415
FXUS65 KGGW 032117
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
317 PM MDT Mon Jun 3 2024

.DISCUSSION...

KEY MESSAGES:

1)Scattered showers and thunderstorms moving through tonight may
produce an isolated severe wind gust to 60 mph between 5pm and
11pm.

2) High winds or near high winds are expected at times over the
Little Rockies including on Highway 191 south of Malta late
tonight through Wednesday morning.

3) Gusty west winds tonight through Wednesday evening will affect
NE Montana area wide and may affect activities on Fort Peck Lake
through that period.

WEATHER PATTERN OVERVIEW:

An upper low will track across the northern Rockies and lift into
Saskatchewan into Tuesday. Scattered showers and isolated thunder
will continue tracking west to east tonight. The latest HREF
ensemble wind gust guidance suggests convection tonight may bring
about wind gusts to 60 mph, and the SPC has placed much of NE
Montana under a high risk for Severe Weather for Day 1.

Gusty west winds look to continue Tuesday and Wednesday across NE
Montana, leading to impacts on Fort Peck Lake. Thus, have issued a
Lake Wind Advisory from midnight tonight through Noon Wednesday.
Over the Little Rockies, latest higher resolution models suggest
near high wind periods both Tuesday morning and again late Tuesday
night into Wednesday morning with a little break in between. HREF
ensemble soundings show 50 to 65 kt winds above 850mb over the
Little Rockies for several hours Tuesday morning with a decrease
Tuesday afternoon, but these winds return Tuesday evening and
continue until Wednesday morning. Given that it would not take
much for this to mix to the surface over higher terrain,
determined the risk justifies hoisting a High Wind Warning for SW
Phillips County from midnight tonight through Noon Wednesday.

Ensembles show ridging beginning to better influence the western
CONUS extending into the Northern High Plains with warmer and
drier weather conditions for the second half of the week.

FORECAST CONFIDENCE and DEVIATIONS:

Gusty winds were added to the thunderstorm attributions in the
weather grids for tonight given the short term support. In
addition, have blended in a little NBM 90 to baseline to nudge
winds up a bit given the anomalous event relative to climatology
per EFI Shift of Tails signals showing up in the western zones for
the coming event.

For Thursday and beyond have opted to stay close to baseline and
ensemble means capture the pattern well reflecting warmer and
drier conditions with the associated ridge.


&&

.AVIATION...
Scattered showers and isolated thunderstorms will roll through the
area tonight. VFR is expected but MVFR/IFR ceilings and
visibilities are possible associated with steadier thunderstorms
tracking directly over a taf site. Look for west winds increasing
tonight to 15 to 25 kts, gusting to 40 kts through Tuesday.


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from midnight tonight to 10 PM MDT Wednesday
for Central and Southeast Phillips-Central and Southern Valley-
Garfield-McCone-Petroleum.

High Wind Warning from midnight tonight to noon MDT Wednesday
for Southwest Phillips.

&&

$$

weather.gov/glasgow