Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 290900

Area Forecast Discussion
National Weather Service GLASGOW MT
300 AM MDT SUN MAY 29 2016

.SHORT TERM...for northeast through Tue...

An upper low hovering over British Columbia will spin off a
short-wave trough into the Inter-Mountain West and the Northern
Rockies before withdrawing to the north. This low will move into
Western Montana tonight.

Today, zonal flow over Northeast Montana and a weak ridge in
Southern Saskatchewan will bring about a warm, dry day with mostly
light westerly wind. Expect highs around 10F above normal.

Tonight, off to the west, the digging trough will begin to back
local upper flow around to the southwest, introducing moisture and
instability to the local area. A weak frontal boundary will
initiate rain showers that will spread over much of the CWA before

Monday, the upper low begins to close off and gain strength,
sending a more distinct cold front across the local area. This
will produce more rain showers and general thunderstorms. QPF does
look not particularly heavy, but showers will last long enough to
be wetting on already damp ground. Cloud cover and rain will cool
moderate temperatures to near normal. The strongest convective
parameters will focus over the southeast zones in late afternoon.
Strong storms are expected east of there, so some may begin to
spin up close to the Yellowstone River.

Monday night and Tuesday, the closed low spins up tight enough to
wrap in dry air for some dry slots. With the low not making much
speed to leave the area, models show some areas with moderate rain
next to dry areas wrapped in. Then Tuesday the back side of the
storm gets pulled across the area for more rain. Continued rain
and cloud cover will drop highs to below normal. The surface low
never quite closes off which will keep winds closer to 20-30kt in
the afternoon. During the duration of the storm, a model blend of
rain totals suggest around a third of an inch in the southwest to
around an inch in the northeast, with a transition in between.


.LONG TERM...Tue night through Sun...

As upper low moves to the east Tuesday Night, northwest flow aloft
will bring drier air into Eastern Montana and end the rain.

Upper ridge will build into Montana on Wednesday with dry weather
and warmer temperatures. A shortwave trough moves across
Saskatchewan on Thursday and brings a dry warm front across the
forecast area.

The upper ridge rebounds on Friday and dominates the weather over
most of the western US through the weekend with dry weather and
warm temperatures. forrester



SYNOPSIS: High pressure will bring mostly clear skies today with a
few high clouds. Look for increasing mid level clouds tonight as
an upper trough moves into Western Montana. Showers and low clouds
are expected Monday morning. Expect VFR conditions today and
tonight. MVFR conditions are possible on Monday.

WX: Fog will be very isolated mainly in the 12-15Z period in
typical low lying areas... widespread fog is no expected. There is
a chance of showers late tonight and widespread showers can be
expected on Monday.

WIND: Variable winds less than 15 knots is expected through the




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