299 
fxus65 kbyz 231605 
afdbyz 


Area forecast discussion 
National Weather Service Billings Montana 
905 am MST Monday Nov 23 2009 


Short term...valid for today and Tuesday... 


Just a few changes to the going forecast. Bumped winds at 
Livingston a bit as gradients were tightening some and models 
consistent on not backing them off. Also raised temperatures a 
couple of degrees over the west as winds kept readings up 
overnight so do not have that far too go to reach forecast highs. 
Probability of precipitation looks good...but did adjust clouds a little bit to increase 
coverage. Will be taking a closer look at potential Wind Advisory 
tonight for the upper Yellowstone and upper Stillwater river 
valleys for the afternoon package. Humphrey 


Long term...valid for Wednesday...Thu...Fri...Sat...sun... 


The extended period begins Wednesday morning with an upper-level 
ridge building over the region. This feature builds through 
Friday with mild temperatures and dry conditions prevailing. The 
next upper-level trough approaches the County Warning Area late Friday into 
Saturday. Model differences between the GFS and European model (ecmwf) are 
significant at this time. The GFS develops a much broader trough 
with energy reinforcing this feature through Monday. The European model (ecmwf) is 
much more progressive with the bulk of its influence occurring on 
Saturday. Continued to trend forecasts toward the European model (ecmwf) but 
lingered low probability of precipitation into Sunday for portions of the County Warning Area. Both 
models hint at building another upper-level ridge over the region 
for early next week. However...the European model (ecmwf) is quick to break down 
this feature with an upper trough on Tuesday. Therefore...dried 
precipitation forecasts for Monday and introduced slight chance 
probability of precipitation for western zones late Monday into early Tuesday. Schuknecht 


&& 


Aviation... 


Weak snow showers...becoming a rain snow mix this 
afternoon...will linger in the east today as an upper-level 
trough pushes eastward across the region today. Brief periods of 
MVFR conditions will accompany areas of precipitation. Gusty west 
to southwest surface winds are expected mainly over western and 
central zones today. Expect winds around 15 kts with gusts up to 
25 kts in most areas...but winds around klvm and near foothills 
will see winds around 25 kts...with gusts to around 35kts this 
afternoon. Winds are expected to pick up later tonight and 
increase through the day tomorrow for the klvm vicinity and 
foothills regions...as well as around 3ht and Judith Gap 
regions...with sustained winds around 35 kts...and gusts to 
around 45kts. Gilstad 


&& 


Preliminary point temp/pops... 


Today Tuesday Wednesday Thursday Friday Sat sun 
------------------------------------------------------- 
bil 042 026/048 030/051 031/055 033/056 032/045 025/038 
1/b 00/north 10/b 00/u 01/b 22/west 11/b 
lvm 039 021/044 024/050 024/053 029/048 021/038 019/038 
2/j 00/north 10/b 00/u 02/west 32/j 11/b 
hdn 046 023/051 028/050 029/056 029/057 030/048 023/041 
2/j 00/u 20/b 00/u 00/b 22/west 11/b 
mls 045 024/049 024/045 026/055 028/056 031/048 021/039 
2/j 00/u 20/b 00/u 00/b 22/west 11/b 
4bq 043 023/049 026/044 025/055 027/056 031/047 021/037 
2/west 00/u 20/b 00/u 00/b 22/west 11/b 
bhk 043 022/047 022/040 021/053 026/054 029/047 019/036 
2/west 00/u 20/b 00/u 00/b 22/west 11/b 
shr 041 020/048 028/048 025/056 026/057 026/045 020/040 
2/j 00/u 31/b 00/u 01/b 22/west 22/j 


&& 


Byz watches/warnings/advisories... 
Montana...none. 
Wyoming...none. 


&& 


$$ 
Weather.Gov/Billings