Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 270015
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
615 PM MDT Mon Sep 26 2016

UPDATED AVIATION SECTION

.DISCUSSION...

Tonight through Wednesday...Breezy and very warm conditions are
expected through Tuesday, then the weather turns cooler on
Wednesday. A weak shortwave will help flatten the upper level high
pressure over the area into Tuesday. This will continue the breezy
west winds and dry conditions over the area. Gusts will likely
exceed 30 mph across much of North Central Montana, but gusts
could exceed 40 mph closer to the Rocky Mountain Front. The
downsloping winds will also help warm temperatures to between 10
and 15 degrees above normal on Tuesday. The passage of the
shortwave will also move a weak Canadian cold front south through
North Central Montana Tuesday night and into Southwest Montana on
Wednesday. As a result, the breezy winds will shift more northerly
across North Central Montana Tuesday night, then more easterly on
Wednesday. These upsloping winds will help move cooler air and
lower clouds south across the area, along with a slight chance of
light rain showers. Temperatures there will likely only warm to
near normal (upper 50s to mid 60s) there on Wednesday. The clouds,
showers, and cooler air will not quite reach Southwest Montana,
so temperatures will remain above normal there into Wednesday.
Coulston

Wednesday night through Monday...Medium range models are once
again in good agreement for midweek into the early portion of
next weekend before solutions diverge for Sunday and Monday.
Forecast period will be dominated by an upper level low off the
British Columbia and Pacific Northwest coast which places Montana
beneath a moist southwest flow aloft. Wednesday evening is
expected to be dry but isolated showers should move into the
mountains near Glacier Park and in Southwest Montana by early
Thursday morning. A somewhat unstable airmass will fuel scattered
mountain showers and a few thunderstorms Thursday and Friday with
an isolated storm or two possibly moving out over the plains. The
upper level low/trough begins to move inland late Friday and will
be accompanied by an associated surface cold front. Models differ
on timing but the upper level trough and associated front will
move into the forecast area sometime next weekend. The
approaching weather system will bring an increasing chance for
showers and thunderstorms beginning Friday night with unsettled
conditions and cooler temperatures likely persisting through
Monday as Monday remains beneath the trough.
mpj

&&

.AVIATION...
Updated 0015Z.
High pressure aloft will continue to provide dry and stable
conditions. Breezy west to southwest winds will decrease after 02z
but will increase again after 18z and become gusty. The strongest
winds will be along the Rocky Mountain Front and adjacent plains.
VFR conditions prevail.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  82  48  68 /   0   0  20  20
CTB  46  77  43  63 /   0  10  20  10
HLN  46  82  45  74 /   0   0   0   0
BZN  45  81  47  76 /   0   0   0   0
WEY  32  74  35  72 /   0   0   0   0
DLN  43  77  44  74 /   0   0   0   0
HVR  47  83  47  69 /   0  10  20  10
LWT  49  80  46  68 /   0   0  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

weather.gov/greatfalls



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