After the storm of this mid October I was also wondering myself what are the consequences of the open water on synoptic forcings for ascent. As a remainder, vertical velocity are stronger for a same forcing with lower static stability. I don't know if there is studies about this subject, or if it is a significant effect, but it is an open question for me. This is probably linked to the displacement of the eddy driven jet, but I am not aware of any study really looking specifically at the consequences of this reduced static stability. This is also leading to higher wind speed at surface, as seen with the last storm. On top of that, strong inversion over ice pack, and now over the continent, is on juxtaposition of this low static stability, leading to increased baroclinic instability. But what is the magnitude of this effect ? I am really clueless. To illustrate, I have compute a crude static stability parameter, by subtracting potential temperature at 700 hPa and at 950 hPa, normalized by the thickness 700 - 950 hPa. All of this multiplied by 10 to better seen what is going on. Below 0, the atmosphere is superadiabatic, and everything above is subadiabatic. Over mountains (like, said, the Rockies...), results are of course useless, as the model interpolate trough the terrain. Maps are for, in order, the 21st to the 24th at 00Z. Didn't try to average trough time, the computer would probably have hoist the white flag before the end... We can see a persistent area of low stability over the Siberian seas.