Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 252059

Area Forecast Discussion
National Weather Service Great Falls MT
259 PM MDT Tue Oct 25 2016


Tonight through Thursday...Moisture ahead of a shortwave trough
will bring scattered showers to the mountains of Western and
Southwest Montana through tonight. A few light showers may also
move across North Central Montana after midnight, but breezy
westerly downslope winds will hinder significant rainfall. An
upper level high pressure ridge will then build back into the
area on Wednesday in the wake of the shortwave. The resulting
moist westerly flow aloft will keep shower activity over Northwest
Montana to the Continental Divide, while continued gusty westerly
winds along the Rocky Mountain Front keep the plains dry. The
ridge will then shift east into the Great Plains Wednesday night
into Thursday, but the resulting southwest flow aloft and
increasing southwest downslope winds will keep precipitation along
and west of the Continental Divide. Wind gusts on Thursday will
mostly be in the 25 to 35 mph range over North Central Montana,
but 40 to 55 mph gusts are possible closer to the Rocky Mountain
Front. Light measurable snow will be possible, but mainly above
8000 feet. Temperatures will cool a few degrees over today in the
wake of the shortwave, but the downsloping winds will warm
temperatures to about 10 degrees above normal on Thursday.
Overnight lows will remain mild and mostly in the mid 30s to
lower 40s.  Coulston

Thursday Night through Tuesday...

AFTERNOON UPDATE: A few minor changes needed for the long term
today. Morning models have the late week system progressing a little
faster...placing rain in the sw Friday morning...spreading northeast
through the day. Rain then lingers through the evening into the
overnight hours. Increased pops during this period to include likely
across many areas. Models also painting higher QPF than previously
indicated...with 0.20 to 0.50 inches possible from Great Falls to
Lewistown and south...with the higher amounts coming across the
south. Brief ridging looks to diminish showers
Saturday...however...GFS indicating a weak wave may bring a few
scattered showers Saturday evening into Sunday. Sunday night through
Halloween is still seeing model differences. GFS and Euro now
indicating more of a weak progressive wave. Either solution still
indicates rain possible for Sunday night into
Halloween...however...the coverage and amount of rain is only at mid
confidence. Models are also indicating rain showers could diminish
by trick or treat time Monday evening. Those with Halloween plans
should keep an eye on the latest forecasts. Please see previous
discussion for further break down of the weather pattern details.

PREVIOUS FORECAST DISCUSSION: A shortwave system ejects from the
Eastern Pacific low and crosses the Great Basin Thursday night.
Timing variations persist among model solutions, but all bring
widespread precipitation through western and central MT sometime on
Friday. One to two-tenths of an inch of rainfall may be possible on
Friday, with higher totals in the mountains. Snow levels of 6500 ft
msl or higher would preclude any impacts for travel over mountain
passes. This system exits quickly with mild and generally drier
conditions for Saturday. The next wave moves through Oregon on
Sunday, and spreads precipitation through our region from the
southwest Sunday night into Monday. As this system passes through,
the flow aloft transitions to a more unsettled zonal pattern.
Temperatures remain above average through the period. PN



Overall VFR conditions...with periods of mid level BKN to OVC
clouds are expected during the forecast period. Moist southwest
flow will bring increase clouds today and again tonight across
the area. VFR cloud ceilings are expected...with periods of BKN
to OVC skies. Breezy winds may also return this afternoon across
most sites...with gusts of 25 to 30 knots possible...with
diminishing winds expected tonight. Only chances of rain today
will come in the mountains...possibly causing mountain
obscuration at times. Anglin


GTF  42  63  47  65 /  10  10  10  10
CTB  37  57  40  59 /  10  10  10  10
HLN  41  65  42  64 /  10  10  10  10
BZN  41  65  42  66 /  10  10  10   0
WEY  34  53  29  57 /  20  10  10  10
DLN  39  64  39  63 /  10  10  10  10
HVR  40  59  41  63 /  10  10  10  10
LWT  42  63  44  67 /  10  10  10  10



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