Following some beneficial showers across the U.S. Virgin Islands in early April, mostly dry weather returned. In addition, some unusually dry air briefly overspread the islands. On April 10, for example, the dewpoint temperature fell as low as 57°F at Rohlsen Airport (TISX) on St. Croix, resulting in a relative humidity of 42 percent. On the same date, King Airport (TIST) on St. Thomas had a minimum dewpoint of 56°F. Weekly (April 6-12) rainfall totaled 0.01 inch at Rohlsen Airport and 0.16 inch at King Airport.
Among volunteer (CoCoRaHS) weather stations in the U.S. Virgin Islands, the highest April 6-12 total was 0.73 inch—all of which fell in a downpour on the 7th—along the northern shoreline of St. John at VI-SJ-3. Just miles away, near Cruz Bay, 0.12 inch fell during the drought-monitoring period at VI-SJ-5. According to the U.S. Geological Survey (USGS) well on St. John, depth to water has steadily increased throughout 2021 and is approaching 15.5 feet. Given the short-term dryness and groundwater shortages, severe drought (D2-S) persisted on St. John.
In recent days, depth to water on St. Thomas has stabilized near 13.35 feet, based on information from USGS well data. Aside from a period in 2020 when information was not available, depth to water has not been greater on St. Thomas since the summer of 2017, shortly before Hurricanes Irma and Maria devastated the U.S. Virgin Islands. During the drought-monitoring period, rainfall at four volunteer (CoCoRaHS) weather stations ranged from zero to 0.07 inch. Given the return to dry weather and lack of well recovery, St. Thomas retained a severe drought (D2-SL) designation.
On St. Croix, drought-monitoring period rainfall at all airport and volunteer (CoCoRaHS) sites totaled less than one-tenth of an inch. Depth to water at the USGS well on St. Croix increased to more than 22.4 feet for the first time since December 2016, although data was missing for part of 2020. As a result, the moderate drought (D1-SL) designation was maintained for St. Croix.