986
FXUS65 KTFX 050533
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1130 PM MDT Tue Jun 4 2024

Updated Aviation Discussion

.SYNOPSIS...

Very windy conditions continue through tonight across the area with
strong winds becoming more widespread across north-central and
central Montana through this evening. Winds gradually decrease on
Wednesday with warmer and drier conditions following through the
rest of the week with just a few showers and thunderstorms across
Southwestern Montana during the afternoons.

&&

.UPDATE...

The forecast is on track. Winds across the North-central and
Central plains will die down a bit overnight and then pick back up
tomorrow morning. Tonight mountain wave activity will keep strong
wind gusts occurring periodically along the Rocky Mountain Front
and adjacent plains. Along the Rocky Mountain Front strong wind
gusts will then continue through tomorrow morning. -IG

&&

.AVIATION...

05/06Z TAF Period

VFR conditions prevail through the period with some broken mid level
clouds across primarily southwest MT overnight and few isolated
showers near the continental divide before any lingering cloud-cover
diminishes Wednesday morning. Strongest mid-level westerly flow is
passing across the region tonight with associated mountain wave
turbulence persisting through the overnight period before gradually
decreasing on Wednesday. Surface winds have de-coupled from the
stronger flow aloft at many TAF sites, resulting in decreased wind
speeds but periodic gusts of 30-40kts are possible at most north-
central MT TAF sites with low-level wind shear common at all sites
through 15z Wednesday. Winds aloft and at the surface gradually
decrease Wednesday afternoon/evening. Hoenisch

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

&&

.PREV DISCUSSION...
/ISSUED 645 PM MDT Tue Jun 4 2024/

Key Points:

-Strong winds continue through Wednesday morning across North
Central and Southwestern Montana

-Warmer temperatures are expected later this week as upper level
ridging builds in with a few thunderstorms across Southwestern
Montana

Through Wednesday Strong winds continue across North Central and
Southwestern Montana today as a strong upper level jet streak
continues to push across the area. Wind gusts this afternoon so
far (as of 3PM) have been around 40-50 mph across the plains, with
scattered wind gusts of 60-70 mph wind gusts along and West of
I-15. Winds have been noticeably lighter across the Southwestern
Valleys, with winds generally gusting to around 20-30 mph. For the
rest of the evening, expect winds to continue to gust across the
plains, with winds generally peaking through this evening across
the plains as a combination of strong winds of 70-90 mph at 700
mb, generally around 5 to 6000 feet above the surface across the
plains, and mountain waves that will propagate across the plains
as these strong winds cross the Rocky Mountain Front. As these
mountain waves propagate across the plains, expect wind gusts to
reach and exceed 60 mph in areas that are hit with these waves.
These strong westerly winds will pose some threat of blow overs
of high profile vehicles, including trailers and RVs, especially
on North/South oriented roadways, along with scattered tree damage
now that the deciduous trees have leafed out.

Winds will remain gusty overnight as some of these mountain waves
continue across the plains, though outside these waves winds will
generally be a bit lighter as we get a slight inversion near the
surface. Winds will increase a bit again tomorrow morning as the
inversion breaks, but as the upper level jet streak moves eastward
and winds aloft weaken wind gusts tomorrow will be notably
lighter than they are today, with gusts generally topping out
around 30-40 mph across the plains, though a few gusts to 50 mph
will be possible east of the Highwood and Bears Paw Mountains.

Wednesday through next Monday Upper level ridging will begin to
build in across the Western US through the second half of the
week, which will bring generally warm and dry weather to North
Central and Southwestern Montana with the exception of a few
showers and thunderstorms across Southwestern Montana during the
afternoon. Temperatures will generally reach the upper 70s and low
80s across the plains, with a few valley locations reaching the
mid to upper 80s by Saturday as the ridge reaches its peak
strength. A weak disturbance will push in for Sunday and early
Monday, bringing increasing clouds and a chance for some rainfall,
especially across Southwestern Montana. Most of this rain will
generally be light to moderate rainfall, with a few convective
elements bringing some locally heavier rainfall as they push
through the area. Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  48  71  42  79 /  10   0   0   0
CTB  43  67  39  76 /  10   0   0   0
HLN  51  75  48  85 /  10   0   0   0
BZN  50  76  44  84 /  10   0   0   0
WYS  44  72  39  77 /  10   0   0   0
DLN  50  76  45  84 /  10   0   0   0
HVR  50  71  44  76 /   0   0   0   0
LWT  47  66  42  75 /  10   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until noon MDT Wednesday for Bears Paw
Mountains and Southern Blaine-Big Belt, Bridger and Castle
Mountains-Cascade County below 5000ft-East Glacier Park Region-
Eastern Glacier, Western Toole, and Central Pondera-Eastern
Pondera and Eastern Teton-Eastern Toole and Liberty-Fergus
County below 4500ft-Hill County-Judith Basin County and Judith
Gap-Little Belt and Highwood Mountains-Meagher County Valleys-
Northern Blaine County-Northern High Plains-Snowy and Judith
Mountains-Southern High Plains-Southern Rocky Mountain Front-
Upper Blackfoot and MacDonald Pass-Western and Central Chouteau
County.

&&

$$

http://www.weather.gov/greatfalls