217
FXUS65 KGGW 200840
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
240 AM MDT Thu Jun 20 2024

.DISCUSSION...

KEY MESSAGES:
- Shower and thunderstorm chances increase through Friday, when
  stronger storms and a more widespread wetting rain is expected.

- An isolated severe cell or two Friday late afternoon and early
  evening may be possible.

- A slow warm up is expected through Sunday when some 90s for
  highs likely appear.

WEATHER PATTERN OVERVIEW:
A dry morning today will lead into afternoon rain showers and
isolated thunderstorms with most coverage looking to be south of
the Missouri River. SPC`s HREF is point toward some gusty winds
with these cells upward of 50 mph. But severe weather is not really
expected.

However, a shortwave arriving Friday afternoon does look like it
has the chance for a isolated severe cell or two with about 1000
J/kg CAPE, bulk shear around 40-50 kts, and precipitable water
over 1 inch. The one problem with this environment appears in the
NAM forecast soundings and that is a cooler than average surface
layer which will keep most convection elevated rather than surface
based, and may prevent strong winds initially. That being said
CAMs are point towards strong cells embedded in light shower
activity which could form their own environments and CAMs also
point towards a couple 50-65 mph gusts that could occur with the
strongest cells. Chance of severe weather in the GGW CWA friday
late afternoon early evening is about 60%. Chance of a single
point getting hit by it is less than 10%. Rain totals with this
passage vary from a tenth to a half inch over the CWA.

GAH



&&

.AVIATION...

LAST UPDATE: 0830Z

FLIGHT CAT RANGE: VFR.

DISCUSSION: SKC morning will lead to SCT/BKN mid level cumulus clouds
in the early afternoon and scattered showers and isolated
thunderstorms in the late afternoon and early evening, especially
south of the Missouri River. Mainly KSDY and KGDV will be
impacted but its not out of the realm of possibility for the other
two terminals to get hit. Isolated activity could last through
midnight.

SFC WIND: Backing E to SE and light through the morning. Then,
increasing to 10-15 kts this afternoon. Calming to less than 10
kts this evening through tonight. Expect gusty and erratic winds
near any thunderstorm.

GAH


&&

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

$$

weather.gov/glasgow