Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 240913
Area Forecast Discussion
National Weather Service GLASGOW MT
313 AM MDT TUE MAY 24 2016
.SHORT TERM...for northeast Montana...today through Thu...
The short term forecast period becomes entirely focused on the
evolution and movement of the stalled upper-low center now over
Model consensus has now begun to paint a clearer picture about
what to expect - at least for today through Wednesday.
The Saskatchewan Low has begun to retrograde back toward the west
and its associated trough will dig back through Montana today and
tomorrow; then begin to progress eastward by the end of this
forecast period. Basically, we try to time out the influence of
the different bands of precipitation spinning around the low
For today, the primary band of rain showers will continue
over our northern and northwestern zones while a minor secondary
band of rain showers sneaks into our southern and southwestern
zones. By tonight, the northern precipiation disappears and the
focus turns to our southern and southeastern zones.
Early Wednesday through Thursday, the low center digging through
Montana will split into a few separate lobes. This will draw more
moisture and instability over our eastern zones as evidenced by
model depictions of dewpoints into the mid 50s and shear values of
30 to 40 knots. Various model QPF outputs indicate that a very
efficient rain storm, thunderstorm, or band of storms is likely to
pinwheel through our eastern zones from south to north. Best model
consensus accumulates up to 1.5 inches of precipitation for
eastern Roosevelt County and Richland County through this time
.LONG TERM...Thu night through Tue...
A shortwave trough over eastern Montana Thursday Night will bring
a chance of showers and thunderstorms to the area. Then, a long-
wave trough will be over the western US and Canada starting on
Friday and remaining there into early next week. Eastern Montana
will be in a south to sw flow aloft for most of the period.
Shortwaves will combine with unstable air mass for a chance of
showers and thunderstorms for most of the period. Models are
timing the waves differently. Will generally broadbrush the
chances of showers and thunderstorms.
On Monday and Tuesday, the GFS keeps the trough to the west of
Montana while the ECMWF wants bring the trough east across the
forecast area. Either way, it looks like unsettled weather
Synopsis: The region will remain under the influence of a
large upper level trough of low pressure over the next several
days. Will see showers and low clouds with mvfr conditions at
times. Expect vfr conditions most of the time.
Cigs: Bkn mid level clouds with ocnl low clouds.
Winds: West around 10 knots today turning northwest this evening
around 5 knots.