613
FXUS65 KTFX 302309
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
509 PM MDT TUE JUN 30 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH AFTERNOON THROUGH
FRIDAY.
- TEMPERATURES WILL GRADUALLY WARM UP THROUGH THIS WEEKEND.
- IT WILL BE BREEZY ACROSS PORTIONS OF NORTH-CENTRAL MONTANA FOR
THE 4TH OF JULY.
DISCUSSION
/ISSUED 244 PM MDT TUE JUN 30 2026/
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON A WEAK UPPER-LEVEL SHORTWAVE RIDGE MOVES OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW
TEMPERATURES TO WARM UP. DUE TO LINGERING INSTABILITY THERE WILL BE
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING.
HOWEVER, DUE TO LIMITED WIND SHEAR, THUNDERSTORMS WILL STAY ON THE
WEAKER SIDE AND ONLY PRODUCE LIGHTNING, HEAVY RAIN, AND GUSTY WINDS.
ON WEDNESDAY THE WEAK UPPER-LEVEL RIDGE REMAINS OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA. WEDNESDAY AFTERNOON AN UPPER-
LEVEL SHORTWAVE WILL MOVE THROUGH AND BRING ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO MOST OF THE AREA WEDNESDAY AFTERNOON/EVENING.
DUE TO INCREASING WIND SHEAR FROM THE SHORTWAVE THERE WILL BE
ISOLATED STRONGER THUNDERSTORMS THAT HAVE THE POTENTIAL TO PRODUCE
SOME STRONG WIND GUSTS. SEE THE FORECAST CONFIDENCE & SCENARIOS
SECTION FOR DETAILS.
ON THURSDAY THE UPPER-LEVEL RIDGE SLIDES SLIGHTLY TO THE EAST AND
GIVES NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA SOUTHWEST
FLOW ALOFT. THIS WILL ALLOW WARM TEMPERATURES TO CONTINUE WITH
ANOTHER DAY OF SHOWERS AND THUNDERSTORMS. ON FRIDAY THE SOUTHWEST
FLOW TRANSITIONS TO MORE ZONAL (WEST TO EAST) FLOW. THIS WILL
KEEP TEMPERATURES STATUS QUO. FRIDAY AFTERNOON THERE WILL BE
ISOLATED SHOWERS AND THUNDERSTORMS. SATURDAY THROUGH MONDAY THERE
WILL BE ZONAL FLOW OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN
MONTANA. THIS KEEPS MOSTLY DRY WEATHER WITH WARM TEMPERATURES
AROUND FOR SATURDAY THROUGH MONDAY. ON SATURDAY STRONG MID AND
LOW-LEVEL WINDS WILL BRING WINDY CONDITIONS TO PORTIONS OF NORTH-
CENTRAL MONTANA. -IG
- FORECAST CONFIDENCE & SCENARIOS:
ON WEDNESDAY THERE IS A 30 - 50% CHANCE FOR THUNDERSTORMS ACROSS
MOST OF SOUTHWESTERN, CENTRAL, AND NORTH-CENTRAL MONTANA
EXCLUDING GLACIER COUNTY. ON WEDNESDAY THE STORM PREDICTION CENTER
HAS ISSUED A MARGINAL RISK (5% CHANCE FOR WIND GUSTS OF 58 MPH OR
GREATER WITHIN 25 MILES OF A POINT) FOR MOST OF NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA EXCLUDING GLACIER COUNTY. ON
WEDNESDAY THERE IS ENOUGH INSTABILITY FOR SEVERE THUNDERSTORMS BUT
THE LIMITING FACTOR IS WIND SHEAR. SOME WIND SHEAR IS BEING
PROVIDED BY AN UPPER-LEVEL SHORTWAVE THAT IS MOVING THROUGH. THE
TIMING OF THE SHORTWAVE WILL AFFECT HOW MUCH SHEAR WILL BE
AVAILABLE TO SUPPORT SEVERE THUNDERSTORMS. THE MOST LIKELY
SCENARIO IS THAT THERE WILL BE A FEW STRONG TO SEVERE
THUNDERSTORMS THAT PRODUCE STRONG WINDS.
ON THURSDAY THERE IS A 15 - 30% CHANCE FOR THUNDERSTORMS ACROSS MOST
OF SOUTHWESTERN, CENTRAL, AND NORTH-CENTRAL MONTANA EXCLUDING
GLACIER COUNTY. ON FRIDAY THERE IS A 30 - 45% CHANCE FOR
THUNDERSTORMS ACROSS MOST OF SOUTHWESTERN, CENTRAL, AND NORTH-
CENTRAL MONTANA EXCLUDING GLACIER COUNTY. ON THURSDAY AND FRIDAY
THERE IS ENOUGH INSTABILITY FOR STRONG THUNDERSTORMS BUT CURRENTLY
HI-RES MODELS HAVE TOO LOW OF WIND SHEAR TO SUPPORT STRONG
THUNDERSTORMS. -IG
AVIATION
01/00Z TAF PERIOD
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THIS
EVENING ACROSS NORTH-CENTRAL AND SOUTHWEST MT, WITH THE POTENTIAL
FOR AN ISOLATED THUNDERSTORM OR TWO IN CENTRAL MT. VFR CONDITIONS
WILL GENERALLY PREVAIL AT ALL TERMINALS THROUGHOUT THE TAF PERIOD,
WITH PERIODS OF MVFR CONDITIONS AND MOUNTAIN OBSCURATION POSSIBLE
DUE TO PASSING SHOWERS OR THUNDERSTORMS. RELATIVELY LIGHT WINDS
FROM THE SOUTHWEST ARE EXPECTED THROUGH TOMORROW, WITH CHANCES FOR
MORE SHOWERS AND THUNDERSTORMS TOMORROW AFTERNOON. -DZOMBA
HYDROLOGY
A FLOOD WARNING REMAINS IN EFFECT FOR A PORTION OF WESTERN
GLACIER COUNTY THROUGH THIS EVENING. SCATTERED
SHOWERS/THUNDERSTORMS ARE EXPECTED OVER THE NEXT FEW DAYS. MINOR
FLOODING IS EXPECTED TO LINGER AT LEAST THROUGH THIS EVENING. AS A
RESULT THE FLOOD WARNINGS HAVE BEEN EXTENDED THROUGH THIS
EVENING. IG/BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 50 75 50 77 / 20 30 20 10
CTB 48 72 47 73 / 10 0 0 0
HLN 51 73 50 76 / 60 70 70 30
BZN 44 74 46 76 / 30 70 50 10
WYS 33 70 36 72 / 20 10 10 0
DLN 43 71 44 75 / 60 70 40 0
HVR 50 79 51 80 / 10 10 40 20
LWT 45 73 46 75 / 10 60 60 40
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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