257
FXUS65 KTFX 191041
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
441 AM MDT FRI JUN 19 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- BRIEF WARM UP TODAY WITH GENERALLY DRY CONDITIONS EXPECTED
ACROSS THE REGION.
- WARM START TO SATURDAY BEFORE A COLD FRONT ARRIVES AND BRINGS A CHANCE
FOR AFTERNOON SHOWERS AND THUNDERSTORMS, SOME OF WHICH MAY BE
HEAVY.
- MORE SEASONABLE TEMPERATURES REMAIN THROUGH THE START OF NEXT
WEEK WITH DAILY CHANCES FOR SHOWERS AND AFTERNOON
THUNDERSTORMS.
DISCUSSION
/ISSUED 1201 AM MDT FRI JUN 19 2026/
- METEOROLOGICAL OVERVIEW:
BRIEF TRANSIENT RIDGING WILL MOVE ACROSS THE REGION FRIDAY ALLOWING
FOR TEMPERATURES TO BRIEFLY WARM UP INTO 70S ACROSS THE NORTHERN
PLAINS AND UP INTO THE LOW 80S FOR SOME PORTIONS OF SOUTHWEST
MONTANA.
ON SATURDAY, A COMBINATION OF MONSOONAL MOISTURE PUSHING INTO
SOUTHWEST MONTANA AND A COLD FRONT DIPPING DOWN FROM CANADA WILL
BRING A CHANCE FOR AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE
REGION. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INITIALLY DEVELOP
IN THE EARLY AFTERNOON ACROSS SOUTHWEST MONTANA AND BECOME MORE
WIDESPREAD INTO CENTRAL MONTANA BY THE MID-AFTERNOON. THE MAIN
CONCERN WITH ANY THUNDERSTORM THAT DEVELOPS WILL BE STRONG, GUSTY
WINDS AND HAIL. FOR SOUTHWEST MONTANA IN PARTICULAR THERE IS AN
ADDITIONAL CONCERN FOR LOCALIZED FLOODING.
STARTING SUNDAY THROUGH TUESDAY, NORTHWESTERLY FLOW RETURNS TO THE
REGION BRINGING MORE SEASONABLE TEMPERATURES TO THE REGION AND DAILY
CHANCES FOR SHOWERS AND AFTERNOON THUNDERSTORMS. FOR WEDNESDAY
THROUGH THE END OF THE WORK WEEK, UPPER-LEVEL RIDGING STARTS TO
BUILD BACK ACROSS THE WESTERN CONUS WHICH WILL ALLOW FOR WARMER
TEMPERATURES TO RETURN TO MONTANA.
- FORECAST CONFIDENCE & SCENARIOS:
NOT TOO MUCH HAS CHANGED IN THE OVERALL PICTURE FOR SATURDAY. MODEST
INSTABILITY AND SHEAR ARE STILL IN PLACE THROUGH THE AFTERNOON HOURS
AND THE CHANCE FOR SCATTERED THE WIDESPREAD SHOWERS AND
THUNDERSTORMS LASTING THROUGH THE EVENING IS STILL RELATIVELY HIGH.
WHEN IT COMES TO SHEAR, NORTH-CENTRAL MONTANA INCLUDING THE HI-LINE
HAS THE BEST VALUES RANGING FROM 20-35KTS THROUGH THE AFTERNOON
HOURS. COMBINED WITH MODEST CAPE VALUES THERE IS A POTENTIAL THAT A
COUPLE THUNDERSTORMS COULD TURN SEVERE. ALTHOUGH THE THREAT WILL
REMAIN QUITE LOCALIZED AND NO WIDESPREAD SEVERE WEATHER IS EXPECTED
ACROSS THE REGION. THE MAIN CONCERNS FOR NORTH-CENTRAL MONTANA,
ESPECIALLY ACROSS THE HI-LINE WILL BE STRONG, GUSTY WINDS.
AS FOR SOUTHWEST AND CENTRAL MONTANA, SOUTHWEST MONTANA IS
COMPARATIVELY LACKING IN SHEAR, WHICH COULD LEAD TO SLOWER STORM
MOTION, AND CENTRAL MONTANA IS A BIT OF A TRANSITION ZONE WITH SOME
POCKETS OF HIGHER SHEAR POSSIBLE BUT OVERALL STILL LESS THAN WHAT IS
CURRENTLY MODELED ALONG THE HI-LINE. WITH SIMILAR CAPE VALUES THE
DIFFERENCE WILL BE THERE IS A HIGHER CHANCE FOR HAIL IN THIS PORTION
OF OUR CWA. BUT THERE IS AN EQUALLY LIKELY POSSIBILITY THAT MOST OF
THE HAIL MIGHT MELT ON ITS WAY DOWN WITH THE RESULT BEING LOCALIZED
HEAVY DOWNPOURS. MODEL SOUNDINGS CONTINUE TO SHOW AND ENVIRONMENT
THAT IS RIPE FOR HEAVY RAIN ACROSS CENTRAL AND SOUTHWEST MONTANA.
THUS, WHILE STRONG WINDS AND HAIL ARE DEFINITELY SOMETHING TO WATCH
FOR THROUGH THE EVENING HOURS, THE BIGGER CONCERN WILL BE LOCALIZED
PONDING OR FLOODING, ESPECIALLY IN TYPICALLY FLOOD-PRONE AREAS. THIS
INCLUDES THE HORSE GULCH BURN SCAR WHICH WILL BE CLOSELY MONITORED
THROUGHOUT THE AFTERNOON AND EVENING HOURS AS, DEPENDING ON HOW SLOW
THE THUNDERSTORMS MOVE, RAINFALL RATES COULD CAUSE SOME FLOODING IN
THE NEARBY CAMPGROUND AREAS.
THE MAIN MESSAGE TO THOSE RECREATING OUTDOORS WILL BE TO CHECK IN
WITH THE LATEST FORECAST BEFORE HEADING OUT, HAVE A WAY TO RECEIVE
WARNINGS IN CASE THE SITUATION DETERIORATES QUICKLY, AND BE PREPARED
TO SEEK HIGHER GROUND AWAY FROM FLOODWATERS IN THE EVENT OF FLASH
FLOODING. -THOR
AVIATION
19/12Z TAF PERIOD
VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TERMINALS
THROUGH THE 1912/2012 TAF PERIOD; HOWEVER, AN ISOLATED SHOWER OR
STORM CAN'T BE RULED OUT OVER THE HIGHER TERRAIN OF SOUTHWEST
MONTANA BETWEEN 21Z THIS AFTERNOON AND 03Z THIS EVENING. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 73 48 82 51 / 0 0 10 30
CTB 70 45 80 46 / 0 0 10 10
HLN 78 50 83 52 / 0 0 20 20
BZN 78 47 79 48 / 0 0 50 50
WYS 80 43 70 39 / 0 0 70 70
DLN 81 49 76 46 / 0 0 60 50
HVR 72 48 82 50 / 0 0 0 50
LWT 70 45 77 48 / 0 0 10 30
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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