Area Forecast Discussion
Issued by NWS Missoula, MT
FXUS65 KMSO 231003
Area Forecast Discussion
National Weather Service Missoula MT
401 AM MDT TUE SEP 23 2014
...Near Record High Temperatures for Wednesday...
.DISCUSSION...Southwesterly flow aloft will persist today allowing
for a weak disturbance with fairly high moisture content to move
into the region, especially northwest Montana. Line of showers
associated with this disturbance will move through northwest
Montana this morning. The atmosphere appears to become fairly
unstable this afternoon with enough moisture to cause scattered
showers across the Northern Rockies. Temperatures today are
anticipated to be a few degrees cooler compared to yesterday due
to the increase in cloud cover.
The ridge is expected to amplify on Wednesday pushing in a very
warm air mass. Near record maximum temperatures are expected by
Wednesday afternoon. Gusty southerly winds will mix to the surface
during the afternoon and evening hours on Wednesday. The
combination of high temperatures and gusty winds could create
hazardous fire conditions.
The ridge axis shifts slightly to the east on Thursday. Clouds
will be increasing across northwest Montana causing a slight
cooling to the area. Lemhi county up into Butte/Blackfoot region
should anticipate another hot day with more gusty winds during the
afternoon and evening on Thursday.
A weak front will have stalled near the Idaho/Montana border on
Friday. There could be scattered showers during the day, but a better
chance may be Friday night into Saturday. The big difference will
be the change from temperatures in the 80s from Thursday to
60s/70s on Friday.
There continues to be a disparity between weather models for the
weekend. The GFS continues to hang on to a much cooler and wetter
solution for Saturday across much of the Northern Rockies than the
ECMWF. Have continued an above normal chance for precipitation
Saturday and Sunday. Temperatures will be near normal on Saturday
but below normal for most places on Sunday.
Early next week: Confidence is poor, but there seems to be a hint
of the upper level trough lingering over Montana which would keep
the threat for showers and temperatures near to below normal.
.AVIATION...A line of showers associated with a weak disturbance
will move through northwest Montana this morning. The atmosphere
destabilizes this afternoon allowing for the development of
scattered showers and thunderstorms. KGPI and KMSO have the best
chance of being impacted by the convection today. WINDS could
become gusty this afternoon across Lemhi county and southwest
Montana. The convection and wind will be diminish this evening,
especially after sunset.