596
FXUS65 KTFX 111006
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
406 AM MDT Thu Jun 11 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Drier today with decreasing clouds and seasonable temperatures
   by this afternoon.

 - Showers and a few thunderstorms develop late Friday with a cold front
   that brings cooler temperatures and another round of showers
   into Saturday.

 - Warmer and drier weather develops early next week.

&&

.DISCUSSION...
/Issued 250 AM MDT Thu Jun 11 2026/

 - Meteorological Overview:

Upper level troughing shifts east into the Northern US Plains states
today with a drier WNW flow aloft developing in its wake across MT.
Early morning clouds and showers lingering near the central MT
mountains will exit by late morning with mainly dry and seasonably
warm conditions across the the area by this afternoon. Afternoon
instability and residual moisture may lead to some isolated shower
and thunderstorm development with areas along and north of US-2
most likely to see some of this activity through early this evening.

After a dry start on Friday the risk for showers and thunderstorms
increases again Friday afternoon as the next shortwave in NW flow
moves into the Northern Rockies from BC with another disturbance
dropping south from AB across the area Friday night through
Saturday. A cold front moves south across the area later Friday
through Friday night, providing enough cooling to lower snow levels
as low as 6500 ft across the central MT mountains with showers
continuing through Saturday morning. Surface high pressure (~1025MB)
also slides south behind the front Friday night with a period of gusty
north winds likely as this moves south across the Plains Friday
evening and through the SW MT Valleys Friday night.

Longer range model consensus amplifies upper ridging through BC
Sunday and Monday, resulting in mainly dry conditions with
temperatures warming above seasonal averages early next week. This
does look to de-amplify later next week with the warmest
temperatures peaking on Tuesday. Hoenisch

 - Forecast Confidence & Scenarios:

High resolution models key on a few thunderstorms developing
Friday afternoon across western portions of north-central MT with
scattered showers and storms tracking ESE through Friday evening.
Instability/CAPE is marginal (<1000J/Kg) but fast mid level winds
and the timing of a Canadian cold front Friday afternoon/evening
could support some stronger wind gusts with cells.

After a relatively cool day Saturday, decreasing clouds Saturday
night will allow overnight temperatures to reach the mid-upper 30s for
many locations. There is 30-50% probability for minimum temperatures
of 36F of less at Bozeman, Dillon, Lewistown and Cut Bank with lower
(10-15%) probabilities at Helena, Great Falls and Havre. Hoenisch

&&

.AVIATION...
11/12Z TAF Period

Moist N/NW flow continues to produce widespread ceilings around
4000-6000ft agl and mountain obscuration this morning with a few
light showers across eastern terminals. Expect clouds to decrease
from west to east after 16z. A few showers develop and track east
near the KCTB and KHVR terminals this afternoon, otherwise mainly
dry conditions are expected this afternoon/evening with breezy
west winds also diminishing this evening. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  71  44  70  40 /   0   0  40  80
CTB  67  41  62  35 /   0   0  80  60
HLN  72  44  74  42 /   0   0   0  60
BZN  70  39  74  38 /   0   0   0  40
WYS  62  29  70  31 /   0   0   0   0
DLN  71  38  76  37 /   0   0   0  10
HVR  70  43  67  37 /  30  20  50  20
LWT  66  40  66  37 /  20   0  20  70

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$
http://www.weather.gov/greatfalls