Some good news is that the dog days of Summer will end earlier than last year's Aug 16 date. Until then a familiar pattern centered further west than 2011 has dominated. An active and fast Pacific jet stream that is common in a La Nina/Low AAM situation has not yet broken down. Furthermore, global AAM tanked just in time for the historic heat wave here in the East. Take a look at the below Water Vapor image from the University of Wisconsin SSEC.
|The fast Pacific Jet buckles in the NW US bringing a trough and cool conditions there.|
Heat gets concentrated on the SE side of the Jet Stream in a process similar to a heat pump.
Changes are afoot as the La Nina-ish Low AAM condition is receiving a big jolt from Mountain Torque. My oversimplified explanation is that the buildup of air particularly at the Andes has led to an ever so slight decrease in the earth's rotation in exchange for a jolt of momentum into the atmosphere at the equator. It will take until the first week of August for the changes to work its way through the global weather machine to NC and VA so just a little more patience is required.
|Image Source: NOAA Earth Science Research Laboratory|
Note: The negative torque in late June/early July was not
THE cause of the heat wave, but b/c of the season be suspected as
a contributor toward the crash in AAM.
One good thing is that even stubborn conditions like the extended La Nina must give way to her brother El Nino if only to temporarily satisfy imbalances in the economics that drive the atmosphere. This and several other influences point the way to a cold winter with a very cold one as a possibility. Until the Pacific warms and the Atlantic cools the overall propensity toward La Nina and extreme weather can be expected.