Marine Weather and Tide Forecast for Jobos, PR

SHORT TERM
Tonight trough Thursday...

The area will remain under the subsidence side of a deep layered low to our northeast. This will promote a drier air mass over the region for most of the short-term period. The precipitable water (PWAT) content is expected to fluctuate between 1 to 1.25 inches, well below normal levels. At the surface, light to moderate north to northeasterly winds will prevail under the influence of an elongated surface low northeast of the region. However, lighter winds are expected on Wednesday and will turn more east to southeast by Thursday as a surface trough approaches from the east. This trough will gradually increase moisture content from Thursday onwards, first across the U.S. Virgin Islands by midday, with PWAT increasing to around 1.50 inches over St. Croix and by Thursday night across Puerto Rico. Therefore, expect showers to increase in areal coverage across the islands in general late in the forecast period.

Overall, fair weather conditions are expected to prevail for the next few days. However, local and diurnal effects will trigger afternoon and early evening convection showers over portions of the Cordillera on Wednesday and over northwestern Puerto Rico on Thursday. Minimum temperatures are forecast to range from the mid-50s across the higher elevations to the upper 60s and low 70s across coastal areas. Maximum temperatures are expected to reach the mid to upper 80s each day across the lower elevations of the islands, and in the low 90s on Thursday as winds acquire a southeasterly component.

LONG TERM
Friday through Monday
from previous discussion

The long-term forecast indicates a warm, wet, and marginally unstable weather pattern. Easterly winds will continue to transport tropical moisture into the region, while a mid-to-upper- level trough and associated jet streak will enhance conditions favorable for thunderstorm development. A weakened trade wind inversion and typical temperatures at 500 mb will further support instability. Additionally, temperatures are expected to exceed normal thresholds, particularly in coastal and urban areas, leading to slightly elevated perceived temperatures. These warmer-than-normal conditions will further contribute to the overall instability and potential for heavy rainfall.

Precipitable water values are expected to rise from around 1.5 inches on Friday to over 1.7 inches by Saturday evening, indicating well-above-normal moisture levels. This, combined with marginal instability, daytime heating, and above-normal temperatures, will support the development of afternoon and early evening showers and thunderstorms. The latest guidance suggests that Monday will likely be the wettest day of the forecast period, with moderate confidence in this trend, though the exact timing and intensity of rainfall and convection remain uncertain and may shift with future updates. As moisture increases, so does the risk for moderate to heavy rainfall, which could lead to urban and small stream flooding, especially in areas prone to frequent afternoon convection. Additionally, localized flash flooding, mudslides, and water surges along rivers and tributaries remain a concern.

With forecast uncertainty still present, it’s important to monitor future updates closely. Conditions are favorable for another active weather weekend, with potential impacts that may evolve as new guidance becomes available.

AVIATION

(18Z TAFs)

Mainly VFR conditions are expected to prevail across all terminals during the next 24 hours. However, brief MVFR cigs are possible in and around TJPS/TISX till early this evening. Winds will continue ENE btw 8-12 kt, bcmg light and variable overnight.

MARINE

A surface high over the western Atlantic and a low northeast of the region will bring moderate northeast winds becoming more light and variables tomorrow, combined with a weak northeasterly swell, maintaining hazardous marine conditions through the night. Small Craft Advisories are in effect for the Atlantic waters, as well as the Mona Passage. Winds will become light and variable on Wednesday and Thursday as the low weakens, with easterly winds returning by the end of the workweek.

BEACH FORECAST

Hazardous coastal conditions with a high risk of rip current across the northern coastal sides of Puerto Rico, Culebra and St.
Thomas for the rest of today into tomorrow. The risk of rip current will improve by Wednesday until Saturday when another northeasterly swell arrives across the local waters.

SJU WATCHES/WARNINGS/ADVISORIES
PR...High Rip Current Risk through late tonight for PRZ001-002-005- 008.

High Rip Current Risk until 6 PM AST this evening for PRZ010.

VI...None.
AM...Small Craft Advisory until midnight AST tonight for AMZ711-712- 741.