Marine Weather and Tide Forecast for Santo Domingo, PR

SHORT TERM
Today through Wednesday...

Shower and thunderstorm activity that had been impacting the municipalities of Arecibo and Barceloneta ended close to midnight, leaving nearly 8 inches of rain in the northeasternmost tip of the Arecibo municipality, with other areas receiving 4 to 6 inches. The rest of the night was much calmer compared to the afternoon and evening hours, with moderate showers occasionally moving over St.
Thomas. Minimum temperatures were mostly in the low to mid-70s across coastal areas of the islands and in the mid to upper 60s in the highest mountains and valleys of Puerto Rico.

Current satellite imagery and GLM data show that the most active part of a deep-layered trough is located north of Puerto Rico, over the offshore Atlantic waters, where the trough is exhibiting the strongest low-level convergence and upper-level divergence. GOES-19 Precipitable Water satellite data continues to show well above normal moisture over the region, particularly upstream of the local islands. Therefore, during the rest of the morning hours, showers and isolated thunderstorms are expected over the regional waters, with some showers occasionally moving over windward coastal areas.

Winds will begin shifting today from southeasterly to easterly, and then to a more northeasterly direction by Wednesday, as a surface high pressure over the western Atlantic gradually pushes a frontal boundary associated with the upper-level trough closer to the CWA
The combination of above-normal moisture, instability aloft, diurnal heating, and orographically driven convection will lead to another active afternoon, with thunderstorms first developing over interior Puerto Rico. The steering wind flow is expected to remain light throughout most of the short-term forecast period. As a result, slow- moving thunderstorms will initially cluster over the Cordillera Central and may later move toward coastal areas as outflow boundaries generate new convective cells. A similar weather pattern is expected on Tuesday.

However, Wednesday appears to be the wettest and most active day, as the aforementioned trough deepens and develops into a cutoff low, closing off by the end of the forecast period, particularly by Wednesday night. Widespread thunderstorm activity may develop, and if it occurs during the evening and night hours, another round of heavy showers and thunderstorms could impact the eastern third of Puerto Rico, including Vieques, Culebra, and the U.S. Virgin Islands. As a reminder, soils are already saturated, and streamflows are running well above normal due to heavy rains over the past several days. Therefore, urban and river flooding is likely to continue, along with the potential for flash flooding and landslides in flood-prone areas and steep terrain, respectively. Continue to monitor the forecast as this unstable weather pattern persists across the region.

LONG TERM
Thursday through Monday...

The long-term forecast continues on track, with a variable and unsettled pattern ahead. The interaction between a high surface pressure in the Western Atlantic and a surface low induced by an upper-level trough will promote light NE-E winds through the period.
Global model ensembles agree that Thursday will be the wettest day of the forecast period, suggesting above normal Precipitable Water (PWAT) values (around 1.75 inches). Colder 500 mb temperatures (-8 to -9 Celsius) and jet dynamics around 250 mb with speed near 70 knots will bring ventilation and instability aloft, supporting deep convection activity. As the mid to upper level trough migrates eastward, drier air will filter into the region, inhibiting deep convection activity. Additionally, temperatures in the 500 mb layer should increase to seasonal values (around -7 Celsius). Although global model ensembles tend to a "drier" pattern this weekend, there's still enough low to mid level moisture available for afternoon convection. With the expected weather conditions, soils saturated, local effects, and diurnal heating, the potential of flooding will remain limited to elevated through this period, with showers during the morning along windward sections and afternoon convection over interior and western/southwestern Puerto Rico each day. Rainfall accumulations will most likely promote ponding of water in roadways and poorly drained areas, as well as urban and small stream flooding.

With the NE-E wind flow dominating the period, 925 mb temperatures should remain near below normals.

AVIATION

(06Z TAFs)

Expect -RA/VCTS posbl at TJSJ/TISX/TIST through 13z. Areas of SHRA and SCT TSRA this aftn could produce tempo MVFR/IFR conds and mtn obsc, particularly ovr TJBQ/TJSJ aft 28/17z.
VCTS/SHRA at TJPS for the most part. Despite this pattern, expect mostly VFR conditions across all terminals through the forecast period. E winds reaching speeds of up to 8-12 knots, accompanied by higher gusts and sea breeze variations aft 28/13z.

MARINE

Light to moderate east to southeast winds will prevail today and tomorrow, turning from the northeast by Tuesday night. A deep layer trough will continue to promote an unstable weather pattern across the local waters. Showers and thunderstorms are expected to persist, producing localized hazardous marine conditions, small craft should exercise caution.

BEACH FORECAST

Latest buoy observations show wave periods between 13 - 14 seconds, suggesting that pulses of the northeasterly swell continue spreading across the local waters. Therefore, the high risk of rip currents was extended through this afternoon for the beaches of northern Puerto Rico, from Aguadilla to Fajardo, and Culebra. As the swell dissipates across the local waters tonight, a moderate risk of rip currents will prevail for the next few days for the beaches in northern Puerto Rico, Culebra, and possibly St. Thomas and St. John in the U.S. Virgin Islands.

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

VI...None.
AM...None.