780
FXUS65 KTFX 051751
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1151 AM MDT TUE AUG 5 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS TODAY, MAINLY OVER THE
PLAINS.
- ANOTHER ROUND OF THUNDERSTORMS AHEAD OF A COLD FRONT THURSDAY
AFTERNOON AND EVENING.
- COOL FRIDAY AND SATURDAY, TRENDING WARMER INTO NEXT WEEK.
UPDATE
/ISSUED 824 AM MDT TUE AUG 5 2025/
CURRENT RADAR SHOWS SCATTERED SHOWERS ACROSS FERGUS AND BLAINE
COUNTIES SLOWLY EXITING OFF TO THE EAST THIS MORNING. FURTHER
WEST ALONG THE HI-LINE, AN UPPER-LEVEL WAVE WILL CONTINUE TO
PRODUCE ISOLATED TO SCATTER SHOWERS AND AN ISOLATED STORM THIS
MORNING ACROSS THE NORTH-CENTRAL MT PLAINS. COVERAGE IN
PRECIPITATION BECOMES MORE ISOLATED THIS AFTERNOON AND EVENING
ACROSS THE NORTH- CENTRAL MT PLAINS. STORMS ARE EXPECTED TO REMAIN
ON THE WEAKER SIDE TODAY, THOUGH I CAN'T RULE OUT A FEW GUSTY
WINDS. -WILSON
DISCUSSION
/ISSUED 824 AM MDT TUE AUG 5 2025/
- METEOROLOGICAL OVERVIEW:
THE MAIN WAVE ASSOCIATED WITH THE SHOWERS AND THUNDERSTORMS FROM
MONDAY IS STILL PASSING ACROSS THE REGION EARLY THIS TUESDAY
MORNING. GIVEN HOW POTENT THIS WAVE IS, SHOWERS AND ISOLATED
THUNDERSTORMS HAVE CONTINUED, AND LOOK TO CONTINUE INTO THE
MORNING, THOUGH DO LOOK TO BECOME LESS WIDESPREAD.
AFOREMENTIONED WAVE IS A BIT SLOW TO EXIT TODAY, WHICH WILL HELP A
FEW SHOWERS AND THUNDERSTORMS FORM THIS AFTERNOON AND EVENING,
LARGELY OVER THE PLAINS. SHOWERS AND THUNDERSTORMS TODAY LOOK TO BE
MUCH MORE ISOLATED IN NATURE.
BRIEF SHORTWAVE RIDGING MOVES OVER THE NORTHERN ROCKIES AHEAD OF A
MORE ROBUST TROUGH OFF THE PACIFIC COAST WEDNESDAY. A LARGELY DRY
DAY IS FORECAST WEDNESDAY, THOUGH BY THE EVENING THE RIDGING DOES
SHIFT EASTWARD. A FEW SHOWERS OR THUNDERSTORMS CANNOT BE RULED
OUT IN THE EVENING WEDNESDAY.
AN IMPRESSIVE TROUGH WITH A COMPACT EMBEDDED CLOSED LOW BEGINS TO
PIVOT ACROSS THE NORTHWESTERN CONUS THURSDAY. AHEAD OF THE UPPER
LOW, SOUTHWESTERLY FLOW ALOFT INCREASES IN MAGNITUDE WHILE ALSO
COOLING THE MID/UPPER LEVELS. THIS SETUP WILL YIELD A CONDITIONAL
RISK FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE REGION AHEAD OF A
PACIFIC COLD FRONT. THIS THREAT IS DEPENDENT ON THE FRONT HOLDING
OFF UNTIL THE AFTERNOON OR EARLY EVENING, WHICH WOULD ALLOW FOR
SUFFICIENT DESTABILIZATION. ASSUMING THIS DESTABILIZATION OCCURS,
THERE WOULD BE MORE THAN ENOUGH FORCING FOR ASCENT AND EFFECTIVE
SHEAR TO RESULT IN AT LEAST A FEW ORGANIZED THUNDERSTORMS, WHICH
WOULD TRANSLATE FROM SOUTHWEST TO NORTHEAST QUITE QUICKLY GIVEN
THE STRONG FLOW ALOFT. CONVERSELY, IF THE FRONT WAS TO ARRIVE
EARLY AFTERNOON OR EVEN EARLIER, THE RISK FOR A STRONGER
THUNDERSTORM WOULD DIMINISH ALMOST ENTIRELY.
ALONG AND BEHIND THE FRONT THERE APPEARS TO BE A PERIOD OF RAIN THAT
LINGERS INTO FRIDAY, WHICH WILL HELP KEEP TEMPERATURES ON THE COOL
SIDE TO CLOSE OUT THE WEEK. TEMPERATURES DO BEGIN TO TREND WARMER
SATURDAY BEHIND THE DEPARTING UPPER TROUGH, BUT A NORTHWESTERLY FLOW
ALOFT WILL HAMPER HOW QUICKLY THE REGION TRENDS CLOSER TO NORMAL.
A BROAD RIDGE LOOKS TO SET UP OFF THE PACIFIC COAST HEADING INTO
NEXT WEEK. A WEAKLY ANTICYCLONIC NORTHWESTERLY FLOW LOOKS TO SETTLE
IN SUNDAY INTO EARLY NEXT WEEK. THIS LOOKS TO ALLOW TEMPERATURES
TO SETTLE NEAR NORMAL, WITH ANY OPPORTUNITIES FOR A SHOWER OR
THUNDERSTORM DEPENDENT ON AN EMBEDDED WAVE TRAVERSING THROUGH THE
RIDGE. -AM
- FORECAST CONFIDENCE & SCENARIOS:
THE MAIN SOURCE OF UNCERTAINTY IS THE TIMING OF THE FRONT THURSDAY.
A QUICKER TO ARRIVE FRONT WOULD DIMINISH CONCERNS FOR STRONGER
THUNDERSTORMS IN THE AFTERNOON. A SLOWER FRONT WOULD ALLOW FOR
INSTABILITY TO DEVELOP AND POSE A RISK FOR STRONG TO SEVERE
THUNDERSTORMS ACROSS PORTIONS OF THE REGION. AT THIS POINT THERE
IS A MARGINAL RISK FOR SEVERE THUNDERSTORMS, MAINLY ACROSS
CENTRAL AND SOUTHWEST MONTANA.
AS FOR THE COOLER PERIOD WITH RAIN LATE THURSDAY INTO FRIDAY: THE
CHANCE FOR 0.25" PRECIP OVER THIS TIMEFRAME IS ROUGHLY 20% OVER
SOUTHWEST MONTANA, TRENDING HIGHER FURTHER NORTH TO AROUND 40% ON
THE HI-LINE.
CHANCES FOR PRECIPITATION SUNDAY ONWARD: THIS WILL BE DEPENDENT ON
ANY WAVES WITHIN THE WEAKLY ANTICYCLONIC FLOW ALOFT. DETERMINISTIC
GUIDANCE DOES HAVE A FEW OF THESE WAVES, BUT STRUGGLES ON TIMING
THEM. HENCE, THERE DOES LOOK TO BE A LOW-END OPPORTUNITY FOR A
SHOWER EARLY NEXT WEEK, BUT THE PROBABILITY IS LOW FOR ANY GIVEN DAY
AT THE MOMENT. -AM
AVIATION
05/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.
THERE IS A 30% CHANCE OF ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING ALONG THE HI-LINE. BRIEF
PERIODS OF LOW-VFR TO MVFR CONDITIONS ARE POSSIBLE UNDER STRONGER
SHOWERS AND STORMS. -THOR
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 80 54 86 57 / 20 20 0 20
CTB 77 50 78 52 / 30 20 0 10
HLN 82 55 87 57 / 10 0 0 20
BZN 83 49 90 52 / 0 0 0 10
WYS 76 38 82 41 / 0 0 0 0
DLN 78 46 85 50 / 0 0 0 0
HVR 79 55 87 58 / 50 30 0 20
LWT 75 52 83 52 / 30 20 0 30
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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