Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 221001
Area Forecast Discussion
National Weather Service Great Falls MT
401 AM MDT Wed Mar 22 2017
Today through Friday...A surface warm front is moving northward
through the region this morning. Warm air as moved in aloft
already, with snow levels generally above 7000 feet. The light
showers generally affecting areas mainly east of a Helena to Ennis
line as of 345 AM. These showers will diminish quite a bit by
9 AM. Some freezing rain could mix in for areas along/north of
Highway 2 this morning with road temperatures near freezing, but
precipitation amounts will be light. Otherwise, warmer air moves
in at the surface for this afternoon, with highs climbing into the
60s. A southwest to westerly flow aloft will then reside over the
region from tonight through Friday. The storm system for
Thursday/Thursday night continues to look like most of
precipitation will stay south of our region, with mainly just the
West Yellowstone/ Big Sky area getting a passing shower.
Afternoon temperatures will cool a touch on Thursday into the
50s, only to rebound back into the 60s on Friday. There will be a
small chance for showers by late Friday afternoon over the front
range of the Rockies as the next upper level trof approaches the
Friday Night through Wednesday...A large scale, but weakening
Pacific trough moves inland Friday night. Orographic precipitation
is likely to develop up to the Continental Divide by Saturday
morning, with snow levels dropping below about 6000 ft. Several
smaller shortwaves will move through this unsettled west-southwest
flow. Models are converging on a solution that would favor rain and
mountain snow across Southwest Montana Saturday afternoon. Some
solutions are wetter than others, but ensemble averages support
around one-tenth to one-quarter inch of liquid QPF and 2-4 inches of
snow above 7500 feet. Fair weather returns for Sunday as an upper
level ridge axis amplifies and crosses the state. The overall
pattern remains progressive, with another large scale Pacific trough
spreading moisture across the intermountain west Monday or Tuesday.
Model solutions diverge widely late in the period, though favoring a
return to fair weather for Wednesday. Temperatures remain slightly
above average through the period. PN
Complex forecast overnight through the morning Wednesday, with
rain showers at times across the region. Some freezing rain can
not also be ruled out, especially far northeast areas as well as
some sheltered valleys of SW MT that do see some rain. However,
any widespread freezing rain threat is minimal. Fog has also
become an issue especially over south and eastern areas, and may
spread north and west across the Plains overnight. Otherwise, a
series of disturbances will move northeast over the region. A mix
of flight categories can be expected until 12z to 18z over the
Plains, when skies will mostly clear out and become VFR as gusty
west to southwest winds develops across the Rocky Mountains and
spreads out over the Plains. Cassell
Updated 400 AM.
No changes this morning to the current hydro highlights.
1. The flood warning for an ice jam on the Big Hole River around
Wise River continues. Some problems continue around Dickey Bridge.
This is a very unpredictable problem/impact with the latest river
observations in the vicinity still showing some erratic effects
from ice. Elsewhere on the Big Hole River, expect high flows over
the next few days, with the potential for additional ice jams.
2. The flood warning continues for Lodge Creek north of Havre. It
has been trending down over the past 36 hours, and it could take
until this evening or a bit later to fall below flood stage.
3. The flood warning continues for the Milk River near Harlem.
This gauge has fallen just below flood stage, but it has remained
nearly steady over the past 12 hours. Thus, a high amount of
water continues to flow through the system, and some minor
flooding impacts are likely to continue today for areas east of
Chinook through Fort Belknap.
.PRELIMINARY POINT TEMPS/POPS...
GTF 63 36 56 32 / 10 0 0 0
CTB 56 34 51 27 / 10 0 0 0
HLN 60 36 54 31 / 10 10 0 0
BZN 58 34 52 29 / 20 10 10 0
WEY 42 25 40 20 / 40 10 20 10
DLN 54 33 51 29 / 20 10 10 0
HVR 62 36 57 29 / 10 0 0 0
LWT 61 36 52 30 / 10 10 10 0
Ice Jam Flood Warning in effect until further notice for the Big
Hole River near Wise River in north-central Beaverhead County.
Flood Warning remains in effect until further notice for the Milk
River near Harlem in Blaine County.
Flood Warning remains in effect until further notice for Lodge
Creek near Havre in Hill County.