Maryland's drought is deepening as more territory is added the region experiencing "severe" drought conditions, according to new data released this morning by the U.S. Department of Agriculture.

The USDA's latest Drought Monitor map shows more than 75 percent of the state is officially in drought. That's unchanged from last week. The ratings are based on measurements of rainfall, soil moisture, streamflow and the health of vegetation as measured by satellites.

But the new drought map has expanded that portion of the drought-affected area now under "severe" drought. It now includes parts of southern Washington County, southwestern Frederick County and western Montgomery County. Southern Maryland, too, including Charles, St. Mary's and southern Calvert counties, remain under severe drought conditions. In all, 17 percent of the state is experiencing severe drought conditions, up from 9 percent last week.

"Moderate" drought continues in a swath from eastern Allegany County to the lower Eastern Shore, including Baltimore City and southern Baltimore County.

The remaining 25 percent of the state, including far western Maryland and the northeast corner (including northern Carroll, Baltimore and Kent countiues, and all of Harford and Cecil), remains "abnormally dry" on the USDA map.

Several Maryland communities, including Frederick, Mt. Airy and Westminster, have already announced voluntary or mandatory watering restrictions. State agriculture officials have submitted data on crop losses to Gov. Martin O'Malley, who was expected to announce today that he will seek a federal drought disaster declaration for portions of the state worst-hit by the dry weather.

Rainfall at Baltimore-Washington International Airport has been unusually scant since mid-April. Since May 1, the airport has recorded a precipitaion shortfall of about 6 inches. The actual deficit in many locations may be far worse, since the airport experienced a very localized 1.8-inch thunderstorm July 10. Spotty showers across the region this week have done little to ease the dry conditions.

Although there are chances for showers and thunderstorms each day for the next week, the National Weather Service forecast shows no prospects for sustained and restorative rains. The tropics, which have frequently provided drought relief for Maryland in the form of remnant tropical storms, remain quiet. 

Some farmers on the lower Eastern Shore and in Southern Maryland say they have had no significant rain in several months. Corn, soybean and hay losses are said to be as high as 50 to 60 percent in some regions.

So far, groundwater resources and the urban reservoir system in Central Maryland are said to be holding up well. But public works officials say supplies could become stretched if the dry weather continues well into August.

Here's the national Drought Monitor map, showing how our conditions fit in with those across the lower 48 states.