341
FXUS65 KTFX 150947
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
347 AM MDT Wed May 15 2024

.SYNOPSIS...

Above average temperatures return today and Thursday, ahead of a
return to more seasonable temperatures for Friday through at least
early next week. Winds will also be on the increase, with gusty
winds expected Thursday and Friday. Unsettled weather will
continue for the first half of next week, with periods of rain and
mountain snowfall expected.

&&

.DISCUSSION...


Key Points:

-A few thunderstorms are expected today, with the best chances
across Southwestern Montana

-Wet weather expected Tuesday, with cooler temperatures for the
rest of the week

Short term (through Tuesday)... Upper level ridging responsible
for the warm temperatures that we have had over the weekend will
begin to shift to the east today, but not before allowing for one
final day of warm temperatures in the 70s across North Central and
Southwestern Montana. As this ridge moves east, a shortwave
trough will begin to slide into the area from the west, which,
combined with the warm temperatures, will help kick off a few
showers and thunderstorms across the area, first across
Southwestern Montana with a few showers popping up across the
North Central plains. While these showers and storms should be
fairly run of the mill type cells, though forecast model soundings
across the plains do support the development of some disorganized
outflows that could produce wind gusts to 40 mph or so. Most of
these showers will dissipate after sunset, with just a few
lingering through the overnight.

A second, more widespread, round of showers and thunderstorms
will move through the area on Tuesday as a cold front pushes into
the area from Canada. Like tomorrow, most of these showers and
storms should be fairly benign, with just a few areas of breezy
winds as the storms pass. Behind these storms, noticeably cooler
air will work into the area, keeping highs in the low to mid 60s.
In addition, this cooler air will potentially be accompanied by a
return of widespread smoke and haze from the wildfires that have
begun to resurrect across Western Canada, but we will need to get
a bit closer to get a better grasp on how much smoke will work
into the area.

Extended (Wednesday through next Monday)... Expect seasonable
weather through the second half of the work week as upper level
ridging over the eastern Pacific keeps our upper level flow
westerly to northwesterly with a few weak disturbances moving
through the area. For the most part, these disturbances will
mostly just result in some periods of gusty winds Thursday and
Friday as a few rounds of cooler air work their way into the area,
but areas along and north of US 2 could see a few periods of
light rainfall Thursday and Friday as these disturbances move
through. Looking towards the weekend, there seems to be some
consensus that a slightly more notable trough will work its way
into the Northern Rockies, which could help spur some more
widespread rain and mountain snow to at least parts of the area
for the weekend. Ensembles diverge for the start of the new work
week, though the overall pattern appears to remain unsettled as we
head into next week. Ludwig

&&

.AVIATION...
15/06Z TAF Period

VFR conditions will prevail across all terminals through the
1506/1606 TAF period, with clearing skies through 12z Wednesday
across most terminal. While a low probability, a period of patchy
fog may occur as skies clear early Wednesday morning, particularly
within the wind sheltered valleys of Southwest and Central Montana.
A period of clear to scattered upper level cloudiness is then
expected through the early afternoon hours on Wednesday before CIGS
begin to lower once again with the arrival of mid-level moisture,
especially over the plains of Central and North Central Montana. A
few rain showers can not be ruled out over the plains from the late
afternoon through evening hours with the arrival of this mid-level
moisture, but VFR conditions are still expected to prevail beneath
any shower. Limited mountain obscuration is expected over the next
24 hours, with most obscuration occurring prior to 12z Wednesday. -
Moldan

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

&&

.HYDROLOGY...

A small stream Flood Advisory remains in effect for Belt Creek in
southeastern portions of Cascade County, generally from just
north of Neihart to Sluice Boxes State Park.

As of Tuesday afternoon, the Monarch Fire Department continues to
report that the creek is coming out of its banks in this area, as
fallen trees in the creek are causing a minor log jam. Additional
showers this afternoon have also aided in the water running out of
the creek in locations that normally do not flood. The flood
advisory will remain in effect until the water returns back to
the creek or the impact has been reduced.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  71  49  77  51 /  10  20  20  20
CTB  70  48  74  45 /  10  10  20  20
HLN  74  52  81  52 /  10  10  10  10
BZN  70  43  79  45 /   0  10  10  10
WYS  63  35  68  37 /   0   0  20  10
DLN  69  43  76  46 /   0   0   0   0
HVR  73  48  77  48 /  10  40  50  30
LWT  66  46  74  47 /  20  20  30  30

&&

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

$$

http://www.weather.gov/greatfalls