Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 232006
Area Forecast Discussion
National Weather Service GLASGOW MT
206 PM MDT Sun Oct 23 2016
.SHORT TERM...for northeast Montana...tonight through Tue...
Synoptic Setup: Hot high pressure currently exists over the
Desert Southwest. This has formed a large broad ridge over the
western half of the CONUS which crests near zonal flow over
Montana. Upstream a large highly amplified trough sets off the
coast of British Columbia and is dipping south off the coast of
the Pacific Northwest.
Today through Monday: broadened ridge influence across the region
will remain the key player during these periods. expected dry
conditions and slight warming pattern. meanwhile the trough to the
west will break up and move inland.
Monday night and Tuesday: As the trough to the west broadens it
will expand in influence and turn flow upstream to a southwestern
pattern. the ridge over our area will amplify Monday night and
then break down Tuesday. A couple models are calling for a slight
shortwave in the flow but these are too few at this time to
produce mentionable PoPs.
.LONG TERM...Tue night through Sun...
The long term forecast remains in fairly decent shape as
described below. Models continue with a break down of the ridge
and a shortwave riding through the flow aloft from Saskatchewan.
WIll therefore maintain slight chance pops for southwest portions
of the area. For the second half of the week, the upper level
ridge will become established once more for a period of warmer and
drier weather conditions. Temperatures were trended up slightly
from previous package given recent consensus blendS and the higher
confidence regarding the persistent midweek ridging. Maliawco
Previous Long Term Discussion...
The extended forecast period begins Tuesday evening with a
collapsing upper ridge, caused by a short-wave disturbance riding
along the upper flow through southern Saskatchewan. This is seen
in both the EC and the GFS. The disturbance might be far enough
north of Northeast Montana to not bring much in the way of
precipitation on Tuesday night or wind on Wednesday. But with a
weak cold front being sent into the local area, will go ahead and
increase overnight pops to slight chance and afternoon winds to
The upper ridge quickly rebounds Wednesday afternoon as the
short-wave moves into Manitoba. Limited moisture riding over the
ridge will meet the stationary frontal boundary over southern
Saskatchewan and areas north of the Hi-Line Wednesday night into
Thursday for the possibility of a few low qpf showers. However
confidence here is less due to the strength of the ridge depicted
by the EC.
Friday night into Saturday with timing more of an issue, another
short-wave rides across the ridge. Then ridging resumes for
Looking out a little further beyond the extended, Monday
afternoon and evening there looks like a cold front and short-wave
disturbance that could bring more rain showers and maybe wind.
VFR conditions are expected overnight. East winds of 5 to 15 kts
will continue as well through the period. Maliawco