498 
fxus65 kpih 151225 aaa 
afdpih 


Area forecast discussion...updated 
National Weather Service Pocatello Idaho 
625 am MDT Monday Mar 15 2010 


Update...we did a quick update to the grids to add patchy freezing 
fog around Bear Lake and near Carey. Otherwise...forecast is on 
track for this morning. Keyes 




&& 


Previous discussion... /issued 246 am MDT Monday Mar 15 2010/ 


Short term...today through Wednesday night. A ridge of high 
pressure will dominate through Tuesday evening. Some high 
cloudiness will work through area but no precipitation is 
expected. We will also need to monitor any daily formation of 
fog/stratus. For this morning...this is already underway in the 
valleys of the upper snake Highlands. The previous forecast had 
patchy freezing fog across portions of the upper snake plain and a 
few other Mountain Valley locations across southeast Idaho through 
middle morning. We will leave that in for now and see how things 
evolve this morning. Otherwise...warmer weather is on tap with 
light winds. The exception to the latter will be downvalley/drainage winds 
in the Magic Valley and out of the Sun Valley/Hailey area. 


Beyond that...the ridge is replaced weak troffing across much of 
the west. The models continue to push toward a drier cold front 
passage later Wednesday. The GFS is the wettest of the models with 
a chance of showers for all of the mountain ranges in our area. 
The NAM and European model (ecmwf) would point toward much drier and keep most of 
the moisture to our north or at least across the central and 
northern mountains. For now...we have not removed the chance of 
precipitation across southern areas but if the models continue to 
trend more north and drier the forecast will obviously push that 
direction. Winds will pick up as the front moves through 
Wednesday. Temperatures will warm up during the period...with 
plenty of 50s tomorrow and Wednesday for highs in the valleys. A 
few 60s should crop up as well. Keyes 


Long term...Thursday through Monday. General agreement between the 
European model (ecmwf) and the GFS on the end of the week pattern. Both models 
amplify the upper ridge along the West Coast on Thursday...which results in 
stronger meridional flow over the forecast area. The GFS develops a 
small upper low in the northerly flow...which passes through eastern Idaho 
by Friday morning. This would serve to increase the chances for precipitation 
over the eastern part of the forecast area Thursday and Friday. Even the more 
undisturbed flow with the European model (ecmwf) would at least raise the precipitation 
chances in the eastern Highlands. Thus...will raise probability of precipitation in the east 
for that time period. For the weekend...both models move the West Coast 
ridge inland...so have removed much of the probability of precipitation for Sat and sun. 
Monday is where the models begin to diverge. The GFS flattens the 
ridge to zonal flow...while the European model (ecmwf) develops a closed upper low 
off the or coast. Will bring probability of precipitation up somewhat over the northern part 
of the forecast area on Monday...more in line with the GFS. Hedges 


Aviation...the upper ridge will result in predominately VFR 
conditions into Tuesday morning. The low level airmass is somewhat dry 
this morning...so not expecting any significant low cigs/vis. May 
see brief IFR conditions at kida this morning...but it should not be 
persistent. Hedges 


&& 


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


$$