924
FXUS65 KTFX 172051
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
251 PM MDT Fri May 17 2024

.SYNOPSIS...

A gusty day is in store for the region as a Pacific cold front
progresses eastward this morning and early afternoon. Cooler
temperatures will be the theme this weekend into next week, with
opportunities for precipitation most days.

&&

.DISCUSSION...

Today and Tonight... Scattered showers and thunderstorms are
already underway across north-central and central Montana. The
chance for thunderstorms will continue through the rest of the
evening, diminishing by 9 PM for most locations and as late as
midnight for locations along the hi-line east of Havre. The risk
for any one thunderstorm turning severe is generally low,
however, some indications remain in the model soundings that
downbursts from decaying thunderstorms could throw out an isolated
60 mph gust. With regards to hail, the dry layer near the surface
persists in this round of updated model soundings so while pea-
sized hail may be possible in stronger storms, nothing beyond that
is expected. The wild card of the evening is that convective
models have been showing a marginal potential for cold air funnels
developing along the hi-line. While not expected to be a
significant concern this afternoon, a cold air funnel or two
cannot be ruled out.

Otherwise, for most of the region, gusty winds will continue
through the rest of the day with the strongest gusts tapering off
after sunset. Some gusty winds will continue through the night
for locations in central Montana including Judith Basin, Fergus,
and Meagher counties. -thor

This weekend... Large scale upper troughing will remain in place
across SW Canada and the far northern portions of the NW CONUS this
weekend, resulting in largely zonal flow aloft, with shortwaves
pivoting across the region at times. The end result is for
unsettled conditions remaining. Temperatures will be on the cooler
side, with opportunities for showers and perhaps a few
thunderstorms.

Sunday looks to be the day more favored for showers and
thunderstorms, as a robust shortwave pivots through the broad
troughing. Confidence in timing is not yet high, but the chance for
a tenth of an inch of precipitation Sunday into Sunday night is
largely greater than 50% across the region.

Next Week... Ensembles favor a continuation of unsettled conditions
heading into next week as large scale troughing remains in place
across much of the Pacific NW and Northern Rockies. Although
confidence is high that unsettled conditions will remain, specifics
with respect to timing and magnitude of any precipitation is murky
at best at this point. -AM

&&

.AVIATION...
17/18Z TAF Period

A Pacific cold front will continue east through eastern portions of
central and southwest MT early this afternoon with a few showers
occurring near the front while additional showers develop this
afternoon across primarily central and north-central MT. Greatest
concentration of showers this afternoon and evening will be along
northern portions of the continental divide including Glacier NP and
eastward along the Hi-line, where a few thunderstorms are also
possible. Mainly VFR conditions are expected with some brief MVFR
and local mountain obscuration in/near any showers or thunderstorms.
Winds will be the most widespread impact to aviation through this
evening with 35-45kt gusts likely at most terminals. Isolated
stronger gusts are possible over the mountains and in the vicinity
of showers. Strong westerly flow aloft across the Rockies will
maintain the risk for mountain wave turbulence until winds aloft
begin to relax later tonight.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  39  62  39  55 /  40  10  10  80
CTB  34  59  33  54 /  50  20  10  80
HLN  39  66  42  57 /  10   0  10  70
BZN  29  65  37  56 /  10   0  10  70
WYS  25  57  34  53 /  10   0  10  40
DLN  29  65  37  56 /   0   0  10  40
HVR  38  63  38  60 /  80  10   0  50
LWT  35  59  37  52 /  30   0  20  70

&&

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

$$

http://www.weather.gov/greatfalls