FXUS65 KTFX 191313

AFDTFX



Area Forecast Discussion

National Weather Service Great Falls MT

713 AM MDT Tue Aug 19 2025



.KEY MESSAGES...



 - Hot temperatures expected today with temperatures reaching the

   low to mid 90s across the lower elevations.

 - Isolated showers and thunderstorms this afternoon and evening,

   some could produce some gusty winds.

 - Not as warm after Wednesday through the weekend, but 

   temperatures trend back upwards for the weekend.



&&



.UPDATE...



A building upper ridge and associated H5 height rises will 

support temperatures rising well above average across the region 

today. The thought is that the peak of the heat will only be

today, with overnight relief tonight before a warm, but not overly

hot day Wednesday. Hence, no Heat Advisories are being considered

at this time. 



After peak heating today attention then turns to a wave

progressing through the southwesterly flow aloft across western

and North-central Montana this evening. This looks to result in at

least widely scattered showers and thunderstorms, initially west 

of the Continental Divide early this evening, which spread across 

North-central Montana late evening into the overnight. The depth 

of the sub-cloud layer and overall magnitude of DCAPE should help 

downdrafts to overcome the building (and largely shallow) surface 

inversion over the plains tonight, hence resulting in a threat for

strong wind gusts from the most robust thunderstorms. 



Overall minor changes were made this morning to account for

current trends. -AM



&&





.DISCUSSION... /Issued 403 AM MDT Tue Aug 19 2025/ 



 - Meteorological Overview:



Upper level ridging building across the Western US will bring 

increasing temperatures to the Treasure State today and Wednesday,

with temperatures rising into the 90s for most lower elevation 

locations this afternoon. While most of us will be dry today, a 

few isolated showers and thunderstorms are expected to develop 

across the Plains late this evening. Depending on the timing of 

these storms, I can’t rule out a few strong to severe wind gusts. 

However, most of these should push through the area late in the 

evening as temperatures begin to fall for the night, resulting in 

an inversion that should keep wind gusts just above the surface. 

With that said, some localized higher elevations could still see 

some isolated gusts from these storms.



Our upper level ridge will begin to break down on Wednesday as an

upper level tough pushes through Alberta, which will keep our 

temperatures slightly cooler Wednesday afternoon, but will also 

result in increased wind gusts and a few isolated to scattered 

showers and thunderstorms in the afternoon. Again, some of the 

storms may produce some stronger wind gusts, particularly before 8

or 9PM when our inversion will set up again.



As we head into the later part of the week, upper level ridging 

will set up to our west, resulting in northwesterly flow aloft 

over us and high pressure at the surface. This will keep us fairly

dry and calm, with temperatures not quite as warm with highs 

generally in the 80s across the lower elevations. Ludwig



&&



.AVIATION...

19/12Z TAF Period 



The initial concern this TAF period will be for patchy smoke from

regional wildfires. Slant-range visibility reductions look to

be more common than surface visibility reductions through the day

today. 



Attention then turns to this evening and overnight, when a period

of showers and thunderstorms is forecast, mainly over the plains

of North-central Montana. Lightning and gusty erratic winds are

the main concern with thunderstorms that do form. 



Refer to weather.gov/zlc for more detailed regional aviation 

weather and hazard information.



&&



.FIRE WEATHER...



Fire weather concerns will continue through Tuesday and Wednesday 

with highs in the 90s expected across the plains and valleys across 

the region. Minimum RH values will range from the single digits to 

the mid teens with Tuesday expected to be the warmest and driest day 

of the week. Winds are less of a concern these days, however, an 

isolated afternoon dry thunderstorm cannot be ruled out which will 

keep fire weather concerns elevated until a cold front passes 

through late Wednesday into Thursday. -thor



&&



.PRELIMINARY POINT TEMPS/POPS...

GTF  96  60  92  55 /   0  30   0  20 

CTB  90  58  86  49 /  10  50  10   0 

HLN  96  60  92  56 /   0  20   0  20 

BZN  96  54  93  53 /   0   0  20  20 

WYS  86  47  85  42 /   0   0  20  20 

DLN  92  52  90  50 /   0   0  20  20 

HVR  96  62  93  55 /   0  40   0  20 

LWT  93  58  88  54 /   0   0   0  40 



&&



.TFX WATCHES/WARNINGS/ADVISORIES...

None.

&&



$$

http://www.weather.gov/greatfalls