Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 211514
Area Forecast Discussion
National Weather Service GLASGOW MT
914 AM MDT Fri Oct 21 2016
.SHORT TERM...for northeast Montana...today through Sun...
Changes to the forecast were first focused on raising
temperatures slightly in the hourlies as temperatures were a bit
warmer this morning than originally anticipated. THis is partially
due to northeast Montana being stuck in the warm sector of a
closed low over southern Saskatchewan at the normal diurnal
minimum time with a weak downslope wind. The second focus was on
refreshing PoPs for tonight with the passage of the post cold
front environment and a shortwave over that environment. Maximum
PoPs rose a small amount but placement did not change much...
lending to high confidence of rain showers passage. GAH
PREVIOUS SHORT TERM DISCUSSION:
Only concerns with the short term forecast period revolve around
the chances for isolated to scattered rain showers early this
morning, then a bit more organized rain showers again on Saturday
Current near zonal flow aloft over the northern Rockies also
carries with it a bit of a subtle short-wave disturbance which is
generating the precipitation of portions of NE Montana early this
morning. The wave is quite quick-moving and should push through
the remainder of the CWA eastward before sunrise based on the
latest near and short term precip model agreement.
This afternoon through this evening, a broad ridge of high
pressure will push through the region giving NE Montana a very
nice and comfortable autumn day.
Late tonight, the ridge over our region becomes replaced by SW
flow aloft and better chances for more organized rain showers
through late Saturday night. Best model agreement places this
precip north of the Missouri River with maybe 0.05 inch
accumulations in places.
Temperatures are expected to remain above freezing.
.LONG TERM...Sun night through Fri...
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 today. Expect increasing clouds this
afternoon 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