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Area forecast discussion 
National Weather Service Great Falls Montana 
955 PM MDT Sat Mar 20 2010 


Update... 


No update this evening as current forecast looks good. High wind 
event for the northern Rocky Mountain front looks marginal...will 
continue to monitor situation. Mercer 


&& 


Aviation... 
updated 2345z. 
VFR conditions will persist across north central...central...and 
southwest Montana at least through the day on Sunday. An upper level 
ridge of high pressure will steadily be flattened through the period 
by a series of disturbances. This will bring increasing mainly high 
level cloudiness to the area. Westerly winds aloft will increase 
during this period and will be strongest along the Rocky Mountain 
front and between 06z and 18z (gusts could reach 60 kt). Winds will 
remain breezy over the plains overnight (kctb kgtf 15 to 20 knots - 
khvr klwt - around 10 kt). These winds will then increase on 
Sunday...with gusts reaching 25 to 35 knots at kctb and kgtf. Winds in 
most Southwest Valley locations will remain light...but khln could 
receive gusts to 25 knots Sunday afternoon. Coulston 


&& 


Previous discussion... 
/issued 545 PM MDT Sat Mar 20 2010/ 
tonight through Monday...a few more hours of quiet 
weather...before things become a bit more active to start the work 
week. As an upper level ridge of high pressure builds over central 
Montana overnight...expect strong winds to develop after midnight 
over the northern Rocky Mountain front. These strong winds will 
last until noon on Sunday...thus a High Wind Warning has been 
issued for this region. Otherwise quiet weather can be expected 
over the region until middle day on Sunday. Afternoon temperatures 
will warm a few degrees more than today over the region...as 
southerly winds continue to usher in milder Spring like air. By 
late afternoon Sunday...the next Pacific storm system will be 
moving into the Front Range of The Rockies. Expect increasing 
chances for rain and snow by Sunday evening to develop over the 
Rocky Mountain front and central Montana. The precipitation will become 
steady over this region by Monday morning...with the heaviest 
precipitation expected to fall over the Rocky Mountain front and south of 
Great Falls...thus probability of precipitation have been increased in this region. The 
precipitation will continue over much region throughout the day Monday. 
Temperatures will cool some for Monday...but still generally 
remain near normal. 


Overall...this system is not expected to be a significant storm at 
lower elevations...with precipitation totals generally less than 
a quarter of an inch liquid...and snowfall totals generally less 
than 2 inches. This storm will be a bit stronger in the 
mountains...where up to a half inch of liquid is 
possible...resulting in the potential for snowfall accumulations 
of 5 to 8 inches. Brusda 


Monday night through Thursday night...while most of the energy 
with mondays system seems to be pushing south towards the Great 
Basin...northwest flow and disorganized shortwaves will pass 
through western and central Montana through Tuesday afternoon. 
Increased probability of precipitation across portions of Montana for Tuesday with 
definite and likely probability of precipitation in the mountains and chance probability of precipitation elsewhere. 
Tuesday night and Wednesday...a transient upper-level ridge should 
move over the region with drier conditions and temperatures around 
seasonal averages. Models differ slightly Thursday with multiple 
shots of light precipitation being hinted at. As a result...have 
stayed pretty close to climatology for temperatures and 
precipitation for the second half of the extended forecast. 


Friday and Saturday...long-range models hint at a weak Pacific 
system moving into the northern rockies on Friday and Friday so kept 
probability of precipitation around climatology with chance probability of precipitation in the mountains and slight 
chance in the valleys. By Saturday...a ridge of high pressure 
is expected to build into the region so lowered probability of precipitation across the 
forecast area. Daytime temperatures are expected to remain around 
to slightly above seasonal averages during the period. Mls 


&& 


Preliminary point temps/pops... 
gtf 37 65 34 49 / 0 0 30 70 
ctb 30 60 30 46 / 0 0 20 50 
hln 29 60 32 45 / 0 0 30 80 
bzn 23 53 30 42 / 0 0 30 80 
wey 12 47 24 39 / 0 0 30 80 
dln 27 54 30 41 / 0 0 30 80 
hvr 22 56 25 44 / 0 0 10 30 
lwt 30 61 33 45 / 0 0 10 50 


&& 


Tfx watches/warnings/advisories... 
High Wind Warning until noon MDT Sunday northern Rocky Mountain 
front. 


&& 


$$ 


Short term...Mercer 
long term...gustafson 
aviation...coulston 


Weather.Gov/greatfalls