Storms put end to state's drought

Rains give Baltimore its wettest September in 65 years, data show

October 01, 1999|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

The rattle of rain on the roof last month was truly the death knell for the drought of 1999 in Maryland.

Meteorologists say a shift in continental weather patterns and a pair of tropical storms have combined to douse the 15-month drought with the wettest September in Baltimore in 65 years.

"In terms of New England and the Middle Atlantic states, the drought is really no longer a concern," said Todd Miner, a meteorologist with Pennsylvania State University's Weather Communications Group.

Some reservoirs and wells have some catching up to do, but the National Weather Service's 90-day outlook calls for near-normal temperatures and precipitation for Maryland, at least through December.

"A little normalcy wouldn't hurt," said forecaster Jim Decarufel, of the weather service's Sterling, Va., office.

The rainfall at Baltimore-Washington International Airport last month totaled 11.49 inches, the second-wettest since recordkeeping in the Baltimore area began in 1871. The wettest September was in 1934, when two hurricanes approached the state and 12.41 inches fell.

At BWI, where records go back to 1950, the month just ended was the wettest September on record.

Most of the deluge occurred in two installments. The fringes of Hurricane Dennis delivered more than 2 1/2 inches of rain at BWI during the Labor

Day weekend as the storm stalled off the North Carolina coast.

Then, Sept. 15 and 16, Hurricane Floyd moved up the coast and dropped 5.8 inches at BWI -- and more than a foot on parts of the upper Eastern Shore.

Precipitation for 1999 is more than 6 inches above normal, and near normal for the past 12 months.

The drought began in July 1998, and every month but two through July of this year had below-normal precipitation. Streams and reservoirs fell, wells in some parts of Maryland dried up, and local watering bans became common.

High temperatures hastened evaporation and increased the demand for water. Temperatures topped 90 degrees on five days in June. In July, Baltimoreans suffered through 22 days of 90-plus temperatures, including one eight-day stretch early in the month and an 11-day ordeal that ended Aug. 1.

It would not be Maryland's worst drought. The National Climate Data Center says the drought of the mid-1960s in Maryland was more severe and lasted longer. But this year was bad enough.

On July 29, Gov. Parris N. Glendening declared a drought emergency, and statewide watering restrictions were imposed Aug. 4. Water consumption in the Baltimore water system dropped by 100 million gallons a day.

In the three weeks that followed, less than 2 inches of rain fell at BWI. "During the summer, there was an upper-air high pressure system that prevailed over the Northeast and Middle Atlantic states," meteorologist Miner explained.

It did two things. First, like a boulder in a stream, it diverted the jet stream north into Canada. The jet stream took with it any storms that might have rained on Maryland.

Second, storm systems that broke through and headed our way were suppressed -- dried up -- by sinking air currents from the big high. The state got rain, but too little.

August brings rain

In August, however, that all began to change. "The high we're talking about started to migrate eastward into the Atlantic Ocean," Miner said. "That allowed the storm systems to track differently."

Three days of torrential storms, from Aug. 24 to Aug. 26, began to revive the parched region. By the end of August, BWI had received more than 6 inches of rain -- 2 inches above normal. The 90-plus weather was over, too.

On Sept. 1, the governor decided the small boost the storms had given some streams and Baltimore's reservoirs was enough to warrant an end to the mandatory watering bans. Hedging his bet, however, he urged Marylanders to continue with voluntary water conservation. They did.

But the shifting weather patterns also opened a door, and Dennis and Floyd crashed in.

"The position of that high helped steer both those storms onto the mid-Atlantic coast," Miner said. Had the summer pattern remained in place another month, "Floyd and Dennis would have been a Florida and Gulf of Mexico problem, rather than an Atlantic coast problem."

Dennis' rain saturated the ground. Floyd arrived the week after. It flooded several Maryland communities and countless basements, dropped thousands of trees and knocked out electrical power to nearly 500,000 Baltimore Gas and Electric Co. customers.

By Sept. 21, more than 10 inches of September rain had been recorded at the airport. Glendening declared an end to the drought emergency. It had lasted 55 days.

Maryland is pulling itself together in the drought's wake. Baltimore's Loch Raven reservoir is full, but Prettyboy and Liberty reservoirs are half full -- below normal for this time of year.

Farther west, things get drier.

Western counties drier

Carroll County officials lifted their watering ban for the communities that receive public water. But some, such as Westminster and Taneytown, have kept them in place because their underground wells have not been fully recharged. Hampstead lifted parts of its ban -- residents may wash their cars, but may not turn on lawn sprinklers.

Maryland's western counties did not see much of Dennis or Floyd and remain very dry as measured by the Palmer Drought Index -- a statistical compilation of data on rainfall, soil moisture, runoff and demand.

They're at the edge of a large region, from northwest Pennsylvania to Indiana and south to the Gulf of Mexico and northern Florida, where the drought drags on.

Sun staff writer Mary Gail Hare contributed to this article.

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