Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 170600

Area Forecast Discussion
National Weather Service Great Falls MT
1200 AM MDT Sat Mar 17 2018


We remain in a rather active pattern through the upcoming weekend
across the area, with several intervals of snow, and perhaps some
mixed precipitation in a few areas. Temperatures will remain
below-normal for all areas through early next week, with the
potential for slight moderation next week with a return to drier


.1130 PM UPDATE...

The band of light to moderate snow that has been impacting
portions of Blaine County this evening is beginning to weaken.
Snow will continue to wind down from south to north across the
county overnight. As the snow moves out, there is still some
potential for light freezing drizzle to continue until early
Saturday morning. Since the snow is diminishing, the current
Winter Weather Advisory for that area will be allowed to expire
at Midnight. However, the fresh snow and some freezing drizzle
will continue to lead to slick conditions are roads into Saturday


Updated 0600Z.

FZFG will continue to cause significant aviation impacts across
Central MT through SAT AM.

The main concern overnight will be continued LIFR/VLIFR conditions
across Central MT due to very low clouds and FZFG. Seeing as there
is no real mechanism to mix the fog out, conditions will remain
poor through SAT AM, possibly even lasting into early SAT
afternoon. Attention then turns to the next wave moving north from
the Great Basin. This system will bring rain and snow showers to
SW MT, possibly even accompanied by some lightning and gusty winds,
with areas of light snow expected over portions of Central MT.
The worst conditions, aviation-wise, look to be over Central
Montana where low clouds and snow will lead to continued IFR/LIFR
conditions. MARTIN


Updated 16/0850 PM.

Emergency management officials have reported little, if any,
change in the minor flooding situation across Jefferson,
Broadwater, and northern Gallatin Counties. Therefore, the Areal
Flood Advisories have been extended at least through the weekend.

Elsewhere along the north and east facing slope areas of the Rockies
across north central Montana and south through the remainder of
southwest Montana, there have been a few reports of low land and
field flooding, along with water approaching rural roadways.
Precipitation should increase once again from the south over the
weekend, which may enhance snowmelt and runoff, especially in the
southwest, so have issued a Hydrologic Outlook to address the
potential for additional minor flooding. Some creeks and streams
will also run high or may even run out of their banks. Although main
stem rivers will also rise a bit, river flooding is not likely, but
cannot rule out the potential for isolated ice jam development. Will
continue to monitor the situation for additional flood highlights.


/ISSUED 859 PM MDT Fri Mar 16 2018/


Shortwave and associated light snow falling this evening over NE
portions of north-central MT will lift N north in SK late
tonight. Still some potential for freezing drizzle in this area as
precip comes to an end later this evening and the winter weather
advisory for Blaine county will continue until midnight. Fog is
main impact elsewhere across north-central MT tonight with
relatively quiet and dry conditions over SW MT until the arrival
of the next shortwave upstream Saturday morning. Have extended the
Freezing Fog Advisory through 9AM Saturday for much of north-
central MT. Dense fog is already fairly widespread from Great
Falls north to Cut Bank and will likely expand east behind the
exiting precipitation area back into NE portions of the forecast
area later night. Cannot rule out some areas of ice accrual or
freezing drizzle in these areas, especially later tonight as the
moist layer deepens, but primary impact will continue to be very
low visibility and related driving hazards. There will be little
to aid in the dispersion of fog Saturday morning though slight
improvement is possible by afternoon as clouds and light
precipitation spread north into the area with the arrival of the
next shortwave. Hoenisch


GTF  25  35  23  33 /  10  60  60  70
CTB  24  30  18  30 /  20  30  40  50
HLN  26  36  25  36 /  10  70  60  50
BZN  24  40  21  37 /  10  40  30  30
WEY  18  36  15  31 /  40  90  50  40
DLN  24  34  22  33 /  20  80  50  50
HVR  24  30  19  30 /  80  10  60  70
LWT  24  36  23  32 /  30  10  40  40



Flood Advisory continues until further notice for snowmelt in
Jefferson...Broadwater...and Northern Gallatin Counties until Friday

Winter Weather Advisory from 3 PM Saturday to noon MDT Sunday
Broadwater...Cascade...Central and Southern Lewis and Clark...
Eastern Teton...Jefferson...Meagher...Southern Rocky Mountain

Freezing Fog Advisory until 9 AM MDT Saturday Blaine...Cascade...
Chouteau...Eastern Glacier...Eastern Pondera...Eastern Teton...
Hill...Liberty...Northern Rocky Mountain Front...Southern Rocky
Mountain Front...Toole.

Winter Weather Advisory from 6 AM Saturday to 6 AM MDT Sunday


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