Puerto Rico and US Virgin Islands from 10NM to 19.5N Marine Forecast
| Rest Of Today...West Winds 5 To 10 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 10 Seconds. Isolated Showers. |
| Tonight...Northwest Winds 10 To 15 Knots, Becoming West After Midnight. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 10 Seconds. Isolated Showers. |
| Thursday...Northwest Winds 10 To 15 Knots. Gusts Up To 25 Knots In The Afternoon. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet, Building To 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 11 Seconds. Numerous Showers. |
| Thursday Night...North Winds 10 To 15 Knots. Gusts Up To 25 Knots In The Evening. Seas 8 To 10 Feet With Occasional Seas Up To 11 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Friday...North Winds 10 To 15 Knots, Becoming Northeast. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Saturday...East Winds 5 To 10 Knots, Becoming South. Seas 8 To 10 Feet With Occasional Seas Up To 11 Feet. Dominant Period 12 Seconds. Isolated Showers. |
| Sunday...Southwest Winds 5 To 10 Knots, Becoming East. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 14 Seconds. |
| Area Forecast Discussion National Weather Service San Juan PR 340am AST Sat Jun 13 2026 .Short Term(Today through Monday)... Issued at 340am AST Sat Jun 13 2026 A relatively dry and stable weather pattern will persist through early next week. Most of the available moisture will remain confined to the lower levels of the atmosphere while the mid and upper levels stay notably dry, limiting the potential for widespread convection. Occasional patches of shallow moisture will support brief passing showers across windward areas, while periods of Saharan dust will promote hazy skies and reinforce the stable pattern. As a result, only isolated to locally scattered afternoon showers are expected over portions of northwestern Puerto Rico, with any thunderstorm development remaining very limited and driven primarily by intense daytime heating and local effects. Brisk easterly winds will keep showers moving quickly, further reducing rainfall accumulations and minimizing flooding concerns. Broad high pressure over the North Atlantic will continue to steer an east to east-southeast trade wind flow, with occasionally windy conditions across exposed and coastal areas. Tropical waves passing south of the region may briefly strengthen the wind field but are expected to have little influence on local moisture or rainfall. The primary weather concern through the period will be the continued warm to hot conditions, with heat index values commonly reaching the upper 90s to lower 100s across urban and coastal areas during the late morning and afternoon hours. While widespread heat risks are not anticipated, residents and visitors should continue practicing routine heat safety by staying hydrated, seeking shade when possible, and limiting prolonged .Long Term(Tuesday through Saturday)... Issued at 340am AST Sat Jun 13 2026 Surface high pressure will maintain brisk winds out of the east- southeast through the next weekend. At the mid levels, a high is also responsible for low relative humidities values and stable conditions aloft. An upper level high will also move high clouds from the Caribbean into the local islands, further hindering the development of showers into the islands. Through at least Thursday, expect limited shower activity, but local effects will trigger localized showers along western Puerto Rico, where ponding of water cannot be ruled out. By the end of the week, an upper level low will develop northeast of the islands, finally increasing instability aloft, with 500 mb temperatures cooling down. This feature will combine with low level moisture from a tropical wave or surface trough to increase the potential of showers along the Virgin Islands and eastern Puerto Rico through the day, and across western Puerto Rico in the afternoon. It is worth mentioning that there are some factors that could work against a rainfall forecast, such as the position of the upper level trough, the intrusion of mid-level dry air, Saharan dust and high clouds reducing the amount of solar radiation. The user should stay tuned as the forecast evolves Regardless, any rain would be beneficial for areas experiencing abnormally dry or moderate drought conditions in Puerto Rico and the Virgin Islands. By the weekend, the upper level low lift toward the north and the air mass will become stable once again. In fact, moderate concentrations of Saharan dust are anticipated, resulting in hazy skies. Marine Issued at 340am AST Sat Jun 13 2026 A strengthening surface high pressure system over the central Atlantic will promote fresh trade winds and choppy marine conditions through at least the middle of next week. Seas are expected to build between 4 to 6 feet, occasionally higher, across the regional waters and local passages. Small craft operators are encouraged to exercise caution across the regional waters and local passages as seas build and trade winds strengthen. Drier air and hazy skies associated with low to moderate concentrations of Saharan dust will persist through the weekend. Beach Forecast Issued at 340am AST Sat Jun 13 2026 A moderate risk of rip currents is expected to prevail across the northern, southern and eastern beaches of Puerto Rico, as well as Culebra, Vieques, and the U.S. Virgin Islands, where life- threatening rip currents are possible in the surf zone. Beachgoers should exercise caution, always swim near a lifeguard and remember to heed the advice of the local beach patrol and flag warning systems. These conditions are expected to persist through the weekend and into next week. A low risk of rip currents will remain along the western beaches of Puerto Rico. However, life- threatening rip currents can occur even when the risk is low, especially near groins, jetties, reefs, and piers. Remain cautious. For additional information and location- specific rip current forecasts, visit weather.gov/beach/sju. Fire Weather Issued at 340am AST Sat Jun 13 2026 Recent rainfall has remained well below normal across portions of southern Puerto Rico, with no significant wetting rains observed recently or expected through early next week. Combined with above- critical KBDI values, increasingly dry fuels, and periods of breezy conditions, these factors will continue to support localized fire weather concerns, particularly across the southern coastal plains. However, prevailing east to east-southeasterly flow and afternoon sea-breeze development should transport maritime moisture inland, limiting the duration and spatial extent of critically low relative humidity values. As a result, while localized periods of elevated fire danger remain possible, widespread critical fire weather conditions are not anticipated at this time. .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. |
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