384
FXUS65 KTFX 291741
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1141 AM MDT THU MAY 29 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- A PACIFIC COLD FRONT WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS THURSDAY EVENING WITH STORMS CAPABLE OF PRODUCING
STRONG WINDS, BRIEF DOWNPOURS, AND SMALL HAIL.
- WELL ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE
WEEKEND WITH SATURDAY EXPECTED TO BE THE WARMEST DAY OF THE
WEEK.
- A COOLER AND WETTER PATTERN WILL SET UP EARLY NEXT WEEK
BRINGING A CHANCE FOR WIDESPREAD PRECIPITATION.
UPDATE
/ISSUED 931 AM MDT THU MAY 29 2025/
CURRENT FORECAST IS ON TRACK. NO CHANGES THIS MORNING. THE MAIN
CONCERN LATER TODAY WILL BE THE THUNDERSTORM POTENTIAL DEVELOPING
AFTER 2 PM ALONG THE DIVIDE AND ACROSS SOUTHWEST MT. EXPECT
LIGHTNING, BRIEF RAINFALL, GUSTY WINDS AND SMALL HAIL FROM ANY OF
THE STRONGER STORMS. BRUSDA
DISCUSSION
/ISSUED 931 AM MDT THU MAY 29 2025/
- METEOROLOGICAL OVERVIEW:
WARMER TEMPERATURES ARE EXPECTED THIS AFTERNOON AHEAD OF AN
APPROACHING SHORTWAVE TROUGH THAT WILL PASS OVER THE REGION THIS
AFTERNOON BRINGING A CHANCE FOR SOME SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE LATE EVENING HOURS.
BEHIND THE SHORTWAVE TRANSIENT RIDGING WILL MOVE ACROSS THE
REGION FRIDAY INTO SATURDAY ALLOWING FOR TEMPERATURES TO WARM INTO
THE UPPER 80S TO LOW 90S ACROSS THE REGION ON SATURDAY.
AN UPPER LEVEL TROUGH MOVES ACROSS THE REGION LATE SATURDAY INTO SUNDAY
BRINGING WITH IT THE NEXT CHANCE FOR WIDESPREAD PRECIPITATION AS
WELL AS MUCH COOLER TEMPERATURES THAT WILL LINGER THROUGH AT
LEAST THE MIDDLE OF THE WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
THUNDERSTORMS TODAY:
THE LATEST HREF GUIDANCE SHOWS 300-500 J/KG CAPE WITH 10-20KTS OF
SHEAR WHICH IS NOT OVERLY IMPRESSIVE BUT WHEN COMBINED WITH STRONG
DIURNAL HEATING THERE IS A CONCERN FOR SOME POP-UP THUNDERSTORMS
EARLY IN THE AFTERNOON. THE MAIN CONCERN WITH THE FIRST ROUND OF
STORMS WILL BE STRONG WIND GUSTS WITH MODEL SOUNDING SHOWING
SUFFICIENT DCAPE AND INVERTED V SOUNDINGS TO SUGGEST SOME WINDS
MAY BE IN EXCESS OF 50 MPH. A BETTER FORCING MECHANISM IN THE
FORM OF THE APPROACHING COLD FRONT WILL ARRIVE LATER THIS EVENING
WHICH IS EXPECTED TO KICK OFF ADDITIONAL SHOWERS AND
THUNDERSTORMS. SIMILAR TO STORMS EARLIER IN THE AFTERNOON, STRONG
WINDS WILL BE THE PRIMARY CONCERNS WITH HEAVY DOWNPOURS AND SMALL
HAIL AS SECONDARY CONCERNS HEADING INTO THE OVERNIGHT HOURS.
WARM TEMPERATURES ON SATURDAY:
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE REST OF
THE WEEK WITH SATURDAY EXPECTED TO BE THE WARMEST DAY AHEAD OF THE
COLD FRONT. ACROSS THE LOWER ELEVATIONS, WIDESPREAD HIGHS ABOVE 80
DEGREES ARE EXPECTED WITH A 50-70% CHANCE OF SOME LOCATIONS ALONG
THE NORTHERN PLAINS EXCEEDING 90 DEGREES. THUNDERSTORMS ARE
POSSIBLE LATE SATURDAY AS THE COLD FRONT STARTS TO MAKE ITS WAY
INTO THE AREA. THE MAIN UNCERTAINTY WITH ANY POTENTIAL SHOWER OR
THUNDERSTORM DEVELOPMENT WILL BE THE TIMING OF THE FRONT.
PRECIPITATION SUNDAY INTO NEXT WEEK:
THERE IS CONTINUING HIGH CONFIDENCE IN COOLER AND WETTER
CONDITIONS RETURNING BY EARLY NEXT WEEK AS THE TROUGH DIGS INTO
MONTANA. THE MAIN UNCERTAINTY THAT CONTINUES WITH THIS EVENT WILL
BE WHETHER OR NOT THE SYSTEM CONTINUES TO TREND FARTHER SOUTH AS
IT HAS OVER THE LAST COUPLE DAYS. A TREND TO THE SOUTH WOULD MEAN
LESS PRECIPITATION ALONG THE HI-LINE AND GREATER CHANCES FOR
HIGHER AMOUNTS IN CENTRAL AND SOUTHWEST MONTANA. AS IT STANDS, THE
HI-LINE CURRENTLY HAS AROUND A 40-60% CHANCE OF 0.25" OR MORE OF
PRECIPITATION THROUGH TUESDAY AND A 20-40% CHANCE OF 0.5" OR MORE.
THE HIGHEST AMOUNTS ARE CURRENTLY FORECASTED SOUTHEAST OF A LINE
BETWEEN GREAT FALLS AND HELENA WHERE THERE IS A 60-80% CHANCE OF
0.5" OR MORE AND A 40-60% CHANCE OF 0.75" OR MORE.
WITH THIS SYSTEM, MUCH COOLER TEMPERATURES WILL RETURN TO THE
REGION WITH HIGHS EXPECTED TO BE 20 TO 30 DEGREES COOLER ON MONDAY
COMPARED TO SATURDAY. ALONG WITH COLDER AIR WILL COME A CHANCE FOR
MOUNTAIN SNOW ALTHOUGH AS IT STANDS MOST OF THE CONCERN FOR
IMPACTFUL ACCUMULATIONS REMAINS WELL ABOVE PASS LEVEL. -THOR
AVIATION
29/18Z TAF PERIOD
AFTERNOON MID-LEVEL CUMULUS CLOUDS ARE BEGINNING TO FORM OVER THE
HIGH TERRAIN. WITH STRONG DAY TIME HEATING, SHOWERS AND
THUNDERSTORMS WILL FORM OVER THE MOUNTAINS THIS AFTERNOON. A COLD
FRONT MOVING THROUGH LATE AFTERNOON AND EARLY EVENING WILL BRING
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS FROM A LINE WEST OF
THE WEST YELLOWSTONE TO HAVRE LINE. THERE IS A SLIGHT CHANCE
SHOWERS AND STORMS START A LITTLE BIT EARLIER WITH STRONG SURFACE
HEATING. WITH THE LATER ARRIVAL OF THE FRONT, THERE REMAINS SOME
UNCERTAINTY IN THUNDERSTORM CHANCES AT KGTF AND KBZN. DEEP MIXING
WITH THUNDERSTORMS CAN BRING GUSTY WINDS, WITH GUSTS OF UP TO
35-40KTS WITH A FEW STRONGER STORMS. -WILSON
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL
AVIATION WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 87 53 77 51 / 20 30 0 0
CTB 86 51 78 48 / 20 20 0 0
HLN 86 54 82 53 / 20 30 0 0
BZN 82 49 79 48 / 20 20 0 0
WYS 74 41 75 38 / 40 40 10 0
DLN 80 48 77 48 / 30 30 0 0
HVR 86 56 79 49 / 10 20 0 0
LWT 79 53 73 49 / 0 10 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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