Marine Weather and Tide Forecast for Mayaguez, PR

.Short Term(This evening through Tuesday)...
Issued at 101 PM AST Sun Apr 12 2026

Overall, calm conditions and partly cloudy skies prevailed through the morning hours, with brief showers moving across the eastern municipalities and producing light accumulations. Mostly clear conditions were observed across western Puerto Rico, where no official weather stations reported temperatures reaching the 90s.
Across the rest of the coastal and urban areas, temperatures remained in the 80s, while mountainous regions ranged from the upper 70s to low 80s. Heat indices along the coastal/urban areas reported values in the low 100s. By early afternoon, shower activity developed across the interior and western portions of Puerto Rico, driven by available moisture and local effects. Winds remained from the southeast at around 10 mph, with occasional higher gusts.

Tonight, moisture will gradually increase as a pre-frontal trough and an upper-level trough approach from the northwest. Model guidance indicates the upper-level trough will deepen by Monday, supporting a moist and unstable pattern through the remainder of the short-term period. Satellite-derived products show an elongated convective area over the Dominican Republic and the western Atlantic that is expected to move into Puerto Rico and the U.S. Virgin Islands by Monday.

Rainfall will increase from Monday into Tuesday, with daily accumulations of 1 to 3 inches and locally higher amounts possible.
Colder-than-normal 500 mb temperatures, ranging from -10°C to -11°C, will enhance instability and support vertical development of convection. Winds will shift to a northerly component from Monday afternoon into early Tuesday as a frontal boundary moves southward across the region, with the most active period expected during this time.

Given saturated soils, this pattern will maintain an elevated to significant risk of urban and river flooding, as well as potential mudslides in areas of steep terrain. A Flood Watch is in effect from 10 AM Monday through 8 AM Wednesday for all of Puerto Rico and the U.S. Virgin Islands. Residents and visitors should continue to monitor the latest forecasts.

.Long Term(Wednesday through next Saturday)...
Issued at 240 AM AST Sun Apr 12 2026

The wet and unsettled weather pattern may extend into the long-term forecast. A surface high pressure is expected to build over the Western Atlantic, gradually increasing the pressure gradient, resulting in strengthening southeasterly to easterly winds. These conditions will bring back breezy to locally windy conditions across the coastal areas of the islands. Nevertheless, the influence of the deep-layered trough and abundant moisture content across the CWA will maintain a limited to elevated risk of flooding. From the latest model guidance, at least through Saturday, PWAT values should increase and remain above normal for this time of the year (between 1.6 and 1.8 inches, low chance for 2.0 inches). Additionally, moisture content in the low and mid levels should remain high through most of the period, with relative humidity above 60 - 70 %, and steep lapse rates in the 850 - 700 mb levels. Due to the proximity of the trough, mid level temperatures will likely remain cooler than normal (around - 8 degrees Celsius), while a jet streak in the high levels will maintain strong winds (70 - 80 kt) through Saturday, allowing ventilation and cloud growth. Additionally, the Galvez-Davison Index (GDI) suggests deep convection activity across the CWA, with isolated to scattered thunderstorms in the afternoons and the night hours. The most likely scenario, from Wednesday through Saturday, is moderate to locally heavy showers and isolated thunderstorms moving over windward sections of Puerto Rico and the U.S. Virgin Islands throughout the day, with afternoon convection over the interior into northwestern/western sections of Puerto Rico.
Due to the expected weather event in the short term, saturated soils and above-normal river levels are very likely and may enhance flooding potential. Hence, the limited to elevated flooding threat remains, with a limited lightning potential. Impacts may include urban and small stream flooding, with localized flash flood, landslides, and rapid river rises. By Sunday into Monday, weather conditions should gradually improve, but there are discrepancies between global solutions for early next week as members of the GEFS are trending to wetter conditions, while ENS members are trending to a seasonal pattern.

AVIATION
(18Z TAFS)
Issued at 101 PM AST Sun Apr 12 2026

VFR conds across most TAF sites with brief MVFR conds TJBQ/TJPS/TJSJ from 18z-23z, +SHRA/TSRA are expected to develop over the interior of PR, causing mostly VCTS. ESE winds between 8-14 kt and occasional higher gust. An approaching front from the NW Atlantic waters could lead to +TSRA across the offshore Atlantic waters and Mona Passage from late tonight into Monday morning.

MARINE
Issued at 101 PM AST Sun Apr 12 2026

A broad surface high pressure across the central Atlantic and a front over the western Atlantic will promote light to moderate trades through at least tonight. Pulses of northerly swell will continue to move through the Atlantic waters and passages, where small craft should continue to exercise caution for the next several days. Between Monday through Wednesday, the combination of the front and associated pre-frontal trough will increase showers and thunderstorms across the local waters, creating locally hazardous marine conditions. Small Craft Advisory conditions are expected across the Atlantic waters due to seas building up to 7 feet through midweek.

BEACH FORECAST
Issued at 101 PM AST Sun Apr 12 2026

A high risk of rip currents (life-threatening rip currents are likely in the surf zone) continues for the northwestern and eastern coastlines of Puerto Rico and Culebra, though conditions will gradually subside through Monday as the northerly swell weakens.
Breaking waves can still reach 6 to 7 feet, particularly along the northern coastline of Puerto Rico.

A moderate risk of rip currents is expected to develop across northern exposed beaches by Tuesday, with conditions becoming more hazardous again by the end of the workweek.

Beachgoers and inexperienced surfers should avoid entering the water, especially near jetties, as life-threatening rip currents remain possible. Heed the advice of lifeguards, beach patrol flags, and posted signs. Access to hazardous beaches may be limited, and individuals should follow all posted warnings and safety guidance.

Visitors should also remain mindful of the weather in addition to surf hazards. A very unsettled weather pattern is developing, with the potential for heavy showers and thunderstorms producing locally gusty winds and brief heavy rainfall. If thunder is heard, seek shelter indoors immediately.

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

HYDROLOGY
Issued at 240 AM AST Sun Apr 12 2026

As a mid-to upper-level trough approaches from the northwest, the likelihood of flooding is increasing from late tonight until at least midweek. An elevated flooding risk is forecast through this period. Showers and thunderstorms will increase in frequency on Monday, but the heaviest activity is anticipated for Monday night into Tuesday. Although a level of uncertainty is still present, the days with the highest potential for flooding are Monday and Tuesday. However, above normal moisture will persist through late in the week. The likelihood of urban and small stream flooding, isolated flash flooding, landslides and rapid river rises continues to increase. Residents and visitors are urged to remain alert to changing weather conditions and to avoid flooded roadways. A Flood Watch (FFASJU) and an Hydrologic Outlook (ESFSJU) are currently in effect to highlight this flooding potential.

SJU WATCHES/WARNINGS/ADVISORIES
PR...High Rip Current Risk through Monday afternoon for PRZ001-002- 005-008-010-012.

Flood Watch from Monday morning through Wednesday morning for PRZ001>013.

VI...Flood Watch from Monday morning through Wednesday morning for VIZ001-002.

AM...None.