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Area forecast discussion 
National Weather Service Pocatello Idaho 
200 PM MST Wednesday Nov 4 2009 


Short term...tonight through Saturday. The latest satellite imagery 
was showing an amplified upper ridge across the region which will 
provide warm and dry conditions through Thursday. By Thursday 
night...the ridge begins to break down under the weight of the next 
approaching Pacific storm system. By Friday...the pattern is expected to 
transition into a nearly zonal flow which will allow short-wave 
features to push inland along the northern tier. The models have been 
somewhat inconsistent with timing and run to run details over the 
weekend. For now...a high chance to likely mention of precipitation 
looks reasonable for the central mountains Friday with the leading 
edge of the precipitation shield spreading inland at that 
time...then the passage of short-wave activity will likely dictate 
when and where the focus of activity will fall and as mentioned 
above...the models have been somewhat inconsistent with the 
details. Huston 


Long term...Saturday night through next Wednesday. The models 
continue to advertise an active period but still some timing issues 
result. We have done nothing more than tweak slowly in one 
direction or the other. It appears now the system for Sunday will be 
much weaker as it crosses Idaho...with the system offshore 
eventually becoming the dominating weather feature. With that in 
mind...the forecast now shows slightly drier conditions for the 
first part of next week. The question is when will the offshore 
system finally come through and how strong/weak will it be. The GFS 
and European model (ecmwf) are not in sync for the middle of next week on this one. 
Thus have continued with probability of precipitation around climatology. Keyes 
&& 


Aviation...VFR conditions will continue although the ridge will be 
sliding on to our east. Keyes 
&& 


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


$$