423
FXUS65 KGGW 150824
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
224 AM MDT Sat Jun 15 2024

.DISCUSSION...

KEY MESSAGES:

- Pattern change starts today as a cold front brings showers and
  thunderstorms with eastern zones seeing the greatest risk of a
  mixed severe hail/wind threat.

- Cooler temperatures begin Sunday, with the coldest readings
  occurring on Monday and Tuesday.

- More widespread rain moves in during Monday and Tuesday.

- Warming trend later this week, but things remain unsettled with
  daily shower and thunderstorm chances.

WEATHER PATTERN OVERVIEW:

Today the first Pacific Northwest Trough will begin to settle
into the area driving a cold front ahead of it. This will not only
be the beginning of a pattern change to below average and wetter
conditions, but this front will be the focusing mechanism for another
round of afternoon and evening thunderstorms. SPC has the eastern
half of our CWA, roughly east of a line from Opheim to Glasgow to
Jordan in a slight risk for severe weather with large hail and
damaging winds the main threat.

Sunday will be cooler behind the front with a little break in the
action overall before a stronger Pacific trough moves in Monday
bringing widespread rain and even cooler temperatures at 10-20
degrees below mid June averages for both Monday and Tuesday.  A
warming trend begins Wednesday with temperatures warming close to
late June averages by the end of the week. Still unsettled with
afternoon showers and thunderstorms continuing to be a
possibility.

FORECAST CONFIDENCE and DEVIATIONS:

There is a moderate to high (50-90%) probability for a wetting
rain (0.10") across much of the region with today`s system with
the highest chances in the northeast corner of the state.
Low to moderate probability (25-60%) of 0.25". QPF`s have trended
downward some, especially in the southeastern zones.

For the Monday/Wednesday AM system, QPF amounts have trended
downward but are higher than today`s system, with a probability
around 70-80% for at least 0.25", 40-60% for 0.50", and 10-35%
for 1".

Confidence is lower Wednesday onward on shower and thunderstorm
chances and timing as models start diverging in that time period.

-Bernhart


&&

.AVIATION...

LAST UPDATE: 0830Z

FLIGHT CAT RANGE: VFR, Brief MVFR possible near storms.

DISCUSSION: Cold front pushing east will trigger numerous showers
and thunderstorms today with the best chances occurring during the
afternoon and evening. A risk of severe storms is possible
especially east of a line from Opheim to Glasgow to Jordan with
strong gusty winds and large hail being the main threat.

WIND:

KGGW: N-NW 10-15kts, increasing to NW 15-20kts, gusts 30-35kts
after 00Z.

KOLF: NE-N 10-15kts, increasing to NW 15-20kts, gusts 30-35kts
after 02Z.

KSDY: E-NE 10-15kts, increasing to NW 15-20kts, gusts 30-35kts
after 03-04Z.

KGDV: E-SE 10-15kts, increasing to NW 15-20kts, gusts 30-35kts
after 01-03Z.
-Bernhart


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from 6 PM this evening to 9 PM MDT Sunday for
Central and Southeast Phillips-Central and Southern Valley-
Garfield-McCone-Petroleum.

&&

$$

weather.gov/glasgow