849
FXUS65 KTFX 201116
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
516 AM MDT SAT JUN 20 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS DEVELOP THIS AFTERNOON AND PERSIST
THROUGH THE EVENING HOURS TONIGHT.
- A COLD FRONT WILL BRING BREEZY AND GUSTY NORTH WINDS TO MOST
AREAS TONIGHT AND THROUGH THE DAY ON SUNDAY.
- ADDITIONAL OPPORTUNITIES FOR SHOWERS AND STORMS ON SUNDAY AND
MONDAY BEFORE TURNING DRIER AND WARMER THROUGH THE UPCOMING
WORK WEEK.
DISCUSSION
/ISSUED 1204 AM MDT SAT JUN 20 2026/
- METEOROLOGICAL OVERVIEW:
WARM ADVECTION AHEAD OF A COMPACT SHORTWAVE DIVING SOUTHEAST WITHIN
QUASI-ZONAL FLOW ALOFT WILL ALLOW TEMPERATURES TO WARM INTO THE
UPPER 70S TO LOW 80S TODAY ACROSS SOUTHWEST THROUGH NORTH CENTRAL
MONTANA, WITH SHOWERS AND THUNDERSTORMS DEVELOPING DURING THE LATE
MORNING/AFTERNOON HOURS AND PERSISTING THROUGH THE LATE EVENING
HOURS TONIGHT. AT THE SURFACE A COLD FRONT WILL DIVE SOUTH FROM
ALBERTA AND ACROSS THE PLAINS OF NORTH CENTRAL MONTANA BY THE LATE
EVENING HOURS TONIGHT, WITH THIS COLD FRONT CONTINUING TO PUSH SOUTH
THROUGH CENTRAL MONTANA THROUGH THE EARLY MORNING HOURS ON SUNDAY
AND SOUTHWEST MONTANA BY THE LATE MORNING HOURS ON SUNDAY. STRONG 6HR
PRESSURE RISES ON THE ORDER OF 6-12MB AND H850 WINDS OF 20-30KTS
WILL HELP TO SUPPORT STRONG AND GUSTY NORTH WINDS IN WAKE OF THE
IMMEDIATE FRONTAL PASSAGE TONIGHT, ESPECIALLY ALONG AND WEST OF THE
US HWY 87 CORRIDOR. BREEZY AND GUSTY CONDITIONS WILL LINGER INTO THE
DAY ON SUNDAY OVER THE PLAINS, WITH HIGH TEMPERATURES FALLING INTO
THE MID-60S TO LOW 70S OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL
MONTANA AND THE 70S ACROSS THE VALLEYS OF SOUTHWEST AND CENTRAL
MONTANA. NORTHWEST FLOW ALOFT IN WAKE OF THE COMPACT SHORTWAVE
TODAY/TONIGHT WILL HELP TO SUPPORT ADDITIONAL OPPORTUNITIES FOR
SHOWERS AND THUNDERSTORMS ON SUNDAY, MOST NOTABLY ACROSS THE GLACIER
NATIONAL PARK REGION AND ALONG AND NORTH OF THE MT HWY 200 CORRIDOR.
WELL BELOW NORMAL TEMPERATURES WILL LINGER INTO THE DAY ON MONDAY AS
NORTHWESTERLY FLOW ALOFT REMAINS IN PLACE, WITH YET AGAIN
AFTERNOON/EVENING SHOWER AND THUNDERSTORMS OPPORTUNITIES.
TRANSIENT RIDGING LOOKS TO THEN SLIDE EAST AND OVER THE NORTHERN
ROCKIES THROUGH THE REMAINDER OF THE WORK WEEK, WITH HIGH
TEMPERATURES WARM TO NEAR NORMAL ON TUESDAY BEFORE CLIMBING WELL
ABOVE NORMAL ON THURSDAY AND FRIDAY. WHILE AN ISOLATED SHOWER OR
THUNDERSTORM CAN'T BE RULED OUT OVER THE HIGHER TERRAIN THROUGH THE
PERIOD, ESPECIALLY ON THURSDAY, DRY CONDITIONS ARE LARGELY EXPECTED
BENEATH THE TRANSIENT RIDGING. - MOLDAN
- FORECAST CONFIDENCE & SCENARIOS:
SHOWERS AND THUNDERSTORMS TODAY...
CONFIDENCE IS HIGH THAT SHOWERS AND THUNDERSTORMS WILL INITIATE
ACROSS SOUTHWEST MONTANA BETWEEN 10AM AND 1PM, INITIALLY OVER THE
HIGHER TERRAIN BEFORE OVERSPREADING THE ADJACENT VALLEYS, WITH THE
AREAL COVERAGE OF PRECIPITATION INCREASING THROUGH THE REMAINDER OF
THE AFTERNOON AS THE SHOWERS AND STORMS DRIFT TO THE NORTHEAST.
FURTHER NORTH OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA
CONVECTIVE INITIATION WILL OCCUR LATER IN THE AFTERNOON, GENERALLY
BETWEEN 2 TO 5PM, INITIALLY ALONG AND WEST OF THE I-15 CORRIDOR.
AREAL COVERAGE OF THESE SHOWERS AND THUNDERSTORMS OVER THE PLAINS
WILL BE LOWER THAN THAT FOR AREAS SOUTH OF THE MONTANA HWY 200
CORRIDOR, WITH THIS ACTIVITY DRIFTING FROM WEST TO EAST THROUGH THE
REMAINDER OF THE AFTERNOON AND EVENING HOURS. WHILE INSTABILITY IS
QUITE LOW/MARGINAL ACROSS SOUTHWEST THROUGH NORTH CENTRAL MONTANA
THROUGH THE DAY TODAY THE PRESENCE OF DRY AIR IN THE LOW TO MID-
LEVEL, AS EVIDENT BY INVERTED-V SOUNDINGS, I CAN'T RULE OUT SOME
STRONGER WIND GUSTS ON THE ORDER OF 45-55 MPH WITH THE STRONGEST
STORMS. ADDITIONALLY, TALL SKINNY CAPE PROFILES, PWATS RANGING FROM
0.5" TO 0.75", AND SLOWER STORM MOTIONS OF 20-30 MPH WILL HELP TO
SUPPORT PERIODS OF HEAVY RAIN. THESE BURST OF HEAVY RAIN, SHOULD
THEY OCCUR OVER RECENT (I.E. LAST 2-3 YEARS) BURN SCARS, WOULD BE
CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING. - MOLDAN
AVIATION
20/12Z TAF PERIOD
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTHWEST MONTANA
LATE THIS MORNING, WITH THESE SHOWERS AND STORMS EXPANDING IN
AREAL COVERAGE THROUGH THE AFTERNOON HOURS. FURTHER NORTH SHOWERS
AND STORMS WILL DEVELOP DURING THE EARLY AFTERNOON HOURS BEFORE
DRIFTING EAST ACROSS THE REMAINDER OF THE AREA. THE MAIN THREAT
FROM ANY SHOWER OR THUNDERSTORMS WILL BE GUSTY AND ERRATIC WINDS,
ALONG WITH VIS REDUCTIONS DUE TO HEAVY RAINFALL. MVFR/LOW-VFR/VFR
CONDITIONS ARE PREDOMINATELY EXPECTED OVER THE NEXT 24 HOURS;
HOWEVER, TEMPORARY IFR CONDITIONS CAN'T BE RULED OUT DUE TO HEAVY
RAINFALL BUT CONFIDENCE IN THIS OCCURRING AT ANY ONE TAF LOCATION
WAS TOO LOW TO MENTION AT THIS TIME. MOUNTAIN OBSCURATION WILL
INCREASE THROUGH 15-21Z TODAY. - MOLDAN
PRELIMINARY POINT TEMPS/POPS
GTF 82 52 71 47 / 20 30 20 30
CTB 80 46 65 43 / 20 20 50 40
HLN 83 52 77 49 / 20 20 0 0
BZN 77 48 77 44 / 60 50 0 10
WYS 69 39 69 37 / 80 70 30 20
DLN 74 46 77 43 / 90 80 0 0
HVR 82 50 72 45 / 0 50 10 20
LWT 77 48 69 43 / 20 40 20 40
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page