Dangerously Dry Mid-Atlantic States And Florida

Fig. 1: Latest (5-week) evaporative drought demand index (EDDI) identifies an extreme need for moisture in the Mid-Atlantic region and Florida.

Discussion: The largest area of drought is across the Southwest U.S. as we enter early warm season in the U.S. Drought is also present, although not as intense, across the west/northwest Great Plains. Interestingly, the most severely dry evaporative drought demand index (EDDI) is not in the primary drought areas, rather the Mid-Atlantic region and Florida (Fig. 1). The reason for the stronger EDDI on parts of the East Coast is due (primarily) to the lengthier period of dry climate encountered in those regions. Notable, and very unusual, is the number of fires seen in the ED4 areas, most recently New Jersey to Cape Cod. The ED4 conditions are located near or across high population areas. In the ED3/ED4 regions, susceptibility to rapidly developing drought (or “flash drought”) is higher than normal along with potential critical water shortages, negative effects on crops, and fire danger.

Heavy rain is forecast to redevelop across Texas tomorrow and Tuesday driven by severe weather outbreaks including tornado risk (Fig. 2). Wet weather shifts to Louisiana/Mississippi as mid-week approaches. Low pressure develops in the southeastern Gulf of Mexico midweek and drifts across the Florida Peninsula to the Southeast Coast in the 6-10-day period. The result is a large mass of heavy rain near and just offshore the Southeast U.S. although affecting the Florida East Coast (Fig. 3). Tropical or subtropical low pressure is possible with this rainstorm.

The U.S. medium range temperature anomaly forecast is best projected by the overnight ECM ENS which indicates a large area of warmer than normal weather across the Southwest U.S. to the North-central States while the Southeast U.S. is rain cooled (Fig. 4). In the 11-15-day period, anomalous warmth is most concentrated on the Midwest States (Fig. 5) although other models are somewhat warmer in the East.

Fig. 2-3: The 12Z GFS 1-5-day and 6-10-day rainfall amount forecast for the Southeast U.S.

Fig. 4-5: The ECM ENS medium range U.S. temperature anomaly forecast.