042
FXUS65 KGGW 250040
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
640 PM MDT Wed Apr 24 2024

.DISCUSSION...

KEY MESSAGES:

1) Warm and dry weather in store through Thursday afternoon, with
gustier winds this afternoon creating elevated to critical fire
weather conditions.

2) Thursday evening, a frontal system and moderate instability
leading to a 30% chance of thunderstorms south of I-94, with
greatest risk of hail remaining in extreme southeast Montana.

3) Remainder of the week introduces daily chances of precipitation
and near-normal temperatures.

MIDDAY UPDATE:

See fire weather section for Red Flag Warning issuance today,
with forecast on track except for RH trending lower and winds
slightly higher than the previous forecast.

-Zanker
WEATHER PATTERN OVERVIEW:

A ridge off in the Dakotas keeps the region under southwest flow
aloft today, leading to calm weather and temperatures as much as
15 to 20 degrees above average. Winds increase (as high as 20 mph
sustained) across far northeast Montana, but RH values quickly
increase as night time creeps in; conditions remains under Red
Flag conditions.

Thursday, a developing surface low in the Great Plains will form
along a surface boundary/front that extends north into eastern
Montana. The NBM currently places this boundary near the
Yellowstone River Valley by Thursday afternoon. This front, though
not a textbook dry-line, is dictated more by a more moist airmass
south of I-94. Throughout the day, low and mid-level moisture
transport will increase instability in this region. As these
levels moisten and daily convection initiates, isolated, discrete
thunderstorms will develop east of the aforementioned boundary,
but will quickly diminish as the cells move into less-favorable
storm environments.

From Friday, upper-level troughing over the region will brings
temperatures back down into near-normal territory (upper 50s to
low 60s) with increased chances of rain showers (20-50%). By
Sunday, upper flow aloft returns from the southwest, bringing
minimal chances for precipitation and an increasing trend for
temperatures.

CONFIDENCE AND POTENTIAL DEVIATIONS FROM BASE FORECAST:

Only potential deviation in the forecast will be for Thursday. Any
shift in the boundary will dictate instability values for
locations south of I-94.

-Enriquez


&&

.AVIATION...

LAST UPDATED: 0030Z

FLIGHT CAT RANGE: VFR

DISCUSSION: Aside from some high cirrus, expect mostly dry
conditions through Thursday morning.

For Thursday afternoon, Scattered showers and isolated thunderstorms
develop south and east of KGDV and will impact it and KSDY
through through the night into Friday. Chance of getting hit by
rain in any given hour look to be around 20-40% and will be
handled by Prob30s through Friday. More limited chances for
thunder are confined to a range of about 23-03Z Thursday evening
for these two sites and will likely not appear as Prob30s until
around then if at all.

SFC WIND: S to SE at 5 to 15kts through the evening. Becoming calm
to light and variable after midnight. Shifting to the northwest at
5 to 15 kts Late Thursday mroning through the evening.

GAH


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM MDT this evening for Fort Peck
Reservation and Daniels/Roosevelt/Sheridan Counties-Northern
Valley and Northern Phillips Counties.

&&

$$

weather.gov/glasgow