A soggy month, but drought watch is still in effect

Officially, a drought watch remains in effect. Yes, you read that right.

That might surprise residents along all those agitated, chocolate-brown waterways who have just lived through the soggiest month in the region's history, one that washed away the old rain records by a good half-foot.

But that drought advisory is the legacy of a summer that got off to such a torrid, arid start that the period from June 1 to Aug. 31 ranked as the fifth-warmest in 138 years of record-keeping in Philadelphia, despite a relatively chilly August. After a bone-dry May, June, and July precipitation was about 21/2 inches - better than 30 percent - below normal.

And while the summer's behavior might appear bipolar, climate experts said they believed the heat and rain might both be connected to worldwide warming.

"We did a lot of irrigating early on," said Pete Johnson of Johnson Farms in Medford. His sprinklers, however, have been on vacation in August.

At Philadelphia International Airport, 19.3 inches were measured during the month, about six months' worth of rain. That not only broke the old August record of 12.1, set in 1911, it topped the 13.07 that fell in September 1999, the month of Floyd and the erstwhile rainiest month.

In New Jersey, the August statewide total was 161/2 inches, said David Robinson, the Rutgers University professor who is the state climatologist. The old standard was 11.95, set in October 2005.

"It's staggering," Robinson said. "It's kind of one of those 'You can't make those numbers up' situations."

The Irene rains of Saturday and Sunday obviously were huge factors, but in Philadelphia more rain fell Aug. 14 and 15, 5.74 inches, than during Irene, 5.70. Philadelphia already has received more than 42 inches of rain in 2011, about average for an entire year.

"We're faced with a question," Robinson said. "Are we looking at new normals?"

Various studies have documented increases in extreme rainfalls; warmer air holds more moisture. The U.S. temperature has increased about 2 degrees Fahrenheit in the last 50 years, according to the National Climate Data Center in Asheville, N.C.

Extreme rain is "one of the most robust signals we have" of worldwide warming, said Tom Peterson, a climate-center researcher. Increased rainfall has not been uniform, he said, but in Philadelphia and elsewhere in the Northeast, precipitation totals rose from 15 to 20 percent from 1958 to 2008.

Last summer was the warmest ever in Philadelphia, and this one was giving it a run for the money before the August deluges.

The meteorological summer, June through August, finished 1.6 degrees behind 2010's 79.6. Nine of the 10 hottest summers have occurred since 1991.

The probability of that happening by chance "is less than 1 in 1,000," said Mark DeLisi, climatologist at the National Weather Service office in Mount Holly.

No new big rainstorms are on the horizon, but the drought watch might be seriously endangered.

The state Department of Environmental Protection declared it for Philadelphia and much of Pennsylvania on Aug. 5. It called for voluntary water restrictions in 40 counties. It has survived as a cautionary measure, said DEP spokeswoman Jamie Legeron, as the state wanted to make certain that the rains were sustained.

The state drought committee meets Thursday. The drought watch might not survive the meeting.