042
FXUS65 KGGW 291113
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
513 AM MDT Wed May 29 2024

.DISCUSSION...

KEY MESSAGES:

- Strong and severe thunderstorms are expected Wednesday afternoon
  and evening, especially along the SPC slight risk area
  straddling the Montana/North Dakota border.

- Warm but moderately unsettled pattern expected through the
  weekend and into next week.

WEATHER PATTERN OVERVIEW:

An upper trough moving toward the northern/Canadian Rockies this
morning is continuing to develop an Alberta surface low with an
associated cold front. As the front moves east today, the low
level jet strengthens, pulling moisture northward along the
Montana/North Dakota border. This will set up a favorable scenario
for severe thunderstorms, initially across the far eastern zones
of eastern Montana for the late afternoon and evening, as noted
by SPC with a slight risk area.

As the upper trough sweeps across the Canadian prairies, cooler
temperatures along with some unstable air lingers over the region
for Thursday. Behind the trough, the flow aloft becomes generally
zonal, with occasional shortwave disturbances, for warmer and
somewhat unsettled conditions through the weekend and into next
week.

CONFIDENCE & DEVIATIONS:

Confidence for severe weather on this afternoon remains high,
with CAPE in excess of 1000-2000 J/kg, and moisture advection on
the strong low level southeast jet with winds in excess of 30kt.
Damaging winds and large hail will be the main threats. HREF
ensemble only giving a 10% probability for updraft helicity in
excess of 75 m2/s2 through 00z Thursday, but it does increase to
30% probability in the early evening. With PW over 1" indicated,
heavy rain is also a possibility near the North Dakota border.


&&

.AVIATION...
VFR through late afternoon when a cold front will cross the region
with scattered showers and thunderstorms. Some of the stronger
storms could result in brief periods of IFR or worse for KSDY and
KGDV if a storm happens to pass directly overhead.

Winds will increase from the northwest behind the cold front,
Gusty, erratic, severe wind gusts are expected near the stronger
storms this evening.


&&

.GGW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory from 11 AM this morning to 9 PM MDT Thursday
for Central and Southeast Phillips-Central and Southern Valley-
Garfield-McCone-Petroleum.

&&

$$

weather.gov/glasgow