Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 260932

Area Forecast Discussion
National Weather Service Great Falls MT
332 AM MDT FRI AUG 26 2016


Today through Sunday...A weakening frontal boundary has advanced
through most of the forecast area early this morning associated
with a passing upper level disturbance. Northerly flow aloft will
continue to push moisture into north-central Montana where partly
to mostly cloudy conditions will continue today. A few rain
showers are moving east of Havre and along the ID/MT border,
producing only trace amounts of precipitation. Additional rain
showers are possible this afternoon amid the cloud cover over
mainly eastern portions of north-central MT. A short wave ridge
will produce mostly clear skies Friday night. The upper level flow
turns more westerly on Saturday as another vigorous shortwave
trough drops through western Canada. Surface pressure falls
associated with this system will induce breezy west winds on
Saturday. This downslope flow, combined with warmer temperatures
and partly to mostly sunny skies will produce low afternoon
humidity and locally elevated fire weather conditions. Given
recent cool and moist weather, fuels are less receptive to fire,
so will not issue any fire weather headlines at this time but
continue to monitor. Breezy, but otherwise fair and seasonal
weather prevails on Sunday with high pressure at the surface and a
brisk westerly flow aloft. PN

Sunday Night through Friday...Fairly quiet start expected for next
week as weather pattern shifts from zonal/westerly flow on Mon to
more southwesterly by midweek. The directional shift looks to be due
in large part to a moderately strong upper-level trof forecast to
develop along the Canadian/PacNW coast and remain along the coast
until at least Thurs night.  A few embedded shortwaves will move
through the flow and combine with a mix of Pacific and monsoonal
moisture to give our region a chance of isolated thunderstorms each
aftn from Tues through Fri.  By Fri, models solutions differ quite a
bit, with the ECMWF bringing the main trof onshore and moving it to
the Idaho Panhandle/NW Montana by late Fri night. Meanwhile, the GFS
keeps the trof axis and central circulation along/offshore until Sat
morning.  As a result, the ECMWF brings in a broader area of showers
and thunderstorms for central/southwest MT on Fri aftn/eve than seen
in the GFS. Thanks to the warm southwest flow, high temperatures
will remain close to seasonal values, reaching the low- to mid 80s
each day next week.


A cold front has moved through north-central Montana and will
continue advancing southward through Friday morning. Satellite and
radar imagery reveals isolated light showers with generally SCT to
BKN mid level clouds across the region. Short-term model guidance
indicates a gradual increase in cloud cover over north-central MT
through Friday afternoon. Scattered rain showers are also indicated
early Friday morning and again Friday afternoon, mainly impacting
KHVR and KLWT. Conditions improve from west to east Friday evening
as the upper level disturbance moves away. VFR conditions prevail in
general, although temporary MVFR are possible near rain showers. PN


GTF  71  51  84  57 /  10   0   0   0
CTB  69  51  80  53 /  10   0   0   0
HLN  73  50  84  56 /  10   0   0   0
BZN  73  44  83  48 /  10   0   0   0
WEY  67  38  70  40 /  20  20   0   0
DLN  73  43  81  48 /   0   0   0   0
HVR  69  48  85  56 /  30   0   0   0
LWT  66  47  81  54 /  20  10   0   0



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