Recent rounds of thunderstorms have brought some much-needed drought relief to the Mid-Atlantic, but the latest data shows that dry conditions remain a significant concern across the region.
The latest U.S. Drought Monitor was released Thursday, July 16, with conditions based on data collected through Tuesday morning, July 14. Approximately 48 percent of the Mid-Atlantic remains classified as abnormally dry or in drought, ranging from D0 Abnormally Dry conditions to D3 Extreme Drought. An estimated 24.7 million people are currently living within areas classified as being in drought.
Recent Storms Provide Uneven Relief
Locally heavy rainfall, including amounts exceeding two inches in some locations, helped improve soil moisture, streamflow and short-term precipitation deficits. The greatest improvements were reported across West Virginia, New Jersey, southern Pennsylvania and portions of Maryland and Delaware. Additional improvement was recorded across parts of Virginia following widespread moderate to heavy rainfall.
The rainfall, however, was highly uneven. Since the beginning of July, some of the driest areas have received only 25 to 50 percent of their normal precipitation, while locations repeatedly affected by thunderstorms have recorded 200 to 300 percent of normal rainfall. This sharp difference explains why drought conditions improved in some communities while worsening in nearby areas that missed the heaviest storms.
Despite the broader improvement, Severe Drought expanded from northern Maryland into northern Virginia. Extreme Drought also expanded in portions of Delaware, New Jersey and Virginia. This means the recent rain has helped stabilize conditions in some areas, but it has not been enough to overcome longer-term precipitation deficits across the entire region.
Heat Continues to Add Stress
The drought has been intensified by persistent summer heat. Temperatures across the Mid-Atlantic have generally averaged between 2 and 10 degrees above normal since July 1. The combination of excessive heat, increased evaporation and high water demand has placed additional stress on crops, lawns, trees and water supplies.
Recent rainfall has improved short-term soil moisture and streamflow in some locations, but groundwater remains much below normal across parts of the Mid-Atlantic, particularly in New Jersey, Virginia and sections of the East Coast. Stream gauges continue to report flows ranging from record-low levels to the lowest 10 percent of historical observations across much of Virginia, Maryland and Delaware, along with southeastern Pennsylvania and southern New Jersey.
Groundwater typically responds more slowly than soil moisture or small streams. Several rounds of widespread, soaking rainfall may therefore be necessary before deeper water supplies show substantial recovery.
Agricultural and Water-Supply Impacts Continue
Drought impacts reported across the region include stressed crops and trees, dry wells, reduced streamflow and water restrictions. Delaware farmers have increasingly relied on irrigation to keep crops alive, with reports indicating that portions of the corn crop may not fully recover from the prolonged heat and dryness.
Additional water restrictions and conservation measures have been implemented elsewhere in the region. Several community water systems in Virginia have mandatory restrictions, while voluntary conservation measures have been requested in portions of Pennsylvania and New Jersey.
While thunderstorms can quickly improve surface conditions, they do not always provide the prolonged, widespread rainfall needed to replenish groundwater, reservoirs and larger river systems. A slow, steady rainfall pattern would be more beneficial than isolated downpours that produce runoff or flooding.
Wetter Pattern May Offer Additional Improvement
There are encouraging signs in the extended outlook. NOAA’s Climate Prediction Center favors above-normal precipitation across the entire Mid-Atlantic during the July 23 through July 29 period. Temperatures are expected to be below normal across northern portions of the region and closer to normal farther south.
Looking through the end of October, the seasonal drought outlook favors improvement or removal of drought across most of the Mid-Atlantic. However, above-normal temperatures remain favored during the August through October period, while the precipitation outlook provides equal chances for wetter, drier or near-normal conditions across most of the region.
The recent rainfall is a positive step, but continued precipitation will be needed to produce lasting improvement. The U.S. Drought Monitor is a weekly assessment rather than a forecast, and local conditions can vary considerably depending on where thunderstorms occur. The next update will be released Thursday morning.
