502
FXUS65 KTFX 271030
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
430 AM MDT SAT JUN 27 2026
KEY MESSAGES
- AN EARLY SUMMER STORM WILL AFFECT THE ENTIRE CWA OVER THE NEXT
FEW DAYS WITH A COMBINATION OF THUNDERSTORMS AND WIDESPREAD
RAIN.
- BELOW NORMAL TEMPERATURES THE NEXT FEW DAYS, BEFORE WARMER AIR
RETURNS BY THE MIDDLE OF NEXT WEEK.
- DAILY CHANCES FOR AFTERNOON THUNDERSTORMS EXPECTED FOR THE 2ND
HALF OF NEXT WEEK.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
A SUMMER STORM WILL AFFECT THE CWA OVER THE NEXT FEW DAYS, WITH A
VARIETY OF DIFFERENT WEATHER CONDITIONS. EXPECT
SHOWERS/THUNDERSTORMS TODAY, WITH THE STRONGEST STORMS LIKELY OVER
THE EASTERN PORTIONS OF THE CWA. LARGE HAIL WOULD BE THE MAIN
IMPACT FROM ANY SEVERE STORMS TODAY. AFTERNOON TEMPERATURES WILL
BE BELOW NORMAL ACROSS THE CWA TODAY, WITH SOUTHWEST MT BEING THE
COOLEST AREA. EXPECT WIDESPREAD PRECIPITATION TO DEVELOP OVER
SOUTHWEST MT THIS MORNING AND SPREAD NORTHWARD INTO CENTRAL MT BY
EVENING. ALL OF THIS PRECIPITATION IS A RESULT OF A SLOW MOVING
UPPER LEVEL LOW THAT WILL MOVE FROM THE PACIFIC NORTHWEST,
SOUTHEASTWARD TOWARDS THE WEST YELLOWSTONE AREA. THIS UPPER LEVEL
LOW WILL THEN SWING NORTHWARD SUN INTO MONDAY, SLOWLY, RESULTING
IN A FEW DAYS OF WIDESPREAD PRECIPITATION, ESPECIALLY OVER NORTH
CENTRAL MT. MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED UNDERNEATH
THIS UPPER LEVEL LOW. FOR ELEVATIONS ABOVE 6500 FEET, THE
TEMPERATURE WILL BE COLD ENOUGH FOR SNOW TO FALL, ESPECIALLY IN
SOUTHWEST MT. THUS THE WINTER WEATHER ADVISORY WILL CONTINUE FOR
THE SOUTHWEST, WITH THE MOUNTAINS IN JEFFERSON COUNTY ADDED TO THE
ADVISORY AREA.
THE PRECIPITATION WILL DIMINISH ON TUESDAY, WITH A WIDESPREAD
RAINFALL OF 1 TO 3 INCHES FOR MOST AREAS, ALONG WITH HIGHER
AMOUNTS ON THE EAST SIDE OF GLACIER NATIONAL PARK.
FOR WEDNESDAY THROUGH THE 4TH OF JULY, EXPECT A RATHER UNSTABLE
SOUTHWESTERLY FLOW ALOFT PATTERN TO SET UP OVER OUR CWA. AN UPPER
LEVEL LOW WILL BE OVER THE PACIFIC NORTHWEST FOR ALL LATE NEXT
WEEK, RESULTING IN WARMER AIR MOVING BACK INTO THE CWA, BUT ALSO
FOR DAILY CHANCES FOR SHOWERS/THUNDERSTORMS. SOME STORMS COULD BE
ON THE STRONG SIDE LATER NEXT WEEK AS THE AIRMASS WILL REMAIN
UNSTABLE, ESPECIALLY DURING THE LATE AFTERNOON/EVENING HOURS.
- FORECAST CONFIDENCE & SCENARIOS:
A MARGINAL RISK FOR SEVERE STORMS CONTINUES TODAY OVER THE EASTERN
PORTIONS OF THE CWA. LARGE HAIL WOULD BE THE MAIN SEVERE WEATHER
IMPACT TODAY.
A WINTER WEATHER ADVISORY CONTINUES FOR THE MOUNTAIN AREAS OF
SOUTHWEST MT, WITH A 3 TO 6 INCH SNOWFALL LIKELY FOR ELEVATIONS
ABOVE 6500 FEET. SOME RIDGE TOPS COULD EXCEED 8 INCHES, ESPECIALLY
THOSE RIDGE TOPS THAT ARE NEAR/ABOVE 9000 FEET.
A FLOOD WATCH WAS ISSUED FOR THE GLACIER PARK REGION, AS THIS AREA
HAS THE POTENTIAL TO GET AROUND 4 INCHES OF RAINFALL. THIS
RAINFALL, COMBINED WITH HIGH ELEVATION SNOWMELT COULD RESULT IN
SOME FLOODING ISSUES ON THE EAST SIDE OF GLACIER NATIONAL PARK BY
LATE SUNDAY OR MONDAY. ADDITIONAL FLOOD STATEMENTS MIGHT BE NEEDED
FOR AREAS THAT RECEIVE OVER 3 INCHES OF RAINFALL OVER THE
REMAINDER OF THE CWA. BRUSDA
AVIATION
27/12Z TAF PERIOD
SCATTERED SHOWERS AND THUNDERSTORMS WILL AFFECT THE CWA THROUGHOUT
THE PERIOD. EXPECT THE PRECIPITATION TO BECOME MORE WIDESPREAD
OVER CENTRAL AND SOUTHWEST MT BY THIS EVENING. SOME OF THE
STRONGER STORMS COULD ALSO PRODUCE SMALL HAIL. ANY MORNING FOG
SHOULD BURN OFF BY 15Z TODAY. MOUNTAINS/PASSES WILL BE OBSCURED AT
TIMES ACROSS THE CWA BY CLOUDS/PRECIP. BRUSDA
HYDROLOGY
PERIODS OF RAIN WILL AFFECT THE CWA FROM TODAY THROUGH MONDAY.
WIDESPREAD RAINFALL AMOUNTS OF 1 TO 3 INCHES ARE EXPECTED ACROSS
THE CWA OVER THE NEXT 3 DAYS.
IN THE GLACIER PARK REGION, RAINFALL COULD BE A BIT HEAVIER,
POSSIBLY UP TO 4 INCHES. ADDITIONALLY, WITH SOME HIGH ELEVATION
SNOW STILL LEFT, THE COMBINATION OF RAINFALL/SNOWMELT COULD LEAD
TO SOME FLOODING ON THE EAST SIDE OF GLACIER NATIONAL PARK. THUS A
FLOOD WATCH HAS BEEN ISSUED FOR THIS REGION STARTING ON SUNDAY.
ADDITIONAL FLOOD STATEMENT MIGHT BE NEEDED IF RAINFALL AMOUNTS
START TO EXCEED 3 INCHES ELSEWHERE ACROSS THE CWA. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 70 48 57 45 / 50 90 90 90
CTB 69 48 61 47 / 30 70 80 100
HLN 66 46 54 45 / 90 90 100 90
BZN 63 41 54 39 / 90 80 80 80
WYS 55 32 49 29 / 90 90 70 70
DLN 59 38 52 37 / 100 90 70 90
HVR 75 50 66 47 / 30 80 80 80
LWT 66 44 56 41 / 90 80 80 70
TFX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM SUNDAY EVENING THROUGH TUESDAY MORNING FOR EAST
GLACIER PARK REGION.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON MDT
MONDAY FOR ELKHORN AND BOULDER MOUNTAINS-GALLATIN AND MADISON
COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS-NORTHWEST BEAVERHEAD
COUNTY-RUBY MOUNTAINS AND SOUTHERN BEAVERHEAD MOUNTAINS.
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