Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
1002 am MST sun Feb 14 2016
Short term...for northeast Montana...today through Tuesday...
update...the going forecast is in over all excellent shape. The
only tweak was to add some flurries this morning based on the
latest radar imagery. Also added some sprinkles for this afternoon across
the Big Sheep Mountains and the adjoining lower Yellowstone valley
based on the latest hrrr. Gilchrist
Previous discussion...northwest flow aloft will prevail over
northeast Montana the next few days with shortwave troughs at
times. The first wave today will stay mainly south and west of the
forecast area. This will give most of northeast Montana a dry and
mild day. Will limit chances for mainly rain showers to the SW
The mainly dry weather continues tonight with a shortwave ridge
over the area.
A more vigorous shortwave trough moves through northeast Montana
on Monday. This will bring a good chance of rain to most of the
forecast area as temperatures will be warm enough aloft for mostly
rain. The best chance will be in the southwest zones where the
deeper moisture is expected. With nighttime lows tonight expected
to below freezing in many areas...a mix of freezing rain is
possible Monday morning. The northeast zones may see no precipitation
from this system as airmass is expected to be drier there. The
system will bring a cold front through the area in the afternoon.
That wave moves to the southeast Monday night. The next wave quickly
follows on Tuesday with a warm front. Will see some overrunning
moisture over the area with a chance of mixed precipitation (rain/snow) as
850 mb temperatures will be near zero celsius near the front and
temperatures east of the front will be below freezing in the
Long term...Tuesday night through Sunday...
Synoptic set up... long range begins with a large broad ridge
over the western half of the Continental U.S. And a series of troughs and
ridges following it from the west over the northern Pacific. To
the north Arctic air has been bottled up over the Canadian
territories and thus far will have little influence over the
forecast due to strong zonal flow.
Tuesday night through Thursday...anticipated the synoptic ridge
to have the most control over the area during these time periods.
Conditions should be dry and seasonably warm. Confidence is high.
Thursday night through Friday... first shortwave is timed to enter
the northern High Plains during this time. Probability of precipitation were increased
accordingly. With temperatures being warm most of the passage
should be rain... however some snow may mix in late for this
event. Confidence is average.
Friday night Onward... model breakdown occurs here. Future runs
may easily change timings of any progressive waves. However... all
incoming waves appear to be Pacific in origin and should be warmer
with the Arctic remaining bottled up during this time. Confidence
is average to just below average. Gah
Radar is showing isolated to scattered light echoes this morning
for low to middle level clouds. Do not expect much in the way of any
precipitation at the terminal areas today through tonight. An
upper level disturbance embedded in the northwest flow will bring
in rain and freezing rain for Monday that could result in MVFR/IFR
conditions at times.
Expect west to northwest wind at 5-15kt today...calming to less
than 10 kts after sunset. Wind will increase Monday to 15-25kt as
the disturbance passes through the region. Scattered