Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 092319
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
519 PM MDT Sun Mar 9 2014
Tonight through Tuesday...Strong westerly flow aloft continues and
is mixing to the surface. The high wind warning will continue into
this evening before winds decrease and the main weather event
commences. An upper trof moves to the Pacific Northwest bringing a
large plume of moisture across southwest Montana later tonight.
Snow levels and temperatures will continue to be the biggest
sticking point with this forecast. Some valleys and lower
elevations will likely see rain to begin the event and then switch
to snow. When the changeover occurs is still a question. Snow
amounts should be high in the mountains with lesser amounts at
lower elevations. Temperatures will cool on Monday but remain
above freezing. Numerous winter weather highlights are in place.
The upper trof swings through the area Tuesday as upper ridging
builds over the west coast. Temperatures will remain near or
slightly below seasonal averages.
Tuesday night through Sunday...Medium range models are in fair
agreement through next weekend, depicting a progressive westerly
flow aloft over western North America, generally dominated by
ridging over western North America. An upper level ridge over the
interior western US Tuesday night through Wednesday will keep the
region dry with temperatures near to somewhat above seasonal
averages. On Thursday, a fast moving shortwave trough moves east
along the US/Canadian border, bringing increased winds to the
forecast area while most(if any) precipitation should remain north
of the border. Another period of upper level ridging moves in behind
the shortwave on Friday before a somewhat stronger wave moves
onshore in southern BC then digs SE through the Northern Rockies and
MT on Saturday. This system looks to bring another period of
stronger winds as well as a wind shift to the NW and cooler
temperatures along with a period of snow showers Friday night into
Saturday. Drier conditions look to move in again Saturday night
through Sunday as another upper level ridge builds over the Northern
Strong west winds across the Rockies and adjacent plains will weaken
through the evening. Moisture across central Montana will increase
tonight as an upper level low pressure trof moves over the West
Coast. This will bring MVFR/IFR conditions across the Rockies and
much of Southwest Montana. These conditions will spread northward by
late Monday morning. Widespread IFR conditions and mountain
obscurations are expected through Monday.
Another round of rain and snow Monday, followed by a warm- up
midweek, will likely increase snowmelt again and potentially
produce areas of flooding.
.PRELIMINARY POINT TEMPS/POPS...
GTF 32 41 23 44 / 30 90 90 20
CTB 27 38 20 43 / 20 90 70 10
HLN 35 42 26 44 / 60 90 90 40
BZN 35 44 25 40 / 60 90 90 40
WEY 35 42 21 36 / 60 90 90 50
DLN 34 43 24 39 / 70 90 90 40
HVR 29 43 22 46 / 10 70 60 10
LWT 35 42 24 42 / 30 90 100 20
HIGH WIND WARNING until 9 PM MDT this evening Blaine...Cascade...
Central and Southern Lewis and Clark...Chouteau...Eastern
Glacier...Eastern Pondera...Eastern Teton...Hill...Judith
Basin...Liberty...Northern Rocky Mountain Front...Southern Rocky
WINTER WEATHER ADVISORY from Noon Monday to 3 AM MDT Tuesday
Broadwater...Cascade...Central and Southern Lewis and Clark...
WINTER STORM WARNING from Midnight tonight to 3 AM MDT Tuesday
Beaverhead...Broadwater...Cascade...Central and Southern Lewis
and Clark...Gallatin...Jefferson...Judith Basin...Madison...
WINTER WEATHER ADVISORY from 6 AM Monday to 3 AM MDT Tuesday
HIGH WIND WARNING until 9 PM MDT this evening For Route 287 over
Norris Hill in Madison County.
AREAL FLOOD WARNING is in effect for Lewis and Clark County until
Urban and Small Stream Flood Advisories are in effect for Gallatin,
Madison, Jefferson, Broadwater, Fergus, Meagher and Judith Basin
Counties until Monday morning.