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Area forecast discussion 
National Weather Service Great Falls Montana
1150 am MDT Wednesday may 6 2015

..update to aviation...

Update...clouds and precipitation continues to move eastward this
morning. Have updated to tweak probability of precipitation and sky cover for the remainder
of today based upon observations and morning model runs. Have also
made some tweaks to winds to be more in keeping with morning
observations and border changes by neighboring offices. Mpj


updated 1750z.

Isolated to scattered showers will continue to affect much of
southwest Montana through Thursday morning. Expect MVFR/VFR ceilings
and mountain obscurations across southwest Montana through the
forecast period. Scattered to broken middle level clouds will linger
across north central Montana with widespread VFR conditions
prevailing through the period. However, areas of MVFR ceilings
remain possible, especially after 00z Thursday. Mpj


Previous discussion...
/issued 450 am MDT Wednesday may 6 2015/

Today through Friday...surface pressure is rising and a cooler
airmass is moving into central Montana. To the west, an upper
level low pressure trough will move into the Pacific northwe3st
today. However, this trough will begin to split with stronger
portions of the system moving into Alberta and California. This
will leave central Montana under the influence of only weak
dynamics. Southwest flow aloft and good diffluence will continue
Wednesday and Wednesday night mainly over southern Idaho and along
the Idaho/Montana border. This area will spread northeast Thursday
but the best chance for precipitation will remain across the
southern portions of southwest Montana. The northern portion of
the trough will cross Alberta Wednesday and Wednesday night and this
will bring an associated cold front into the hiline. Moisture will
be limited with this feature but cooler temperatures will result. A big
split in the upper level trough will be in place by Thursday as the
upper level low center closes off over central California. The
trough will move very slowly and be over The Rockies by late Friday.
The airmass will cool through the period and temperatures will
trend lower. By Friday, temperatures will be around 10 degrees below
normals. Zelzer

Friday night through Wednesday...expect scattered showers to continue
to affect much of southwest Montana through the a slow moving
upper level low moves through the central rockies. Precipitation
amounts will generally be light through the period. Additionally...the
airmass will be cold enough that snow will occur in the mountains.
Most of the accumulating snow will occur above 6500 feet Friday
night and Saturday. Snow accumulations of 1 to 2 inches will be
possible in the Kings Hill and Big Sky areas during this time.
Otherwise...little to no precipitation is expected over much of
north central Montana until next Wednesday. At that time...the next
upper level low pressure system is expected to move inland from the
Pacific northwest. Thus probability of precipitation have been increased a bit closer to
climatology for this period. In terms of will remain
cool through the weekend...then a slow warming trend is expected for
Monday through Wednesday. Brusda


Preliminary point temps/pops...
gtf 59 33 53 36 / 10 10 10 10
ctb 55 28 53 28 / 0 10 10 10
hln 63 37 54 36 / 10 20 30 20
bzn 60 36 51 33 / 20 40 40 30
wey 58 30 52 28 / 50 40 50 40
dln 58 36 50 34 / 30 50 60 30
hvr 62 30 56 32 / 10 10 10 10
lwt 58 31 51 35 / 20 10 10 20


Tfx watches/warnings/advisories...



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