April 6, 2021 National Drought Summary

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilizedinclude the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast webpage used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

Weather Summary: 123

Northeast: 123

Southeast: 123

South: 123

Midwest: 123

High Plains: 123

West: 123

Caribbean: 123

Late-March and early-April showers were generally lighter and more scattered across St. John (unchanged at D2-S) and St. Croix (also unchanged at D1-SL), although a few spots noted more than an inch of rain. The observer at Windswept Beach on the north shore of St. John received less than 2 inches of rain in each of the first 3 months of the year for only the third time in the last 38 years, along with 2011 and 2019. For the 7-day period ending April 6, Windswept Beach received 0.55 inch, while volunteer observer VI-SJ-5 collected 0.53 inch. Farther south, a very dry March on St. Croix was followed by scattered showers late in the month and in early April. March rainfall at Rohlsen Airport on St. Croix totaled 0.55 inch (35% of normal), followed by 0.55 inch from April 1-6. Rainfall for the week ending April 6 was a bit heavier at volunteer (CoCoRaHS) observation site VI-SC-8, where 1.01 inches fell, and VI-SC-10, which received 1.05 inches.

During the drought-monitoring period ending April 6, portions of the U.S. Virgin Islands received beneficial showers as a frontal boundary stalled to the northwest. Some of the most significant rain fell across St. Thomas in early April, when showers and thunderstorms developed in a deep layer of tropical moisture south of the boundary. King Airport on St. Thomas received 1.35 inches of rain on April 2-3. During all of March, rainfall at King Airport totaled just 0.61 inch (43% of normal). Elsewhere on St. Thomas, volunteer (CoCoRaHS) observer VI-ST-5 also received more than an inch of rain, with 1.07 inches falling in early April. Despite the rain, the D2-SL designation was retained on St. Thomas, partly due to lingering impacts from earlier dryness and the lack of groundwater response, as shown by the U.S. Geological Survey well on the island. In addition, recent heat on St. Thomas has aggravated the effects of a drier-than-normal spring. On the 30th, King Airport reported a 90-degree reading in March for the first time since 1996.

Pacific: 123

During the drought-monitoring week of March 31 - April 6, there was little overall change in the weather pattern across the U.S.-Affiliated Pacific Islands. As a result, there were no map changes in the depiction of dryness and drought. For the Commonwealth of the Northern Mariana Islands, mostly drier-than-normal weather continued. The NWS office on Guam reported that recent showers have resulted in a slight lowering of the Keetch-Byram Drought Index (KBDI) to 651 by April 5. However, KBDI values above 600 can still be indicative of dryness/drought and potentially erratic fire behavior, when fires occur. Guam International Airport received rainfall totaling 1.05 inch from March 31 – April 6, warranting a continuation of D0-S. Dryness (D0-S) also continued across Rota. Less than 2 inches of rain fell during March at all reporting sites on Saipan, where moderate drought (D1-S) persisted. All Saipan stations received less than an inch of rain from March 31 - April 6.

In the Federated States of Micronesia (FSM), all islands were free of dryness and drought except Kapingamarangi, where long-term severe drought (D2-L) persisted, owing to lingering impacts such as poor water quality from wells and stressed vegetation and crops. The weather observer on Kapingamarangi recently reported that water storage tanks are more than half full and that vegetation is slowly recovering, with green taro sprouts noted. Well water on Kapingamarangi is still not potable but is being used for other purposes. Elsewhere in the FSM, a few islands have experienced drier weather in recent days. For example, Yap had rainfall totaling just 0.44 inch from April 1-6, but since March 1 has received 9.07 inches (142 percent of normal).

In the Republic of the Marshall Islands (RMI), water conservation measures remain in place on some northern islands. Wotje received more than an inch of rain (1.02 inches) during a drought-monitoring period for the first time since late 2020—but remains in extreme drought (D3-S). On Kwajalein, where moderate drought (D1-S) persists, only light rain has fallen over the last month, with the last significant event occurring when 3.34 inches fell from March 8-10. Most other islands in the RMI continue to receive abundant rainfall; March totals included 24.40 inches on Ailinglapalap; 21.26 inches on Mili; and 15.00 inches on Majuro. Reservoir storage on Majuro exceeded 30 million gallons on March 30, peaking at 30.473 million gallons (85% of capacity) on April 3.

Weekly rainfall totals were above the minimum needed to meet most water requirements in the Republic of Palau, where the international airport measured 1.66 inches. The airport reported 8.84 inches of rain in March. As a result, D-nothing continued in the Republic of Palau. Similarly, plenty of rain fell in American Samoa, where D-nothing continued as the international airport collected 9.68 inches during March and 2.55 inches during the March 31 - April 6 drought-monitoring period.

Looking Ahead: 123

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