236
FXUS65 KTFX 090548
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1148 PM MDT Sat Jun 8 2024

Aviation Section Updated

.SYNOPSIS...

After a dry but slightly breezy day across the area today, showers
and thunderstorms will develop across Southwestern Montana on
Sunday, bringing a few strong wind gusts and localized heavy rain
to the area. The week will start out a bit on the breezy side, but
building upper level ridging will lead to a warm and dry second
half of the week.

&&

.UPDATE...

No adjustments were made to the forecast tonight beside lowering
overnight minimum temperatures a tad bit due to some radiational
cooling in the Southwest Valleys. Other than that, the forecast
remains on track. -Wilson

&&

.AVIATION...

09/06z TAF Period

VFR conditions continue through the beginning of the TAF period with
conditions having potential to degrade across Southwest Montana late
Sunday afternoon through the overnight hours Sunday. Thunderstorms
are likely to develop between the 09/20z and 10/06z period for
Southwest Montana airfields, but quickly move through with some
lingering rain showers behind the storms. Primary concerns for any
developed thunderstorm is lightning, gusty winds, small sized hail,
and a brief heavy downpour that can lower visibility. KBZN will need
to be monitored for low forecasted ceilings after the rain showers
move through the airfield tomorrow night into Monday morning.
Scattered rain showers move into Central Montana after the 10/00z
time frame into Monday morning. VFR conditions prevail for KCTB and
KHVR through the TAF period. Webb

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

&&

.PREV DISCUSSION...
/ISSUED 624 PM MDT Sat Jun 8 2024/

Key Points:

-Showers and thunderstorms Sunday afternoon across Southwestern
Montana, with a few showers across the Plains Sunday night and
Monday

-Breezy Monday through Wednesday with a few locations seeing
wind gusts over 45 mph

-Dry and mild after Monday

Through Monday While mostly clear skies continue across North
Central and Southwestern Montana this afternoon, an approaching
cold front is bringing a few clouds and isolated showers along the
Hi-Line this afternoon, along with gusty winds across the plains.
While any showers should remain confined to the areas north and
east of Havre, the surface cold front will continue to push a bit
further south through the rest of the day today, allowing a
slightly cooler air mass to spread across the North Central
Plains.

Moisture will begin to work into Southwestern Montana late
tonight and Sunday, which will help to kick off showers and a few
thunderstorms across the Southwest Sunday afternoon and evening.
Given that most of the storm bases will be 6-8000 feet above the
surface with dry air below them, we will have to watch for some
gusty outflow winds, which has prompted the Storm Prediction
Center to highlight portions of Southwestern Montana with a
marginal risk for severe wind gusts (5% chance within 25 miles of
any point). The other thing that will need to be watched will be
the chance for a few areas of heavy rain from these storms, but
this threat should be isolated and given the recent dry spell
soils should not have an issue absorbing the rain that falls with
these storms. Storms will reach the plains on Monday as the
southwest dries out, but these storms will not have much
opportunity to cause any issues other than some lightning strikes.
With that said, Monday will be a breezy day as deep mixing allows
some 40-50 mph winds aloft to occasionally reach the surface.

Tuesday through next Saturday Tuesday will be another gusty day
across North Central and Southwestern Montana as a weak shortwave
moves through the area. As this shortwave moves through, deep
mixing of the boundary layer is expected once again, which will
help bring winds of 30-50 mph to the surface once again during the
day. Winds will begin to die down for Wednesday as this system
moves east and as upper level ridging begins to build across the
Western US. This ridge will then remain across the Western US
through the end of the week, keeping us warm and dry. Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  73  53  76 /  10  10  60  40
CTB  40  67  48  73 /   0  10  40  30
HLN  47  77  56  79 /   0  30  70  40
BZN  45  75  52  76 /   0  40  70  60
WYS  44  75  47  69 /   0  60  80  70
DLN  46  76  51  75 /   0  60  70  30
HVR  44  72  51  74 /  10  10  50  50
LWT  44  72  50  72 /  10  10  70  50

&&

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

$$

http://www.weather.gov/greatfalls