Area Forecast Discussion
Issued by NWS Glasgow, MT

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

FXUS65 KGGW 070442

Area Forecast Discussion
National Weather Service Glasgow MT
1042 PM MDT Wed Jul 6 2022

Evening Update:

The Severe Thunderstorm Watch was allowed to expire at 10 PM MDT
this evening. That said, an isolated severe threat remains
possible tonight, though heavy rainfall with lingering storms is
the primary threat. Additional thunderstorm potential will exist
for Thursday, especially during the afternoon into Thursday night.

Previous Discussion:
Increased POPs and QPF to reflect model guidance that had training
storms over our southwestern zones along with PWAT values above 1
inch and up to 1.5 inches in some areas. Training storms over the
last few days have left the area saturated and prone to
additional minor flooding, hence the flash flood watch that was
added to our western and central zones.

Otherwise, no major changes to the forecast.

Synoptic Setup: Hot high pressure lies anchored over the Four
Corners with a ridge jutting northward out of it through Idaho and
into British Columbia. A closed low lies off the coast of British
Columbia and is providing an express lane for pacific moisture over
northern California through central Montana between the two
airmasses. Weak disturbances appear to be making their way through
this express lane as well and providing for strong to severe
afternoon thunderstorms in northeast Montana.

Today and Tonight: Some patchy fog is expected across far
northeast Montana early this morning, but it should quickly burn
away with sun up. Clear to partly cloudy skies are expected for
the rest of the morning. Thunderstorms are expected to develop
over the central Montana mountains during the early afternoon
hours and then begin their migration across the high plains by the
late afternoon and early evening. Organization of cells does not
look particularly strong with weak shear through most of the
afternoon. However, there is expected to be sufficient CAPE and
DCAPE to provide for some strong up and downdrafts and lead to
more of a wind threat with stronger cells in the multicellular
chaos. Cells are expected to last through the overnight hours but
severity should trail off into the late evening and early morning.

Thursday through Friday: Showers and thunderstorms are expected to
continue into Thursday with severe chances lasting into the
afternoon hours on Thursday and Friday. The ridge axis over
western and central Montana is expected to shift east Thursday
night which may increase the chances for severe weather as it
moves by Friday.

Friday night through Saturday night: Flow will turn southwest
during these periods. Afternoon showers and thunderstorms for the
CWA again seem certain but details are limited.

Sunday onward: On the larger scale a trough is expected to break
off of the BC low and blunt the ridge as it transverses the
International Border bringing cooler air to the region at the
surface Sunday before leaving Monday. This should shut off the
showers and thunderstorms for awhile and place the area under dry
northwestern flow through the middle of next week. GAH




DISCUSSION: Another round of thunderstorms are again expected in
the late afternoon and overnight hours today and tonight. These
are not expected to start impacting the terminals until after

WIND: East to southeast at 10 to 15 kts this evening through the
overnight hours. Gusty and erratic winds will be possible near
any thunderstorms.



Flood Watch until 6 AM MDT Thursday for Central and Southeast
Phillips...Central and Southern Valley...Garfield...McCone...
Petroleum...Prairie...Southwest Phillips.


$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.