Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 202107
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
307 PM MDT Fri Jul 20 2018

.DISCUSSION...

With an upper level ridge over the central Rockies and northern
high plains region and an upper level low pressure trough moving
over British Columbia and Washington state, the steering flow will
become enhanced from the west-southwest over our area through this
weekend. Unfortunately, model precip data has been inconsistent
and disagreeable. Tried to blend the most realistic and likely
solutions.

Tonight, satellite imagery from this afternoon already shows
healthy cloud development near the western edge of our CWA.
Expecting some of those clouds to develop into isolated to
scattered thunderstorms and then move through northern portions of
our CWA. Some of the initial outflow from those storms could
easily reach Fort Peck Lake as early as 6:00 pm. Felt it was best
to begin the Lake Wind Advisory at 6:00 pm as well to cover that
possibility. Otherwise, persistent winds from southeast around 15
to 20 mph are expected through Saturday morning. Could see some
gusts up to 30 mph.

Saturday through Saturday night, a cold front will approach the
area from the west, and compressional warming seems to be ready to
enhance the development of thunderstorms. SPC has upgrade our
eastern zones into a slight risk area for severe thunderstorms.
Sometime between 6 pm and 9 pm, a line of thunderstorms is
expected to develop generally Scobey through Poplar and through
Glendive. Severity of thunderstorms development could be quick and
large hail and damaging wind will be possible as the line of
storms move toward North Dakota.

Sunday, after the cold front moves through the area, any lingering
showers from the Saturday storms will continue clearing away
toward the east as clear and sunny skies approach from the west.
Northwest winds behind the cold front are expected to increase
into the 20 to 30 mph range and would necessitate another Lake
Wind Advisory.

This upper-level trough and its cold front on late Saturday /
through Sunday will essential signal a change to more seasonable
temperatures. High temperatures each day next week with top out
only in the low to mid 80s. No more 90 degree days in the next
several days.

Models are showing a slight chance for a quick-passing few showers
and thunderstorms over our NE zones late Monday into Tuesday
morning, then again into the latter part of the week through
central and southern Montana.          BMickelson

&&

.AVIATION...

Expected Flight Category: Mainly VFR, maybe IFR this evening for
KGGW.

Synopsis: Expecting mainly dry and hot conditions with the
influence of high pressure over the region. There is the off
chance for a thunderstorm or its outflow winds through KGGW this
evening.

Winds: Southeast winds between of 15 to 20 kts will be gusty at
times.

BMickelson


&&

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

&&

$$

weather.gov/glasgow



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