Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 201100
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
455 AM MDT Mon Mar 20 2017

Hydro Section Updated

.DISCUSSION...

Today through Wednesday...SFC analysis this morning shows a
stationary front draped across far SW MT. To the north, a cold
front was located over southern AB/SK, with high pressure building
in behind it over British Columbia. This high will shift east
today, pushing the Canadian cold front south into Montana.
Meanwhile, the front stalled over SW MT will begin to lift north
as a warm front as an upper level shortwave (now moving into NRN
CA) moves across the southern half of Montana.

The front across SW MT this morning will be the focus for scattered
to numerous showers, especially this afternoon and evening.
Temperatures this morning should be cold enough for snow or a
rain/snow mix at lower elevations. As the front lifts north, warm
air should allow any snow to change to rain at lower elevations by
this afternoon. However, as the Canadian front sinks south, it may
turn cold enough once again for a transition back to snow tonight,
especially along/north of I-90. At lower elevations, snowfall
amounts look to be light, if any at all. Accumulating snow will
mainly be confined to the mountains where 2-4 inches will be
possible through tonight. Moisture will attempt to work north
tonight into central Montana, but drier air associated with the
Canadian front should limit precip there.

On Tuesday, the front across SW MT will lift NE through the
remainder of central/SW MT. Areas of light precip will be possible
areawide as the front moves through. Of note, warm air aloft with
the front will likely override sub-freezing temps at the SFC
which may allow a brief period of a wintry mix to develop, mainly
along the Hiline and the colder valleys of SW MT. Given the light
nature of the precip and the recent mild temperatures, though,
significant impacts are not expected. By Wednesday, a breezy
westerly downsloping wind should put an end to any lingering
precip from west to east. Martin

Wednesday night through Sunday...It will be an unsettled weather
pattern during the extended period...with Friday looking to be the
one nice day though. A warm front will have moved through the
region by Wednesday night, with showers on the decrease through
Thursday. By Friday, an upper level ridge will be over the region,
resulting in mostly dry/mild conditions. However, the next upper
level trof moves into the region by Saturday afternoon, resulting
in a chance for precipitation over Southwest MT. The precip could
spread northward into North Central MT Saturday night into Sunday.
The GFS progs about 0.50 inches with this system, while the EC is
half that. Showers decrease on Sunday, but with a cool
northwesterly flow aloft developing by Monday, a few scattered
showers will once again be possible. Overall, Friday afternoon
temperatures look to be the warmest, with highs in the 60s,
otherwise seasonable temperatures in the 50s are expected most
other days during the extended. Brusda

&&

.AVIATION...
Updated 0410Z.

The westerly flow aloft will continue mountain top obscuring showers
over Southwest Montana through Monday evening, while energy in the
flow aloft continues showers with occasional MVFR conditions at the
terminals there (KBZN KEKS). The best chance for these lower flight
conditions will be after 18Z. Otherwise, VFR conditions are expected
along and north of a KHLN-KLWT line. Mid and high level clouds will
increase over this area after 12Z, with scattered showers slowly
spreading along and just north of this line (including the KGTF
area) after 18Z. Winds will shift from light and northerly to breezy
and more northeasterly after 12Z.
Coulston

&&

.HYDROLOGY...
455 AM Update.

The areal flood advisory for northern Hill/Blaine counties has been
cancelled.

However, locations along Lodge and Battle Creeks are experiencing
flooding per Blaine County Sheriff Office. Thus a point flood
warning has been issued for these locations. Impacts to homes/fields
have been reported...with large trees/ice moving down the creeks.
The flood warnings will continue until the rivers fall below flood
stage and impacts have decreased. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  28  52  36 /  10  20  10  30
CTB  41  23  45  30 /   0  10  10  30
HLN  44  28  54  36 /  50  60  20  30
BZN  47  27  52  35 /  60  50  20  30
WEY  44  30  48  32 /  60  50  30  50
DLN  51  32  57  36 /  60  60  30  30
HVR  44  24  44  30 /   0  10  10  30
LWT  40  25  42  31 /  10  30  20  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...

Flood Warning for Lodge and Battle creeks until further notice.

&&

$$

weather.gov/greatfalls



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