Marine Weather and Tide Forecast for Culebra, PR

.Short Term(Today through Monday)...
Issued at 232 AM AST Sat Apr 18 2026

A mid- to upper-level trough will persist across the region through Monday, maintaining an unstable and wet pattern. Precipitable water values remain near to above normal, generally between the 50th and 75th percentile, while sufficient mid-level moisture and 500 mb temperatures near or below -8 C will support convective development and periods of locally heavy rainfall. The primary concern continues to be flooding, lightning and rapid river rises.
Soils are saturated and rivers remain elevated; therefore, any additional rainfall may quickly lead to urban and small stream flooding, river rises, and isolated flash flooding, particularly in areas that receive repeated rounds of rainfall.

This afternoon, convection is expected to develop across the interior and western Puerto Rico. The Metropolitan area should see some rainfall activity during the morning and afternoon hours from time to time. On Sunday, a similar diurnal pattern is expected, with afternoon convection across interior and western Puerto Rico followed by additional showers overnight. By Monday, lingering moisture and instability will continue to support shower activity, although gradual improvement cannot be ruled out. Across the USVI, rainfall coverage and intensity will remain more variable, with lower confidence compared to Puerto Rico.

Residents and visitors should continue to monitor forecasts, as flooding impacts may develop quickly where heavier showers persist.

.Long Term(Tuesday through Saturday)...
Issued at 232 AM AST Sat Apr 18 2026

The current forecast remains consistent with the previous discussion, showing no significant changes. Drier and more stable conditions are anticipated to return as the influence of the short term period’s upper-level trough weakens and moves away from the region. A stable air mass will be present aloft due to a building mid-level ridge over the area. At the surface, a dominant high- pressure system over the central Atlantic will maintain light to moderate easterly winds through the middle of the week then becoming northeasterly and southeasterly at the second half of the week.
Precipitable water (PWAT) values are expected to drop to normal values with high end normal to above normal values at times.

Local weather will be seasonal with passing showers over windward sectors during the morning and afternoon hours. This will be followed by afternoon convective activity across the interior and W PR on Tuesday with steering wind variations prompting afternoon convection over SW PR on Wednesday and W-NW PR on Thursday and N PR on Friday and Saturday. The combination of available moisture, daytime heating, and local effects could lead to moderate to heavy rainfall and isolated thunderstorms during these afternoons.
Temperatures at 500 mb are forecast to remain seasonal (-6 C to - 8 C), isolated thunderstorms are still possible, particularly to end the period due to a nearby mid to upper trough. Given previous rainfall, saturated soil, and elevated river levels, the potential for flooding remains. Temperatures at 925 mb will also stay seasonal throughout most of the period.

AVIATION
(06Z TAFS)
Issued at 232 AM AST Sat Apr 18 2026

Mainly VFR conditions prevail across all TAF sites. Period of VCTS/SHRA possible after 18/14Z across TJSJ, TJBQ, and TJPS.
Therefore brief periods of MVFR are possible across those terminals. Prevailing winds should remain from east around 10 to 15 kts gusts around 22 knots after 18/14Z near SHRA/TSRA and with sea breeze variations.

MARINE
Issued at 232 AM AST Sat Apr 18 2026

An unstable weather pattern across the regional waters will persist through the weekend, resulting in periods of strong thunderstorms, with the strongest activity expected offshore across the western regional waters, including the Mona Passage and Atlantic waters, each afternoon. Thunderstorms will produce locally higher winds, frequent lightning, and reduced visibility. A surface high over the Atlantic will promote mainly moderate easterly winds, occasionally fresh at times, resulting in moderate to locally choppy seas through the weekend. A small northeasterly swell will also continue to propagate across the Atlantic waters and Caribbean passages through early next week.

BEACH FORECAST
Issued at 232 AM AST Sat Apr 18 2026

A moderate risk of rip currents is expected to persist throughout the weekend across northern exposed beaches. This may result in life- threatening rip currents. Heed the advice of lifeguards, beach patrol flags, and posted signs.

Visitors should also remain mindful of the weather in addition to surf hazards. An unsettled weather pattern will continue, with the potential for heavy showers and thunderstorms producing locally gusty winds and brief heavy rainfall, mainly during the afternoon hours. If thunder is heard, seek shelter indoors immediately.

For additional information and location-specific rip current details, please visit: weather.gov/beach/sju.

SJU WATCHES/WARNINGS/ADVISORIES
PR...None.
VI...None.
AM...None.