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000
FXUS65 KGGW 230249
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
849 PM MDT Fri Sep 22 2023

.DISCUSSION...

EVENING UPDATE:

Most convective storms from this afternoon have diminished,
becoming predominately stratiform rain by now. The 00Z HRRR has a
good representation of the showers moving in from the Dakotas. The
afternoon`s update of the PoP grids seemed reasonable to me, so no
adjustments were made there, aside from slightly increasing the
value slightly over the northwestern zones.

The main update made was the visibility grids as many locations
have hovered near 6SM with brief drops in visibility below that.
As such, I did a broad brush of 6SM visibility for most of the CWA
by the morning, so as to include the mention of patchy fog.

No changes to the Lake Wind Advisory as sites around Fort Peck are
occasionally gusting over 20 mph. Will let the next shift to
decide on canceling or expiring at 6 AM MDT.

-Enriquez

PREVIOUS DISCUSSION:

Tonight through Saturday Night:
Showers and a few thunderstorms have remained persistent today
from the Little Rockies into Petroleum and western Garfield
counties, but little to nothing has fallen elsewhere. Looking at
the upper-level divergence zone and axes of dilatation at the
surface, precipitation production has been funneled into this
area, despite a record high amount of precipitable water from this
morning`s sounding at Glasgow. The remaining moisture to be seen
should become more widespread, but generally be light and
scattered shower activity. Thus, forecast rain totals have
decreased, especially for Valley and Phillips counties where
amounts around tenth of an inch or less will be common. However,
there is high confidence in low clouds and patchy fog hanging
around through at least Saturday morning. Easterly winds
gradually start to subside tonight as the system moves away,
bringing an expected end to the Lake Wind Advisory.

Sunday and Beyond:
A distinct dry and warm period is becoming more clear for the
first half of the upcoming week, with some locations likely
reaching back into the 80s Monday and Tuesday. Then, the
uncertainty lies in how a developing trough over the Pacific
Northwest develops, which has the potential to bring moisture and
more seasonal temperatures by next weekend.

-Zanker



&&

.AVIATION...
UPDATED: 0245Z

FLIGHT CAT RANGE: VFR - IFR

DISCUSSION: Shower activity becoming more widespread, moving in
from the Dakotas and toward the northwest. KGDV and KSDY will have
the greatest threats with visibility dropping to IFR conditions at
times. Patchy fog will be prevalent most of the night and into the
morning.

WINDS: East winds shifting to more northeast winds at 10-15 kts
after midnight. By sunrise, locations south of the Missouri River
will be light and variable, while locations north of the Missouri
will still see 10-15 kt northeasterlies.

-Enriquez

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 6 AM MDT Saturday For Fort Peck Lake
for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow