March 2012 Tornadoes and Southern Snow

On March 2nd, just two days after the Harrisburg, IL tornado, this huge trough over the central US produced another major tornado outbreak.

A 988 mb low was just south of Lake Michigan:

An area of 2,000 J/kg CAPE was coincident with 0-1 km helicity of 500 m2/s2:

40 people were killed, including 11 by an EF4 with a path of 49 miles through Indiana and Kentucky.

On March 7th, a storm near Iceland reached 944 mb:

Northwest Pacific storm on March 12th:

On the afternoon of March 15th, several tornadoes touched down in eastern Michigan where 500 mb winds were only 25 knots.

This is a good example of the fact that there seems to be an exception to almost every rule in meteorology.

On March 18th, this intense western US trough dug into Mexico:

500 mb wind speeds reached 80 knots about 100 miles south of the border:

Winter storm warnings (pink) were issued in southeast Arizona down to the Mexican border, and winter weather advisories (purple) were issued for the Santa Ana Mountains:

Accumulating snow fell on the Mexican border south of Tucson: