139
FXUS65 KTFX 031935
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
135 PM MDT FRI APR 3 2026
KEY MESSAGES
- FOG LOOKS TO DEVELOP TONIGHT ALONG AND NORTHEAST OF A
LEWISTOWN, TO GREAT FALLS, TO CUT BANK LINE, ESPECIALLY WITHIN
THE MILK RIVER VALLEY OF HILL AND BLAINE COUNTIES.
- OVERALL DRY CONDITIONS ARE EXPECTED THIS WEEKEND, BUT A FEW
SHOWERS CAN'T BE RULED OUT OVER THE PLAINS AND MOUNTAINS OF
CENTRAL AND NORTH CENTRAL MONTANA SATURDAY NIGHT AND SUNDAY AS
A WEAK FRONT MOVES SOUTH.
- WINDY CONDITIONS LOOK TO RETURN ON TUESDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
UPPER LEVEL TROUGH AND ASSOCIATED CLOSED LOW RESPONSIBLE FOR
WIDESPREAD PRECIPITATION ACROSS THE NORTHERN ROCKIES YESTERDAY AND
TODAY WILL LIFT NORTHEAST AND OVER THE UPPER MISSISSIPPI RIVER
VALLEY THROUGH TONIGHT, WITH QUASI-NORTHWEST FLOW REMAINING IN PLACE
OVER SOUTHWEST THROUGH NORTH CENTRAL MONTANA. SKIES BENEATH THIS
DRY, NORTHWEST FLOW ALOFT WILL CLEAR THROUGH THE EVENING HOURS
TONIGHT, WHICH COMBINED WITH RECENT PRECIPITATION AND/OR SNOW COVER
WILL SET THE STAGE FOR FOG DEVELOPMENT, ESPECIALLY WHERE WINDS
REMAIN LIGHT. LOW TEMPERATURES TONIGHT WILL FALL QUICKLY WHERE SNOW
COVER EXIST, WITH LOCATIONS ALONG THE IMMEDIATE EASTERN SLOPES OF
THE ROCKY MOUNTAIN FRONT WARMING BEYOND THE MIDNIGHT HOUR AS
SOUTHWEST TO WESTERLY SURFACE WINDS INCREASE. TEMPERATURES LOOK TO
REBOUND THROUGH THE DAY ON SATURDAY AS SOUTHWEST TO WEST WINDS
ACROSS THE REGION; HOWEVER, A WEAK COLD FRONT DROPPING SOUTHEAST AND
ACROSS THE PLAINS OF NORTH CENTRAL AND CENTRAL MONTANA LATE SATURDAY
WILL HELP TO COOL TEMPERATURES SLIGHTLY FOR THE DAY ON SUNDAY. WHILE
A FEW LIGHT RAIN/SNOW SHOWERS CAN'T BE RULED OUT ALONG AND BEHIND
THIS FRONT SATURDAY NIGHT AND INTO THE DAY ON SUNDAY MOST AREAS WILL
REMAIN DRY THROUGH THE WEEKEND AS UPPER LEVEL RIDGING AMPLIFIES OVER
THE WESTERN CONUS/CANADA. - MOLDAN
AN UPPER LEVEL SYSTEM THEN LOOKS TO BREAK DOWN THE RIDGE ON TUESDAY,
INITIALLY BRINGING GUSTY WESTERLY WINDS TO THE PLAINS AHEAD OF A
COLD FRONT. UPPER LEVEL TROUGHING HANGS AROUND IN SOME CAPACITY FROM
THE MIDDLE TO LATE PORTION OF NEXT WEEK, WHICH WILL AT THE VERY
LEAST COOL TEMPERATURES ACROSS THE REGION. UNCERTAINTY BUILDS WITH
RESPECT TO HOW MUCH PRECIPITATION RESULTS FROM THIS STRETCH OF
TROUGHING. -AM
- FORECAST CONFIDENCE & SCENARIOS:
REDUCED VISIBILITY THIS EVENING THROUGH SATURDAY MORNING :
HI-RES ENSEMBLE FORECAST (HREF) GUIDANCE INDICATES A 30-70% CHANCE
FOR VISIBILITIES TO FALL BELOW 3 MILES DUE TO FOG WITHIN THE MILK
RIVER VALLEY OF HILL AND BLAINE COUNTIES, WITH EVEN A 10-30% CHANCE
FOR VISIBILITIES TO FALL BELOW 0.5 MILE. ONE LIMITING FACTOR WILL BE
MID-LEVEL CLOUD COVER, WHICH COULD HOLD BACK VISIBILITIES FROM
FALLING TOO LOW. - MOLDAN
WINDS ON TUESDAY:
THE EUROPEAN EXTREME FORECAST INDEX CONTINUES TO HIGHLIGHT TUESDAY
AS A DAY FOR GUSTY WINDS, MOSTLY ACROSS THE PLAINS AND ADJACENT
AREAS. FORECAST SOUNDINGS OVER THIS TIMEFRAME DO NOT SHOW MUCH
RIDGETOP STABILITY, WHICH WILL MAKE THIS A PRESSURE GRADIENT AND
DIURNALLY DRIVEN MIXING TYPE OF EVENT. THERE IS QUITE A BIT OF
UNCERTAINTY ASSOCIATED WITH IT HOWEVER, AS COOLER AIR SINKING
SOUTHWARD FROM CANADA LATE TUESDAY AFTERNOON OR TUESDAY EVENING
WOULD SHUT DOWN THE WINDS RATHER QUICKLY. SHOULD THIS FRONT ARRIVE A
BIT QUICKER THE THREAT FOR STRONGER WINDS TUESDAY WOULD BE SHORTER
IN DURATION AND MORE LOCALIZED.
UNSETTLED WEDNESDAY THROUGH FRIDAY:
CLUSTER GUIDANCE FAVORS TROUGHING ACROSS THE REGION OVER THIS
TIMEFRAME, BUT STRUGGLES MIGHTILY WITH RESPECT TO TIMING AND
STRENGTH OF THE TROUGHING. THIS RESULTS IN A LOWER CONFIDENCE FROM A
PRECIPITATION PERSPECTIVE. CONFIDENCE IS HIGHER WITH RESPECT TO
COOLING TEMPERATURES HOWEVER. THE MAIN TAKEAWAY OVER THIS TIMEFRAME
WILL BE FOR OVERALL COOLER AND UNSETTLED CONDITIONS AT TIMES. -AM
AVIATION
03/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL AT ALL BUT THE KHVR AND KLWT TERMINALS.
AT THE KLWT TERMINAL SNOW WILL LINGER FOR THE NEXT COUPLE OF HOURS
WITH IFR LEVEL CEILINGS. AT THE KHVR AND KLWT TERMINALS LOW CLOUDS
WILL MOVE OUT OF THOSE AREAS BY 04/00Z. AROUND THE KCTB TERMINAL
OVER TO THE ROCKY MOUNTAIN FRONT FROM 04/06Z THROUGH THE END OF THIS
TAF PERIOD THERE WILL BE ISOLATED INSTANCES OF LOW-LEVEL WIND SHEAR.
DURING THE FIRST 6 HOURS OF THIS TAF PERIOD THERE WILL MOUNTAIN
OBSCURATION ACROSS PORTIONS OF NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. AT ANY TAF SITE WHERE SNOW FELL
YESTERDAY/LAST NIGHT AND CLEARS OUT OVER NIGHT, FOG HAS THE
POTENTIAL TO FORM. THE MOST LIKELY TAF SITES FOR FOG TO FORM ARE
THE KBZN, KLWT, AND KHVR TERMINALS WITH A 10 - 30% CHANCE FOR FOG
TO FORM AT ANY OF THOSE TAF SITES. -IG
PRELIMINARY POINT TEMPS/POPS
GTF 27 57 28 50 / 10 0 0 10
CTB 27 55 26 47 / 0 10 10 10
HLN 24 58 27 58 / 0 0 0 0
BZN 19 58 24 61 / 10 0 0 0
WYS 13 48 17 56 / 0 0 0 0
DLN 21 57 26 63 / 0 0 0 0
HVR 24 57 29 47 / 0 10 10 0
LWT 23 51 28 49 / 10 10 10 10
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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