Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 122130
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
230 PM MST Tue Dec 12 2017

.DISCUSSION...

An upper ridge near the West Coast will continue to reign supreme
through Thursday while disturbances drop southeast in the
northwest flow into the Northern Plains or the Great Lakes. Since
this storm pattern is to our east, we`ll remain above normal in
the temperature department, but it will be a bit cooler than
today.

The first clipper this afternoon is dropping into southern
Manitoba with a Pacific cold front sweeping through the area this
afternoon/evening. Mid-level winds (850 mb) will be about 50-55
kts (with 700 mb winds higher). Depending on maximum temperatures
this afternoon shape up will determine how much mechanical mixing
takes place this evening. Winds look to miss the mark with high
wind criteria as we are experiencing the shortest days of the
year.

Expect winds to decrease later tonight as cold front and surface
low moves away. Temperatures will be held up with clouds, expect
lows in the 20s to low 30s, close to normal daytime highs.

Wednesday, clouds will increase with increasing 850/700 mb
moisture and approaching disturbances. Temperatures will only
reach the mid 30s to mid 40s. 15-20 degrees cooler than today, but
still about 10 degrees above normal. TFJ

Previous Discussion...
The next wave on NW flow aloft drops SE across the region
Wednesday Night with another cold front.

Another wave comes through late Wednesday night. Again windy
conditions are possible over eastern Montana, and some spotty
precipitation. The system may have enough moisture for a chance of
rain and/or snow depending on temperatures. That system moves to
the southeast Thursday morning. Thursday will be mainly dry and
cooler with highs in the 30s in most areas.

The upper ridge builds back into Montana Thursday and Thursday
Night which will bring warmer air to the forecast area on Friday.
However, a shortwave trough will flatten the ridge on Friday and
move through the state Friday Night and Saturday with a cold
front Friday Night. Models differ at this point on where to track
the moisture with this system. Could see a chance of rain and
snow depending on temperatures Friday Night and Saturday morning.

Models are pointing towards a shortwave ridge on Sunday with dry
weather and continued above normal temperatures for mid December.

NW flow aloft prevails Monday and Tuesday. A cold front is
expected Sunday Night or Monday. Then, the models differ on
whether to keep the front to the south of the forecast area on
Tuesday or bring it back east as a warm front. Could see a chance
of rain or snow at times. Forrester


&&

.AVIATION...

Flight Condition: VFR.

Winds: NW winds will ramp up this afternoon with some LLWS issues
this evening. Winds will diminish after midnight.

Otherwise, expect some passing high clouds tonight. Scattered low
VFR clouds will huge eastern Montana from North Dakota Wednesday.
TFJ

&&

.FIRE WEATHER...

Winds are increasing across the area this afternoon as the airmass
is very dry and warm. Humidity should creep up over the next few
hours as temperatures cool. Higher winds diminish tonight as a
cold front moves southeast of the area. Otherwise, the red Flag
Warning continues across the area until 10 pm. TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 10 PM MST this evening for MTZ135>137.

&&

$$

weather.gov/glasgow


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