253
FXUS65 KGGW 192116
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
316 PM MDT Mon May 19 2025

.DISCUSSION...

KEY MESSAGES:

- Low pressure system will continue rain opportunities through
  Tuesday.

- Opportunities for rain will return, mainly Thursday night into
  the weekend.

WEATHER PATTERN OVERVIEW:
Upper low that has brought the area some needed rainfall will
remain centered over South Dakota til it moves east on Wednesday.
A moisture surge from southeast to northwest will keep rain
chances lingering over the NE zones longer with the chance of
rainfall till about Tuesday night or Wednesday. The SW zones are
expected to receive less than a tenth of an inch while northern
and eastern zones should see close to a quarter of an inch, the
most being in Sheridan county with close to a third of an inch.

For tonight, clouds are expected to linger and could limit fog
formation. I`ll leave inherited patchy fog as there is ample low
level moisture in place. With light winds, fog is still possible
if skies in places clear.

On Tuesday, a weak ridge to our west will begin pushing in,
proving some clearing and thus warmer temps. Temps should reach
the 60s west but clouds and scattered showers over the east will
keep things cool here.

Temperatures will gradually warm into Thursday as sunshine will
gradually modify the airmass. Look for highs Thursday to be in the
60s most places.

A small but closed system enters the picture on Friday that could
bring a wetting rain to parts of the CWA. This will also cool
temps across the area back below normal.

Afterwards, the models seem to be in disagreement so confidence on
what happens is quite low. Steering currents look quite weak and
the longwave models are trying to build an upper ridge over the
western states while Friday`s disturbance may linger over eastern
Montana.

FORECAST CONFIDENCE & DEVIATIONS:
Pretty much went with the NBM through the entire 7 day period.

With the Aviation grids, sided with the HIRESarw for ceilings and
Preferred Blend for visibilities.


&&

.AVIATION...
FLIGHT Category: MVFR, possible IFR

MVFR ceilings will linger but could drop to IFR at KSDY and will
remain at IFR at KGDV tonight. But confidence in these lower
ceilings are moderate at best as observations have been higher
than expected lately.

WINDS: East/NE winds will decrease tonight.

There is a slight chance of patchy fog late tonight but widespread
conditions are not expected. TFJ

&&

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

$$

weather.gov/glasgow