Our great summer weather pattern continues here in the Mid-Atlantic region with temperatures starting off the month of August at below normal levels (DC: -1.5°, Central Park, NY -1.1°, Philly -2.4°). Yesterday was the first time this month that Philly Airport reached 90 degrees and temperatures over the weekend couldn’t escape the 70’s. In fact, a huge chunk of the nation has started off the month of August with below normal temperatures (see plot above). July turned out to be slightly below normal in temperatures for the big cities along the I-95 corridor (DC, Philly, NYC).
As far as the rest of the month of August is concerned, indications are quite strong that the overall cooler-than-normal weather pattern will continue in much of the country. One longer-range computer forecast model called the Climate Forecast System (CFS version2) predicts cooler-than-normal temperatures in much of the same area in each of the next three weeks (green regions in forecast maps below for weeks 1, 2 and 3). Similar to the first five days of August, much of the nation is predicted to experience below normal temperatures with the exceptions being the western states and extreme Northeast. The CFS computer forecast model has a pretty good track within these type of time scales. Looking even farther ahead, there are a few signs that a change to warmer-than-normal is possible for much of the nation come September.