Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 271001
Area Forecast Discussion
National Weather Service GLASGOW MT
301 AM MST Mon Feb 27 2017
.SHORT TERM...for northeast Montana...today through Wed...
Main forecast challenge today focuses on the ongoing snow event
across southern and central portions of our northeast Montana CWA.
Latest model agreement and consensus shows good support for an
extension of the Winter Weather Advisory into McCone, Dawson, and
Richland Counties given the expected 2 to 3 inches of new snow
fall this morning and today. Went ahead and expanded the headline
with this morning forecast package.
Snow fall will taper off from west to east throughout this
afternoon and into early this evening. Small portions or corners
of other counties may see similar amounts of snow fall, but as
most of those counties are expected to see less than 2 inches,
felt it was best to leave them out of the advisory.
Tonight through Tuesday, a nearly zonal to slightly WSW flow aloft
persists over the region with periods of scattered light snow off
and on through the early portion of this week. Another larger upper-
level low pressure trough axis pushes through the area by late
Tuesday night into Wednesday morning with NW flow aloft becoming
more prominent thereafter.
.LONG TERM...Wed night through Mon...
Upper trof moves through the region midweek with flow pattern
transitioning to flatter westerly flow off the Pacific during the
end of the week. This will result in warming temperatures into the
Precipitation chances through the period are less clear. Models
indicate some overrunning precipitation possible on Thursday night
as warm air begins to work into the region. A weak cold front
drops south from Canada on Saturday with scattered showers
possible. A stronger shortwave trof pushes through the state on
Sunday bringing the best potential for accumulating snowfall.
An upper level trough along with a surface front across the area
will be the focus for the main body for snow for the region.
Flight conditions will drop to MVFR/IFR as the snow spreads east
early this morning. Although the snow is expected to exit the
region this afternoon, the poor flying conditions will persist
Although water levels on the Yellowstone River have now fallen
well below flood stage, large chunks of ice present still pose a
threat for ice jams and may be frozen in place.
With little change in runoff and no melting of the ice jams
expected early this week, the Flood Watch continues through this
Later this week, a return to warmer temperatures may melt and/or
move any remaining ice jams further downstream.
Winter Weather Advisory until 5 PM MST this afternoon for
Flood Watch through this afternoon for Dawson...Richland.