Marine Weather and Tide Forecast for Aguas Claras, PR

SHORT TERM
Today through Friday...

Current satellite derived precipitable water (PWAT) values indicate around 0.87 to 1.15 inches over the islands, below normal values for this time of the year. Since midnight, radar estimated rainfall accumulations show around 0.46 inches over Dorado but overall minimal accumulations over northern municipalities of Puerto Rico.
Official and unofficial stations reported overnight lows from the upper 50s to low 60s at higher elevations of Puerto Rico and in the the upper 60s to low 70s over most lower elevations of Puerto Rico, and the U.S. Virgin Islands. ASCAT winds report generally light to moderate northeasterly to east-northeasterly surface flow, with the stronger winds that affected us earlier in the week now over the western Mona Passage and the Dominican Republic.

PWAT values of 0.8 to 1.25 inches are forecast to remain over the islands through at least Thursday afternoon, as a drier air mass remains over the area. Most available moisture will be confined to below 800 mb through Friday, as we remain under the subsidence side of a deep layer low to our northeast. Winds will veer to become east to southeast on Thursday as a surface trough moves in from the east.
This trough will bring in a surge in moisture, starting from the southeast, on Thursday and Friday. Current model guidance has St.
Croix surpassing 1.5 inches of PWAT, normal values for this time of the year, by Thursday afternoon. By Friday morning, this surge in moisture will increase PWAT values over easternmost PR and the USVI to between 1.5 to 1.7 inches. By this time, southeasterly flow will prevail. By Friday night, most of the islands will be above 1.5 inches of PWAT while easternmost PR and the USVI reach 1.8 inches, above normal values for this time of the year.

Overall generally stable and dry conditions will persist today, with Thursday being a transition day to a wetter end of the week. Local and diurnal effects will still result in limited afternoon convective showers, mainly over the interior and W/SW PR today, and northwestern PR on Thursday. Advective showers will continue to affect windward sectors at times as patches of low-level moisture reach the islands in the form of isolated to scattered showers.
Under more favorable conditions and increased moisture, expect a stronger version of this pattern on Friday, with a limited excessive rainfall risk as chances moderate to heavy rainfall with t-storms increases. 925 mb temperatures are forecast to be below normal to normal today, gradually climbing to normal values and above during the period as southeasterly flow establishes itself.

LONG TERM
Saturday through Tuesday...

Model guidance indicates a persistently wet and unstable pattern through early next week. Deep tropical moisture will stream into the region, with Precipitable Water (PWAT) values well above climatological thresholds, ranging from around 1.7 inches on Saturday morning to about 2.2 inches by Monday morning. A mid-to- upper-level trough and associated jet streak will enhance lift and divergence aloft, creating favorable conditions for thunderstorm development. While 500 mb temperatures will remain near normal for most of the period, a notable dip to around -9°C by Monday night into Tuesday will increase upper-level instability, supporting deeper convection.

At the surface, easterly winds will dominate, gradually shifting from a southeasterly flow on Sunday and Monday to a northeasterly flow by Tuesday. This evolving wind pattern will lead to warmer- than-normal temperatures during the weekend and early next week, particularly in coastal and urban areas. A cooling trend is expected to begin on Tuesday.

Flooding risk will persist throughout the forecast period. Monday and Tuesday are likely the wettest days, bringing the highest potential for moderate to heavy rainfall and localized flooding, especially in urban, low-lying, and mountainous areas. While exact rainfall amounts and timing may vary, confidence in this wet pattern remains moderate. Given the potential for impactful weather, users should follow forecast updates as conditions evolve, particularly heading into the weekend.



AVIATION
(06Z TAFs)

Mainly VFR conditions expected to prevail during the period. Winds from the ENE gradually veering to become E, at 8 to 13 knots, with higher gusts and sea breeze variations after 23/14Z, decreasing after 22/23Z. VCSH possible across windward areas and over Coridillera during the afternoon.



MARINE

As the low weakens and dissipates to the north, light and variable winds will prevail through Friday, with moderate easterly winds returning by Friday night into Saturday. Overall conditions should remain favorable for small craft, though localized hazardous marine conditions may develop near showers and thunderstorms, which are expected to become more active by the end of the week.



BEACH FORECAST

Rip current risk will decrease today but remain moderate along most north- and east-facing beaches over the next few days, meaning life-threatening conditions are still possible. Even where risk is lower, rip currents near groins, jetties, reefs, and piers can be dangerous. By Saturday, a weak northerly swell will increase the risk to high. Check the Coastal Hazard Message (CWFSJU) and Surf Zone Forecast (SRFSJU) for the latest info.



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