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000
FXUS65 KGGW 212019
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
219 PM MDT Sun Apr 21 2024

.DISCUSSION...

KEY MESSAGES:

1) Strong winds and near critical fire weather concerns come in
on Monday.

2) Otherwise, a broad ridge pattern builds into the area this
week resulting in mostly dry and seasonable conditions.

WEATHER PATTERN OVERVIEW:

A much warmer day is in store ahead of the next quick moving cold
front tonight and associated low pressure system. Winds will be
switching direction to the west tonight, with high (80 percent)
confidence that wind gusts will reach or exceed 40 mph on Monday.
Very little precipitation accumulation, if any, will be associated
with this disturbance. The combo of wind and lack of
precipitation suggest near critical fire weather conditions, so a
Fire Weather Watch remains in place for much of the day Monday.
See fire weather section below for more details. A quieter pattern
quickly resumes on Tuesday with broad upper level ridging and no
major disturbances hinted at amongst ensembles through the rest of
the week.

CONFIDENCE AND POTENTIAL DEVIATIONS FROM BASE FORECAST:

Confidence is high for temperatures, low precipitation amounts and
the general wind pattern through the extended period. With regard
to near critical fire weather conditions moving into red flag
criteria Monday, moderate confidence continues to exist. No
departures were made from the NBM at this time, but the focus will
be on the accuracy of wind and humidity forecast values through
Monday night.

-Zanker/Stoinskers


&&

.AVIATION...

LAST UPDATED: 2030Z

FLIGHT CAT RANGE: VFR

DISCUSSION: A departing high pressure system will give way to a
cold front by this evening that primarily brings gusty west winds
and an increase in mid level clouds. There is a low (20%) chance
for a rain shower along the front at KSDY and KGDV from 03Z-09Z
tonight.

WIND: Southwest winds 10 to 20 knots, becoming west at 10 to 20
knots after 00Z, becoming northwest at 20 to 30 knots with gusts
to 40 kts after 16Z.


&&

.FIRE WEATHER...

A strong cold front will move through the area tonight. Wind
speeds and relative humidity as low as 15 percent are critical in
some areas today with south winds becoming west sustained between
15 and 25 mph, with gusts to 35 possible. Therefore, a Red Flag
Warning has been issued from now through 8 PM today. The latest
forecast guidance suggests wetting rain probabilities are low
(under 20%) and mainly north of the Missouri River. Northwest
winds of 25 to 35 mph will be widespread across the entire area
Monday, along with gusts to 50 mph. Over the past two weeks,
Dawson, Prairie and Wibaux counties have received around 30
percent of normal precipitation. Based on this, there is high (90
percent) confidence locations south of a line from the Little
Rockies to Wibaux will have critical conditions for fire weather
on Monday. This is in response to forecast winds reaching and/or
exceeding RH values during Monday afternoon. Therefore, a Red Flag
Warning has been issued, and is in effect for Zones 122, 135,
136, and 137 on Monday from 10 AM to 9 PM. By Tuesday, there will
be little change in RH, but winds back off considerably.


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 6 AM MDT Tuesday for Central and
Southeast Phillips-Central and Southern Valley-Garfield-McCone-
Petroleum.

Red Flag Warning from 10 AM to 9 PM MDT Monday for
Dawson/McCone/Prairie/Richland/Wibaux Counties-Southern
Petroleum and Southern Garfield Counties-The Little Rockies-The
Lower Missouri River Breaks including the Charles M Russell
National Wildlife Refuge.

Red Flag Warning until 8 PM MDT this evening for
Dawson/McCone/Prairie/Richland/Wibaux Counties-Southern
Petroleum and Southern Garfield Counties.

&&

$$

weather.gov/glasgow