Kory
Member
COD is known as the “circle of death” regarding the MJO strength. It is a weak phase of the MJO where other background forcing takes effect.What is the "COD" in this context?
Why are those particular MJO phases more favorable for severe weather in the CONUS?
Early April always seems to be tricky, anyway. You can get the occasional biggies (much like March and Beauregard), but you're just as likely if not more to see issues with moisture return (cold fronts too close together), meridional flow, etc. Look at 2017 - all those high risks and nothing anywhere near that significant. The first part of mid-April is only now getting into fantasy range of the GFS.
Those phases over Africa and Indian Ocean help poleward flux of heat (I believe), due to the enhanced convection associated with the MJO, which then forces changes in the jet stream and teleconnections such as the PNA/AO/etc. those phases tend to have Pac jet extensions into North America and large scale troughing that is centered in the West/Central U.S....a more favorable pattern for severe weather.