Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Glasgow Montana
223 PM MDT Fri Oct 21 2016
Short term...for northeast Montana...tonight through sun...
Synoptic setup: hot high pressure exists over the Desert Southwest
with it arching up into the intermountain west forcing southwest
to zonal flow over northern California through Idaho and Montana.
A large Pacific trough sets off the coast of British Columbia and
is trying to move inland.
Tonight through Saturday morning: a shortwave is moving through
the flow and should be able to impact northeast Montana between
roughly midnight tonight and noon tomorrow. Most of this should
stay warm enough to remain rain. Coverage should be north of the
Missouri River. Totals are anticipated between couple hundredths
and a tenth of an inch.
Saturday afternoon through monday: ridge should immediately
rebound in the wake of the trough with the crest starting to
reform over Idaho and then moving across eastern Montana during
these periods. Expect dry conditions with a slight warming trend.
Long term...Sun night through Fri...
the long term period as described below remains largely on
track, with models showing little run to run variation. A cold
front Tuesday night will bring some shower activity to the area,
and increased pops to chance category due to the increased
confidence. However, confidence remains limited for the end of the
week with greater ensemble spread. For now will lean on slightly
cooler temperatures and occasional slight chances for shower
Previous long term discussion...
an upper ridge will be building over the northern plains through
the weekend, opening the region to southwest flow aloft. Warm and
generally dry condition are expected Monday with a warm front
lifting across the state.
The upper trof digging off the Pacific northwest will begin
ejecting shortwaves across the northern rockies to break down the
ridge early in the week. Lee side low develops in southern Alberta
on Tuesday then pulls a cold front through Montana Tuesday night.
Some precipitation chances with the frontal passage although
moisture looks to be limited.
Forecast confidence drops for the end of the week as models now
trending toward building the ridge back up over the northern
rockies with the upper trof splitting over the eastern Pacific.
VFR conditions will prevail tonight. Increasing clouds are
expected with showers possible tonight from kggw to kolf. West
winds of 10 to 15 kts will become light from the southeast late
this evening. Maliawco