Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 282111

Area Forecast Discussion
National Weather Service GLASGOW MT
311 PM MDT Tue Mar 28 2017

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

Upper trof/front moving across eastern Montana this afternoon. A
few showers have developed ahead of this system mainly south of
the Missouri River but have been spreading north through the

Flatter westerly flow followed behind the front with warmer and
drier conditions. Stacked westerlies will persist through
Wednesday. Other than some potential for fog over the still wet
ground in the far northeast corner of the state early in the
morning, mild conditions expected for Wednesday. Ebert

A new trough will dig into the western U.S. on Thursday as the
ridge slides downstream. This will provide large scale forcing for
ascent and a gradual return to wetter conditions. Maliawco

.LONG TERM...Thu night through Tue...

Main focus of the extended forecast period is now becoming the
storm system set to impact most of NE Montana from Thursday
afternoon through Friday night. This is in response to an expected
strong upper level trough digging through the western states
region. Models are lining up fairly good with timing, placement
and rain amounts.

Thursday afternoon, the rain showers will approach from central
Montana, then overtake the rest of eastern Montana through late
Thursday night. Early Friday morning through Friday night the rest
of the rain will spin through our CWA and finally clear away
toward the southeast by late Friday night. Total rainfall amounts
up to half an inch are possible over those two days.

A brief period in a colder air regime toward the beginning of
next week is possible and could bring a slight chance of a rain
and snow mix, but is too far away at this time to say any more
than slight chance for now. BMickelson

Previous long term discussion: A split upper level trough moves
inland from the Pacific Thursday. The base of the southern trough
digs into the desert southwest Thursday Night and Friday and
becomes a closed low. Models bring a shortwave with decent
moisture into Northeast Montana Thursday Night in southwest flow
ahead of this trough. The GFS has become colder and wetter with
this system than the ECMWF. They remain in agreement with rain
Thursday Night but the GFS is more widespread with the rain and
continues the precipitation through all day Friday and even tries
to bring in cold enough temperatures for snow. The ECMWF shifts
most of the moisture to the east Friday morning. Will have likely
pops east and chance pops west with temperatures warm enough for
all rain.

During the day on Friday, Northeast Montana switches to the drier
northern stream and a shortwave trough moves through the area and
moves most of the moisture to the east by Friday Night.

Upper ridge will bring dry weather on Saturday.

Models bring a shortwave trough with a cold front across the area
on Sunday with GFS wet and ECMWF dry. Will mention a chance of
rain over most areas.

Models differ with a broad upper trough for Monday and Tuesday
next week. Will maintain a chance of rain, possibly snow if
temperatures are cold enough. Forrester



VFR conditions. A few rain showers are possible ahead of a frontal
boundary moving east of the region this evening. Generally clear
skies are expected tonight and Wednesday although some patchy fog
or low clouds are possible during the early morning hours over
the northeast corner of the state.




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