247 
FXUS65 KGGW 082013
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
213 PM MDT Mon May 8 2017

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

GOES imagery clearly shows a short-wave trough containing a closed 
low spinning through Saskatchewan. Northern Montana has been dry- 
slotted today with CAA. Models show the low lifting northeast into
Manitoba tonight. Overnight temperatures will be cool again, and
ground remains damp from last night's rains. With clearing skies,
fog may develop. However, models used for fog do not develop any,
likely due to the overall moderate upper RHs. So will not add fog
for now.

The Manitoba low is the northern portion of a much larger split 
trough, with the southern low centered over the northern reaches 
of the Sea of Cortez. This southern low also lifts northeast to 
begin a teleconnection through eastern Montana with the northern 
low. On Tuesday, this increased troughiness along a weak thermal 
boundary will generate rain showers in Wyoming and southeast 
Montana, and possibly also local areas south of Montana State 
Highway 200. Flow aloft turning southwest will aid in bumping
temperatures slightly higher than Monday.

An upper level ridge builds up with its axis centered over the
Divide. This will begin a warming period with highs drifting
higher into the 70s.

Templer

.LONG TERM...Wed night through Mon...

Afternoon update: The forecast as described below stands featuring
a warm and dry upper ridge late in the week, followed by an upper
trough bringing cooler, more showery conditions for the weekend
and early next week. Gilchrist

Previous discussion: Synoptic Setup: The long range begins with a
ridge axis running up from northern california through western 
Montana then turning north into Alberta. Undercutting the ridge, a
closed low sets over the Desert Southwest. To the west a large 
trough sets over the northeastern Pacific. 

Tuesday night through Friday: Developing ridge to the west will 
get a reinforcing shot of hot dry air from California and amplify. 
This ridge will slowly progress across Montana and raise 
temperatures to above normal while keeping skies clear to partly 
cloudy and dry. The ridge itself amplifies considerably for Friday
as its axis passes through with much higher temperatures overall. 

Friday night onward: Trough from the Gulf of Alaska will make its 
push across the Pacific Northwest. This should force the ridge 
axis over the CWA Friday night and may spark off some 
thunderstorms with embedded severe elements. Saturday onward 
is still fuzzy as model ensembles break apart and the trough may 
move through, or flatten the ridge and take the bulk of the cold 
air north, or rip itself apart and bounce off of the ridge while 
staying in place. Every one of these scenarios means increased 
precipitation higher than climatology but the spread also keep 
surface temperatures in flux for the long range. GAH


&&

.AVIATION...

VFR.

Synopsis: Low pressure will exit the region today, allowing for 
excellent flying weather over the next 24 hours. 

Winds: Gusty northwest winds at 15 to 25 kts will linger through
sundown, going light and southeast overnight tonight.  

Gilchrist

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

weather.gov/glasgow