185
FXUS65 KTFX 180221
AFDTFX

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


.SYNOPSIS...

Strong and gusty winds behind a cold front will continue into
this evening across much of North Central, Central, and Southwest
Montana. Scattered showers with a few thunderstorms will also
diminish through midnight. Gusty, but not quite as strong, winds
will return to the region for Saturday, with a chance for mainly
mountain showers. A disturbance will then bring more widespread
shower activity to the area for Sunday, with cooling temperatures
and a chance for thunderstorms as well.

&&

.UPDATE...

Strong, gusty winds associated with today`s Pacific shortwave and
attendant cold front are diminishing this evening, while
scattered showers continue over much of Central/North-central MT.
The loss of diurnal heating should preclude higher end gusts from
transferring to the surface, but winds may gust up to 40 mph in
spots through midnight or so. Colder air aloft has resulted in
some light mountain snow, mostly over the Little Belt Mountains
and the higher terrain along the Rocky Mountain Front. Snowfall
amounts for tonight will be light and impacts are expected to be
minimal. The current forecast handles things reasonably well, so
no updating will be needed this evening. - RCG

&&

.AVIATION...
18/00Z TAF Period

Scattered shower/thunderstorm activity, most numerous over
Central/North-central MT, will diminish through 18/06Z, though at
least some shower activity will persist into the overnight hours
along the Continental Divide and the plains. Gusty west to
northwesterly winds will also begin to diminish with the loss of
diurnal heating, but brief gusts up to and exceeding 50 kts can be
expected, particularly during showers/storms through 18/04Z. Breezy
conditions continue overnight tonight and Saturday but will
generally be less than 30 kts. Mountain wave turbulence and
instances of low level wind shear will be present through 18/12Z.
- RCG

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

&&

.PREV DISCUSSION...
/ISSUED 619 PM MDT Fri May 17 2024/

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

&&

.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