209
FXUS65 KGGW 101918
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
118 PM MDT Mon Jun 10 2024

.DISCUSSION...

KEY MESSAGES:

- Isolated strong thunderstorms will move through from now through
  9 PM tonight.

- Elevated wind speeds and gusts behind the cold front that passed
  earlier has warranted the Lake Wind Advisory to continue through
  9 PM this evening.

- Multiple warm days with above-normal temperatures is expected
  through Saturday, and scattered thunderstorms are forecast for
  late Friday.

WEATHER PATTERN OVERVIEW:
A shortwave trough that is entering North Dakota has allowed
clearing to occur on the backside of this disturbance, so
thunderstorms are already underway in central MT and beginning to
move into northeast MT. Surface based CAPE is expected to be
between 1000 and 1500 J/kg this afternoon as peak solar heating is
occurring, and bulk shear from 0 to 6 km is around the 30 to 40
mph mark, so this will support a few isolated strong
thunderstorms. There is low (20 percent) confidence in any one
storm producing a severe wind gust and severe hail. This activity
will end by 9 PM as the storms move into ND by this time.

Another shortwave trough will move through Tuesday night into
Wednesday morning, but little to no rainfall accumulation is
expected given much drier air will be in place by then.

Shortwave ridging will build in for Wednesday through early
Friday ahead of the next disturbance, bringing seasonably warm and
dry weather. Much of the GFS ensemble is hinting at a shortwave
trough moving through the region late Friday. However, the ECMWF
is only indicating a very weak shortwave trough passing through
around the same time.


FORECAST CONFIDENCE and DEVIATIONS:
There is moderate to high confidence in timing of showers and
thunderstorms today, with low confidence in location of the
strongest storms. There is low to moderate confidence in fire
weather conditions occurring particularly for the southwest
portion of the CWA on Wednesday. Low confidence exists for the
timing and location of thunderstorms over the area Friday night
and beyond.

-Zanker/Stoinskers



&&

.AVIATION...

LAST UPDATE: 2000Z

FLIGHT CAT RANGE: VFR, with MVFR/IFR in thunderstorms.

DISCUSSION: As the remaining showers end across eastern MT,
ceilings will improve to VFR. However, isolated thunderstorms have
begun in central MT and will move through TAF sites from 21Z
through 02Z from west to east. There is moderate to high (50 to 70
percent) confidence these storms will produce MVFR ceilings, and
low (30 percent) confidence conditions could reach IFR. Expect VFR
after 03Z.

WIND: West at 13 to 20 knots with gusts to 25 knots, becoming
west at 5 to 12 knots after 04Z. Gusty and erratic winds may
occur in the vicinity of thunderstorms.

EQUIPMENT: The METAR for KSDY is missing, thus AMD NOT SKED.


&&

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

&&

$$

weather.gov/glasgow