Short-term moderate and severe drought expanded this week in eastern and southern portions of Puerto Rico, and moderate drought expanded eastward to include the islands of Vieques and Culebra. Vegetation impacts increased amid short-term precipitation deficits and reduced streamflow. Rainfall was mostly below normal in Puerto Rico, while temperatures there ranged from mostly 1-3 degrees warmer than normal.
During much of the past drought week (Wed, Jul 1 - Tue, Jul 7, 2026), a typical summertime trade wind pattern persisted across Puerto Rico and the USVI. This featured a broad surface high pressure area over the central Atlantic which maintained moderate east-southeast winds. This pattern favored passing showers across the USVI and eastern Puerto Rico during the overnight and morning hours, followed by isolated afternoon showers over the interior and western sections of Puerto Rico. In addition, concentrations of Saharan dust produced hazy skies, reduced visibility, and degraded air quality. Persistent high-level cloudiness, warm surrounding waters, and continued onshore flow limited nighttime cooling, with many coastal areas seeing temperatures falling to only around 80-82 degrees. The lack of overnight relief, combined with a shallow increase in low-level moisture confined below 850 mb, resulted in higher humidity and dangerous heat indices.
The 7-day satellite-based precipitation estimates from NASA SPoRT/Imerg showed rainfall amounts under a half-inch, consistent with ground-based measurements. The amounts shown below are for individual stations and valid for the full 7-day period unless noted otherwise.
In St. Croix, sorted (from lowest to highest) individual station measurements include: Rohlsen Airport (#11624, a trace), VI-SC-20 (Frederiksted 1.7 ESE, 0.01-inch), VI-SC-09 (Christiansted 4.1 ESE, 0.03-inch, 5 days of data), East Hill (#672560, 0.08-inch), VI-SC-23 (Christiansted 6.5 W, 0.09-inch, 5 days of data), VI-SC-30 (Christiansted 1.7 SW, 0.17-inch), VI-SC-35 (Frederiksted 1.3 ENE, 0.21-inch, 4 days), VI-SC-25 (Christiansted 4.4 W, 0.25-inch, 6 days), VI-SC-10 (Christiansted 1.6 E, 0.32-inch), and VI-SC-29 (Frederiksted 2.5 NNE, 0.41-inch). The Standardized Precipitation Index (SPI) values for Rohlsen Airport for 1-, 3-, and 6-months are, respectively, -3.40, -1.60, and -1.99 which suggests careful monitoring for further degradation in the near future. At East Hill, the SPI values at 1-, 3-, 6-, 9-, and 12-months are: -1.53, -1.23, -0.19, -0.90, and -0.39, which are more consistent with current D2-S conditions. The Adventure 28 Well experienced a gradual decline in water level, ranging from 23.07 feet to 23.55 feet below the ground surface.
At St. John’s, precipitation amounts ranged from 0.01-inch at VI-SJ-5 (Cruz Bay 1.6 E) to 0.03-inch at VI-SJ-10 (Cruz Bay 3.1 NNW) and at VI-SJ-3 (Windswept Beach). An observer at Windswept Beach noted “Dry and windy with lots of Saharan dust….but at least the wind and the ocean moderate the heat.” The SPI values at 1-, 3-, 6-, 9-, and 12 months at Windswept Beach are, respectively: -2.10, -1.37, -0.02, -1.13, and -0.19, which are generally consistent with St. John’s current D2-S drought designation. Well water levels at the Susannaberg Dpw-3 Well fell from 16.14 feet to 16.44 feet below the ground surface this week.
Dry conditions persisted at St. Thomas this week as well. Station VI-ST-15 (Charlotte Amalie West 1.3 N, 4 days of data) reported no rain, and King Airport (#11640) measured only a trace of rain this week. The King Airport SPI values at 1-, 3-, 6-, and 9-months were, respectively: -2.67, -2.52, -0.29, and -1.23, which emphasizes the heavily “front-loaded” (more recent) dryness. Provisional well water data from the USGS Grade School 3 Well featured a very slow downward trend in water level until the last day when it “tanked” significantly. The values ranged from 9.45 feet below the ground surface early in the week to 9.89 feet at week’s end.
Based on the recently observed precipitation amounts, provisional USGS well water levels, and latest SPI values, the drought designations at the three USVI stations remain at D2-S this week. One contributor towards the current drought situation is the presence of El Nino, which typically introduces enhanced westerly wind shear across the Caribbean Sea and tropical Atlantic. This increased shear is unfavorable for the formation of tropical cyclones, which usually bring significant rainfall to the northeastern Caribbean region in summer.
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