Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 012124
Area Forecast Discussion
National Weather Service GLASGOW MT
224 PM MST Wed Mar 1 2017
.SHORT TERM...for northeast Montana...tonight through Fri...
Synoptic Setup: Short term begins with Northwest flow aloft
running from the central US Plains through Montana and over and
off the coast of British Columbia. Behind this is a meso-scale
Ridge/Trough couplet over the Gulf of Alaska. Water vapor is
showing some pacific Moisture in the northwest flow aloft.
This afternoon through tonight: Northwest flow will deliver
Pacific Moisture over a baroclinic zone that is slowly tilting
more to the west. because of this PoPs will shift south and west
overnight as a dry slot moves across the central portions of the
Thursday through Thursday night: A brief clearing is expected
Thursday morning but by the late afternoon the ridge upstream
will have moved inland and enlarge into synoptic size. this will
force a weak shortwave-trough out ahead of it which should impact
the area overnight. If this comes in contact with Pacific moisture
a burst of snow showers could result for large sections of the
CWA. this wave will likely last not more than 6 hours for any
specific location and totals should be less than an inch.
Friday: Ridge should hit in full force with 40s for highs and
clear to partly cloudy skies through most of the day.
.LONG TERM...Fri night through Wed...
The extended forecast period remains in overall decent shape as
described below. Latest 12z models have SW upper flow over the
region Friday night with relatively dry weather conditions until
the latter half of the weekend and into next week. As the primary
cold front pushes through Sunday night into Monday portions of the
area could pick up a light accumulating snow, especially in the
northeast zones. Lower predictability continues beyond the early
part of the week as ensemble 500mb heights exhibit increasing
spread. This part of the forecast was simply trended toward latest
consensus model blends for now. Maliawco
Previous Long Term Discussion...
By Friday night, SW flow aloft begins to increase and strengthen
over the area. No precipitation is expected to emerge over the
Rocky Mountains until Saturday night through Monday morning.
This main push of moisture and storm activity could bring some
accumulating precipitation as the cold front and main low pressure
system passes through NE Montana Sunday night into Monday morning.
This may bring a new round of 1 or 2 inches of snow, especially
for our NE zones.
After the storm system passes through the region on Monday
evening, GFS and EC model depictions fall completely out of phase
with each other significantly reducing any forecast confidence
that far out in the forecast.
FLIGHT CATEGORY: Returning to VFR.
SYNOPSIS: Scattered snow showers will continue to end across the
area, including at KSDY by this evening. Rising CIGS and improving
VSBYS to P6SM will result and persist into tonight.
WIND:West winds will continue at 10 to 20 kts with higher gusts
before becoming light late tonight. Maliawco