Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 250258

Area Forecast Discussion
National Weather Service Great Falls MT
858 PM MDT Sat Sep 24 2016


Upper level low now straddling the ND/SD/MT border will continue
to drift NE tonight while broad upper level ridging continues to
build east across MT with anticyclonic NW flow aloft. Area of
mid-level clouds, strato-cu beneath a subsidence inversion,
continues to slide SE across central MT this evening with clearing
behind it to the W and NW. As low pressure continues to track
away from the region over ND, surface pressure gradient will
continue to relax overnight with winds continuing to diminish.


Updated 2323Z.

VFR conditions will continue at least through the day on Sunday. A
weakly unstable northwest flow aloft will continue to bring
scattered to broken mid level clouds to the forecast area through
03Z, as well as a few light showers over the North Central MT
plains. The gusty northwest winds will also decouple through that
time. High pressure aloft will then bring mostly clear skies to the
area for the rest of tonight and at least through Sunday. Scattered
mid level clouds and breezy westerly winds will redevelop after 16Z,
but showers are unlikely and winds will not be as strong as today.


/ISSUED 523 PM MDT Sat Sep 24 2016/

This afternoon through Monday...A weak disturbance in the
northwest flow aloft will continue mostly cloudy skies over the
forecast area into this evening, with a few light showers
possible over the plains of North Central Montana. The gusty
northwest surface winds will also decrease somewhat during the
evening, as the winds aloft weaken in the wake of the
disturbance. The remainder of this forecast period will remain dry
with mostly clear skies and warming temperatures as high pressure
aloft builds into the area from the west. Westerly downslope
surface winds will remain breezy through the period, but they
won`t be nearly as strong as those today. The winds will also help
hinder fog development across the area overnight. Low temperatures
will fall into the 30s to lower 40s through the period, while
highs warm from near normal on Sunday to between 5 and 10 degrees
above normal for Monday.

Monday night through Saturday...Medium range models remain in
good agreement. Period starts off with weak shortwave ridging
over the Northern Rocky Mountain region for dry and warm
conditions through Tuesday afternoon. An upper level disturbance
moving eastward through Canada flattens the ridge by Tuesday
night. This feature works in tandem with an upper level low that
develops off the British Columbia coast on Wednesday. Model
solutions for this low diverge somewhat, but the overall pattern
common to both models ends up with troughing along the Pacific
Northwest coast with energy moving inland along the West Coast by
late Friday. Forecast for Wednesday through Saturday remains
relatively unchanged from what was seen yesterday. The warmest
day of the forecast period will be Tuesday with temperatures in
the upper 70s and possibly the lower 80s. Wednesday through
Friday will see more seasonable temperatures with isolated
showers gradually increasing in coverage over the western
mountains each day. Models move a surface cold front into Montana
by Saturday for cooler temperatures and a better chance for
showers. mpj


GTF  41  67  45  77 /  10   0   0   0
CTB  38  66  42  76 /  10  10   0   0
HLN  40  69  43  78 /  10   0   0   0
BZN  36  65  43  76 /  10   0   0   0
WEY  31  59  30  70 /  10   0   0   0
DLN  35  66  40  74 /   0   0   0   0
HVR  41  66  43  76 /  20   0   0   0
LWT  38  63  44  75 /  20   0   0   0



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