836
FXUS65 KTFX 312054
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
254 PM MDT SUN MAY 31 2026
KEY MESSAGES
- AREAS OF RAIN CONTINUE TO CIRCULATE ACROSS MUCH OF NORTH-
CENTRAL MONTANA THROUGH MONDAY ALONG WITH BREEZY TO WINDY
CONDITIONS AND UNSEASONABLY COOL TEMPERATURES.
- RISK FOR MINOR FLOODING IS DECREASING BUT SOME CREEKS AND
RIVERS EMANATING FROM THE ROCKY MOUNTIAN FRONT AND GLACIER NP
WILL REMAIN ELEVATED THROUGH EARLY THIS WEEK.
- DRIER CONDITIONS BY WEDNESDAY WITH A LATE WEEK WARMING TREND
BUT SOME RISK FOR SHOWERS AND THUNDERSTORMS THURSDAY AND AGAIN
NEXT WEEKEND.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THE MID TO UPPER LEVEL LOW THAT BROUGHT WIDESPREAD AND LOCALLY
HEAVY PRECIPITATION TO THE AREA THIS WEEKEND IS CURRENTLY CENTERED
OVER CENTRAL/EASTERN MT AND WILL ONLY SLOWLY LIFT NORTHWARD THROUGH
EARLY THIS WEEK. THERE IS STILL A FAIRLY ROBUST PLUME OF DEEP
MOISTURE FEEDING INTO THIS CIRCULATION TO MAINTAIN WIDESPREAD RAIN
THROUGH MUCH OF TONIGHT ACROSS NORTH-CENTRAL MT WHILE SHOWERS
DECREASE ACROSS PORTIONS OF SW MT SOUTH OF I-90 THROUGH THE
OVERNIGHT PERIOD. THE UPPER LEVEL LOW CIRCULATION DOES ELONGATE
E-W ON MONDAY, ALLOWING FOR A NORTHWARD SHIFT OF THE MORE
WIDESPREAD AREA OF RAIN/SHOWERS ACROSS NORTH-CENTRAL MT WITH SOME
DRYING ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. MOST MODEL
GUIDANCE LIFTS THE CIRCULATION CENTER NORTH INTO SOUTHWEST SK
MONDAY NIGHT THROUGH TUESDAY, MAINTAINING SHOWERS ACROSS PRIMARILY
NORTHERN PORTIONS OF THE FORECAST AREA BEFORE THE SYSTEM
EVENTUALLY MOVES OFF TO THE EAST TUESDAY NIGHT.
GUSTY NORTHWEST WINDS OCCURRING ACROSS NORTH-CENTRAL MT WILL ALSO
CONTINUE THROUGH MONDAY AS SURFACE LOW PRESSURE ONLY SLOWLY SHIFTS
NORTH OUT OF NORTHEAST MT WHILE A COOLER AIRMASS AND HIGH PRESSURE
CONTINUES TO BUILD SOUTHWARD FROM AB BEHIND THE THE LOW. THIS WILL
ALSO KEEP TEMPERATURES BELOW SEASONAL AVERAGES THROUGH TUESDAY,
ESPECIALLY ACROSS NORTH-CENTRAL MT WHERE DAYTIME MAXIMUM
TEMPERATURES REMAIN IN THE 50S WHILE TEMPERATURES MODERATE CLOSER TO
SEASONAL AVERAGES BY TUESDAY ACROSS SW MT.
TEMPERATURES WARM BACK TO SEASONAL LEVELS ACROSS THE ENTIRE AREA ON
WEDNESDAY AND ARE LIKELY TO TREND ABOVE AVERAGE THURSDAY AND
FRIDAY AS A SOUTHWESTERLY FLOW ALOFT DEVELOPS ACROSS THE REGION.
AN UPPER LEVEL WAVE MOVES ACROSS THE NORTHERN ROCKIES AND MT
THURSDAY/THURSDAY NIGHT BRINGING SOME SHOWERS AND THUNDERSTORMS
WITH A LARGER SCALE TROUGH MOVING IN FROM THE WEST AT SOME POINT
NEXT WEEKEND BRINGING ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS. HOENISCH
- FORECAST CONFIDENCE & SCENARIOS:
THERE IS A 60% OR HIGHER PROBABILITY FOR ADDITIONAL PRECIPITATION
AMOUNTS OF 0.25" OR MORE ACROSS MUCH OF NORTH-CENTRAL MT THROUGH
MONDAY. A LOBE OF ENERGY/MOISTURE ROTATING WESTWARD AROUND THE LOW
ACROSS SK AND SOUTHERN AB MONDAY WILL BRING HIGHER AMOUNTS TO
GLACIER COUNTY WHERE THERE IS 60% OR HIGHER CHANCE FOR ADDITIONAL
RAINFALL OF 1.00" OR MORE FROM EASTERN PORTIONS OF GLACIER NP AND
EAST ALONG THE AB BORDER.
WILL NEED TO WATCH THUNDERSTORM POTENTIAL LATER THIS WEEK ON
THURSDAY AND AGAIN THIS WEEKEND WITH RECENT MOISTURE PROVIDING SOME
ADDED BUOYANCY AND THESE SYSTEMS LIKELY TO PROVIDE ADEQUATE WIND
SHEAR FOR ORGANIZED CONVECTION. HOWEVER THERE IS STILL CONSIDERABLE
UNCERTAINTY WITH TIMING AND MORE
THERE IS A 60% OR HIGHER PROBABILITY FOR ADDITIONAL PRECIPITATION
AMOUNTS OF 0.25" OR MORE ACROSS MUCH OF NORTH-CENTRAL MT THROUGH
MONDAY. A LOBE OF ENERGY/MOISTURE ROTATING WESTWARD AROUND THE LOW
ACROSS SK AND SOUTHERN AB MONDAY WILL BRING HIGHER AMOUNTS TO
GLACIER COUNTY WHERE THERE IS 60% OR HIGHER CHANCE FOR ADDITIONAL
RAINFALL OF 1.00" OR MORE FROM EASTERN PORTIONS OF GLACIER NP AND
EAST ALONG THE AB BORDER.
WILL NEED TO WATCH THUNDERSTORM POTENTIAL LATER THIS WEEK ON
THURSDAY AND AGAIN THIS WEEKEND WITH RECENT MOISTURE PROVIDING SOME
ADDED BUOYANCY AND THESE SYSTEMS LIKELY TO PROVIDE ADEQUATE WIND
SHEAR FOR ORGANIZED CONVECTION. HOWEVER THERE IS STILL CONSIDERABLE
UNCERTAINTY WITH TIMING AND AND MORE SPECIFIC DETAILS AT THIS TIME.
HOENISCH SPECIFIC DETAILS AT THIS TIME.
HOENISCH
AVIATION
31/18Z TAF PERIOD
THERE WILL BE RAIN ACROSS ALL TERMINALS DURING THIS TAF PERIOD. AT
ALL TERMINALS DURING AT LEAST A PORTION OF THIS TAF PERIOD THERE
WILL BE MVFR-LEVEL CEILINGS. AT THE KHLN, KHVR, AND KLWT TERMINALS
DURING A PORTION OF THIS TAF PERIOD THERE IS AT LEAST A 30% CHANCE
FOR IFR-LEVEL CEILINGS. DURING THE DURATION OF THIS TAF PERIOD THERE
WILL BE MOUNTAIN OBSCURATION. AT THE KWYS TERMINAL IF IT CLEARS OUT
TONIGHT THERE IS A LOW CHANCE FOR FOG TO FORM MONDAY MORNING.
BETWEEN 01/00Z AND THE END OF THE TAF PERIOD THERE WILL BE ISOLATED
INSTANCES OF LOW-LEVEL WIND SHEAR AND MOUNTAIN WAVE TURBULENCE. -IG
HYDROLOGY
A FLOOD ADVISORY REMAINS IN PLACE THROUGH THIS EVENING TO HIGHLIGHT
IMPACTS FROM RECENT PRECIPITATION, INCLUDING ELEVATED STREAMFLOWS ON CREEKS
NEAR THE CENTRAL MT MOUNTAINS AND ROCKY MTN FRONT AS WELL AS
LINGERING PONDING OF WATER IN SOME LOW-LYING AREAS. THESE IMPACTS
SHOULD CONTINUE TO DECREASE THIS EVENING AS PRECIPITATION RATES
REMAIN LOW (.01-.10"/HR). WE WILL CONTINUE TO WATCH SEVERAL LARGER
CREEKS/RIVERS ALONG THE ROCKY MTN FRONT, WHICH ARE NEAR OR FORECAST
TO REMAIN CLOSE TO BANKFUL THROUGH MONDAY. HOENISCH
PRELIMINARY POINT TEMPS/POPS
GTF 41 53 41 58 / 100 80 50 60
CTB 36 45 37 51 / 100 90 90 80
HLN 43 59 42 64 / 90 60 20 40
BZN 37 62 37 67 / 50 30 30 20
WYS 30 62 30 66 / 30 10 20 0
DLN 36 64 38 68 / 20 20 40 10
HVR 39 54 39 61 / 100 90 80 70
LWT 37 55 37 61 / 90 60 30 50
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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