899 
fxus65 kpih 181951 
afdpih 


Area forecast discussion 
National Weather Service Pocatello Idaho 
151 PM MDT Thursday Mar 18 2010 


Short term...tonight through Sunday. 


A cold front has passed through the region today. A line of light 
showers is over southeast Idaho. Expect these showers to continue 
to propagate away from the area this evening. Am monitoring 
another piece of energy sliding down the Montana side of the 
Continental Divide. Models show this energy continuing down The 
Divide. As a result...looks like most of the moisture with this 
system tonight and on Friday should stay near or east of the 
Wyoming border. A brief ridge settles in for Saturday providing 
dry weather to the entire area. 


Long term...Sun night through next Thursday night. 500mb 5-wave 
continues to keep eastern Idaho on the fringe of the storm track. 
Thus do not see any major storms but precipitation threat does 
exist. By end of this period...longwave ridge currently to the west 
of the forecast area shifts to overhead. Factoring in short 
waves...break down of upper level ridge begins Sun night and 
unsettled weather continues through Tuesday afternoon. On Wednesday...brief 
upper level ridging clears things out and shortwaves come in phase 
with longwave ridge that moves into the Great Basin for the last 24 
hours of the forecast. Have generally beefed up probability of precipitation and clouds from 
Monday night through Tuesday night. Temperatures now trending colder than 
previous thinking...both lows and highs. Best chance for 
precipitation continues to be Tuesday. The biggest concern will 
actually be wind. MOS guidance is consistent with yesterday in 
keeping wind very strong. On Monday night...forecast is now for 28kt 
and 24kt sustained in the MOS output for kpih. This seems extreme 
and the gridded output has nothing of this magnitude...so have not 
totally bought this scenario. Messick 


&& 


Aviation...skies are starting to clear behind this mornings front. 
Some low level cumulus is developing in the eastern Magic Valley and 
requires some monitoring...but otherwise expect unlimited visibility 
and middle-level ceilings at worst through Friday morning. Ceilings 
expected where northwesterly flow encounters orographic 
uplift...which will be kbyi and kpih. West to north flow setting up 
behind front should be somewhat gusty mainly at kida...but will 
subside during the overnight as the inversion develops. No serious 
impact on aviation interests. Messick 


&& 


Pih watches/warnings/advisories... 
none. 
&& 


$$