497
FXUS65 KTFX 151745
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1145 AM MDT Wed May 15 2024

Updated Aviation Discussion

.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.

&&

.UPDATE...

Some slight adjustments were made to the afternoon precipitation
chances along our northeastern zones to reflect updated model
guidance. Wind gusts along the Rocky Mountain front were increased
through midnight tonight using the latest hi-res model guidance
to better reflect the observed trends. Otherwise no major changes
were made to the going forecast.

-thor

&&

.AVIATION...
15/18Z TAF Period

VFR conditions prevail across north-central and southwest MT through
Thursday morning with a gradual increase in west-northwest flow
aloft bringing some periods of increased mid-high level clouds while
a weak disturbance tracks east across southern AB/SK tonight. A few
showers in association with the disturbance could affect the KHVR
terminal tonight with some lower VFR ceilings and terrain
obscuration possible near the Bears Paw. Breezy west to northwest
surface winds develop this afternoon and gradually decrease late
this evening and overnight. The next disturbance tracks east into
the Northern Rockies on Thursday for more widespread windy
conditions. Hoenisch

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.

&&

.PREV DISCUSSION...
/ISSUED 500 AM MDT Wed May 15 2024/

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  71  50  77  51 /  10  20  20  20
CTB  70  50  74  45 /  10  10  20  20
HLN  74  52  81  52 /  10  10  10  10
BZN  70  42  79  45 /   0  10  10  10
WYS  63  34  68  37 /   0   0  20  10
DLN  69  43  76  46 /   0   0   0   0
HVR  73  49  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