657
FXUS65 KTFX 171726
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1126 AM MDT SAT OCT 17 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- HIGH WINDS WILL LEAD TO DANGEROUS TRAVEL, ESPECIALLY FOR HIGH
PROFILE VEHICLES, AND BACKCOUNTRY RECREATION ALONG THE ROCKY
MOUNTAIN FRONT AND PORTIONS OF THE HI-LINE THROUGH THIS
EVENING.
- HIGHS WILL BE WELL ABOVE NORMAL TODAY, WITH TEMPERATURES
COOLING TO NEAR NORMAL ON SUNDAY.
- OVERALL DRY CONDITIONS ARE EXPECTED THROUGH MONDAY, WITH LOW
CHANCES FOR PRECIPITATION ARRIVING ON TUESDAY ACROSS SOUTHWEST
AND CENTRAL MONTANA.
DISCUSSION
/ISSUED 446 AM MDT SAT OCT 17 2026/
- METEOROLOGICAL OVERVIEW:
UPPER LEVEL RIDGING OVER THE WESTERN CONUS EARLY THIS MORNING WILL
CONTINUE TO BE FLATTENED AS A POTENT SHORTWAVE OVER THE GULF OF
ALASKA SLIDES EAST OVER BRITISH COLUMBIA AND THE CANADIAN PRAIRIE
PROVINCES THROUGH THE DAY TODAY. INCREASING CROSS BARRIER FLOW OVER
THE NORTHERN ROCKIES WILL LEAD TO STRENGTHENING SOUTHWEST TO WEST
WINDS ACROSS SOUTHWEST THROUGH NORTH CENTRAL MONTANA, MOST NOTABLY
ALONG THE ROCKY MOUNTAIN FRONT AND INTERNATIONAL BORDER. THESE
DOWNSLOPING SOUTHWEST TO WEST WINDS WILL LEAD TO ANOTHER DAY OF
ABOVE NORMAL TEMPERATURES ACROSS THE REGION, WITH HIGHS PEAKING IN
THE MID-60S TO NEAR 70 DEGREES IN THE VALLEYS OF SOUTHWEST AND
CENTRAL MONTANA TO THE LOW 70S TO NEAR 80 DEGREES OVER THE PLAINS OF
CENTRAL AND NORTH CENTRAL MONTANA. "COOLER" TEMPERATURES ARE THEN
EXPECTED INTO THE DAY ON SUNDAY IN WAKE OF A WEAK PACIFIC FRONT,
WHICH WILL SLIDE EAST AND OVER THE NORTHERN ROCKIES LATE TONIGHT,
WITH HIGHS TOPPING OUT IN THE UPPER 50S TO LOW 60S. DESPITE
PERSISTENT ZONAL FLOW OVER THE NORTHERN ROCKIES ON SUNDAY WEAK
SURFACE HIGH PRESSURE SETTLING IN OVER THE PACIFIC NORTHWEST AND
NORTHERN ROCKIES WILL HELP TO SUPPORT LIGHT SURFACES WINDS AND
CONTINUED DRY CONDITIONS. - MOLDAN
BY MONDAY MORNING, WEAK RIDGING TAKES ITS PLACE AS AN UPPER LEVEL
TROUGH BEGINS TO MOVE DOWN THE PACIFIC COAST TOWARDS NORTHERN
CALIFORNIA. THIS WILL CREATE SOUTHWESTERLY FLOW ALOFT BY MONDAY
EVENING, WHICH WILL LAST THROUGH THE MIDDLE OF NEXT WEEK, ALLOWING
FOR SEASONABLY AVERAGE TEMPERATURES. BY THURSDAY, THE TROUGH WILL
HAVE MOVED SOUTH OF THE GREAT BASIN, CREATING A MORE DIRECT
SOUTHERLY FLOW ALOFT, BEFORE MOVING NORTHEAST TOWARDS WYOMING. THIS
WILL ALLOW TEMPERATURES TO WARM ON THURSDAY BEFORE COOLING DOWN ON
FRIDAY. INCREASED MOISTURE ALOFT WILL GET CARRIED NORTH BY THE UPPER
LEVEL SOUTHERLY LOW, INCREASING PRECIPITATION CHANCES TOWARDS THE
END OF NEXT WEEK INTO NEXT WEEKEND. THERE REMAINS SHEARING AND
SPLITTING IN THE TROUGH LATE THURSDAY INTO NEXT WEEKEND, SO WHILE
ONE CAN EXPECT COOLING TEMPERATURES AND INCREASED PRECIPITATION
CHANCES LATE IN THE FORECAST PERIOD, CONFIDENCE IN THE FORECAST
SPECIFICS FOR THIS TIME REMAINS LOW. -DZOMBA
- FORECAST CONFIDENCE & SCENARIOS:
HIGH WINDS THROUGH THIS EVENING...
CONFIDENCE IS VERY HIGH THAT HIGH WINDS WILL DEVELOP ALONG AND WEST
OF A SWEET GRASS, TO CUT BANK, TO DUPUYER, TO CHOTEAU, TO AUGUSTA
LINE BY THE LATE MORNING HOURS TODAY AND PERSIST THROUGH THE EVENING
HOURS TONIGHT. THE STRONGEST WINDS WITHIN THE REGION ARE LIKELY TO
OCCUR ACROSS THE BLACKFEET NATION, MOST NOTABLY IN AND NEAR THE
BROWNING AND HEART BUTTE COMMUNITIES WHERE ISOLATED WIND GUSTS
APPROACHING 90 MPH WILL BE POSSIBLE. WHERE CONFIDENCE BEGINS TO
DECREASE IS FOR AREAS EAST OF CUT BANK ALONG THE US HWY 2 CORRIDOR,
WITH THE EXCEPTION OF AREAS IMMEDIATELY DOWNWIND OF THE SWEET GRASS
HILLS WHERE LOCALIZED STRONG WINDS WILL OCCUR DUE TO MOUNTAIN WAVE
ACTIVITY. CONFIDENCE IS LOWER FOR THESE AREAS ALONG THE US HWY 2
CORRIDOR GIVEN LIMITED SUPPORT FOR DEEP MIXING WITHIN BUFKIT DATA;
HOWEVER, WITH 60KTS AT H700 OVERSPREADING THESE AREAS WITHIN A
FAVORABLE WINDOW FOR MIXING AND SUBSEQUENT MOMENTUM TRANSFER TO THE
SURFACE IT WILL NOT TAKE MUCH FOR STRONG WINDS TO MATERIALIZE ACROSS
HILL AND BLAINE COUNTIES. FOR NOW I WILL HOLD COURSE WITH NOT
EXPANDING THE AREAL FOOTPRINT OF THE HIGH WIND WARNING FURTHER EAST,
BUT THERE IS A 10% CHANCE THAT WIND GUSTS COULD EXCEED 60 MPH IN
HILL AND NORTHERN BLAINE COUNTIES; IN ADDITION TO THE WIND PRONE
AREAS ALONG THE NORTHERN SLOPES OF THE LITTLE BELT MOUNTAINS.
BELOW IS A TABLE OF NBM5.0 WIND GUST SCENARIOS FOR SELECT LOCATIONS
ACROSS NORTH CENTRAL AND CENTRAL MONTANA, WITH THE "LOW END"
SCENARIO BEING THE NBM10PCT, "MOST LIKELY" SCENARIO BEING THE
NBM50PCT, AND THE "HIGH END" SCENARIO BEING THE NBM90PCT.
24 HOUR MAXIMUM WIND GUSTS
LOCATION LOW END | MOST LIKELY | HIGH END
EAST GLACIER 60 MPH | 65 MPH | 70 MPH
BROWNING 65 MPH | 70 MPH | 80 MPH
CUT BANK 50 MPH | 60 MPH | 70 MPH
SHELBY 35 MPH | 45 MPH | 55 MPH
HAVRE 45 MPH | 50 MPH | 60 MPH
GREAT FALLS 45 MPH | 50 MPH | 60 MPH
LEWISTOWN 25 MPH | 35 MPH | 40 MPH
- MOLDAN
AVIATION
17/18Z TAF PERIOD
BREEZY TO GUSTY WEST TO SOUTHWEST WINDS CONTINUE TO DEVELOP THIS
AFTERNOON ACROSS NORTH-CENTRAL MT AND KEKS, WITH THE HIGHEST WIND
SPEEDS POSSIBLE OVER THE ROCKY MOUNTAIN FRONT. HIGHER END GUSTS
CAN REACH NEAR 50KTS AT TIMES AT KCTB. WINDS DECREASES IN THE
EVENING BETWEEN 18/03Z TO 18/06Z BEFORE BECOMING LIGHT THROUGH THE
REST OF THE TAF PERIOD. MOUNTAIN WAVE ACTIVITY PERSISTS THROUGH
THE REST OF THE EVENING. -WILSON
PRELIMINARY POINT TEMPS/POPS
GTF 72 42 61 39 / 0 0 0 0
CTB 69 34 58 30 / 0 0 0 0
HLN 70 35 62 35 / 0 0 0 0
BZN 67 33 60 30 / 0 0 0 0
WYS 57 23 59 22 / 0 0 0 0
DLN 65 31 61 31 / 0 0 0 0
HVR 78 37 62 33 / 0 0 0 0
LWT 73 39 59 35 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WARNING UNTIL MIDNIGHT MDT TONIGHT FOR EAST GLACIER
PARK REGION-EASTERN GLACIER, WESTERN TOOLE, AND CENTRAL PONDERA-
EASTERN TOOLE AND LIBERTY-NORTHERN HIGH PLAINS-SOUTHERN HIGH
PLAINS-SOUTHERN ROCKY MOUNTAIN FRONT.
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