527 
fxus65 kbyz 191217 aaa 
afdbyz 


Area forecast discussion...updated 
National Weather Service Billings Montana 
617 am MDT Friday Mar 19 2010 


Short term...valid for today and Sat... 


Made a quick update this morning to drop the advisory for 
Wheatland and Golden Valley counties. Atmosphere was drying out 
from north to south across Montana and returns were decreasing 
northwest of Billings. Rest of advisory in good shape. Humphrey 


Long term...valid for sun...Mon...Tue...Wed...Thu... 


Made a few changes to the extended forecast based on latest model 
trends. Both the GFS and European model (ecmwf) have slowed down the Pacific wave 
that was to approach the area Sun night. Result will be a dry and 
warmer sun and a drier Sun night. Have trimmed back the Sun night 
probability of precipitation to keep them west of kbil. The trough will cross the area Monday 
through Tuesday ushering cooler air into the region along with a good 
chance of precipitation Monday into Monday night. Have trended higher with 
probability of precipitation for Monday night and raised probability of precipitation to chance in the east on Tuesday with 
departing system. Raised high temperatures a bit on Monday ahead of the 
system. Upper ridging will build into the area for midweek. Have 
dried out Wednesday and kept Wednesday night dry. GFS suggested possible cold 
front pushing southeast through the area on Thursday. The European model (ecmwf) did not have 
this feature but did forecast a shortwave moving along the 
Montana/Canadian border. Thus introduced climatological probability of precipitation for Thursday and 
kept these in through Thursday night. Temperatures will be near normal 
for Wednesday through Thursday. Arthur 




&& 


Aviation... 


Expect MVFR to LIFR conditions this morning from kbil to kshr west with 
widespread mountain obscurations as snow showers move southeast through 
the area. MVFR to IFR conditions will occur over eastern areas due 
to scattered snow showers. Mainly VFR/MVFR conditions will occur this 
afternoon as chances for snow showers decrease a bit over the 
area. Pockets of lower conditions will be possible in any heavier 
snow showers. The beartooth/absaroka and NE Big Horn Mountains 
will remain obscured. There will be areas of obscuration over the 
Crazy Mountains. Conditions will improve to VFR tonight and 
obscurations will decrease over the mountains. Arthur 




&& 


Preliminary point temp/pops... 


Today Sat sun Monday Tuesday Wednesday Thursday 
------------------------------------------------------- 
bil 036 020/051 032/064 039/051 029/044 028/048 032/054 
6/j 20/u 00/north 14/west 43/west 21/b 12/west 
lvm 034 016/051 032/062 035/048 025/040 023/046 029/052 
8/j 20/north 00/north 35/west 44/west 21/b 12/west 
hdn 038 017/053 024/064 033/051 031/046 026/050 029/058 
4/j 20/u 00/b 14/west 43/west 21/b 12/west 
mls 035 018/048 025/057 032/051 029/043 025/047 027/051 
2/j 10/u 00/b 13/west 43/west 21/b 12/west 
4bq 035 017/047 023/059 030/052 029/044 024/047 028/054 
3/j 20/b 00/u 04/west 43/west 21/b 12/west 
bhk 032 016/044 023/053 027/048 026/038 022/042 024/047 
3/j 20/u 00/b 02/west 33/west 21/b 12/west 
shr 031 014/047 020/061 027/052 029/045 024/046 024/053 
6/j 20/b 00/b 04/west 44/west 21/b 12/west 


&& 


Byz watches/warnings/advisories... 
Montana...Winter Weather Advisory in effect until noon MDT today for 
zones 34-40-41-65. 
Winter Weather Advisory in effect until 4 PM MDT this 
afternoon for zones 56-66. 
Wyoming...none. 


&& 


$$ 
Weather.Gov/Billings