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Area forecast discussion 
National Weather Service Great Falls Montana
143 PM MDT sun Aug 30 2015

Discussion...
have updated to raise high temperatures a couple of degrees in the
west as 1 PM temperatures were near forecast highs. Also decreased
cloud cover in the east for the rest of this afternoon. Not much
was showing on the radar as of 130 PM but still expect scattered
showers and thunderstorms to develop after mid-afternoon. Blank

&&

Aviation...
updated 1735z.

Scattered showers and thunderstorms will develop during the
afternoon except over the far northwest plains (kctb). Their will be a risk
of wind gusts of 40 to 50 kts and MVFR conditions in brief heavy
rain with the thunderstorms..mainly north of an east-west oriented line
through kbzn. Outside the showers and thunderstorms expect gusty
westerly winds 15 to 25 kts into the evening with stronger winds
over the far northwest plains. Skies will clear and winds diminish from west
to east over the forecast area during the 02z-08z time frame. As for
smoke have low confidence in forecast visibilities and ceilings. Do
expect the MVFR ceilings and visibility conditions from kgtf to klwt
to improve this afternoon. Although do not have a mention of MVFR
ceilings and visibilties for later tonight into Monday morning MVFR
conditions can not be ruled out for any portion of the forecast
area. Blank

&&

Fire weather...
cooler temperatures and higher humidity values on Sunday will
provide a brief break in critical fire weather conditions but a
second cold front is forecast to arrive Sun afternoon bringing
another round of strong winds that will last through sun evening
especially across fire weather zone 112 where a High Wind Warning
is in effect from noon until midnight Sunday. Waranauskas/suk

&&

Previous discussion...
/issued 1135 am MDT sun Aug 30 2015/

Ahead of the main upper level trough...now moving into WA/OR...a
lead shortwave is just about to move out of central Montana. Shower
and thunderstorm activity associated with the lead wave will exit
eastern sections of central Montana by 18z. In its wake...skies are
quickly clearing from west to east at this time. With daytime
heating...expect the atmosphere to destabilize this afternoon ahead
of the next Pacific cold front with weak to modest instability
developing. At the same time...the approaching upper level trough
will provide more than sufficient wind shear aloft for storm
organization. Thinking isolated to widely scattered showers and
thunderstorms will develop early to middle-afternoon as the front
approaches from the west. Highest coverage of storms is expected
across central Montana. Storms earlier this morning were fairly
efficient in mixing down stronger wind gusts with several reports of
40-50 miles per hour accompanying the showers. Based on this and the above-
mentioned shear/instability...the strongest storms this afternoon
could produce strong gusty winds in excess of 55 miles per hour. Outside of the
thunderstorm activity...strong winds are still expected to develop
along and just east of the northern Rocky Mountain front area this
afternoon and evening so the High Wind Warning still looks good.
Martin

&&

Previous discussion...
/issued 546 am MDT sun Aug 30 2015/
Sunday through Tuesday...an active weather period will continue
Sunday as second cold front will move across the area bringing
widespread showers and thunderstorms throughout the day.
Atmospheric moisture remains high for this time of the year and
heavy rain can be expected briefly with any storm that does
develop. However winds aloft are rather strong and will quickly
transport storms across the area and will limit the amount of
rainfall that can be expected at a particular location.
Temperatures will be cooler than Saturday and close to seasonal
averages. Smoke has returned to the majority of the area after a
brief respite behind the first cold front. Some clearing may be
possible after the second cold front on Sunday...however the smoke
will likely return just as quickly as it did on Saturday.

Another concern with the frontal passage will be the expected high
winds along the northern Rocky Mountain front and Glacier County.
Relative humidity values have recovered behind the cold front and are not
expected to drop low enough to necessitate a red flag warning.
However some locations may see near critical fire weather mainly
due to the strong gusty winds.

Monday and Tuesday look to have less active weather with drying
conditions expected and temperatures remaining slightly below to
near seasonal averages. Breezy winds are expected continue to
transport smoke from fires in Idaho and western Montana into the
area and long term reductions in visibility from smoke are
expected to continue through the first part of the work week. Suk

Tuesday night through Sunday...medium range models continue to
trend toward cooler and wetter conditions for Wednesday night
through Saturday. Models are still keeping the solution for Tuesday
night into Wednesday relatively unchanged with seasonable or above
temperatures and breezy conditions. However, by Thursday the upper
level trough along the West Coast of Canada moves inland across the
Pacific northwest and into the northern Rocky Mountain region. This
pattern looks increasingly favorable for scattered to numerous rain
showers with high temperatures likely to top out in the low to middle
60s for Thursday, Friday and Saturday. Model solutions differ by
Sunday with the European model (ecmwf) keeping cooler and wetter conditions in place
while the GFS trends drier and warmer. Have leaned toward the GFS
solution for now. Mpj

&&

Preliminary point temps/pops...
gtf 81 49 74 52 / 40 20 10 10
ctb 77 46 69 48 / 20 10 10 10
hln 80 45 76 46 / 30 10 0 0
bzn 82 43 77 45 / 30 10 0 0
wey 71 32 69 34 / 20 0 0 0
dln 79 41 76 45 / 20 0 0 0
hvr 81 49 75 50 / 30 20 0 10
lwt 80 44 74 49 / 40 50 0 0

&&

Tfx watches/warnings/advisories...
High Wind Warning until midnight MDT tonight for mtz009-010.

&&

$$

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