The rains are back, and weather experts say the renewed rainfall in December and January has eased the lengthening drought in the Baltimore region.
"We're still on the dry side," said Robert Livezey, senior scientist at the National Centers for Environmental Prediction in Camp Springs. The soil remains short of water. But there is a promise of more wet weather. "This wasn't a flash in the pan," said Livezey.
Weather instruments at Baltimore-Washington International Airport have recorded 3.55 inches of precipitation in January. That's a half-inch more than the 30-year norm for this month.
It's the first time BWI has topped its monthly average since last March, when more than 5.5 inches of rain fell, swamping that month's 3.38-inch norm.
And more is on the way, with rain or showers forecast for tomorrow, Friday, Saturday and Sunday.
It's quite a switch. From July through December, the airport received only 7.06 inches of precipitation, barely a third of the 20.73-inch average for the period. The lack of rain pushed all but extreme Western Maryland into what climatologists ranked as "moderate" to "extreme" drought conditions.
In September, the U.S. Department of Agriculture declared drought disasters in nine counties in Southern Maryland and the Eastern Shore. The declaration made farmers there, and in seven nearby counties, eligible for low-interest loans to help finance this spring's crops.
By mid-November, the region between Baltimore and the Patuxent River was the driest east of the Mississippi River.
Last week, federal drought index maps -- a summation of soil and crop moisture readings, evaporation and runoff data -- showed some improvement. No part of Maryland remained in extreme drought conditions, and Western Maryland and the lower Eastern Shore have returned to normal.
The maps continued to show moderate drought conditions from Frederick County to the upper Eastern Shore, where 4 to 6 inches above normal rainfall amounts are needed to replenish moisture. Severe drought persisted south of the Baltimore-Washington corridor, where 8 to 9 inches of extra rain are needed.
"That would make it look like an uphill battle to get out of dry conditions," Livezey said. But patterns have changed for the better. "We're into a much more normally wet period now," he said. "There's no reason to expect the drought to worsen or to continue."
The drought was fueled by persistent high-pressure systems that steered major rainmaking storms to the north and west of the Middle Atlantic states from July into December. Just before Christmas, that changed, and now high-altitude winds are carrying storms south out of Canada and eastward across the region, bringing rain, snow and ice.
"The quantities have not been enormous," Livezey said. But the moderate amounts are allowing much of the water to soak into the ground, where it's needed.
Dry weather in the southeastern United States is consistent with predictions for the La Nina weather pattern that began last summer. However, historical weather data indicate that Maryland is too far north to expect a consistent pattern of dry weather every time La Nina appears.
La Nina is the name for a periodic cooling of surface waters in the eastern Pacific Ocean.
Livezey said the mild winter enjoyed so far by Marylanders -- recent highs have been more typical of March 19 than Jan. 19 -- is consistent with La Nina and with long-term global warming trends.
"The fact we've been on the mild side so far doesn't surprise us around here," Livezey said. "That doesn't mean we're not going to get a cold blast from time to time. But we don't expect it will be long-lived or of record proportions."
Pub Date: 1/21/99