A warmer stratosphere means stronger jet streams.
At lower latitudes these intense low-pressure systems and the associated wind effects of a strong jet stream do not normally occur.
The storms repeatedly swinging in from the Atlantic bringing the damaging winds and rain are being driven by an unusually strong jet stream.
An unusually strong jet stream from the Pacific Northwest propelled a stormthrough the nation's midsection Tuesday, downing power lines in five states andforcing the cancellation of hundreds of flights at Chicago airports.
But, Mr. Bunting said, there was an "active pattern" in which large-scale conditions like stronger jet streams interacting with widespread areas of unstable air were making an environment more favorable for tornadoes to form.
So this very strong jet stream has kept this cold air locked in, and then suddenly it's been allowed to be released, sort of splurged out southwards, due to various meteorological factors.
The storms, which began in Texas on Tuesday, rode a strong jet stream through the Mississippi Valley and into Louisiana, Alabama, Georgia and the Carolinas before trailing off through Florida on Thursday, leaving in its wake drops in temperature of as much as 15 degrees and serious structural damage.
The European Commission worries that G.E.'s aircraft-leasing company, the world's largest, could decide to buy only Honeywell avionics for its jets, or that G.E. could use its strong jet engine business to bolster sales of Honeywell avionics, shutting out competitors like United Technologies and Rockwell.
This winter that contrast has been particularly large, creating a strong jet stream driving across the Atlantic.
"The storm went through this process as it passed by the south of Greenland thanks to a strong jet stream running in excess of 230mph.
