692 
fxus65 ktfx 212050 
afdtfx 


Area forecast discussion 
National Weather Service Great Falls Montana 
250 PM MDT Thursday Aug 21 2008 


Discussion... 


Tonight through Saturday...a cool and moist Pacific storm system 
will continue to affect the forecast area through Friday morning. 
Anticipate precipitation to be most concentrated along the 
Continental Divide and across the Central Mountain ranges. Surface 
winds from the west and southwest will remain strong along The East 
Slope of The Rockies and adjacent north Central Plains through 
Friday morning...with gusts to 40 miles per hour at times. Precipitation 
chances will diminish from west to east throughout the overnight 
tonight...with clearing taking place during the morning and early 
afternoon on Friday. Temperatures will remain below the seasonal 
average during Friday as the upper level low pressure trough moves 
across central Montana. By Saturday morning...temperatures will 
drop well below the seasonal average throughout the region...with 
some valley locations in southwest Montana dropping below freezing. 
High pressure will the dominant feature from Friday afternoon through 
the end of the short term forecast period...with dry 
conditions...warming temperatures...and mostly clear skies 
present. Zumpfe 


Saturday night through Tuesday night...the biggest changes to the 
previous forecast were to slightly warm the lows on Sunday night 
and the maxes on Monday. Also dried out the probability of precipitation on Monday. The 
upper ridge remains in place through Monday with very warm 
temperatures. A weak weather system moving across the area will 
trigger some thunderstorms into the early evening hours on Monday. 
The upper ridge moves eastward on Tuesday and Wednesday as an 
upper trough develops over the West Coast and cooler air filters 
in across the area. This cooler air will bring a seasonal chance 
of precipitation with low probability of precipitation across the area Tuesday and 
Wednesday. Db 


Wednesday and Thursday...long range models indicate an upper 
level low pressure system moving into the Pacific northwest. 
During this period used climatology for precipitation due to 
timing of disturbances flowing through the northwest flow aloft 
and the position of the jet stream. Temperatures are expected to 
be near normal for much of west and central Montana. Saucier 


&& 


Aviation... 
bands of rain showers and a few thunderstorms will continue to 
develop and move east through the area this afternoon and early 
evening. Although predominately VFR conditions are expected there 
will be local IFR conditions...both ceilings and visibilities 
..in heavier rain. Also expect isolated thunderstorms this 
afternoon and early evening. Gusty southwest winds early this 
afternoon will shift to the west and northwest from middle to late 
afternoon. Local gusts to 45 knots are possible. Expect clouds to 
decrease this evening. Expect to see some cloudiness in Canada 
spread southeast near and after midnight over the plains. Models 
differ on whether there will be ceilings or not and have decided to 
go with ceilings 5000-7000 feet. There is a possibility of MVFR 
ceilings and rain with this cloudiness mainly over hill and Blaine 
counties. Blank 


&& 


Preliminary point temps/pops... 
gtf 48 75 43 84 / 40 0 0 0 
ctb 45 69 41 81 / 20 10 0 0 
hln 51 77 47 87 / 40 10 0 0 
bzn 43 75 40 87 / 50 0 0 0 
wey 36 72 38 81 / 30 0 0 0 
dln 40 74 40 84 / 30 0 0 0 
hvr 49 73 38 85 / 40 20 0 0 
lwt 45 69 40 82 / 50 0 0 0 


&& 


Tfx watches/warnings/advisories... 
&& 


$$ 


Short term...zumpfe 
long term...db/Saucier 
aviation...blank 


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