Marine Weather and Tide Forecast for Guanica, PR

.Short Term(Today through Wednesday)...
Issued at 304 AM AST Mon Mar 9 2026

Overnight, bands of showers fueled by a patch of moisture dragged by the trades moved across the U.S. Virgin Islands, Vieques, Culebra, and the eastern and southeastern coasts of Puerto Rico. Doppler radar estimated rainfall accumulations between 0.10 and 0.80 inches, with the highest totals concentrated over the El Yunque Rainforest, particularly along the mountain slopes of Naguabo and Ceiba. Across the U.S. Virgin Islands, accumulations remained below 0.10 inches.
Overnight lows ranged from the low to mid-70s in lower elevations to the mid and upper 60s across higher terrain. Winds prevailed from the east at 5 to 15 mph, though the Cyril E. King Airport in St.
Thomas recorded a maximum sustained wind of 23 mph and a gust of 38 mph at approximately 2:15 AM AST during a passing shower.

Weather conditions are expected to remain very similar as in recent days as a surface high pressure continues to dominate the central Atlantic. This system will maintain a tight pressure gradient, promoting fresh to strong easterly winds across the region. By late Tuesday into Wednesday, as the high migrates toward the eastern Atlantic, winds will shift more east-northeasterly and gradually diminish through the end of the workweek.

In the mid-to-upper levels, a trough extending from Jamaica and eastern Cuba will drift toward Hispaniola by Tuesday through Wednesday, weakening by Thursday as it moves eastward. Over the next few days, the influence of this feature, combined with a persistent upper-level jet and an increase in low-level moisture, will support instability and periods of enhanced shower activity and locally heavy rainfall. Precipitable water (PWAT) values will be near or slightly above seasonal normals (1.5 to 1.75 inches).
Meanwhile, the 500 mb temperatures will remain cool, ranging from -8°C to -10°C, further supporting an unstable environment.
Residents and visitors should expect morning showers across eastern and northern Puerto Rico, Vieques, Culebra, and the U.S.
Virgin Islands, followed by afternoon development over interior and western Puerto Rico.

.Long Term(Thursday through Monday)...
Issued at 304 AM AST Mon Mar 9 2026

A trough in the mid and upper level will allow for temperatures to cool down at the mid levels by Thursday. This, along with moderate moisture content at the lower levels, will result in increasing showers along eastern Puerto Rico and the Virgin Islands during the day. However, the heaviest activity is expected for the interior and west in the afternoon hours. Urban and small stream flooding will be likely, and there is a medium chance of experiencing thunderstorms as well. From Friday and into the weekend, strong surface high pressure centered over the northeastern Atlantic Ocean will steer the winds from the east-southeast. Speeds will be moderate, around 15 knots for this time period. In the lower levels, patches of moisture will be dragged in at times. Conditions aloft will not be as favorable as on Thursday, but in general, the pattern will favor passing showers across eastern Puerto Rico and the Virgin Islands, followed by stronger showers in the interior and west each afternoon. While urban and small stream flooding could occur in some areas, the most likely scenario is that the showers will lead to ponding of water in roadways, as well as water surges in creeks and small rivers. Also, with southeast winds, temperatures will warm up a little, with highs mostly in the mid and upper 80s for coastal areas.

AVIATION
(06Z TAFS)
Issued at 304 AM AST Mon Mar 9 2026

VFR conds expected across all TAF sites thru the period. Passing SHRA will result in VCSH at TIST/TISX/TJSJ/TJPS thru 09/14Z. By mid- morning into the afternoon hours SHRA development will result in -RA at TJBQ/TJSJ/TJPS thru 09/22-23Z. E winds btwn 15-20 kt with gusts higher than 30 kt and sea breeze variations aft 09/14Z.

MARINE
Issued at 304 AM AST Mon Mar 9 2026

A broad surface high-pressure system extending across the Central Atlantic will continue to support widespread moderate to fresh trade winds across the region, resulting in rough seas in local waters.
Recent buoy observations and global model guidance suggest a similar pattern will persist from Monday into midweek, with wind-driven seas up to 7 feet and steady easterly winds up to 20 knots, occasionally producing gusty winds and passing moisture patches. As a result, the Small Craft Advisory will remain in effect for most of the local waters. Conditions are expected to gradually improve across the nearshore waters early in the week; however, choppy conditions will likely persist across the offshore waters. Small craft operators are urged to exercise caution and check the latest marine forecasts before venturing into the local waters.

BEACH FORECAST
Issued at 304 AM AST Mon Mar 9 2026

A broad surface high-pressure system over the Central Atlantic, extending into the Caribbean, will support a tightening of the pressure gradient across the forecast area. As a result, wind-driven seas will continue, with seas between 5 and 7 feet across the Atlantic nearshore waters and the local passages. Therefore, a high risk of rip currents is expected to persist today across the northern beaches of Puerto Rico, Culebra, and the U.S. Virgin Islands. Beachgoers are urged to stay out of the water or exercise extreme caution. Across the rest of the exposed beaches along the west, south, and southeast coasts, the rip current risk will remain moderate, with seas up to 5 feet and winds up to 20 knots, along with occasional gusty conditions during the day. Improving coastal conditions are forecast from Tuesday onward as wind-driven seas gradually diminish across the nearshore coastal waters. For more detailed information, visit: www.weather.gov/sju/marine.

SJU WATCHES/WARNINGS/ADVISORIES
PR...High Rip Current Risk through this afternoon for PRZ001-002-005- 008-012-013.

VI...High Rip Current Risk through this afternoon for VIZ001-002.

AM...Small Craft Advisory until midnight AST Tuesday night for AMZ711.

Small Craft Advisory until midnight AST tonight for AMZ712-716- 726.

Small Craft Advisory until noon AST Tuesday for AMZ723-733-741.