The AVN like the Eta, despite its apparently better depiction of the moisture plume, is still generating significant snow in the 18- to 00-Z time period. Why is this so? The AVN is not as fast with the short wave as hinted by GOES and AMSU. Also, the AVN may be generating too much precipitation due to the moderate-to-strong upslope developed within the model. The lack of high-resolution terrain generates upslope flow from the Washington coast to the Washington-Idaho border, ignoring details of the Cascades and lower basin over central and eastern portions of Washington.

The AVN is regenerating precipitation across northeast Washington and southern B.C. This regeneration is in an area where GOES water vapor trends indicate upper-level subsidence will be occurring at that time. This area of precipitation is also disconnected from the main moisture plume. The models do not hint at any wrap around moisture back into northeast Washington and southern B.C. Even if shallow upward motion were to occur (it can't be deep upward motion because that would contradict the water vapor imagery), moisture for significant precipitation is lacking. The resulting expectation would be for no more than scattered snow showers with no significant accumulation.