Why we could see an active severe weather period in early/mid May

[Ellinwood]

I'm not an expert in medium-range forecasting, but I did manage to put a discussion together to explain why we could have an active severe weather period in the Central Plains, Midwest and Tennessee Valley regions as we head into May. I used the NAO and PNA forecasts, drought conditions and ENSO trends to support the discussion. I did this to plan my storm chasing expedition for the first half of May, but I thought that I should also share it with the forum for comments/criticisms.

http://madusweather.com/?p=1046

[MidwestChaser]

Would be nice; I leave on the 12th.

[janetjanet998]

Looks good. I think all the pieces have come together this spring including a warm Gulf. Medium range severe weather forecasting isn't my forte but I think i read(maybe at eastern) La nina years start off strong but the CAP takes over later in May and June and slows things down?

also if you are correct, after this month....this is just nuts

[Indystorm]

Thanks for sharing this and hope you have a productive experience. I've been concerned with the drought in the plains that the dry line might move farther east than usual which has been the case with some notable tornadic events in the midwest in prior years.

[Ellinwood]

A follow-up regarding the concerns of a ridge in the West to start May:

...a progressive upper-level ridge in the West could bring a lull in the action until another system tries to push it east and break it down going into May 6th.

...let’s see what the models have been doing wrong lately. Past the day+7 lead time, the models have struggled to capture the effects of the soil moisture across the South and Southeast, which has helped to keep temperatures above normal in the Southern Plains, Southeast and southern Mid-Atlantic. Conversely, the below normal temperatures in the northern and western areas have come in cooler than forecast, which would lead me to think that the -PNA influence (should it verify on the negative side) and soil moisture could alter the storm track that is presented by the models. While not negating the transient ridge in the West during the first week of May, it could definitely verify weaker than anticipated, which would allow the ridge to break down more at the end of the first week of May when a storm system moves in off of the Pacific. This will hopefully reset the pattern and push us into an active severe weather pattern as we head into the second week of May.

[Ian]

GFS off and on is showing a nice trough building over the rockies/southwest by like the 4th-6th and sorta sitting around for a while-- though this is still la la land and some runs don't have it. But I'm hopeful. I'm into range where I can't think of much else other than being out there.