Sidney, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

341
FXUS65 KGGW 220849
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
149 AM MST Sun Dec 22 2024

.DISCUSSION...

KEY MESSAGES:

 - Freezing rain expected through this afternoon. A Winter
   Weather Advisory has been issued.

 - Stretch of above normal temperatures continues for several days
   through next weekend.


WEATHER PATTERN OVERVIEW:
A warm upper ridge will be the main weather player through early
this week making for warm temperatures (especially just off the
surface). This temperature profile, colder sub freezing temps at
the surface with warm temps aloft (close to 5C at ~2k feet agl)
will set the stage for a freezing rain event starting in the west
around 09z this morning as a disturbance passes through the upper
ridge. Precipitation took a slightly more southern move this
morning and had to add Garfield County to the current Winter
Weather Advisory early this morning. The threat for FZRA tapers as
temps warm above freezing in the mid-afternoon. The precipitation
pushes off to the east this evening as the disturbance exits.

High pressure ridging will return tonight, resulting in
a warm and dry day Monday. Temperatures will remain above normal
all week into the weekend. The upper ridge flattens somewhat on
Christmas Day with another disturbance pushing through, however
with this disturbance most of the energy stays well to the south.
A warm SW flow aloft is expected Thursday and Friday.


FORECAST CONFIDENCE & DEVIATIONS:
Confidence is high on the freezing rain mainly north of the
Missouri River and along the Lower Yellowstone Valley early Sunday
morning and afternoon. Confidence is high on above normal temps
for the next several days. Stayed with higher pops than the base
forecast(NBM PPI01) today, by blending NPoPs from the CAMs. Winds
for this afternoon were a 50/50 blend of NBM/NBM90 and Sky Grids
at the same time were a built from a tool using NBM10 and NBM90
blended with NBM to get SKC and Overcast skies in their respected
locations through the first 18 hours. /GAH


&&

.AVIATION...

LAST UPDATED: 0830Z

FLIGHT CAT RANGE: VFR - IFR

DISCUSSION: VFR starting out. Possible IFR Vsby with FREEZING FOG
through 17Z at KSDY(40-60%) and maybe KOLF(10-30%).

FREEZING RAIN could begin impacting the KGGW terminal as early as
10Z this morning and expand west to all terminal by 14Z. This
disturbance could bring icing on runways and aircraft wings with
this passage as up to 0.10" inches is possible. Freezing fog and
rain threats should end by about 20-21Z this afternoon at which
point conditions go back to VFR.

There is a chance (20-40%) that low MVFR clouds could return to
KOLF and KSDY late tonight into Monday morning.

WIND: Light and variable this morning. Becoming W at 5-15 kts
this afternoon. Then becoming light again this evening through
tonight.

LLWS: Low level wind shear could impact the terminals starting at
14Z this morning and last till around 20-21Z this afternoon.
Terminals most likely to be impacted are KGGW(50-80%) and
KGDV(30-60%).

GAH


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 AM MST this morning for Central
and Southeast Phillips-Central and Southern Valley-Garfield-
Northern Phillips-Northern Valley.

Winter Weather Advisory from 5 AM early this morning to 5 PM MST
this afternoon for Daniels-Dawson-Eastern Roosevelt-McCone-
Richland-Sheridan-Western Roosevelt-Wibaux.


&&

$$

weather.gov/glasgow