374
FXUS65 KTFX 041747
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1147 AM MDT SAT APR 4 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- LOCALIZED PATCHY FOG THIS MORNING.
- SLIGHTLY COOLER SUNDAY BEHIND A COLD FRONT.
- WINDY ON TUESDAY AHEAD OF AN UNSETTLED REST OF THE WEEK.
DISCUSSION
/ISSUED 519 AM MDT SAT APR 4 2026/
- METEOROLOGICAL OVERVIEW:
UPPER LEVEL RIDGING BUILDING IN ACROSS THE WEST IS RESULTING IN A
CLEARING TREND EARLY THIS MORNING ACROSS THE REGION. GIVEN RECENT
PRECIPITATION AND SNOW MELT, AREAS WHERE CLEARING SKIES OVERLAP WITH
LIGHT WINDS WILL SEE AT LEAST PATCHY FOG THROUGH THE MORNING. SOME
HIGH LEVEL CLOUDINESS SHOULD LIMIT SPATIAL EXTENT OF FOG THAT
DOES FORM THIS MORNING, HOWEVER. A WEAK WAVE TRAVERSING THE
BUILDING RIDGE WILL PUSH SLIGHTLY COOLER AIR IN FROM NORTH TO
SOUTH THIS AFTERNOON INTO THE EVENING, AND GET REINFORCED BY A
BUILDING SURFACE HIGH WELL OFF TO THE NORTHEAST IN SK. SLIGHTLY
COOLER TEMPERATURES THAT MOVE IN LATE SATURDAY WILL PERSIST
THROUGH THE DAY SUNDAY, WITH JUST A LOW END OPPORTUNITY FOR A
LIGHT SHOWER AT TIMES SUNDAY.
SOME MODERATION OCCURS INTO MONDAY AS UPPER LEVEL RIDGING PERSISTS.
THE RIDGE IS QUICKLY BROKEN DOWN HEADING INTO TUESDAY BY AN UPPER
LEVEL SYSTEM DIVING SOUTHEASTWARD FROM BC TOWARD THE NORTHERN
ROCKIES. THE INITIAL IMPACT WILL BE STRONG WESTERLY TO SOUTHWESTERLY
WINDS THROUGH THE DAY, DRIVEN BY THE COMBINATION OF DAYTIME MIXING
AND AT LEAST A BRIEFLY STRONG PRESSURE GRADIENT. AS THE SURFACE LOW
IN SOUTHERN BC SHIFTS EASTWARD TUESDAY NIGHT, A CANADIAN COLD FRONT
PUSHES SOUTHWARD ACROSS THE REGION WEDNESDAY MORNING. THERE REMAINS
TREMENDOUS UNCERTAINTY WITH RESPECT TO HOW MUCH PRECIPITATION WOULD
RESULT FROM THIS FRONTAL PASSAGE, THOUGH CONFIDENCE IS HIGH THAT
TEMPERATURES WILL FALL TO OR A TOUCH BELOW NORMAL BEHIND THE
FRONT.
A CONVOLUTED PATTERN WITH CUTOFF LOWS AND ADDITIONAL WAVES WITHIN A
BROADLY CYCLONIC FLOW ALOFT ACROSS THE WEST WILL KEEP THE REGION
UNSETTLED THROUGH THE REMAINDER OF THE WEEK, WITH DAILY
OPPORTUNITIES FOR AT LEAST LIGHT PRECIPITATION. -AM
- FORECAST CONFIDENCE & SCENARIOS:
WINDS TUESDAY AND COLD FRONT INTO WEDNESDAY:
ENSEMBLES ARE LARGELY ON BOARD WITH THIS SYSTEM MOVING ACROSS THE
REGION DURING THE DAY TUESDAY. THIS WILL RESULT IN FAVORABLE
CONDITIONS TO MIX DOWN STRONGER WINDS ALOFT THROUGH THE AFTERNOON
AND EARLY EVENING AHEAD OF A COLD FRONT. EFI (EUROPEAN EXTREME
FORECAST INDEX) VALUES ARE LARGELY BETWEEN 0.6 AND 0.8 FOR WIND
GUSTS TUESDAY, WITH A SHIFT OF TAILS OF 0 ACROSS NEARLY THE ENTIRE
REGION. THESE VALUES INDICATE INCREASED CONFIDENCE IN STRONG WINDS,
WITH POTENTIAL FOR ANOMALOUS GUSTS FOR THIS TIME OF THE YEAR.
WHILE CONFIDENCE IS INCREASING IN THE AFOREMENTIONED GUSTY PERIOD,
IT REMAINS LOW WITH RESPECT TO HOW MUCH PRECIPITATION FOLLOWS THE
COLD FRONT WEDNESDAY INTO LATE WEEK. TIMING AND LOCATION (WHICH
IS LOW CONFIDENCE AT THIS RANGE) OF SEVERAL TRAILING UPPER LEVEL
DISTURBANCES LATER IN THE WEEK WILL PLAY A LARGE PART IN WHICH
AREAS RECEIVE PRECIPITATION. -AM
AVIATION
04/18Z TAF PERIOD
A WEAK COLD FRONT MOVING SOUTH AND EAST OVER THE PLAINS OF CENTRAL
AND NORTH CENTRAL MONTANA WILL BRING A WIND SHIFT FROM THE
SOUTHWEST/WEST TO NORTHWEST/NORTHEAST THIS AFTERNOON. WHILE A
SHOWER CAN'T BE RULED OUT ALONG AND THEN BEHIND THE FRONT THROUGH
SUNDAY MORNING AT THE KCTB AND KHVR TERMINALS THE PROBABILITY FOR
ANY ONE SHOWER IMPACTING THESE TWO TERMINALS IS TOO LOW TO MENTION
AT THIS TIME. MAIN IMPACT FROM THE PASSING FRONT WILL BE LOWERING
CIGS AT THE KCTB, KHVR, AND KGTF TERMINALS; WITH IFR/MVFR CIGS
EXPECTED BEYOND 09Z SUNDAY. FURTHER SOUTH VFR CONDITIONS WILL
PREVAIL AT THE KHLN, KBZN, AND KEKS TERMINALS.
PRELIMINARY POINT TEMPS/POPS
GTF 58 28 51 30 / 0 10 10 0
CTB 55 27 49 26 / 0 10 10 0
HLN 59 32 59 33 / 0 0 10 0
BZN 59 29 62 31 / 0 0 0 0
WYS 51 19 57 24 / 10 10 0 0
DLN 59 29 65 33 / 0 0 0 0
HVR 58 30 50 28 / 0 10 10 0
LWT 53 28 50 28 / 0 10 10 10
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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