240
FXUS65 KGGW 140840
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
240 AM MDT Wed May 14 2025

.DISCUSSION...

KEY MESSAGES:

- Storm system tracking over eastern Idaho this morning will move
  east along the MT/WY border today and into the Dakotas tonight
  and become stacked with a surface low over North Dakota on
  Thursday. The low will slowly drift into Minnesota on Friday.


- Expected rainfall amounts have diminished for the most part
  today and tonight compared with earlier forecast. They have
  significantly increased in the east for Thursday and Thursday
  night.

WEATHER PATTERN OVERVIEW:
Upper low currently over eastern Idaho is bringing precipitation
to south central and southwest Montana early this morning. This
low will drift east along the MT/WY border today and some of this
moisture will move north across eastern Montana bringing rain
showers at times. Ensembles and models are pointing towards these
showers being scattered and sporadic today with most areas seeing
a tenth of an inch or less and the SW zones being the main areas
with a good chance of receiving a tenth of an inch or slightly
more today.

The upper low moves into the Dakotas tonight and becomes stacked
with a surface low in North Dakota by Thursday morning. Deep Gulf
moisture will bring heavy rains to the Dakotas some of which will
wrap around into far eastern Montana starting late tonight and
continue Thursday and Thursday night before diminishing on Friday
as the system slowly moves east.

The NBM probability of one inch or more rain between today and
Friday is as high as 70 percent along the North Dakota border but
diminishes to about 30 percent along MT Highway 13, and is less
than 10 percent in the west.

The flow pattern becomes weak overall Friday and Saturday, with
occasional hit- or- miss storms moving through. Models and
ensembles have an upper trough Sunday and Monday with showers
likely.
FORECAST CONFIDENCE & DEVIATIONS:

Low confidence in timing any showers today. High confidence in the
rain in the east late tonight and Thursday and low confidence in
any showers to the west of the main rain band.

For today and tonight, deviated from NBM to blend the best model
consensus of short-term, high resolution models providing detail
for this upcoming storm system. Kept NBM for the remainder of the
forecast.


&&

.AVIATION...

LAST UPDATE: 0840Z, Wednesday morning, May 14th

FLIGHT CAT RANGE: VFR early becoming mainly MVFR today and mainly
IFR tonight.

DISCUSSION: Expect lowering cloud bases this morning with rain
showers at times. Most areas are expected to have MVFR ceilings by
15z with some areas of low VFR mixed in. Ceilings will lower
further to IFR in most areas this evening and continue into
Thursday with frequent rain showers.

WIND: Mainly north today 10 to 15 knots and north to NW 5 to 15
knots tonight.


&&

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

$$

weather.gov/glasgow