The U.S. Virgin Islands are waking up to hazy skies produced by Saharan dust and brisk easterly trade winds. King Airport on St. Thomas reported 82 °F with 79 % humidity at 5:53 AM AST. The National Weather Service (NWS) forecast office in San Juan notes that a surface high pressure over the central Atlantic and a series of tropical waves will promote moderate to fresh trade winds and hazy conditions through the remainder of the week.
General Conditions
Winds & Seas: NWS marine forecasts call for east winds 15–20 knots with gusts up to 30 knots and seas 4–6 ft for the Atlantic waters near the Virgin Islands. Small craft should exercise caution. Trade winds weaken slightly early next week but remain in the 10–20 kt range.
Temperature & Humidity: The NWS predicts highs near 92–94 °F (33–34 °C) and lows around 82 °F, with hazy skies and moderate humidity. Weather Underground’s data (via WeatherForYou.com) shows slightly cooler highs around the upper 80s, while ECMWF-based meteoblue guidance suggests maximum temperatures near 27 °C (~81 °F) at higher elevations, reflecting altitude differences. Long‑term climate averages indicate July UV indices in the extreme range (11+) and sea surface temperatures near 28 °C (82 °F).
Precipitation: All three models agree on low rain chances today (10–20 %), increasing to 60–70 % Sunday as a tropical wave approaches. ECMWF ensembles give a 90 % chance of precipitation on Sunday, whereas NWS and Weather Underground assign a 70 % chance.
Island‑by‑Island Forecast
St. Thomas
- Thursday: Partly cloudy to hazy with isolated showers. High around 92 °F per NWS, 88 °F according to Weather Underground. East winds 15–20 mph (gusts 30 mph); seas 5–6 ft. ECMWF gives a high of roughly 27 °C (81 °F) and a 20 % chance of rain.
- Friday–Saturday: Cloud cover increases. NWS predicts scattered showers and isolated thunderstorms Friday afternoon with highs again near 92 °F; Weather Underground forecasts highs around 88 °F and a 50 % chance of showers. Saturday remains breezy with isolated morning showers turning scattered in the afternoon. ECMWF shows rain probabilities rising from 25 % to 90 % by Sunday.
- Outlook: Sunday and Monday may bring numerous showers and isolated thunderstorms as the tropical wave passes. Expect highs near 92 °F, lows near 82 °F, and rain chances around 70 % Sunday dropping to 40 % Monday. Weather Underground concurs, showing a 70 % chance of thunderstorms Sunday and 30 % Monday. Heat indices could reach the upper 90s; hydrate and seek shade during peak sun.
St. Croix
- Thursday: Mostly sunny with haze; isolated morning showers. NWS forecasts a high near 94 °F, while Weather Underground lists 89 °F. East winds 15–20 mph; humidity moderate. Rain chance less than 20 %.
- Friday–Saturday: NWS calls for a mostly sunny Friday with highs around 93 °F and a breezy Saturday with isolated showers. Weather Underground’s forecast is drier Friday (0 % rain) but indicates a 20 % chance of showers Saturday.
- Weekend Storms: Both NWS and Weather Underground warn of numerous showers and isolated thunderstorms Saturday night into Sunday. ECMWF increases the rain probability to 90 % Sunday. Temperatures remain in the lower 90s (NWS) versus upper 80s (Weather Underground).
- Early Next Week: Scattered showers continue Monday and Tuesday with highs around 93–94 °F. Winds remain easterly at 15–20 mph; seas 4–5 ft.
St. John
- Thursday: Sunny and breezy. NWS uses the St. Thomas zone forecast (adjacent islands) and calls for highs near 92 °F, but Weather Underground’s Cruz Bay forecast shows a cooler 83 °F high. East winds 18–22 mph with gusts to 29 mph. Rain chance 0–20 %.
- Friday–Saturday: Scattered showers arrive Friday (40 % chance) and Saturday morning (20 % chance) with highs holding near the low 80s. Winds remain brisk (15–21 mph). Saturday night could see showers and thunderstorms (60 % chance).
- Sunday–Tuesday: A tropical wave increases rain and thunderstorm chances to 70 % Sunday. Afterward, skies clear somewhat with only isolated showers Monday and Tuesday. Highs stay around 83 °F, lows near 82 °F. Visitors should pack light rain gear and plan indoor activities Sunday.
Sea & Surf Outlook
The NWS Coastal Waters Forecast (FZCA52 TJSJ) advises small craft to exercise caution through at least Saturday. East winds 15–20 knots with gusts up to 30 knots and seas 4–6 ft dominate the local waters. Waves are mostly easterly at 7‑second periods; scattered showers are possible overnight. Swimmers should expect a moderate risk of rip currents along eastern and northern beaches, especially near reef passes. The Saharan dust reduces visibility; mariners should maintain proper lookout and use navigational aids.
3‑Day Outlook (Thu–Sat)
- Dry to start: All sources agree on mostly dry, hazy conditions today with breezy east winds. Highs range from the low 80s (ECMWF/Weather Underground) to the lower 90s (NWS). UV index is extreme (11+); sun protection is essential.
- Increasing cloudiness Friday: Scattered showers and isolated thunderstorms develop Friday afternoon, particularly over St. Thomas and St. Croix. Winds remain 15–20 mph; seas gradually subside.
- Saturday unsettled: Isolated morning showers give way to scattered afternoon showers. By Saturday night a tropical wave brings numerous showers and the first thunderstorms, with rain chances reaching 60 % in all models.
7‑Day Outlook
Through mid‑week next week, the models show persistent easterly trade winds and periodic showers. The NWS and Weather Underground anticipate another round of showers and isolated thunderstorms Wednesday. ECMWF maintains elevated precipitation probabilities (50–70 %) throughout the week, suggesting a wetter pattern. Temperatures vary by model but generally stay in the upper 80s to low 90s, with overnight lows around 80 °F.
What Residents and Visitors Should Do
- Stay Hydrated & Protect Against Heat: Daytime temperatures will feel like the upper 90s due to humidity; drink plenty of water and avoid prolonged sun exposure midday. Use broad‑spectrum sunscreen, wear hats and sunglasses, and seek shade.
- Prepare for Showers: Carry a light rain jacket or umbrella for sudden tropical showers, especially Friday evening through Monday. Use waterproof bags to protect electronics.
- Maritime Caution: Boaters should heed small craft advisories, secure vessels, and monitor marine forecasts. Snorkelers and beachgoers need to be aware of rip currents and reduced visibility due to Saharan dust.
- Monitor Forecast Updates: The tropical wave could bring localized flooding in low‑lying areas; stay tuned to local radio and NWS advisories for potential flash‑flood warnings.
Today’s weather across the U.S. Virgin Islands is characterized by hazy skies, strong easterly breezes and warm temperatures. Models agree that showers will remain isolated until late Friday, when a tropical wave increases moisture and produces thunderstorms through Sunday. Differences between models primarily involve temperature (NWS being warmer) and the timing and likelihood of rainfall (ECMWF wetter). By Tuesday, conditions should improve with only scattered showers and continued trade‐wind breezes. Islanders and tourists should prepare for both intense sun and intermittent downpours over the next few days.
Advertisements
