Sidney, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

243
FXUS65 KGGW 191014
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
414 AM MDT Sat Jul 19 2025

.DISCUSSION...

KEY MESSAGES:

- Thunderstorms will return today with the possibility of them
  being severe especially in the central and eastern zones in the
  afternoon and evening.

- A gradual warm up will continue into the upcoming weekend with
  afternoon highs recovering into the 80s.

WEATHER PATTERN OVERVIEW:
A generally zonal pattern will continue over the northern part of
the country over the next week. But an upper low over British
Columbia will drop a bit today that will help destabilize things
over eastern Montana. Southeast winds will continue to be marginal
for lake wind but will keep advisory due to weekend activities.
Winds will be slightly stronger to the east, which will provide
an influx of low level moisture for thunderstorm development.

With the warm unstable airmass over the region, especially in the
east, and a weak trough crossing the state today to provide focus
for stronger thunderstorm development this afternoon, SPC outlook
has updated to slight risk over the eastern zones today and
tonight. Along with the hail and gusty wind potential,
precipitable water is expected to be over an inch over most of the
region with the flow pattern tapping into some monsoonal moisture,
for heavy rain potential as well.

Dewpoints in the 60s are expected to linger over the eastern zones
Sunday but surface boundary may push into western ND while the
upper low provides decent upper level shear/dynamics.

Afterwards, southwest flow aloft will deepen, along with a
potential stronger link with monsoonal moisture, for
thunderstorms increasing on Tuesday. Temperatures will cool as the
upper trough moves through the region midweek.

FORECAST CONFIDENCE & DEVIATIONS:
Increased winds today to align more closely with Lake Wind
Advisory using NBM90. Also blended CAMS for pops for today.


&&

.AVIATION...
VFR, but could lower through the afternoon and evening in places.
Clouds will increase through the day with the development of
showers and thunderstorms. The storms could bring brief heavy rain
which could drop conditions to MVFR for short periods. Some storms
could be severe this afternoon and evening with hail and strong
erratic winds.


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 6 PM MDT this evening for Central and
Southeast Phillips-Central and Southern Valley-Garfield-McCone-
Petroleum.

&&

$$

weather.gov/glasgow