Geraldine, Montana Weather Forecast Discussion

933
FXUS65 KTFX 051053
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
453 AM MDT Fri Sep 5 2025
Aviation Section Updated.
.KEY MESSAGES...
- Dry conditions are expected for most locations through the
  weekend with temperatures warming up to around 10 degrees above
  average by Sunday.
- Isolated shower and thunderstorm activity will slowly increase
  over the southwest and along the Continental Divide this
  weekend.
- Monsoon moisture increases areawide next week and brings daily
  rounds of widely scattered showers and thunderstorms for much of
  the workweek.
&&
.DISCUSSION...
/Issued 302 AM MDT Fri Sep 5 2025/
- Meteorological Overview:
Partial clearing skies, radiational cooling, and decreasing winds
may encourage some early morning patchy fog and or frost
development over portions of the plains and the more wind
protected valleys of Central and Southwest Montana. Otherwise,
ridging aloft will bring mostly dry conditions and warming
temperatures through the weekend. Troughing over the Pacific
Northwest will begin to flatten the ridge some this weekend while
moisture and weak disturbances begin to encroach the Northern
Rockies. The main impact from this will be a day to day increase
of isolated shower and thunderstorm/lightning activity over the
dry southwest, mostly on Sunday.
Ensembles favor the Pacific Northwest trough deepening and
sending additional moisture into the region early next week via a
high amplitude southerly flow aloft. Afternoon temperatures will
warm to around 10 to 15 degrees above average through the mid-week
period while daily rounds of widely scattered shower and
thunderstorm activity increase areawide with the added moisture
and instability. - RCG
- Forecast Confidence & Scenarios:
Shower and thunderstorm activity increasing this weekend into
next week...
Monsoon moisture slowly returns to the Northern Rockies this
weekend into next week. Isolated shower and thunderstorm activity
will initially impact southwestern areas south of I90 Saturday
afternoon and night. The primary concern will be for some storms
offering lightning but little rainfall given dry surface
conditions. Shower and thunderstorm activity expands north and
eastward on Sunday, but Southwest Montana and areas along the
Continental Divide will see the most activity. There will be more
productive storms on Sunday, but higher CAPE in the 500 to 1,000
J/kg range will be capable of producing more lightning than on
Saturday. Additionally, some storms may still be on the dry side
with strong erratic winds gusts due to minimum RHs in the 20s and
lower in some cases.
Deeper southerly flow will bring periods of widely scattered
showers and thunderstorms to all areas Monday through Wednesday.
Precipitable water values nearing the 0.75 to one inch mark
combined with afternoon instability and forcing from the trough
may be sufficient for the development of a few stronger storms
Tuesday into Wednesday with gusty winds, brief downpours, and some
hail in addition to lightning. Cooler, breezy, and showery
conditions are expected towards the end of the workweek behind the
weakening and departing trough. - RCG
&&
.AVIATION...
05/12Z TAF Period
Isolated instances of patchy fog will be the primary concern through
05/15Z, most notably in the KCTB area. Otherwise, ridging aloft will
build in and bring general VFR conditions and light winds for the
duration of the TAF period. The greatest concentration of smoke and
haze from regional wildfires is expected to shift southward into
Southwest Montana today with impacts mostly limited to compromised
slantwise visibility and some surface visibility reductions in the 6
to 9 sm range. - RCG
Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF  72  41  81  49 /   0   0   0   0
CTB  71  39  78  44 /   0   0   0   0
HLN  77  46  84  53 /   0   0   0   0
BZN  75  40  83  49 /   0   0   0   0
WYS  72  32  77  40 /   0   0   0  10
DLN  75  42  82  49 /   0   0   0  10
HVR  69  39  77  44 /   0   0   0   0
LWT  67  39  76  47 /   0   0   0   0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls

NWS TFX Office Area Forecast Discussion