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Area forecast discussion 
National Weather Service Great Falls Montana
514 am MDT Tuesday Sep 1 2015

Discussion...
Tuesday through Thursday...windy conditions will develop again
today especially along the Rocky Mountain front. A red flag
warning has been issued for fire weather zone 112. Conditions will
also be close on fire weather zone 114...however confidence that
humidity values will be dangerously low is not as strong so will
hold off on issuing any product for the time being. Near critical
fire weather conditions will exist on Tuesday and Wednesday for
much of the area. Models continue to slow down the progression of
the next approaching system. Have decreased probability of precipitation and quantitative precipitation forecast on
Wednesday and increased them on Thursday due to this continued
trend. Temperatures are still expected to remain near seasonal
averages for the next two days with cooler conditions expected
Wednesday evening and Thursday. Some locations at higher
elevations especially along the Rocky Mountain front could see a
some light snowfall overnight Wednesday with this next system. Suk

Thursday night through Tuesday...an upper level low pressure trough
will be over the Pacific northwest Thursday night with the low
beginning to close and slowing down. The associated cold front will
be crossing the zones during the night and should be well into
southwest Montana by morning...and cooler temperatures will follow on
Friday. The air mass will moisten well ahead of the trough and
Thursday night and Friday precipitation should be rather
widespread...and models have increased precipitation values ahead of the
trough during the past 24 hours. The European model (ecmwf) and GFS are quite similar
through 12z Sat. Beyond this point, the European model (ecmwf) remains a closed low
while the GFS moves east as an open wave. With the slower movement
of the ECMWF, precipitation would start later and temperatures would be
slower to cool. With the faster movement, the GFS brings the trough
over the Idaho Panhandle Saturday night and the trough is broadened as
a shortwave moves into the trough from the west. The models differ
here as well. The GFS shortwave is much weaker and the air mass
begins to dry Sunday night. The deeper low of the European model (ecmwf) would delay
movement of the trough east and delay any drying of the air mass until
Monday. This would keep precipitation in the forecast longer as well
and keep temperatures cooler into Monday. With the model
uncertainty, will remain cautious and blend through this period. The
air mass will be quite dry again Monday night and Tuesday, high
pressure aloft will be building, and temperatures rising back above
seasonal normals. Zelzer



&&

Aviation...updated 1113z.

VFR conditions are expected to prevail through the taf period. Gusty
winds will return to the plains of central and north central Montana
this morning through sunset. Some obscurations due to smoke will
remain possible through this time. Suk

&&

Fire weather...new red flag warning now in effect for fire zone 112
for noon to 9 PM Tuesday. Gusty winds return to the Rocky Mountain front
and adjacent plains in Glacier/Toole/Liberty counties tomorrow which
will combine with afternoon humidity values again dropping into the
15-20 percent range. Low humidity will also develop over much of
central Montana but wind speeds should remain below critical fire weather
criteria. Waranauskas

&&

Preliminary point temps/pops...
gtf 84 54 81 50 / 0 0 10 30
ctb 77 51 72 44 / 0 0 10 50
hln 84 50 82 48 / 0 0 10 20
bzn 85 49 86 47 / 0 0 10 10
wey 77 39 76 37 / 0 0 0 0
dln 83 49 82 46 / 0 0 10 10
hvr 83 50 82 50 / 0 0 0 30
lwt 83 56 85 47 / 0 0 10 10

&&

Tfx watches/warnings/advisories...
red flag warning from noon today to 9 PM MDT this evening for
mtz112.

&&

$$

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