Sidney, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

645
FXUS65 KGGW 142030
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
230 PM MDT Sun Jun 14 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms tomorrow afternoon.

- Increasing temperatures through Tuesday.

- Much cooler, wetter, and breezier conditions Wednesday.

- Near average temperatures and unsettled weather returns late in the
  week.


&&

.DISCUSSION...
WEATHER PATTERN OVERVIEW:

Northwesterly flow aloft will prevail the next few days. Embedded
shortwave influences will allow several chances for showers
thunderstorms in the afternoons, especially near the MT/ND
border. HREF max ensemble wind gust guidance suggest this
convection may lead to the downward transfer of higher momentum
air, leading to isolated wind gusts of 40 to 50 mph.

A cold frontal passage on Tuesday will result in enough low level
convergence and lift to initiate afternoon and evening showers
and thunderstorms. Initial forecast soundings suggest PWAT values
approaching the 90th percentile, between 1 - 1.2", so steady
rainfall could result from some of this and persist into the
middle of the week. Forecasted CAPE values on Wednesday night
have been hovering around 250 J/kg, however, with sufficient
frontogenetical forcing even modest CAPE will allow for more
widespread showers. Along with cooler temperatures, breezy
conditions following the Canadian cold front may support a Lake
Wind Advisory for Fort Peck Lake.

Ensembles point to a warm up toward more seasonable conditions
late in the week as a Pacific ridge begins to come ashore and
translate eastward over the Rockies and Northern High Plains.

FORECAST CONFIDENCE & DEVIATIONS:

Increased PoPs following collaboration. Heavy influence from GFS
1-hr for this afternoon and used a blend of HiRes FV3 and ARW &
SREF through Tuesday afternoon. Left NBM for Tuesday
night/Wednesday.

Overall confidence is high on a cool and wet midweek, but would
point out below normal confidence on gusty winds with
thunderstorms on Monday due to the isolated or limited coverage
expected.


&&

.AVIATION...
UPDATED: 1930Z

FLIGHT CAT RANGE: VFR

DISCUSSION: Mostly sunny skies this afternoon with low end chances
for light isolated showers in the early evening. Opted to leave
out of TAFs at this time. Mid level, overcast skies characterize
the region tonight and continued chances for rain showers during
the day tomorrow.

WINDS: Northwest winds 10 to 15 kts, increasing to 15 to 25 kts
tomorrow.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

weather.gov/glasgow