721
FXUS65 KTFX 271952
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
152 PM MDT SAT JUN 27 2026
KEY MESSAGES
- TRANSITION TO A COOLER SYSTEM BEGINS THIS AFTERNOON, WITH LOWER ELEVATION
RAIN AND HIGHER ELEVATION SNOW BECOMING MORE WIDESPREAD ACROSS
SOUTHWEST MONTANA THIS EVENING.
- BETTER PRECIPITATION ARRIVES ACROSS NORTH-CENTRAL MONTANA,
PARTICULARLY WEST OF I-15, SUNDAY EVENING.
- PRECIPITATION GRADUALLY MOVES OUT LATE MONDAY, THOUGH UNSETTLED
CONDITIONS REMAIN THROUGH THE REMAINDER OF THE WEEK.
DISCUSSION
LARGE SCALE UPPER LEVEL TROUGHING WILL BRING A COUPLE WAVES OF
PRECIPITATION TO THE REGION OVER THE NEXT FEW DAYS. THE INITIAL PUSH
OF BETTER PRECIPITATION ARRIVES THROUGH THE REMAINDER OF THE DAY AND
TONIGHT, PRIMARILY ACROSS SOUTHWEST MONTANA INTO PORTIONS OF CENTRAL
MONTANA. SNOW LEVELS FALL WITH THE ARRIVAL OF THE COOLEST AIR ALOFT,
DROPPING DOWN TO AS LOW AS 6,000 FT OR SO AT TIMES, LOWEST SOUTH
OF I-90. BRIEF SPURTS OF SNOW LEVELS LOWER THAN 6,000FT WILL NOT
BE UNREASONABLE GIVEN THE PRECIPITATION RATES THAT LOOK TO EXIST
AS CONVECTIVE ELEMENTS SLOWLY TRANSITION TO BE MORE STRATIFORM IN
NATURE.
AS THE INITIAL CORE OF THE UPPER LEVEL LOW FILLS ACROSS SOUTHWEST
MONTANA INTO SUNDAY, DEEPENING WITHIN THE TROUGHING LOOKS TO ENSUE
FURTHER NORTH ACROSS NORTH-CENTRAL MONTANA. A CLOSED MID-LEVEL LOW
LOOKS TO DEVELOP SOMEWHERE OVER NORTHERN MONTANA AS A RESULT, AND
GRADUALLY NUDGE BACK WESTWARD DURING THE DAY SUNDAY. THIS WILL
RESULT IN NOT ONLY A FAVORABLY FORCED ENVIRONMENT FROM A DYNAMICAL
PERSPECTIVE OVER THE PLAINS, BUT THERE WILL BE SOME UPSLOPE
ENHANCEMENT AS NORTHERLY OR NORTHEASTERLY FLOW ON THE WESTERN SIDE
OF THE MID LEVEL FLOW INTERACTS WITH TERRAIN. ALL THIS TO SAY
THERE LOOKS TO BE A FAVORABLE REGIME FOR WIDESPREAD PRECIPITATION
OVER NORTH-CENTRAL MONTANA BEGINNING SUNDAY AFTERNOON, BUT PEAKING
SUNDAY NIGHT INTO EARLY MONDAY BEFORE GRADUALLY DIMINISHING. PEAK
PRECIPITATION AMOUNTS WILL FOLLOW WHERE THE BEST FORCING ULTIMATELY
SETTLES, BUT ALSO OCCUR IN UPSLOPE FAVORED AREAS ALONG THE ROCKY
MOUNTAIN FRONT. THE OVERALL ORIENTATION OF TERRAIN FAVORS THE
NORTHERN ROCKY MOUNTAIN FRONT OVER THE SOUTHERN EVER SO SLIGHTLY
FOR GREATER PRECIPITATION AMOUNTS. A FLOOD WATCH REMAINS IN EFFECT
FOR AREAS IN AND NEAR THE EASTERN SIDE OF GLACIER NP EAST OF THE
CONTINENTAL DIVIDE.
A SURFACE LOW LOOKS TO FOLLOW A SIMILAR TRACK AS THE AFOREMENTIONED
MID LEVEL LOW SUNDAY INTO MONDAY. AS THIS OCCURS, GUSTY WINDS LOOK
TO DEVELOP OVER THE PLAINS. WHILE THE OVERALL MAGNITUDE OF THESE
WINDS/GUSTS IS NOT PARTICULARLY NOTABLE FOR THE REGION, THE TIME OF
THE YEAR AND DIRECTION OF THE STRONGER WINDS (DIRECTION WILL VARY
QUITE A BIT, DEPENDENT ON WHERE THE SURFACE LOW TRACKS WITH RESPECT
TO ANY GIVEN AREA) DOES LOOK TO BE A BIT ABNORMAL, WHICH MAY POSE
GREATER IMPACTS.
THE UPPER LEVEL DISTURBANCE MOVES OUT INTO TUESDAY, THOUGH A
LINGERING SOUTHWESTERLY FLOW ALOFT AND GENERAL TROUGHING ACROSS THE
WEST WILL KEEP AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS IN
THE FORECAST FOR MUCH OF THE REMAINDER OF THE WEEK. -AM
AVIATION
27/18Z TAF PERIOD
SCATTERED SHOWERS AND THUNDERSTORMS WILL AFFECT THE CWA
THROUGHOUT THIS TAF PERIOD. THUNDERSTORMS WILL DISSIPATE THIS
EVENING, MOVING SOUTHWEST TO NORTHEAST OUT OF THE CWA BY EARLY
TOMORROW MORNING. MORE CONSISTENT PRECIPITATION WILL BEGIN
FOLLOWING THE EXITING OF THESE THUNDERSTORMS. THERE WILL BE MVFR
CONDITIONS AND MOUNTAIN OBSCURATION AT TIMES DUE TO PASSING
SHOWERS. -DZOMBA
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 49 58 46 59 / 90 90 90 100
CTB 49 63 48 60 / 60 90 100 100
HLN 46 54 45 57 / 100 100 100 100
BZN 41 52 39 55 / 100 100 90 100
WYS 32 48 29 48 / 90 90 90 100
DLN 38 50 37 56 / 100 90 90 90
HVR 50 67 47 66 / 80 100 90 90
LWT 44 55 41 57 / 90 90 80 90
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-RUBY MOUNTAINS AND
SOUTHERN BEAVERHEAD MOUNTAINS.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON MDT MONDAY
FOR NORTHWEST BEAVERHEAD COUNTY.
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