Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 192016
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
216 PM MDT Thu Apr 19 2018

.DISCUSSION...

Satellite imagery reveals a trough/closed low swinging through
California into the Great Basin today. The base of this trough is
pumping moisture into Montana in the form of cloud cover. This
trough feature will prevent the ridge from forming too strongly
over our area. Additionally, high surface pressure to our east has
maintained a strong easterly flow of cooler air with more low
level moisture over the local region. Expect, fog again tonight,
but not as widespread and dense like last night and this morning.

By Saturday the next feature will be a clipper-like trough zipping
east along the international border. In advance of its associated
cold front, expect a rather warm, above average day. Thickness
heights reach 555dm, lapse rates increase for good mixing of
warmer air aloft to the surface, and all winds will be
southwesterly. This should be the warmest day in quite awhile.
Given decreasing snow cover extent and still brown/dry fuels,
fw conditions will need to be monitored should wind speeds come
in stronger than expected. When the clipper advances into
Saskatchewan, there might be, locally, a quick band of rain
generated. Then temperatures will be knocked back down to around
normal for Sunday.

Finally the next weather feature will be a short-wave trough,
Monday, that will undercut our area mostly. This will likely
bring snow transitioning to rain for southeast Montana that may
clip our southern zones. Expect a return to ridging on Tuesday.

Templer

&&

.AVIATION...

VFR this afternoon. Tonight there could be fog again, though not
as dense as last night/this morning. Therefore MVFR/IFR expected
to be intermittent, and not yet in the TAFs.

A large closed low drifting east through the Great Basin and
across the Central Rockies will undercut our region, weakening the
upper trough. Expect a mild day Friday.

Wind: Southeast 10-15kt, slowly diminishing tonight to around
5-10kt.

&&

.HYDROLOGY...

Flood warnings remain in effect for the Milk River and its
tributaries until further notice.

The Milk River will be on the rise in the next 24-48 hours from
Dodson through Nashua. The main concern is from Tampico to
Glasgow where Moderate Flood Stage is expected to hold into next
week.

The Beaver Creek has risen to Major Flood Stage, but has crested.
With the lack of snow in the basin, levels will continue to fall.

Snowmelt from the Frenchman basin in Sask will give rise to river
levels and aggravate the Milk River into next week.

Some country roads in southern Sheridan County have been flooded
and are closed. A Flood Advisory is in effect until Saturday
evening April 21st. TFJ

To monitor river stage readings, go to our Advanced Hydrologic
Prediction Service (AHPS) page at www.weather.gov/glasgow then
click on "Rivers and Lakes" then "River Observations". Data for
this page are provided by the USGS.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

weather.gov/glasgow



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