547
FXUS65 KGGW 161948
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
148 PM MDT Mon Sep 16 2024

.DISCUSSION...

KEY MESSAGES:

1) Warm temperatures through Tuesday will give way to near average
temperatures afterward.

2) Scattered thunderstorms overnight, and then strong to severe
storms late Tuesday afternoon.

3) Western zones could see a significant rain event Tuesday night
through Thursday morning. Lower amounts for eastern zones.


WEATHER PATTERN OVERVIEW:
A warm front slowly moving across the area is creating enough
forcing to produce scattered mid clouds. These clouds are doing
their best to produce light rain and virga. As the upper low moves
closer, the low level jet and warm front will work together to
produce scattered, weak thunderstorms after 8 PM through about
noon Tuesday. One more warm day with dewpoints in the 50s and low
60s on Tuesday in tandem with the upper low and surface low will
aid in strong to severe thunderstorms developing from north to
south. There is moderate to high (50 to 70 percent) confidence of
storms developing between 5 PM Tuesday and 1 AM Wednesday with 0
to 6 km shear being around 30 to 40 knots and surface CAPE around
1000 to 2000 J/kg, according to the CAMs.

The initial thunderstorms will move through first, but as the
surface low and upper low remain overhead, moisture will continue
to get dragged into the area from the Pacific and Gulf of Mexico.
This will lead to precipitation amounts being rather high for
central Montana. An example is Zortman, where there is high (80 to
90 percent) confidence of greater than 1" of rainfall occurring
Tuesday night through Thursday morning, with moderate (40
percent) confidence of greater than 2".

Temperatures closer to seasonal average will settle across the
region behind the front starting on Wednesday. The upper level low
will depart to the northeast on Thursday taking the rain with it.
Temperatures will remain close to average through the end of the
weekend.

FORECAST CONFIDENCE & DEVIATIONS:

High confidence exists on above average temperatures occurring
today and Tuesday as well as the upcoming cooldown starting
Wednesday.

There is low to moderate confidence of strong to severe storms
occurring late Tuesday afternoon through the early overnight.

High confidence of rainfall greater than 1" occurring in western
Phillips and Petroleum county, with medium confidence of 1"
further east.


&&

.AVIATION...
Last Updated: 2045Z

Category: VFR, brief MVFR after 03Z.

Discussion: Weak showers this afternoon will give way to scattered
thunderstorms from around 03Z through 18Z Tuesday, which may bring
brief MVFR conditions in locations directly impacted by storms.

Winds: East southeast at 6 to 16 knots.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

weather.gov/glasgow