BE AT THE
GREATEST RISK FOR STRONG NORTHWEST WINDS EARLY WEDNESDAY.
THE CORE OF THE MAIN DISTURBANCE FINALLY EXITS EASTWARD WEDNESDAY
AFTERNOON. THAT SAID, A MUCH WEAKER WAVE PROGRESSING THROUGH THE
LINGERING NORTHWESTERLY FLOW ALOFT LATE WEDNESDAY OR WEDNESDAY NIGHT
WILL KEEP A LOW-END MENTION OF SHOWERS IN THE FORECAST OVER THIS
TIMEFRAME.
RIDGING DEVELOPS THURSDAY, WHICH WILL HELP DRY THINGS OUT AND ALLOW
FOR TEMPERATURES TO TAKE A COUPLE STEPS WARMER THROUGH SATURDAY. A
DEEP FETCH OF SOUTHERLY OR SOUTHWESTERLY FLOW ALOFT LOOKS TO RESULT
IN SOME AT LEAST WEAK INSTABILITY SATURDAY AFTERNOON, MAINLY OVER
THE TERRAIN. AFTERNOON SHOWERS AND A FEW THUNDERSTORMS APPEARS
REASONABLE, WITH AREAS SOUTH OF I-90 MOST FAVORED FOR THUNDERSTORMS
AT THIS TIME. CONFIDENCE THEREAFTER DECREASES, WITH ENSEMBLE AVERAGES
LARGELY FAVORING AT LEAST A WEAK SOUTHWESTERLY FLOW ALOFT. ALTHOUGH
THE SOUTHWESTERLY FLOW ALOFT IS FAVORED TO CONTINUE SUNDAY INTO NEXT
WEEK, COOLER SURFACE AIR SLOWLY SINKING SOUTHWARD OUT OF CANADA
LOOKS TO TREND TEMPERATURES COOLER, RAISING UNCERTAINTY IN THE
DEVELOPMENT OF ANY INSTABILITY. A MORE STRATIFORM TYPE PRECIPITATION
WILL BE FAVORED WHERE THE COOLER AIR MAKES INROADS. -AM
- FORECAST CONFIDENCE & SCENARIOS:
WINDS TODAY:
MANY 'NUDGERS' WILL BE IN PLACE SUGGESTING STRONG WINDS WILL BE
TRANSLATED TO THE SURFACE THROUGH THE DAY TODAY. THESE INCLUDE
STRONG MID LEVEL ZONAL FLOW, OVERALL TIMING OF THE EVENT WITH
RESPECT TO DIURNAL MIXING, AND COOLING TEMPERATURES THROUGH THE
AFTERNOON IN MOST AREAS (PROMOTING STEEP LOW LEVEL LAPSE RATES AND
THUS MIXING) AMONG OTHER FACTORS. A COMPLICATING FACTOR WILL BE FOR
SCATTERED CONVECTIVE SHOWERS AND ISOLATED THUNDERSTORMS ACROSS
SOUTHWEST MONTANA THIS AFTERNOON EAST OF I-15. THESE WILL ALSO BE
CAPABLE OF MIXING THE STRONGEST WINDS ALOFT TO THE SURFACE LOCALLY.
THE EUROPEAN EXTREME FORECAST INDEX HAS BACKED OFF THE HIGH-END 0.9+
VALUES ACROSS THE REGION, BUT STILL LARGELY SITS AROUND THE 0.8 TO
0.9 RANGE. ALTHOUGH THIS TREND DOWN RAISES SMALL CONCERNS, THE
AFOREMENTIONED 'NUDGERS' STILL INDICATE A VERY WINDY DAY IS IN STORE
ACROSS THE REGION. THE MAIN TAKEAWAY FOR TODAY IS THAT TRAVEL WILL
BE DIFFICULT, PARTICULARLY FOR HIGH PROFILE VEHICLES. BLOWING DUST
CANNOT BE RULED OUT TODAY, MOSTLY IN AREAS THAT HAVE SEEN LIMITED
PRECIPITATION RECENTLY.
WINDS WEDNESDAY:
ALTHOUGH WINDS LARGELY DIMINISH ACROSS THE REGION THIS EVENING,
ANOTHER WAVE OF STRONGER MID LEVEL FLOW MOVES ON THE BACK SIDE OF
THE SYSTEM WEDNESDAY MORNING. NORTHWESTERLY MID LEVEL FLOW OF 50+
KTS LOOKS TO BE TRANSLATED TO THE SURFACE EAST OF US-87, LARGELY
IN AREAS SOUTHEAST OF TERRAIN. THESE STRONGER WINDS DIMINISH
TOWARD WEDNESDAY AFTERNOON.
THUNDERSTORMS SATURDAY:
THE EUROPEAN EXTREME FORECAST INDEX HAS TRENDED UP ON THE SIGNAL FOR
CONVECTIVE ACTIVITY SATURDAY, MAINLY ACROSS SOUTHWEST AND CENTRAL
MONTANA ASSOCIATED WITH AN IMPRESSIVE FETCH OF SOUTHERLY FLOW ALOFT.
EFI VALUES OF 0.7 TO 0.8 SUGGEST RATHER IMPRESSIVE INSTABILITY FOR
THIS TIME OF THE YEAR ON SATURDAY IN THESE AREAS. WHILE CONFIDENCE
REMAINS LOW IN ANY STRONGER THUNDERSTORMS, THOSE PLANNING TO
RECREATE SATURDAY SHOULD BE PREPARED FOR THE THREAT OF THUNDERSTORMS
IN THE AFTERNOON. -AM
AVIATION
07/12Z TAF PERIOD
STRONG AND GUSTY SURFACE WINDS, MOUNTAIN WAVE TURBULENCE, AND
INSTANCES OF LOW LEVEL WIND SHEAR ALONG THE ROCKY MOUNTAIN FRONT
EXPAND EAST AND SOUTHEAST OVER MUCH OF THE FORECAST AREA BY THIS
AFTERNOON. WEST TO SOUTHWESTERLY WINDS WILL GENERALLY GUST IN THE
40 TO 60 KT RANGE, HIGHEST OVER THE PLAINS WEST OF THE I15
CORRIDOR. A CANADIAN COLD FRONT CROSSES THE INTERNATIONAL BORDER
AROUND 07/18Z AND BRINGS A NORTH TO NORTHWESTERLY WIND SHIFT.
WIDELY SCATTERED SHOWER ACTIVITY WILL ACCOMPANY THE COLD FRONTAL
PASSAGE AND MAY BRING SHORTER BURSTS OF STRONGER WIND GUSTS PRIOR
TO WINDS DECREASING IN A NORTHWEST TO SOUTHEAST FASHION HEADING
INTO THE LATE AFTERNOON AND EVENING HOURS. LOW VFR/MVFR CLOUDS MAY
ALSO DEVELOP BEHIND THE FRONT, MOSTLY FOR THE HI-LINE TERMINALS.
- RCG
FIRE WEATHER
GUSTY SOUTHWEST TO WEST WINDS WILL COMBINE WITH MODESTLY LOW
RELATIVE HUMIDITY TO RESULT IN LOCALIZED ELEVATED FIRE WEATHER
CONCERNS TODAY. THE AREAS OF CONCERN WILL BE IN AREAS THAT HAVE SEEN
LITTLE PRECIPITATION RECENTLY AND HAVE NOT HAD ANY GREENING UP
YET. -AM
PRELIMINARY POINT TEMPS/POPS
GTF 62 26 49 28 / 20 30 0 10
CTB 55 21 47 23 / 50 30 0 10
HLN 65 30 58 31 / 10 20 0 0
BZN 67 27 59 30 / 20 20 0 0
WYS 60 25 55 27 / 20 20 0 0
DLN 65 28 62 32 / 0 0 0 0
HVR 62 26 47 25 / 20 20 0 20
LWT 65 24 46 26 / 20 30 0 10
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR EAST GLACIER
PARK REGION-EASTERN GLACIER, WESTERN TOOLE, AND CENTRAL PONDERA-
NORTHERN HIGH PLAINS-SOUTHERN HIGH PLAINS-SOUTHERN ROCKY
MOUNTAIN FRONT.
HIGH WIND WARNING FROM 9 AM THIS MORNING TO 9 PM MDT THIS
EVENING FOR BEAVERHEAD AND WESTERN MADISON BELOW 6000FT-BIG
BELT, BRIDGER AND CASTLE MOUNTAINS-CASCADE COUNTY BELOW 5000FT-
EASTERN PONDERA AND EASTERN TETON-EASTERN TOOLE AND LIBERTY-
ELKHORN AND BOULDER MOUNTAINS-GATES OF THE MOUNTAINS-HELENA
VALLEY-JUDITH BASIN COUNTY AND JUDITH GAP-LITTLE BELT AND
HIGHWOOD MOUNTAINS-MADISON RIVER VALLEY-MEAGHER COUNTY VALLEYS-
NORTHWEST BEAVERHEAD COUNTY-UPPER BLACKFOOT AND MACDONALD PASS-
WESTERN AND CENTRAL CHOUTEAU COUNTY.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO NOON MDT WEDNESDAY
FOR BEARS PAW MOUNTAINS AND SOUTHERN BLAINE-FERGUS COUNTY BELOW
4500FT.
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