CAMP SPRINGS - As raindrops trickled down their windowpanes yesterday, National Weather service forecasters said that drought conditions likely will persist through September in Central Maryland, and in much of the East and Gulf coast states. But summer showers should bring at least some relief.
"The East Coast drought will slowly improve as the summer unfolds," said John E. Jones Jr., deputy director of the National Weather Service. Scattered water shortages, however, are likely to crop up during normal summer dry spells.
Yesterday's showers delivered 0.37 inches of rain at Baltimore-Washington International Airport by evening. More than an inch fell in some locations, and none in others as the hit-and-miss showers and thunderstorms rolled through.
Rainfall for the month was running above normal yesterday at BWI. But the airport has seen one month - April - since September that ended with a surplus of precipitation.
From September through May, BWI recorded 59 percent of its normal precipitation, according to the weather service. For the 12 months endingJune 10, rainfall shortages across the state ranged from 2.2 inches in Garrett County, to 14 inches in Harford County.
The 12-month deficit in Baltimore is more than 12 inches.
"We're barely holding even, and in fact, we're not even doing that too well," said Jim Laver, director of the weather service's Climate Prediction Center. "Even though things have greened up quite well," he said, "it takes well-distributed rainfall over a longer term" to end a drought.
'Hydrological' problem
Central Maryland's drought is officially classified as "severe," but it is a "hydrological" drought. That means it is primarily affecting ground-water supplies and stream flows. Farmers and landscapers have generally received enough rain to keep surface soils moist and crops and shrubs healthy.
Ground-water levels, however, were hitting record lows in some Maryland streams last month for the fifth straight month. Stream gauges operated by the U.S. Geological Survey showed yesterday that water levels remained at or near record lows.
Records were set in the Little Falls and Patapsco River in Baltimore County; Deer Creek and Winters Run in Harford County; the Monocacy River at Jug Bridge in Frederick County; and Clement Creek in St. Mary's County.
The drought emergency in Central Maryland, and the mandatory restrictions in water consumption imposed in April by Gov. Parris N. Glendening, remain in force. They include Carroll, Harford, Frederick, western Howard, northern Montgomery and northern Baltimore counties.
Drought warnings and voluntary watering bans remain in place in Southern Maryland and in the suburbs of Baltimore and Washington served by city water supplies.
Nationwide drought
The drought conditions that persist in Maryland east of Allegany County are part of a much larger pattern. Conditions ranging from abnormally dry to extreme drought persist from Maine to Florida, and westward along the Gulf Coast to southern Texas.
The driest conditions in the East, threatening agriculture and water supplies as well as raising the fire danger, are in central Georgia, the Carolinas and southern Virginia.
In the West, drought conditions dominate from the High Plains to Southern California, and from the Canadian border to Mexico. The driest conditions are in the Four Corners region of Colorado, Arizona, Utah and New Mexico.
"It's normal to have drought in the United States," Laver said. But "the area covered by drought this year is rather exceptional - nearly 50 percent."
Waiting for El NiM-qo
The dry conditions, especially in the West, have built up over a number of years, he said. There may be no relief until the El NiM-qo phenomenon that is beginning to warm water temperatures in the eastern tropical Pacific Ocean begin to influence global weather patterns.
Abnormally cool water in that region of the Pacific - a phenomenon known as La Nina - has contributed to several years of dry conditions in middle latitudes worldwide, including the devastating drought in Afghanistan, Laver said.
"Until you have an El NiM-qo to bring moisture back to the mid-latitudes, including the United States," he said, "your chances for [drought] relief tend to be reduced."