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Area forecast discussion 
National Weather Service Great Falls Montana 
530 am MDT Sat Aug 30 2008 


Updated aviation 


Discussion... 


Today through Monday...a strong southwest flow aloft will continue 
today over the area. The airmass will also continue to warm and 
the resulting mixing of the atmosphere will allow breezy 
conditions. Because of this and because of the very low relative 
humidities over portions of southwest Montana...a red flag warning 
has been issued for fire zone 118 until 9 PM this evening. Some 
moisture will also work its way into the area and isolated 
afternoon thunderstorms are a possibility. The main threat from 
these storms will be gusty winds. A strong upper trough will 
continue to move toward the area tonight with precipitation 
forming out ahead of the trough axis. As the upper trough moves to 
western Montana Sunday...significant precipitation will develop. 
Much cooler air will also accompany the trough passage and snow 
levels will lower allowing for snow accumulation on the higher 
peaks. Accumulating snow may reach some of the mountain passes and 
winter weather highlights may become necessary. The upper trough 
will slowly move across the area Monday bringing more rain and 
cool temperatures. Temperatures will remain above seasonal 
averages today but fall well below seasonal averages Sunday and 
Monday. Emanuel 


Monday night through Saturday...a deep upper level trough moves 
out of the region Tuesday night and Wednesday...leaving a cool 
cyclonic northwest flow aloft along with a series of short wave 
troughs moving through the flow through Thursday. This will result 
in a cool and unsettled weather pattern with isolated to scattered 
showers...especially over the mountains. By Friday...an upper 
level ridge over the West Coast...moves and builds in over western 
Montana for drier and milder conditions...with temperatures 
warming to near seasonal average by Saturday. Williamson District of Columbia 


&& 


Aviation... 
updated 1130z. 
An unstable southwest flow aloft will develop today...brining in middle 
level moisture...in advance of an upper level trough over the West 
Coast. There will be gusty southwest winds of 20 to 35 miles per hour across 
southwest Montana this afternoon. Isolated thunderstorms will 
develop this afternoon. There will be scattered showers and isolated 
evening thunderstorms through 12z Sunday. VFR conditions will 
prevail...except for MVFR in and near showers and thunderstorms. 
Williamson District of Columbia 


&& 


Fire weather... 
southwest flow ahead of an upper level trough will increase over 
the region today. Deep mixing ahead of the front will bring gusty 
winds to southwest Montana this afternoon and evening along with 
low afternoon humidities and very warm temperatures. These 
critical fire weather conditions will mainly be experienced south 
of a line from Helena to Lewistown. In addition...isolated 
thunderstorms will also be possible. Some of these storms may 
produce strong and gusty winds with little precipitation. The main 
threat for widespread critical fire weather conditions will be 
zone 118 of the Helena National Forest. A red flag warning for 
that area has been issued for this afternoon through early 
this evening. 


&& 


Preliminary point temps/pops... 
gtf 84 49 57 40 / 20 30 50 70 
ctb 76 44 50 40 / 20 20 80 70 
hln 88 53 59 48 / 10 20 50 60 
bzn 92 49 72 43 / 20 20 30 60 
wey 81 46 66 39 / 0 20 50 60 
dln 85 48 68 40 / 10 20 30 50 
hvr 86 46 61 37 / 10 30 50 60 
lwt 88 48 64 39 / 20 20 30 60 


&& 


Tfx watches/warnings/advisories... 
red flag warning from noon today to 9 PM MDT this evening for 
mtz118. 


&& 


$$ 


Short term...Emanuel 
long term...Williamson District of Columbia 
aviation...blank 


Weather.Gov/greatfalls