463
FXUS65 KGGW 212049
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
249 PM MDT Tue May 21 2024

.DISCUSSION...

KEY MESSAGES:

1) More widespread chance for showers and thunderstorms will
begin Wednesday afternoon through Friday.

2) A brief pause is expected on Friday night or Saturday morning
before another round of showers and thunderstorms settles in for
Saturday evening into Monday.

WEATHER PATTERN OVERVIEW:

An upper trough pattern looks to continue across the western
CONUS through the second half of this week. Expect occasional
shortwaves helping produce enough lift and instability for daily
shower and thunderstorm chances.

A significant low pressure system will track through the northern
Rockies over the next few days with a more widespread opportunity
for wetting rains from showers and thunderstorms. This unsettled
weather pattern looks to linger into the upcoming weekend.

CONFIDENCE LEVEL and POTENTIAL DEVIATIONS FROM BASE FORECAST:

Confidence remains high that a wetter weather pattern is set to
unfold for the second half of this week. Confidence is lower but
increasing on exact precipitation amounts and precise location
given the challenges associated with the convective nature of
expected precipitation. In general, look for greater QPF to the
southwest and lesser to the northeast. The NBM 72 hour probability
of at least a half of an inch through Saturday morning remains
about 50 percent in the southwest and 20 to 30 percent across the
northeast zones. Will continue to trend toward the base forecast
for now but future shifts will be better positioned to add detail
based on mesoscale or near term CAMS.


&&

.AVIATION...
VFR conditions are expected though an isolated shower or
thunderstorm remains possible this afternoon and evening.

Winds will be northwest at 10 to 20kts this afternoon, becoming
light and variable tonight.


&&

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

$$

weather.gov/glasgow