354
FXUS65 KTFX 151928
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
128 PM MDT MON SEP 15 2025
KEY MESSAGES
- UNSETTLED WITH NEAR AVERAGE TEMPERATURES EXPECTED TODAY AND
TUESDAY.
- WARMER AND DRIER WEATHER RETURNS FOR THURSDAY AND FRIDAY.
- SHOWER AND THUNDERSTORM CHANCES RETURN FOR SATURDAY.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
BROAD UPPER LEVEL TROUGHING OVER THE AREA TODAY HAS RESULTED
NOTICEABLY COOLER TEMPERATURES ACROSS THE AREA COMPARED TO
YESTERDAY, WITH MANY LOCATIONS AROUND 5 TO 10 DEGREES COOLER THAN
THEY WERE YESTERDAY AT THIS TIME. WITH THE UPPER LEVEL LOW AROUND,
EXPECT A MIX OF CLOUDS AND SUN THIS AFTERNOON, WITH A FEW RAIN
SHOWERS DEVELOPING LATER THIS AFTERNOON AND EVENING. THIS TROUGH
WILL SHIFT EASTWARD A BIT OVERNIGHT TONIGHT AND TUESDAY, BUT
NORTHERLY FLOW WILL KEEP US ON THE COOL SIDE ON TUESDAY.
UPPER LEVEL RIDGING BUILDING INTO THE AREA ON WEDNESDAY WILL
BRING AN END TO THE SHOWERS AND WILL ALLOW TEMPERATURES TO CLIMB
BACK ABOVE AVERAGE A LITTLE BIT FOR THE SECOND HALF OF THE WEEK.
THE WARMTH WILL PEAK ON SATURDAY AS SOUTHERLY FLOW DEVELOPS AHEAD
OF OUR NEXT UPPER LEVEL TROUGH, WHICH WILL BRING RENEWED CHANCES
FOR SHOWERS ALONG WITH SOME BREEZY WINDS FOR THE WEEKEND AND EARLY
NEXT WEEK.
- FORECAST CONFIDENCE & SCENARIOS:
LOW CHANCE FOR HEAVY DOWNPOURS THROUGH TUESDAY:
AS OUR UPPER LEVEL TROUGH CONTINUES TO SLOWLY PUSH THROUGH THE
AREA TODAY AND TUESDAY, EXPECT A FEW SHOWERS AND POSSIBLY
THUNDERSTORMS TO DEVELOP, ESPECIALLY LATER DURING THE AFTERNOON
HOURS TODAY AND TUESDAY. FOR THE MOST PART, THESE SHOWERS AND
STORMS SHOULD NOT BE OVERLY HEAVY TODAY SINCE THEY WILL BE DRIVEN
PRIMARILY BY LARGE SCALE LIFT, BUT MODEL SOUNDINGS TOMORROW
AFTERNOON SUGGEST SOME CONVECTIVE INSTABILITY WILL DEVELOP
TOMORROW AFTERNOON AS DAYTIME HEATING CONTRASTS WITH COLD AIR
ADVECTION OCCURRING ALOFT. THIS COULD BRING SOME LOCALIZED HEAVY
RAINFALL, WHICH COULD RESULT IN SOME PONDING OF WATER IN LOW LYING
OR POOR DRAINAGE AREAS.
WINDS SATURDAY NIGHT - EARLY NEXT WEEK:
AS OUR NEXT UPPER LEVEL RIDGE BREAKS DOWN OVER THE WEEKEND, ZONAL
UPPER LEVEL FLOW ALONG WITH A DEVELOPING LEE TROUGH WILL RESULT IN
THE DEVELOPMENT OF A MODEST PRESSURE GRADIENT THAT RESULTS IN SOME
GUSTY WINDS ACROSS THE AREA SUNDAY AND MONDAY. WHILE WINDS DON’T
LOOK OVERLY STRONG, THE NBM IS CURRENTLY SHOWING GENERALLY A
25-40% CHANCE OF 45 MPH ACROSS MOST OF THE AREA NORTH OF I-90.
WHILE NOT UNSEASONABLE, IT WILL BE A NOTED CHANGE FROM THE
RELATIVELY LIGHT WINDS WE HAVE BEEN EXPERIENCING AS OF LATE.
LUDWIG
AVIATION
15/18Z TAF PERIOD
VFR CONDITIONS WILL PREVAIL DURING THE DURATION OF THIS TAF PERIOD
OUTSIDE OF DURING ANY THUNDERSTORMS. AT THE KGTF, KLWT, AND KEKS
TERMINALS THERE IS A 30 - 60% CHANCE FOR RAIN SHOWERS DURING THE
MAJORITY OF THIS TAF PERIOD. AT THE KBZN, KHLN, AND KCTB TERMINALS
THERE IS A 20 - 40% CHANCE FOR SHOWERS DURING THE MAJORITY OF
THIS TAF PERIOD. AT THE KBZN, KEKS, KHLN, AND KWYS TERMINALS THERE
IS A 15 - 40% CHANCE FOR THUNDERSTORMS BETWEEN NOW AND 16/06Z. AT
THE KGTF, KCTB, KHVR, AND KLWT TERMINALS THERE IS A 15 - 30%
CHANCE FOR THUNDERSTORMS TO FORM BETWEEN 16/00Z AND 16/09Z. AT THE
KEKS AND KWYS TERMINALS THERE IS A 10 - 20% CHANCE FOR FOG TO
FORM BETWEEN 16/10Z AND 16/14Z. ANY THUNDERSTORMS WILL PRODUCE
FREQUENT LIGHTNING A BRIEF HEAVY DOWNPOUR, AND GUSTY, ERRATIC
WINDS. DURING THUNDERSTORMS THERE WILL BE BRIEF PERIODS OF
MOUNTAIN OBSCURATION. -IG
PRELIMINARY POINT TEMPS/POPS
GTF 52 74 47 79 / 60 20 0 0
CTB 49 73 44 78 / 40 10 0 0
HLN 50 72 48 78 / 60 40 0 0
BZN 44 67 43 74 / 70 60 10 0
WYS 32 62 31 68 / 30 40 10 0
DLN 40 66 40 72 / 20 20 0 0
HVR 52 77 48 77 / 20 10 0 0
LWT 48 69 46 74 / 70 60 20 10
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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