Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 140959

Area Forecast Discussion
National Weather Service Great Falls MT
359 AM MDT Wed Mar 14 2018

An upper level ridge of high pressure will be over the region this
morning, but this ridge will move eastward by tonight, as a strong
upper level disturbance moves into the region. Expect rain and snow
showers to develop late this afternoon over Southwest MT and then
gradually move northeastward and spread into Central MT tonight. On
Thursday, expect colder air to move into the region, allowing for
the potential for a period of freezing rain, sleet or snow to fall
over much of North Central MT.


Today through Thursday...A southwest flow will reside over the
region today, resulting in another mild day over Southwest MT.
Much of the Hi-line area will not mix out, and be quite a bit
colder, along with some morning dense fog. Showers will develop
over Southwest MT late this afternoon and move into Central MT
this evening. An isolated lightning strike is possible over the
Southwest towards evening, but with minimal CAPE, kept lightning
out the grids for now. Both the GFS/WRF have a narrow area of 0.50
to 0.75 inches of precip extending from Judith Basin
northwestward to Cut Bank late tonight and thru the day on
Thursday. The GFS is further west and a bit more widespread with
the heavier precip. Thus a winter storm watch has been issued for
this region. Overall there is the potential for a narrow band of
near 8 inches of snow at lower elevations in the watch area. There
is also the potential for a mix of freezing rain/snow/sleet over
much of the eastern half of North Central MT. No highlights for
this yet, but Hill/Blaine/Fergus county might need an advisory.
Temperatures will be well below normal on Thursday.

For Thursday night through Sunday...most models indicate a rather
unsettled period of weather with periods of mostly snow falling.
Overall during the day on Saturday looks to be the one period
where we should have a break in the precipitation. Overall daily
snowfall accumulations of 1 to 3 inches seem possible in most
areas. Again, temperatures will remain below normal.

For Monday through Wednesday, the GFS/EC have different solutions
for the region, as the EC is quite a bit colder, with periods of
snow, especially over North Central MT. The GFS is not quite as
cold/snowy. Overall, leaned towards a blend for Mon thru Wed, but
confidence is low at this time for this period. Brusda


Updated 1000Z.
Mid/high level clouds will continue to increase through today.
Some patchy dense fog is possible over North Central MT, mainly
before 14z. Rain/snow showers will develop over Southwest MT
after 20z Wed and then gradually spread northeastward this
evening. An isolated lightning strike is possible mainly before
03z Thu. Expect mountains/passes to gradually become obscured
towards this evening. Widespread IFR conditions will develop after
06z over Central MT, as a mix of rain/snow/freezing rain develops.
The snow could become heavy by 12z Thu in the Great Falls area.


Updated 400 AM.
The flood advisory will continue for portions of Southwest MT, as
minor flooding continues to be reported via emergency managers.
Based on local emergency manager feedback, areas that are not
flooding could begin to see flooding during the afternoon and
evening hours over the next few days.

Mild temperatures are expected again today over Southwest MT, but
cloud cover should limit some melting. Rain/snow will move into
the region late this afternoon and evening. Overall liquid
rainfall should be less than 0.25 inches in most areas, thus
significant new flood issues are not anticipated at this time.


GTF  48  25  38  21 /  10 100  90  10
CTB  36  23  32  16 /  10  40  90  20
HLN  47  30  40  25 /  20  90  90  20
BZN  50  30  42  24 /  20  90  80  40
WEY  46  25  36  18 /  60  70  60  50
DLN  49  27  38  22 /  30 100  80  40
HVR  23  17  29  17 /   0  30  70  10
LWT  50  26  38  24 /   0  70  60  30



Winter Storm Watch from late tonight through Thursday afternoon
Cascade...Chouteau...Eastern Teton...Judith Basin...Southern
Rocky Mountain Front.

Winter Storm Watch from late tonight through Thursday afternoon
above 4500 feet for Central and Southern Lewis and Clark.

Winter Storm Watch from Thursday morning through Thursday
afternoon Eastern Glacier...Eastern Pondera...Liberty...Northern
Rocky Mountain Front...Toole.

Flood Advisory for Snowmelt until further notice for
Jefferson...Broadwater...and Northern Gallatin Counties.


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