Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 290251 AAA
Area Forecast Discussion...UPDATED
National Weather Service GLASGOW MT
851 PM MDT SAT MAY 28 2016
.SHORT TERM...for northeast Montana...tonight through Mon...
The short-wave trough and cold front that brought rain showers to
Northeast Montana today has moved out of the area. As the trough
lifts farther north, a weak ridge will move in behind. The result
will be clearing skies tonight. Expect west winds of 10kt or less
overnight. The grids mostly match expectations. Patchy fog may
develop before morning in the east. The grids account for this
possibility. Therefore few grid edits were needed.
Synoptic setup... A Hot ridge runs from western Mexico through
Arizona and terminates over Nevada. To the north a trough runs the
north/south extent of British Columbia In between a zonal to
slightly southwestern flow has set up over the Pacific Northwest
and high plains of Wyoming and Montana.
This afternoon... A narrow slow moving line of showers and
thunderstorms runs from northeast Richland county through eastern
Roosevelt and western Sheridan county. These showers have set up
along an upper level front and are expected to exit into the
Dakotas by 6PM if not earlier.
Tonight through Sunday... warm air is expected to advect in from
the south aloft forcing a little bit of a meso-ridge during these
24 hours and keeping shower and thunderstorms activity minimal if
not nonexistent. Rain showers across the far northeast from this
afternoon will have moistened the boundary layer enough to
generate some light fog in those locations. Meanwhile, the trough
to the northwest will dislodge and begin moving inland over
Alberta ans western Montana.
Sunday night through Monday... trough will attempt to dig in but
be blunted by the warm air over Wyoming. This will tighten up the
jet around it and create quadrant level dynamics for increased
lift and strong thunderstorms across eastern zones during Monday
.LONG TERM...Mon night through Sat...
Upper low tracks across the region early in the period. Adjusted
the pops slightly to account for latest forecast guidance
regarding position of the the precipitation around the low. Area
begins to dry out and warm up by mid week with an upper ridge
building into the northern Rockies. Ebert
Previous long term discussion: Upper low will be over Eastern
Montana Monday Night. This low will combine with an inverted
surface trough and deep moisture to bring showers with embedded
thunderstorms to the forecast area. This low will move into North
Dakota on Tuesday and back side wrap around moisture will remain
over Eastern Montana the entire day with showers and embedded
Tuesday Night and Wednesday, the low moves to Minnesota and upper
ridge moves into Western Montana. Drier air moves into the
forecast area allowing the showers to diminish.
The upper ridge moves into Eastern Montana on Thursday with warmer
temperatures and dry weather.
A weak shortwave trough Thursday Night and Friday will flatten the
ridge. With limited moisture, will maintain dry forecast. Ridge
rebounds on Saturday with warm and dry weather. Forrester
SYNOPSIS: The upper trough has exited the region this evening.
This will allow for VFR conditions to last through the period.
WX: Fog will be very isolated mainly in the 12-15Z period in
typical low lying areas, widespread fog is not expected.
WIND: Less than 15 knots is expected through the period.