Summer: Cooler outlook

Given the recent performances, we are wary of putting much stake in any seasonal outlook, but as a public service on a gray day we offer a somewhat positive forecast, or at least a cooler one.

The summer of 2013 won't be as punishing as the previous three, according to the outlook released this morning by Weather Services Inc., a forecasting service in Massachusetts.

With generous spring rains expected from the Plains eastward, drought conditions should be pushed westward, according to WSI meteorologist Todd Crawford.

Drought is closely correlated with ground-baking heat that is self-perpetuating. Heat in the West, in turn, makes cooling in the East more likely.

The last three summers collectively were the warmest nationwide since the late 19th Century, he noted. Locally, in Philadelphia they constituted the warmest three summers in the period of record, dating to 1974.

The outlook calls for a cool May, and a cool July after a warmer than normal June in the Northeast, which includes Philadelphia.

We mention that last spring, WSI called for a summer cool-down.

What followed was the fifth-warmest June 1 to Aug. 31 period -- that's the meteorological summer -- on record, with an average temperature of 78.1, finishing just ahead of 2011's 78.0. No. 1 is 2010, 79.6.