Drought in Maryland, June 1 to 30, 1999

High pressure was the dominant weather feature across Maryland during the month. This weather pattern directed rain producing low pressure systems north of the region and continued the climatological drought that has gripped the area since last simmer. The drought warning issued by the Maryland Department of the Environment remained in effect through June. By the last week of the month the Palmer Drought Index, a measure of long term drought conditions, indicated North Central and Northeast Maryland were in a severe drought, and South Central and Western Maryland were in an extreme drought. June was the 8th month in the past 12 months that precipitation was below normal. From July 1998 through June 1999 precipitation was a staggering 15 inches below average, the 2nd driest 12 months on record. Only 2.04 inches of rain fell at Baltimore/Washington International Airport (BWI) during the month of June, 1.63 inches below normal. BWI received 0.86 inches of this total on the 24th. The Maryland Science Center at Inner Harbor Baltimore reported a total of 2.42 inches. Additional June rainfall totals included Allegany County at 1.8 inches, Washington County at 2.8 inches, Frederick County at 2.6 inches, Prince Georges County at 2.5 inches, Carroll County at 1.7 inches, Northern Baltimore County at 2.4 inches, Howard County at 1.3 inches, Anne Arundel County at 2.2 inches, Montgomery County at 1.5 inches, Charles County at 2.2 inches, and St. Mary's County at 2.4 inches. The lack of rainfall affected water levels along the Potomac River and the Chesapeake Bay. The flow of water past Washington D.C. hovered around 18% of average, and many new record low daily flows were recorded in upstream tributaries of the river. Unusually high proportions of river flow, 33%, were diverted out of the Potomac River into public water supplies during the month. The normal diversion rate is about 5%. Monthly flow rates of the Potomac River have been below average for the last 10 months. Flows in the Potomac were equal or slightly below minimum June daily mean flow values recorded during the 1980-82 drought. Many gaging stations reported streamflow at or below the 90 percent exceedence. The total flow into the Chesapeake Bay has been below average for the past 11 months. Freshwater inflow to the Chesapeake Bay in June was less than 74% of the previously recorded low set in 1964. The deficit of fresh water resulted in an increase of salinity levels in the bay and had an impact on animal and plant life. Several towns in Carroll County, including Mt. Airy imposed mandatory water restrictions at the beginning of the month. A popular swimming beach at Greenbriar State Park near Hagerstown remained closed because the water level remained well below the capacity of the 50 acre reservoir. The lack of precipitation also continued to beat down crops and pastureland. Watering holes and irrigation sources continued to dry up, forcing many farmers to carry water to livestock. Hay producers reported less than half of their normal yields from their second cutting. Soybean planting came to a halt in many locations. Corn crops that should have been knee-high by mid month were only 1 foot tall. Some farmers had to reduce their herd sizes in order to stretch hay and water supplies. Tobacco, normally a drought-tolerant crop, suffered in the fields. 37% of pastureland, 18% of corn, and 21% of soybeans across the state were reported in poor or very poor condition. 59% of topsoil was reported as short or very short of moisture by the end of the month.