Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 302007
Area Forecast Discussion
National Weather Service Glasgow MT
207 PM MDT Sun Apr 30 2017
.SHORT TERM...for northeast Montana...tonight through Tue...
Synoptic Setup: Short term begins with relatively zonal low
across the northern Half of the CONUS and southern Canada.
Embedded within the flow are smaller regional waves with a ridge
axis over eastern Montana and northern Wyoming. To the west a
broad weak amplified trough is moving into Washington and Oregon.
Today through Tonight: As the ridge axis exits this afternoon a
jet band ahead of the trough axis will push in behind rapidly
destabilizing the atmosphere. A lee surface trough off of the
front range will be the initial focal point for this afternoon
but the jet aloft will end up picking up this front and dragging
it across the CWA overnight. A dry slot is anticipated to fill in
behind the surface trough around midnight.
Monday: axis of the trough aloft should move through along with
CAA and strong winds reducing temperatures for daytimes high and
producing enough condensation for more widespread showers post
front especially across the northeastern zones. GAH
Monday night and Tuesday: An unsettled northwest flow aloft will
continue, making for scattered to isolated showers and cool
.LONG TERM...Tue night through Sun...
Afternoon update: The going forecast as described below stands.
The only tweak was a gentle nudge toward the latest model
PREVIOUS LONG TERM DISCUSSION:
Period starts with Upper trough digging to our east with a ridge
to our west putting northeast Montana in a NW flow. But ridge
builds over the Northern Rockies by Thursday that slowly drifts
east. A trough in response will dig along the West Coast and not
push ridge too quickly east. This will result in several days of
temperatures above normal (beginning Thursday). Highs will be in
the 80s many places Saturday, but not expecting records to be
challenged at this point.
Showers/thunderstorms will probably be held off till at least
Saturday Night. TFJ
FLIGHT CAT: VFR-MVFR.
SYNOPSIS: A system will push through the area from the NW
tonight. This will allow isolated to scattered showers to pass
through the terminals. By Monday a cold front will arrive
expanding shower coverage and increasing winds. A few MVFR
ceilings are possible Monday with the fronts arrival.
WIND: Southwest at 5 to 15 kts today... veering to the NW
tonight... and increasing to 15 to 25 kts Monday afternoon.