Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 191620
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
920 AM MST Thu Jan 19 2017

.SHORT TERM...for northeast Montana...today through Sat...

Fog continued to be reported at OLF (Wolf Point Airport) and thus
will keep patchy fog going in the forecast for the next couple of
hours. Otherwise, tweaked temps (downward) and clouds (downward).
Rest of forecast looked good. Jamba

Previous Discussion...
Upper trough will move inland from the Pacific today as the base
of the trough will dig into California and Arizona. This trough
will split tonight and weaken into a shortwave as the northern
branch moves into Wyoming this evening.

For Northeast Montana, it will remain dry as some high clouds
ahead of the system moves across the area. Temperatures aloft will
cool from +9C at 850 mb this morning to +4C this evening as a weak
cold front moves through the area today. Temperatures in the west
will likely be not as warm as yesterday while the east should have
temperatures similar to yesterday.

The shortwave moves across Eastern Montana tonight and Friday on
SW flow aloft. Moisture at this point looks to limited to the
southern zones of the forecast area with a chance of mixed precip
as lows will be near freezing.

Friday highs will be somewhat cooler with cloud cover and cooler
air aloft (850 mb temp +2).

Friday Night and Saturday, an upper trough moves slowly north
across the Dakotas with enough moisture for a chance of snow
showers as temperatures by this time should be cold enough for all
snow. Forrester


.LONG TERM...Sat night through Thu...
Synoptic Setup: Long range begins with a large trough over the
middle half of the United States and Canada. A Pacific airmass
inhabits this trough from the Four Corners to southern Alberta. At
that point modified arctic air takes over and runs north into
full blown arctic airmass over Alaska. To the west a slightly
warmer ridge runs up the coast from California to British Columbia
with an even larger trough directly behind it over the northeast
Pacific.

Saturday night onward: as cooler air moves in from the north...
the pacific air across the region will continue to modify
becoming slightly colder each night with a gradual cool down of
the high temperatures through Thursday of next week, highs
returning to normal values. There are no major cold fronts, one
weak cold front late Sunday night into Monday within the long
range but there are subtle features which bring slightly cooler
temperatures with showery unsettled conditions through next
Wednesday, only light localized accumulations forecast.

Models point to a warm up Thursday bringing in a new pacific
ridge. So, no arctic plunge or big snowfall event is anticipated
in the long range at this time. Confidence is average. GAH


&&

.AVIATION...

FLIGHT CAT: VFR.

SYNOPSIS: A weaken low pressure trough is forecast to move into
the west side of the central U.S. upper level high pressure
ridge. This will be the first in a series of disturbances moving
inland from a strong Pacific NW low pressure system. Very little
precipitation will make it over the Divide today with
temperatures above freezing in NE MT. Expect melting or patchy
ice on some runways.

FOG: There is a chance of patchy river fog to develop along the
Milk and Missouri river valleys again tonight. At this time
chance is too low for an insert in TAF. Will amend if necessary.

WIND: Southwest at 5 to 15 kts, except at KGGW where winds may be
more southeasterly at times. Winds will shift to a more W-NW
direction this evening into Thursday .

TC/GAH


&&

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

&&

$$

weather.gov/glasgow


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