Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
219 PM MDT sun Sep 21 2014
Short term...for northeast Montana...tonight through Tuesday...
Synoptic set up...a synoptic scale ridge resides over the western
half of the US and Canada. Embedded directly under this... is a
closed low centered over Idaho/Utah/Nevada triple point. To the
east a trough is spread out over the upper Mississippi Valley and
Great Lakes. The trough ridge combo has placed northeast Montana in
north to northwest flow with the ridge quickly gaining more
influence. Off to the west a large trough is developing over the
Gulf of Alaska.
Today through Tuesday... the ridge will move in and center over
eastern Montana by Monday. This create dry and stable conditions
through middle week. The closed low will move across Wyoming under
the ridge and may bring a few high clouds to the southern portions
of the County Warning Area by Tuesday. Aside from that the weather of the short
term should remain uneventful. Gah
Long term...Tuesday night through Sunday...
adjustments to forecast mainly for collaboration as models
continue to struggle with the trough moving into the western states
at the end of the week. The GFS continues to suggest a cooler and
wetter solution as it brings the trough across the Great Basin over
the weekend. The ec holds back the trough by forming a cut off low
over Nevada that does not lift out until early next week. The CMC
is close to the ec but does not close off the trough as quickly.
Previous long term discussion...
upper ridge will prevail over Montana on Wednesday as flow aloft
becomes increasingly amplified with digging upper trough on West
Coast. This will bring warm and dry weather to the forecast area.
Model differences develop starting on Thursday as the GFS wants to
bring this deep trough inland and bring cooler and wetter weather
to the forecast area by the weekend. The European model (ecmwf) wants to keep this
trough to the west through the weekend and keep warm and dry
weather over Montana although not as warm as midweek. Given the
model uncertainty... will gradually cool temperatures into the
weekend and maintain a slight chance of showers and thunderstorms
for the weekend. Forrester
VFR with clear skies and generally light winds as high pressure
lingers over the region.