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FXUS65 KGGW 252108

Area Forecast Discussion
National Weather Service GLASGOW MT
208 PM MST Sat Feb 25 2017

.SHORT TERM...for northeast Montana...tonight through Mon...

Raised afternoon pops across the NE zones and added mention of
flurries and morning patchy fog. TFJ

Previous Discussion...
Shortwave dropping out of Canada this morning, pushed a band of
snow through eastern Montana overnight. Amounts were light but
have resulted in slick roads. Additional precipitation is expected
today before the shortwave moves into the Dakotas. 

A weak shortwave ridge develops Saturday night temporarily ending
the snow threat although skies will remain cloudy. 

The next shortwave trof to impact the area will feature an Arctic
wave which slides east through central Canada, but provides
another push of colder air to northeast Montana. Main portion of
the trof will move through the Great Basin on Monday. A weak 
east-west convergence zone develops through central Montana to
provide focus for slight more intense snow Sunday night into
Monday. Ebert

.LONG TERM...Mon night through Sat...

The extended period as described below remains largely in shape
with a large trough ejecting east and downstream of the region
from the middle of next week into the late week ahead of a
building ridge. Expect chances for snow with the trough but a
drying and warming trend for the end of the week. Maliawco

Previous Long Term Discussion...

Synoptic Setup: long range starts with a large trough over the
western third of the CONUS which runs north into an Arctic airmass 
over the Canadian Shield. Upstream a ridge resides over the Gulf 
of Alaska nosing on shore over the Yukon. Behind this is yet 
another trough over Alaska. 

Monday night through Tuesday night: Trough will move across the
areas bringing pacific moisture and increased PoPs. 

Wednesday through Thursday night: Flow becomes Northwest as a the
ridge to the west builds. This will decrease PoPs slightly due to
lack of moisture, but quick shortwaves could still be caught in 
the flow for isolated showers. 

Friday: the Ridge itself will pass through the area. Warm up is
expected to be strong at this time. But model spread is wide so
this could change rapidly. 

Friday night onward: At this point models present a large spread
of possibilities, from maintained ridge to Arctic plunge and 
nearly everything in between. Confidence is practically non-
existent as of tonight with hope for better consistency by 


VFR conditions may occur at times this evening aside from
near remaining snow showers across terminals, however, light snow
will again approach from north to south tonight with lingering 
low stratus and reduced visibilities. As a result MVFR to IFR will
prevail tonight. Winds will become light and variable tonight 
before becoming south by Sunday morning. Maliawco



Ice jams and high water levels continue on the Yellowstone River
with continued fluctuating river levels.

No new information came in today, so the assumption is that the 
ice jams from yesterday are frozen in place. 

With little change in runoff and melting of the ice jams expected,
the Flood Watch is in effect through Monday.

Later next week, things could change a bit as warmer air could 
melt or move ice jams along.


Flood Watch through Monday afternoon for Dawson...Richland. 


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