April 1, 2025 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/.

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Surface high pressure dominating the tropical Atlantic contributed to breezy and windy conditions across the USVI during this most recent drought week (Wed, Mar 26-Tue, Apr 1, 2025). Trade-wind showers occurred early in the drought week, with precipitation coverage increasing later in the week as a pre-frontal trough approached the region from the northwest. No changes were made to the drought depictions for the three islands this week, as the USVI region is transitioning from its (climatological) dry season to its wet season.

In St. Croix, precipitation measurements ranged from 0.18-inch at VI-SC-24 (Christiansted 2.1 ENE) to 1.45 inches at VI-SC-20 (Frederiksted 1.7 ESE).

Intermediate rainfall amounts for the week included 0.51-inch at VI-SC-10 (Christiansted 1.6 E), 0.55-inch at VI-SC-25 (Christiansted 4.4 W), 0.64-inch at VI-SC-23 (Christiansted 6.5 W), 0.65-inch at VI-SC-30 (Christiansted 1.7 W), 0.72-inch at VI-SC-29 (Frederiksted 2.5 NNE), 1.14 inches at VI-SC-35 (Frederiksted 1.3 ENE), and 1.18 inches at VI-SC-34 (Frederiksted 1.9 NE).

Provisional data from the USGS Adventure 28 Well showed that until several days ago, the Depth to Water Level (feet below land surface) had been steadily declining throughout the month of March, from about 16.6 feet to 17.0 feet. On March 29-30, passing showers and/or thundershowers resulted in a spike in the well data time series that showed a very brief rise in groundwater level to 16.2 feet, before falling and settling around 16.7 feet at the end of the month, just as another round of precipitation moved into the region.

In St. John, rainfall totals for the drought week ranged from 0.27-inch at VI-SJ-4 (Cruz Bay 0.8 NE) to just under an inch (0.99-inch) at VI-SJ-10 (Cruz Bay 3.1 NNW). Several intermediate rainfall totals included 0.47-inch at VI-SJ-8 (Cruz Bay 7.4 E), 0.60-inch at VI-SJ-3 (Windswept Beach), and 0.96-inch at VI-SJ-5 (Cruz Bay 1.6 E).

For Windswept Beach, the total rainfall for 2024 was 70.02 inches, making it the third wettest year on record behind 2017 and 2010. The monthly rainfall totals for January, February, and March, 2025, were respectively: 1.52 inches, 2.16 inches, and 3.54 inches. In addition, March was both wet and very windy, with more than 60 percent of the monthly rainfall occurring on one day (March 14th). The Standardized Precipitation Index values for Windswept Beach for the 1, 3, 6, 9, and 12-month time scales were, respectively: +1.61, +0.60, +1.00, +1.05, and +1.55. This indicates wet conditions for all periods.

Provisional data from the USGS Susannaberg DPW-3 Well showed a gradual decline in wellwater level occurred during the month of March, starting around 8.4 feet (below the land surface) at the beginning of the month and ending near 9.7 feet. A brief break in the pattern occurred on March 13-14, when the wellwater level rose from 9.11 feet to 8.71 feet, before reassuming its declining trend. This coincided with a period of shower/thundershower activity.

In St. Thomas, rainfall measurements taken during this drought week ranged from 0.28-inch at VI-ST-14 (Nadir 0.3 E, Tropical Marine) to 1.07 inches at VI-ST-13 (Charlotte Amalie 1.2 NNW). A couple of other reports included 0.71-inch of rain at VI-ST-15 (Charlotte Amalie West 1.3 N) and 0.92-inch at VI-ST-5 (Charlotte Amalie West 4.2 WNW).

Provisional data from the USGS Grade School 3 Well showed groundwater levels ranged between 4.0 and 7.0 feet (below the land surface) during the month of March, with a value near 6.0 feet reported at month’s end. An abrupt rise in wellwater level occurred on March 13-15 (from 7.0 feet to 3.9 feet), before gradually subsiding to its present level. The abrupt rise in wellwater level in mid-March coincided with a period of shower/thundershower activity.

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During the past drought week (Wed-Tue, Mar 26-Apr 1, 2025), passing trade wind troughs and fragmented shear lines brought relatively light showers and breezy conditions to the Commonwealth of the Northern Mariana Islands (CNMI). A weak disturbance south of the Republic of Palau helped to displace an area of trade wind convergence towards the Republic and the western Federated States of Micronesia (FSM), but rainfall was very limited for the week. Over the eastern FSM, a mesoscale convective system (MCS) and trade wind convergence brought heavy rainfall to parts of the region. Relatively dry trades prevailed across the Republic of the Marshall Islands (RMI), with most stations falling far short of the 2-inch weekly rainfall threshold required to meet most water needs. South of the equator, American Samoa experienced showers and thunderstorms during portions of the drought week from two separate mid-level troughs that approached from the northeast. Excessive rainfall and flash flooding were not an issue this week, thanks in large part to the South Pacific Convergence Zone (SPCZ) remaining well south of the islands.

Satellite-based rainfall estimates for the past 7 days (SPoRT IMERG) across the tropical western Pacific ranged from 0.0 to 2.0 inches (locally greater), with the more significant rainfall over the central and eastern FSM, and parts of the RMI. Approximately one inch of rain was indicated over the vicinity of American Samoa this week.

The Republic of Palau experienced a dry week (i.e. less than the 2-inch weekly minimum threshold to meet most water needs), with 0.21-inch of rain reported at Koror and 0.82-inch at the WSO Palau (Airai). As every month since April 2024 has been wet, drought-free conditions continue at Palau.

Across the FSM, Yap received 0.69-inch of rain this week, which fell well short of the weekly minimum rainfall requirement. The past 4 months have been dry. Yap’s drought depiction remains unchanged at D1(S) as the previous week’s amount of 2.96 inches of rain helped to offset additional degradation. Rainfall data was unavailable at Ulithi and Fananu this week, while no precipitation was reported at Woleai (3 days missing, but remains free of drought). Chuuk Lagoon reported 1.17 inches of precipitation this week. Although considered a “dry” week, this amount of rain combined with 10 of the past 12 months being wet, helped to maintain its drought-free designation. Drought-free conditions persist at Lukunor, which experienced a wet week (3.02 inches), and the last 4 months (Dec 2024-Mar 2025) have also been wet. North Fanif came in wet this week, with 2.63 inches of rain. Nukuoro also came in wet this week, registering over three times the weekly minimum requirement (6.38 inches). The past 6 weeks and past 7 months have also been wet, ensuring drought-free conditions will continue for a while. Kosrae and Pohnpei also came in wet this week, with 5.27 inches and 2.48 inches of rain, respectively. Both locations easily remain drought-free this week. Kapingamarangi received 3.58 inches of rain this past drought week. Monthly rainfall has been highly variable during the past 12 months. Its depiction remains unchanged at D0(S), though if next week is also wet, its depiction may be upgraded to drought-free. In contrast to the wet week for much of the central and eastern FSM, Pingelap came in dry this week (0.78-inch). Of the past 12 weeks, only one was wet (the week ending 18 March, with 3.28 inches). For now, its depiction remains unchanged at D0(S). If next week is dry, it would make three dry weeks in a row, and likely require a one-category degradation.

A dry week ensued across the CNMI (less than the 1-inch weekly minimum requirement) with precipitation totals ranging from a meager 0.13-inch of rain at Guam to 0.72-inch at the Saipan International Airport (IAP). In Guam, the week ending 4 March was the only wet week in the past 12 weeks (3.93 inches), with this rainfall total falling just short of the monthly minimum requirement of 4 inches. From June 2024-January 2025, each month was wet; though more recently, February and March 2025 were dry. The Keetch-Byram Drought Index (KBDI), which attempts to measure the amount of precipitation necessary to return the soil to full field capacity, breached 600 this week in Guam (zero represents a saturated soil and 800 an absolutely dry soil). For this week, Guam’s depiction remains unchanged at D0(S). Intermediate precipitation amounts for the CNMI include Tinian (0.18-inch), Dededo (0.22-inch), Saipan (AMME NPS, 0.22-inch), Agat (0.47-inch), and Rota (0.50-inch). Like Guam, the past 12 weeks in Rota have been mostly dry, with only the week ending on 4 March being wet (2.17 inches). Its depiction remains D0(S) this week. The last wet month in Saipan was in November 2024, when 6.14 inches of rain fell. Saipan’s depiction remains at D2(S) this week.

Across the RMI, weekly rainfall amounts ranged from zero inches at Wotje and Utirik to 2.51 inches at Mili. Wotje has been dry the past 12 weeks, and during the past 4 months (Dec 2024-Mar 2025). Its depiction remains at D1(S) this week, but conditions appear ripe for additional deterioration next week unless significant precipitation falls. Utirik received a scant 0.14-inch of rain in March, but retains its D1(S) depiction for now. In contrast, 6.20 inches of rain was measured at Mili in the month of March, though this still falls well short of the 8-inch monthly minimum requirement. Mili remains drought-free. Intermediate rainfall amounts of 0.22-inch was noted in Ailinglaplap, 1.14 inches in Kwajalein (most of which fell on the last day of the drought week), 1.30 inches in Majuro, and 1.45 inches in Jaluit. In Ailinglaplap, each month from May 2024 through December 2024 was wet, but so far in 2025, the first three months have been dry. Its drought depiction remains at D0(S). This same depiction of D0(S) continues for both Jaluit and Majuro. The latter location reported that nine of the past 12 months have been wet. Majuro’s reservoir contains 23.4 million gallons of freshwater (64.3 percent of capacity). In Kwajalein, the last 12 weeks (and the last 4 months) have been dry. Its current designation of D1(S) may require a one-category deterioration next week, if no significant rain falls before that.

South of the equator, Pago Pago in American Samoa reported a wet week with 2.86 inches of rain. The past 5 months have been wet, with 17.28 inches of rain being reported in March. The precipitation measurements at higher altitude sites include 1.16 inches at Toa Ridge and 1.00-inch at Siufaga Ridge. This week’s drought designation at Tutuila remains unchanged with drought-free conditions.

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