589
FXUS65 KTFX 062122
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
322 PM MDT TUE MAY 6 2025
KEY MESSAGES
- MILD TO WARM TEMPERATURES ARE EXPECTED FOR THE REMAINDER OF THE
WEEK, WITH AFTERNOON HIGHS PEAKING WELL INTO THE 80S THIS WEEKEND.
- WESTERLY WINDS MAY BRIEFLY BECOME STRONG ALONG THE
NORTHERN ROCKY MOUNTAIN FRONT WEDNESDAY NIGHT INTO THURSDAY.
- MORE GUSTY WINDS ARE EXPECTED THIS WEEKEND, ESPECIALLY OVER
SOUTHWEST MONTANA.
- GENERAL DRY CONDITIONS ARE EXPECTED, BUT SHOWER AND THUNDERSTORM
ACTIVITY SLOWLY INCREASE EACH DAY BEGINNING THURSDAY THROUGH THE
WEEKEND.
- COOLER AND UNSETTLED CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
A REX BLOCKING PATTERN SETS UP OVER THE WESTERN CONUS FOR THE
NEXT 24 HOURS BEFORE RIDGING BECOMES MORE DOMINANT FOR THE SECOND
HALF OF THE WORK WEEK. SOME LINGERING COOLER AIR ALOFT WILL
MAINTAIN SCATTERED TO BROKEN CLOUD COVER OVER SOUTHWEST AND
PORTIONS OF CENTRAL MONTANA THROUGH TONIGHT AND A STRAY SHOWER OR
SPRINKLE CAN'T BE RULED OUT OVER THE CENTRAL ISLAND AND
MADISON/GALLATIN MOUNTAIN RANGES. OTHERWISE, GENERALLY DRY
CONDITIONS ARE EXPECTED FOR AT LEAST THE NEXT COUPLE OF DAYS
BEFORE AN INCREASINGLY UNSTABLE SOUTHWESTERLY FLOW ALOFT BECOMES
MORE ESTABLISHED AND INITIATES SHOWER AND THUNDERSTORM ACTIVITY
HEADING TOWARDS THE WEEKEND. THERE WILL ALSO BE A QUICK MOVING,
MOSTLY DRY SHORTWAVE THAT BRINGS BREEZY TO WINDY CONDITIONS
WEDNESDAY INTO THURSDAY, WITH THE STRONGEST WINDS EXPECTED ALONG
THE NORTHERN ROCKY MOUNTAIN FRONT AND ADJACENT HIGH PLAINS.
ISOLATED HIGH BASED SHOWERS AND THUNDERSTORMS BEGINS TO DEVELOP
OVER AREAS OF HIGHER TERRAIN THURSDAY AFTERNOON THANKS TO
INCREASING MOISTURE AND INSTABILITY FROM THE AFOREMENTIONED
SOUTHWESTERLY FLOW ALOFT. THIS ACTIVITY IS EXPECTED TO INCREASE
EACH DAY THROUGH THE WEEKEND AS THE SOUTHWESTERLY FLOW STRENGTHENS
IN RESPONSE A DEEPENING TROUGH OVER THE PACIFIC NORTHWEST. THE
COMBINATION OF ROBUST DIURNAL HEATING FUELING MLCAPE LEVELS AS
HIGH AS 1,000 J/KG WITH INCREASING LARGE SCALE ASCENT FROM THE
APPROACHING PACIFIC TROUGH WILL ENCOURAGE SOME STORMS TO BECOME
STRONG TO SEVERE WITH STRONG GUSTY WINDS, HAIL, AND BRIEF
DOWNPOURS. THE STRONGEST AND MOST WIDESPREAD STORMS WILL BE ON
SUNDAY AHEAD OF A COLD FRONTAL PASSAGE. IN ADDITION TO THE SHOWERS
AND THUNDERSTORMS, A 40 TO 50 KT H700 JET WILL BRING GUSTY
SOUTHERLY WINDS TO SOUTHWEST MONTANA LATE SUNDAY INTO MONDAY.
THERE ARE DISCREPANCIES TO SORT OUT WITH THE EVOLUTION OF THE
TROUGH HEADING INTO EARLY NEXT WEEK, BUT THERE IS AN EXPECTATION
FOR COOLER AND UNSETTLED CONDITIONS TO FOLLOW SUNDAY'S COLD
FRONTAL PASSAGE. - RCG
- FORECAST CONFIDENCE & SCENARIOS:
ROCKY MOUNTAIN FRONT WINDS WEDNESDAY INTO THURSDAY...
A FAST MOVING SHORTWAVE WILL BRING STRONG WIND POTENTIAL ALONG
THE ROCKY MOUNTAIN FRONT AND ADJACENT HIGH PLAINS LATE WEDNESDAY
INTO THURSDAY. WITH H700 WINDS PEAKING IN THE 50 TO 60 KT RANGE
DURING THE OVERNIGHT AND EARLY MORNING HOURS, THERE WILL BE A
RELIANCE ON MOUNTAIN WAVE ACTIVITY TO BRING THE STRONGER WINDS
BEYOND THE IMMEDIATE EASTERN SLOPES OF THE NORTHERN ROCKY MOUNTAIN
FRONT. THERE IS A 70 TO 90% CHANCE FOR GUSTS OVER 55 MPH IN THESE
AREAS. THIS PROBABILITY DROPS OFF TO AROUND 40% GOING EAST OF
BROWNING TOWARD CUT BANK. THE PRIMARY IMPACT WILL BE TO
RECREATIONAL INTEREST IN OR NEAR GLACIER NATIONAL PARK.
WEEKEND STRONG THUNDERSTORM AND WIND POTENTIAL...
SHOWER AND THUNDERSTORM ACTIVITY WILL SLOWLY RAMP UP EACH DAY
THURSDAY THROUGH THE WEEKEND, WITH SUNDAY LIKELY SEEING THE MOST
WIDESPREAD ACTIVITY WITH STRONG GUSTY WIND, HAIL, AND BRIEF
DOWNPOUR POTENTIAL IN ADDITION TO LIGHTNING. BOTH SATURDAY AND
SUNDAY WILL BE CLOSELY MONITORED FOR SEVERE WEATHER CONCERNS.
EVEN WITHOUT THUNDERSTORMS, WINDS IN SOUTHWEST MONTANA WILL BE ON
THE STRONGER SIDE LATE SUNDAY NIGHT INTO MONDAY. THERE IS AROUND A
60 TO 70% CHANCE FOR WIND GUSTS IN EXCESS OF 55 MPH OVER THE NORTH
TO SOUTH ORIENTED SOUTHWEST VALLEYS AND THE HIGHER MOUNTAIN PEAKS.
- RCG
AVIATION
06/18Z TAF
VFR EXPECTED THROUGHOUT THE TAF PERIOD WITH HIGH PRESSURE
CENTERED OVER MANITOBA, RETREATING WITH TIME... LEADING TO
VARIABLE FLOW OUT OF THE NORTHEAST TO SOUTHEAST THROUGH TONIGHT.
WIND SPEEDS ARE GENERALLY LIMITED TO 10-20 KTS THROUGH THIS
EVENING, SPARE FOR A FEW GUSTS UP TO 20-25 KTS. SPEEDS DIMINISH TO
5-15 KTS OVERNIGHT. MEANWHILE A WEATHER SYSTEM CENTERED OVER
WYOMING OFFERS VFR DECKS WHICH WILL CLEAR AND PULL EAST THROUGH
THE EVENING AND OVERNIGHT... WITH SKC ALREADY IN THE OBS ACROSS
THE HI-LINE. LOW PRESSURE APPROACHING FROM THE NW ON WEDNESDAY
PULLS WINDS SOUTHERLY, OR SOME VARIATION OF, BY THE END OF THE TAF
PERIOD. -CASEY
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 37 76 46 74 / 0 0 0 10
CTB 33 74 46 69 / 0 0 0 0
HLN 37 76 48 77 / 0 10 0 20
BZN 32 72 42 75 / 0 0 0 30
WYS 28 65 33 67 / 0 0 0 40
DLN 33 71 41 73 / 0 0 0 20
HVR 36 78 47 79 / 0 0 0 10
LWT 32 71 46 72 / 0 0 0 30
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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