It is not that difficult.If I may?
July 17, 2013
0100 GMT (8:00 EST)
The Weather Channel Actual High Temperatures
In the water vapor satellite below it is very easy to discern the PATH tropical water vapor is taking and it ain't along the ICZ (Intertropical Convergence Zone - click here)
July 17, 20131730:18z (1230 PM EST)
UNISYS Water Vapor Satellite of North and West Hemisphere
There is a water vapor system that descended from the arctic region cooling temperatures and causing storms over the orange colored region of the country. That arctic air movement was documented here on this blog. As a result the water vapor along the ICZ migrated north and carried equatorial and hot air north. Once it hit the Jet Stream at the Canadian and American border the movement of that tropical air mass took a sharp turn directly east. That is the reason there are hotter temperatures in the northern regions of the USA than southern temperatures. Got it now?
