028
FXUS65 KTFX 191849
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1249 PM MDT TUE MAY 19 2026
KEY MESSAGES
- SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON
THROUGH THIS EVENING ACROSS THE REGION.
- MORE WIDESPREAD PRECIPITATION TOMORROW THROUGH THURSDAY.
- SNOW LEVELS DROP WEDNESDAY NIGHT INTO THURSDAY, ALLOWING FOR
LIGHT SNOWFALL ACCUMULATION IN THE MOUNTAINS.
- WARM AND DRY CONDITIONS ARE EXPECTED FRIDAY THROUGH THIS
WEEKEND.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
RESIDUAL MOISTURE FROM THE BACKSIDE OF AN UPPER LEVEL TROUGH
EXITING TO THE EAST WILL BRING SLIGHT CHANCES FOR PRECIPITATION
THIS AFTERNOON THROUGH THIS EVENING. THERE IS ENOUGH INSTABILITY
TO SUPPORT WEAK THUNDERSTORM DEVELOPMENT, ESPECIALLY IN CENTRAL
AND NORTH-CENTRAL MT. ANOTHER UPPER LEVEL TROUGH MOVES DOWN FROM
THE CANADIAN ROCKIES INTO MONTANA TOMORROW, BRINGING WIDESPREAD
WETTING PRECIPITATION. THERE WILL STILL BE ENOUGH INSTABILITY TO
WHERE A RUMBLE OF THUNDER COULD BE HEARD ACROSS THE REGION. A WEAK
COLD FRONT PASSING THROUGH TOMORROW NIGHT WILL CAUSE SNOW LEVELS
TO DROP TO AROUND 6,000 FT. THIS WILL ALLOW FOR LIGHT SNOWFALL
OVER THE MOUNTAINS AND HIGHER ELEVATION MOUNTAIN PASSES TOMORROW
NIGHT THROUGH THURSDAY MORNING. THE EXCEPTIONS ARE THE GALLATIN
AND MADISON RANGES, WHICH COULD SEE A FEW INCHES.
THURSDAY THE UPPER LEVEL TROUGH BEGINS TO MOVE SOUTHEASTWARD OUT
OF MT, ALLOWING TEMPERATURES TO BEGIN TO RISE. RIDGING BUILDS OVER
THE WESTERN CONUS THROUGH THE LATER PART OF THIS WORK WEEK INTO
THE WEEKEND, ALLOWING WARM TEMPERATURES, SUNNY SKIES, AND DRY
CONDITIONS TO PREVAIL. CURRENT MODELS ARE SHOWING BREEZY
CONDITIONS THIS WEEKEND, BUT AS OF NOW NOTHING IMPACTFUL. -DZOMBA
- FORECAST CONFIDENCE & SCENARIOS:
HI-RES MODELS ARE SHOWING PRETTY SCATTERED 15-30% CHANCES FOR
PRECIPITATION ACROSS THE REGION TODAY. 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 CENTRAL AND NORTH-CENTRAL MT
THERE IS STILL GOOD AGREEMENT FOR WIDESPREAD WETTING RAINS
TOMORROW. THE HEAVIEST AMOUNTS ARE CURRENTLY EXPECTED ALONG A
STRETCH FROM THE NORTHERN ROCKIES DOWN THROUGH CENTRAL MT
INCLUDING GREAT FALLS AND HELENA INTO LEWISTOWN. PROBABILITIES OF
MORE THAN 0.10" OF PRECIPITATION IN THIS AREA ARE CURRENTLY
80-100%, WHILE PROBABILITIES OF 0.25" OF PRECIPITATION ARE
CURRENTLY SITTING AT 50-70%. WHILE PRECIPITATION AMOUNTS ACROSS
THE REMAINDER OF NORTH-CENTRAL AND SOUTHWEST MT ARE NOT EXPECTED
TO BE QUITE AS HIGH, THERE IS STILL A 20-40% CHANCE FOR A TENTH OF
AN INCH OR MORE. -THOR AND DZOMBA
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 40 58 38 63 / 20 80 70 20
CTB 38 55 34 63 / 10 80 40 0
HLN 38 64 38 63 / 20 60 90 40
BZN 34 63 35 58 / 20 40 90 60
WYS 26 57 30 55 / 10 40 80 40
DLN 34 62 35 60 / 20 20 70 40
HVR 40 62 36 66 / 30 50 10 10
LWT 36 58 35 57 / 20 80 80 50
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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