Could the warm winter cause EML and instability issues?

[Ben Toms]

While watching the towers being squashed by the subsidence/mid level dry punch along the dryline today in south-central Kansas, it was brought to my attention by Zach Young that the extreme temperatures across much of the U.S. this winter and early spring could possibly lead to more widespread EML problems throughout the rest of the chasing season. I hadn't thought much about this before he brought it up, but it makes sense. If the atmosphere is warming quicker and deeper than it usually would, could this affect lapse rates (and therefore instability) and result in an increased number of EML busts in the future?

I'm no expert on meteorological trends by any means, but I am under the impression that as we transition into El Nino surface temperatures tend to remain below average for much of the late spring and summer. My concern is the juxtaposition of these two extremes could lead to capping issues throughout the rest of the season. Am I justified for this concern? I'm sure there have been studies on this, I just can't seem to get my hands on them.

Ben Toms

 

[David Wolfson]

I see two things happening. First , the entire intermountain region including BC, Alberta, and Saskatchewan is already mostly clear of snow cover. This is promoting ridging over the west and a warm EML, as you say. Meanwhile the Northwest Territories, Hudson's Bay, and much of a Laurentides remains ice covered. The AO has of late been flipping neutral-to-negative, reflecting this I think as cold air tends to accumulate over these areas and slide southeast. The result at mid- and upper-levels is a tendency toward a trough axis around the Great Lakes and Northeast. The polar jet may already be fixing to migrate up toward the Canadian border while gulf moisture is attenuated by continental flow. Not a very happy picture I'm afraid for mid-May if the pattern holds true.

Hopefully for the beginning of May a somewhat favorable flow pattern and mediocre moisture can overcome the rather stout capping and lack of forcing and produce some storms in the upslope areas of southeast CO and southwest KS. FWIW.