2007 North America South and Eastern Heatwave - Meteorological Setup

Meteorological Setup

The heat wave was triggered by several factors. First an unusually strong upper level ridge that has settled over the southern plains and southeast near the Ozarks. Another was the sharp troughing over the Pacific Coast and the offshore Atlantic. This in turn created an Omega block pattern over the central US and caused extreme heat to build for weeks, in some cases. The ridge eventually retrograded back towards the west which allowed some short term relief for the northeastern states and Mid-Atlantic, but in the Mississippi River Valley and southeast there remained oppressive heat for at least several more days. Some more widespread relief came by the end of the September, but before long much warmer the normal conditions returned across eastern North America by the first week of October, this time shattering long held records through to the end of the end of that month and finishing as the warmest October in 5 states in the region. August 2007 turned out to be one of the 20 warmest Augusts for the United States since 1895.