656
FXUS65 KTFX 191703
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1103 AM MDT TUE MAY 19 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SLIGHT CHANCE FOR AFTERNOON SHOWERS AND THUNDERSTORMS THIS AFTERNOON
ACROSS MUCH OF THE REGION.
- MORE WIDESPREAD PRECIPITATION IS EXPECTED ON WEDNESDAY THROUGH THURSDAY.
- TEMPERATURES WILL GRADUALLY WARM THROUGH THE WEEK WITH THE WARMEST
TEMPERATURES EXPECTED THIS WEEKEND.
DISCUSSION
/ISSUED 513 AM MDT TUE MAY 19 2026/
- METEOROLOGICAL OVERVIEW
AFTER A COOL START TO THE MORNING, TEMPERATURES WILL WARM MODESTLY
INTO THE 50S AND 60S. LINGERING MOISTURE ON THE BACKSIDE OF THE
UPPER-LEVEL TROUGH COMBINED WITH MODEST INSTABILITY WILL ALLOW FOR
POP-UP SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON TODAY.
ON WEDNESDAY ANOTHER UPPER-LEVEL TROUGH WILL ARRIVE BRINGING A
CHANCE FOR WIDESPREAD WETTING PRECIPITATION TO THE REGION. SNOW WILL
BE GENERALLY CONFINED TO LOCATIONS ABOVE 7,000 FEET WITH THE REST OF
THE LOWER ELEVATIONS SEEING PRIMARILY RAIN THROUGH THE EVENT.
AS THE UPPER-LEVEL TROUGH STARTS TO SLOWLY EXIT THE AREA TOWARDS THE
END OF THE WEEK, TEMPERATURES WILL GRADUALLY START TO WARM UP AS
UPPER-LEVEL RIDGING BEGINS BUILDING OVER THE WESTERN CONUS THROUGH
THE WEEKEND.
- FORECAST CONFIDENCE & SCENARIOS:
FOR TODAY, HI-RES MODELS WERE SHOWING PRETTY SCATTERED 15-30%
CHANCES FOR PRECIPITATION ACROSS THE REGION. IN GENERAL, MOST
LOCATIONS WILL REMAIN DRY THROUGHOUT THE DAY EXCEPT FOR WHERE THESE
POP-UP SHOWERS END UP DEVELOPING. THE HIGHEST CHANCES FOR
THUNDERSTORM ACTIVITY WILL BE ACROSS NORTH-CENTRAL MONTANA WITH ANY
PRECIPITATION IN CENTRAL AND SOUTHWEST MONTANA EXPECTED TO BE MORE
STRATIFORM IN NATURE.
THERE IS STILL GOOD AGREEMENT FOR WIDESPREAD WETTING RAINS. THE
HEAVIEST AMOUNTS ARE CURRENTLY EXPECTED ALONG A STRETCH FROM THE
NORTHERN ROCKIES DOWN THROUGH CENTRAL MONTANA INCLUDING GREAT FALLS
AND HELENA INTO LEWISTOWN. PROBABILITIES OF MORE THAN 0.25" OF
PRECIPITATION ARE CURRENTLY SITTING AT 60-80% WITH A 20-40% CHANCE
OF 0.5" OR MORE. WHILE PRECIPITATION AMOUNTS ACROSS THE REMAINDER OF
NORTH-CENTRAL AND SOUTHWEST MONTANA ARE NOT EXPECTED TO BE QUITE AS
HIGH THERE IS STILL AT LEAST A 40% CHANCE FOR A TENTH OF AN INCH OR
MORE. -THOR
AVIATION
19/18Z TAF PERIOD
INITIAL CONCERN THIS TAF PERIOD WILL BE FOR AFTERNOON AND EARLY
EVENING SHOWERS AND ISOLATED THUNDERSTORMS. BRIEFLY GUSTY AND
ERRATIC WINDS WILL ACCOMPANY THIS SHOWERY ACTIVITY. CONCERN THEN
TURNS TO A COLD FRONT MOVING FROM NORTH TO SOUTH LATE TONIGHT INTO
WEDNESDAY, PRIMARILY IMPACTING TERMINALS OVER THE PLAINS. A MIX OF
SHOWERY AND STRATIFORM PRECIPITATION WILL ACCOMPANY THE WIND SHIFT TO
A MORE NORTHWESTERLY DIRECTION BEHIND THE FRONT. LOWERING CEILINGS
OVER THE PLAINS WEDNESDAY MORNING WILL RESULT IN INCREASING MOUNTAIN
OBSCURATION. -AM
PRELIMINARY POINT TEMPS/POPS
GTF 64 40 58 38 / 40 20 80 70
CTB 62 38 55 34 / 20 10 80 40
HLN 65 38 64 38 / 20 20 60 90
BZN 62 34 63 35 / 10 20 40 90
WYS 54 26 57 30 / 10 10 40 80
DLN 61 34 62 35 / 10 20 20 70
HVR 68 40 62 36 / 30 30 50 10
LWT 60 36 58 35 / 30 20 80 80
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page