Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 181017
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
417 AM MDT Sat Mar 18 2017

.DISCUSSION...
Today through Monday...An upper level ridge of high pressure will
be over the region today, allowing for near/record breaking
afternoon temperatures in many areas. Additionally, ample Pacific
moisture will flow into the western mountains today, allowing for
scattered showers along the divide. A Pacific cold front will move
eastward through the region tonight. Strong winds are possible for
a short time as the cold front moves through. Thus a high wind
watch has been issued for the northern portion of the region for
tonight. Temperatures will be cooler on Sunday behind the cold
front, with scattered showers continuing over Southwest MT. For
Sunday night into Monday, expect a rather cold Monday morning
over North Central MT, while scattered rain/snow showers continue
in Southwest MT. Snow accumulations of 3 to 6 inches will be
possible in the mountains around Big Sky/West Yellowstone during
this period...but mainly for elevations above 7000 feet.
Otherwise, afternoon temperatures will continue the cooling trend
into Monday. Brusda

Monday Night through Saturday...The models remain in fairly good
agreement in the extended period with what will likely be a very
progressive pattern. Within this pattern, several shortwaves are
expected to traverse the area. However, it still looks like the main
storm track will remain south/east of the area. Temperatures look to
be near to above normal for most of the week, then potentially
followed up by a cooling trend by next weekend. This pattern does
not appear to favor any significant wind events at this time with
the main jet stream remaining south/east of the area.

The best chance of seeing a bit more widespread precipitation may
come WED/THU. During this time, the models suggest a SFC low may
track northeast through SE Montana which could favor areas from
Bozeman to Lewistown and points east. Right now, the general
consensus is a weaker system with lighter precip amounts (and mostly
rain at lower elevations). Something to watch in coming days,
though, as a stronger/deeper system could mean heavier precip
amounts, especially in that Bozeman to Lewistown area, with a
greater potential for snow at lower elevations. For the plains of
north-central Montana, this pattern continues to look like a drier
one, but each passing shortwave may bring at least a low chance for
showers. Of note, the models this morning continue to suggest enough
instability for some thunder mid-week, but confidence remains too
low to include in the forecast for now. In the mountains, precip may
be enhanced at times next week with the moist W/SW flow aloft and is
where the highest precip totals are expected. Martin

&&

.AVIATION...
Updated 0450z.

Expect BKN/OVC mid/high level clouds over the region through the
period, but overall VFR conditions will prevail. There will be lower
ceilings with some rain/snow showers over the Rocky Mountain Front,
especially overnight tonight. Gusty southwest winds develop Saturday
afternoon across the region and continue through the remainder of
the TAF period, strongest from KCTB to KGTF. Cassell

&&

.HYDROLOGY...
400 AM Update.

Flood highlights from last night continue and are unchanged.
Hill/Blaine counties seem to be most impacted right now, with
minor flooding occurring from snowmelt in southern Canada and the
water flowing southward into the Milk River basin.

Otherwise, the main concern today will be near record highs.
There is the potential for flooding to quickly develop late this
afternoon/early this evening for small streams and creeks that
flow out of the mountains because of the warm temperatures.
However, a Pacific cold front will move through the region late
tonight, slowing down/diminishing the flood threat on Sunday
morning. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  72  38  52  25 /   0  10   0   0
CTB  64  31  44  20 /  10  10   0   0
HLN  69  39  54  31 /   0  10   0  10
BZN  70  41  57  33 /   0  20  20  30
WEY  51  35  44  32 /  10  70  90  40
DLN  66  40  57  33 /   0  10  10  20
HVR  70  37  51  24 /   0  10   0   0
LWT  72  38  48  26 /   0  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...

Flood advisory until 230 PM Today for a portion of Hill...Blaine
counties.

Flood Watch through Sunday morning Blaine...Hill.

Flood Watch from Noon MDT today through Sunday morning Judith
Basin...Meagher...Beaverhead.

High Wind Watch from this evening through late tonight Eastern
Glacier...Northern Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls



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