We had a weak upper-level trough brush by last night. That trough is presently moving across the upper midwest and eastern Rockies, with nothing upstream except a high amplitude ridge.
|IR satellite imagery and 500-mb geopotential height analysis for|
1200 UTC 17 September 2012.
|Source: Penn State E-Wall|
All of the ensemble members keep the jet well to our north throughout the 384 hour forecast period. A few bring the occasional rogue closed low into the area.
Forecast skill degrades with time, so one needs to be cautious about surprises as the forecast lead time increases, but it appears we are in for an extended spell of clear fall weather. Meteorologists call this a blocking pattern because the ridge acts to block or redirect troughs and cyclones away from our area, leaving us relatively high and dry.