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fxus65 ktfx 220524 
afdtfx 


Area forecast discussion 
National Weather Service Great Falls Montana 
1100 PM MDT sun Mar 21 2010 


Update... 


Upper level shortwave continues to slowly move into the region 
tonight...jet maximum pushing across the region with central and SW 
Montana in the favored right entrance region. Scattered light rain 
showers have pushed into the region in the lower elevations...with 
possible light snow showers in the higher elevations of the 
mountains. Valley locales that have seen light rain have had 
significant increase in dewpoints to around 33 or 32 degrees...with 
likely wet bulb temperatures above freezing the chances for snow in lower 
elevations is much lower...but some cooler air is working east 
overnight. Dry slot seen on WV/infrared Sat pics...will allow for 
things to possibly become more convective and showery through the 
next 12 to 24 hours across the region. Overall the forecast looks 
to be in great shape...will make one addition to the forecast with 
this update. Due to the convective nature of the precipitation allowing 
for a quick spurt of moderate to heavy snow across the SW 
portions of the state...will consider Winter Weather Advisory 
across portions of SW Montana above 6000 feet starting early 
Monday morning into early Tuesday morning. --Schott 


&& 


Previous discussion... 
/issued 635 PM MDT sun Mar 21 2010/ 
tonight through Tuesday...expect a change in the weather pattern 
to begin tonight...as a Pacific storm system moves into the 
region. Scattered rain and snow showers should develop over 
southwest Montana this evening...and become more widespread by 
Monday morning. The precipitation will continue throughout the day 
on Monday over the southwest and the Rocky Mountain front. Snow 
accumulations look to be on the minor side at lower elevations 
because of the warm surface temperatures expect some melting of 
the snow...and for rain to be mixed with the snow at times. A bit 
more snowfall is possible in the mountains...mainly above 6000 
feet. Temperatures should be a few degrees below normal on Monday. 
The precipitation will continue into Monday evening...but should become 
more scattered and light. The chances for precipitation will decrease 
though-out the day on Tuesday...with only isolated mountain showers 
remaining on Tuesday afternoon. Temperatures should warm backup 
above seasonal normals by Tuesday afternoon. Brusda 


Tuesday night through Friday night...moisture associated with the 
Pacific system that impacted the region Tuesday will linger across 
central and southwest Montana until Tuesday night. Any precipitation 
received should be mountain snow and mixed precipitation over the 
plains and valleys. Tuesday night and Wednesday...a transient 
upper-level ridge will pass over the region with drier conditions 
and warmer temperatures around seasonal averages. Models differ 
slightly Thursday into Friday with scattered light precipitation 
moving into the region from the west. As a result...stayed close to 
climatology for temperatures and a little above climatology for 
precipitation during the second half of the extended forecast. 


Saturday and Sunday...latest models differ on timing of a quick 
moving Pacific disturbance expected to move into the region over 
the weekend. There will be a chance for snow showers along the 
Continental Divide and the central mountains. The plains can 
expect isolated rain and snow showers through the period. On the 
Central Plains temperatures are expected to be near average on 
Saturday and slightly above average on Sunday. 


&& 


Aviation... 
updated 0500z. 
The southwest flow aloft ahead of an approaching Pacific weather 
system will become increasingly moist over southwest...central... 
and north central Montana through 12z. Middle level clouds will 
increase over the terminals overnight with precipitation obscuring 
mountains of western and southwest Montana. A surface low pressure 
area will also move southeast through the area during the day on 
Monday as the Pacific system moves into the state. Mountains will 
become generally obscured in snow...while more widespread rain and 
snow showers will develop over the plains of north central and 
central Montana as surface winds there shift more northwesterly. 
These showers will again bring occasional MVFR conditions. Coulston 


&& 


Preliminary point temps/pops... 
gtf 36 47 29 49 / 20 70 40 10 
ctb 30 45 25 48 / 20 50 30 10 
hln 31 47 27 49 / 50 90 20 30 
bzn 31 45 23 45 / 30 90 50 30 
wey 23 37 12 38 / 40 90 70 40 
dln 29 44 23 44 / 50 90 20 20 
hvr 24 45 19 47 / 10 40 30 10 
lwt 34 46 27 45 / 20 40 40 20 


&& 


Tfx watches/warnings/advisories... 
Winter Weather Advisory from 3 am Monday to 1 am MDT Tuesday for 
elevations above 6000 feet for Gallatin...Madison. 


&& 


$$ 


Short term...brusda 
long term...Emanuel 
aviation...coulston 
update...schott 


Weather.Gov/greatfalls