922
FXUS65 KTFX 071507
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
907 AM MDT THU AUG 7 2025
KEY MESSAGES
- NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING
ACROSS THE REGION, WITH A FEW ON THE STRONG TO SEVERE SIDE.
- MUCH COOLER FOR FRIDAY, WITH SHOWERS AND A FEW THUNDERSTORMS IN
THE AFTERNOON.
- TRENDING BACK WARMER THIS WEEKEND INTO NEXT WEEK.
UPDATE
MORNING CONVECTION IN FERGUS AND BLAINE COUNTY THIS MORNING HAS
EXITED OFF TO THE EAST. A WAVE OF SHOWERS WEST OF THE CONTINENTAL
DIVIDE WILL CONTINUE TO MOVE EAST, BRINGING SHOWERS TO AREAS ALONG
THE ROCKY MOUNTAIN FRONT THIS MORNING BEFORE THE MAIN WAVE OF
PRECIPITATION HITS THIS AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO INITIATE EARLY THIS AFTERNOON.
CLOUDS ALONG THE CONTINENTAL DIVIDE MOVING EAST WILL LIKELY LIMIT
INSTABILITY DEVELOPMENT FOR STORMS THIS AFTERNOON. THOUGH, GOOD
DEEP LAYER SHEAR NEARING 50-60KTS AT TIMES AND LOWER AMOUNTS OF
HELICITY WILL KEEP THE STRONG TO SEVERE STORM THREAT ISOLATED.
AREAS FARTHER EAST OF THE DIVIDE (FERGUS AND BLAINE COUNTIES) WILL
HAVE MORE CLEARING FOR SURFACE HEATING. THOUGH, INSTABILITY DON'T
SEEM TO BE STRONG TODAY OVER THERE(~1,000 J/KG). IT SEEMS LIKE
THIS WILL BE THE BEST CORRIDOR FOR STRONGER TO SEVERE
THUNDERSTORMS THIS AFTERNOON. STORMS WILL HAVE A WIND AND HAIL
THREAT WITH GOOD LAPSE RATES AND LOWER FREEZING LEVELS (WHICH HELP
LIMIT HAIL MELTING), WITH FERGUS COUNTY AT A BETTER CHANCE FOR
LARGE HAIL. HOWEVER, THIS WILL BE HIGHLY DEPENDENT ON HOW MUCH
INSTABILITY AND SURFACE HEATING BUILDS IN THIS MORNING. -WILSON
DISCUSSION
/ISSUED 537 AM MDT THU AUG 7 2025/
- METEOROLOGICAL OVERVIEW:
THE INITIAL WAVE ASSOCIATED WITH AN APPROACHING UPPER TROUGH OVER
THE PACIFIC NW IS MOVING OVERHEAD EARLY THIS MORNING. SUFFICIENT
FORCING FROM THIS WAVE HAS ALLOWED FOR ELEVATED SHOWERS AND
THUNDERSTORMS TO DEVELOP, MAINLY OVER THE PLAINS. THIS ACTIVITY WILL
SPREAD EASTWARD THROUGH THE REMAINDER OF THE OVERNIGHT AND EXIT THIS
MORNING.
ATTENTION THEN TURNS TO THIS AFTERNOON AND EVENING, WHEN THE MAIN
WAVE OF THE AFOREMENTIONED TROUGH BEGINS TO SWING THROUGH. STOUT
FORCING FROM THIS TROUGHING WILL HELP MAXIMIZE WHAT LITTLE
INSTABILITY DEVELOPS THROUGH THE AFTERNOON, RESULTING IN NUMEROUS
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. THE MOST
ROBUST THUNDERSTORMS THAT FORM WILL BE CAPABLE OF TAKING ON AT LEAST
BRIEF SUPERCELL CHARACTERISTICS GIVEN THE STRONG SHEAR IN PLACE.
FORECAST HODOGRAPHS FEATURE LONG, STRAIGHT SHEAR PROFILES,
SUGGESTING LARGE HAIL WILL BE A CONCERN IN THE MOST ROBUST
THUNDERSTORMS, ON TOP OF STRONG WIND GUSTS. THE SETUP WILL BE
DISCUSSED A BIT FURTHER IN THE UNCERTAINTY SECTION BELOW.
COOLER TEMPERATURES MOVE IN BEHIND A FRONT, WHICH WILL ALLOW FOR A
COOL DAY FRIDAY AS THE CORE OF THE UPPER TROUGH MOVES ACROSS THE
NORTHERN ROCKIES. ALTHOUGH SURFACE TEMPERATURES WILL BE BELOW
AVERAGE, SUFFICIENTLY COOL TEMPERATURES ALOFT WILL STILL ALLOW FOR
AFTERNOON SHOWERS AND THUNDERSTORMS. THE RISK FOR A STRONG
THUNDERSTORM IS LOW, THOUGH IT SHOULD BE MENTIONED THAT A PERIOD
OF MORE WIDESPREAD (SYNOPTIC) GUSTY WINDS DO LOOK TO DEVELOP
DURING THE DAY FRIDAY OVER THE PLAINS.
THE UPPER TROUGHING MOVES OFF TO THE EAST THIS WEEKEND, ALLOWING FOR
A NORTHWESTERLY FLOW ALOFT TO DEVELOP WELL OFF TO THE EAST OF A
BUILDING RIDGE OVER THE EASTERN PACIFIC OCEAN. THIS SETUP MORE OR
LESS CONTINUES INTO THE MIDDLE OF NEXT WEEK. GLANCING BLOWS FROM
WAVES TRAVERSING THROUGH THE NORTHWESTERLY FLOW ALOFT MAY PROMOTE
LOW-END CHANCES FOR SHOWERS AND THUNDERSTORMS AT TIMES EARLY NEXT
WEEK, BUT THE MAIN TAKEAWAY IS FOR A WARMING AND LARGELY DRYING
TREND HEADING INTO EARLY NEXT WEEK. CONFIDENCE IN SPECIFICS
DECREASES SIGNIFICANTLY LATE NEXT WEEK, BUT ENSEMBLE MEANS DO
FAVOR TROUGHING IN SOME CAPACITY. -AM
- FORECAST CONFIDENCE & SCENARIOS:
THERE STILL REMAINS SOME UNCERTAINTY WITH RESPECT TO HOW WELL THE
REGION DESTABILIZES TODAY. FORCING FROM THE APPROACHING TROUGH LOOKS
TO RESULT IN QUITE A BIT OF CLOUD COVER, WHICH WOULD LIMIT JUST HOW
MUCH SURFACE HEATING AND RESULTING INSTABILITY DEVELOPS. SHOULD
CLOUD COVER HOLD OFF A BIT MORE IN THE LATE MORNING AND EARLY
AFTERNOON, A TREND TOWARD MORE NUMEROUS STRONG TO SEVERE
THUNDERSTORMS THUNDERSTORMS WOULD BE REASONABLE. CONVERSELY, IF THE
REGION FAILS TO CLEAR OUT IN A MEANINGFUL WAY, THE RISK FOR A STRONG
TO SEVERE THUNDERSTORM WOULD BE LOWER. OVERALL, THE AREA WITH THE
BEST CHANCE FOR AMPLE INSTABILITY TO DEVELOP WOULD BE IN THE
LEWISTOWN AREA AND VICINITY. -AM
AVIATION
07/12Z TAF PERIOD
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A SHORTWAVE OUT IN
ADVANCE OF THE MAIN TROUGH HAVE MOSTLY ENDED THIS MORNING. THE
TROUGH AXIS WILL APPROACH THE NORTHERN ROCKIES LATER TODAY AND
SEND A COUPLE MORE WAVES OF SHOWERS AND THUNDERSTORMS THROUGH
SOUTHWEST AND NORTH-CENTRAL MONTANA BETWEEN 07/18 AND 08/06Z. THE
STRONGEST STORMS LOOK TO OCCUR OVER AREAS EAST OF A KHLN TO KHVR
LINE AND NORTH OF I90. THIS WILL BE FOLLOWED BY LIGHTER END SHOWER
AND EMBEDDED THUNDER ACTIVITY OVER CENTRAL/NORTH-CENTRAL MONTANA
DURING THE OVERNIGHT HOURS. SOME STORMS IN THE AFTERNOON AND
EVENING WILL BE CAPABLE OF STRONG, GUSTY WINDS, HAIL, BRIEF
DOWNPOURS IN ADDITION TO LIGHTNING. - RCG
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 76 49 71 53 / 50 60 30 20
CTB 72 50 65 50 / 70 40 60 20
HLN 76 48 72 51 / 50 80 20 10
BZN 81 44 73 45 / 50 80 20 10
WYS 76 36 68 32 / 30 40 20 0
DLN 78 40 71 40 / 30 50 10 0
HVR 80 53 70 54 / 70 50 70 50
LWT 74 46 67 49 / 80 60 40 20
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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