Marine Weather and Tide Forecast for Fajardo, PR

SHORT TERM
Tonight through Saturday...

Showery weather persisted through the morning hours over St. Thomas and, occasionally, St. Croix. A few passing showers were also observed across the eastern portions of Puerto Rico. Doppler radar and GOES-19 satellite data indicated an area of above-normal moisture, with cloudiness and shower activity being advected toward the southeastern portions of the CWA by midday. Later in the afternoon, convective activity began to develop across the interior and northwestern portions of Puerto Rico. This activity is expected to persist through at least the evening hours.

Model guidance continues to suggest the presence of a mid-to upper- level trough moving in from the west, which is expected to linger through the weekend. Several indicators of favorable dynamics will accompany this feature, including 250 mb height falls, reduced 1000- 500 mb thicknesses, cooler 500 mb temperatures, and steeper lapse rates in both the 850-700 mb and 700-500 mb layers. At lower levels, a surface-induced trough and an associated shearline will cross the CWA tonight and into tomorrow, enhancing low-level convergence across the northeastern Caribbean. Precipitable water values are forecast to surge to 1.85 inches or higher, exceeding the 90th percentile of the climatological normal for this time of year.
Although the most active portion of the trough is expected to remain to the north and northeast of the area, the surface-induced trough will still contribute strong local dynamics favorable for the development of showers and thunderstorms. Wind speeds will also decrease significantly on Friday as the axis of the surface trough moves over the area, resulting in slow-moving storms that could lead to a substantial increase in rainfall accumulations. Winds will gradually increase out of the northeast through the weekend.

For tonight and tomorrow morning, several model tools, such as the ECMWF's Extreme Forecast Index and the GFS Galvez-Davison Index, indicate that the strongest signal for convective activity is centered over the U.S. Virgin Islands, Vieques, Culebra, and the eastern third of Puerto Rico. On Friday afternoon, additional shower and thunderstorm activity may develop across the interior of Puerto Rico and spread outward, aided by diurnal heating and sea breeze convergence, provided that cloud cover does not inhibit surface heating. An unstable and wet weather pattern will continue into Saturday, although coverage is likely to be less widespread than on Friday. This short-term forecast scenario increases the potential for urban and small stream flooding, as well as quick river rises.
Flash flooding and landslides cannot be ruled out, particularly in flood-prone areas and steep terrain.

LONG TERM
Sunday through Thursday...

A wet and unstable weather pattern will be present for the first part of the long-term period. At the upper levels, 250 mb height suggests a strong upper-level trough, then converting in a cut-of- low just north of the CWA, resulting in unstable weather conditions aloft and colder temperatures at the 500 mb, rounding between -8 to -10 C degrees. These conditions create a favorable atmosphere with good potential for intense thunderstorm activity.
At the surface, a building surface high pressure located over the western Atlantic will increase the pressure gradient across the region, and more moderate to locally strong winds will be in place, becoming from the northeast between 15 to 25 mph, with gusty winds. As a result, residents and visitors can expect windy conditions with fast-moving shower activity, resulting in less rainfall accumulation from Sunday into Monday.

Improving weather conditions will be in place from Tuesday onwards; at the upper levels, the divergence zone of the upper low moves out of the region. A mid-level ridge will also be in place, inducing more stable weather conditions. At the surface, the combination of the surface ridge and the reflected cut of low at the surface will keep the northeasterly wind flow across the region. For now, model guidance suggests an a more drying trend; however, given the proximity of the surface, low pressure, cloudiness, and moisture are likely across the region during this period. Therefore, residents and visitors can expect frequent passing showers along the eastern and northeastern sections of Puerto Rico and the U.S. Virgin Islands.

AVIATION
(18Z TAFs)

VFR conditions with intermittent MVFR conditions will prevail this afternoon across most TAF sites due to some VCTS and SHRA with a reduction in VIS and lower ceilings. Tonight, frequency and intensity of showers will increase, as a result USVI and TJSJ TAF sites have high chances to experience VCSH and SHRA during the overnight period and Friday morning resulting in reduce vis and lower ceilings. Winds will prevail mainly from the ESE at 10 to 15 mph with some higher gusts, then becoming lighter after 17/23Z.
Tomorrow winds will remain lighter and more from the east.

MARINE
A strengthening high-pressure system over the western Atlantic will continue to support moderate to fresh easterly winds, gradually shifting to an east-southeasterly direction tonight.
this pattern will aid in transporting the remnants of a weak frontal boundary across the region, leading to an increase in showers and thunderstorms , particularly over the local waters.
These storms could create localized hazardous marine conditions, therefore small craft operators should remain cautious.
Furthermore, the combination of strengthening winds and a weak northerly swell is expected to lead to deteriorating marine conditions as the weekend approaches.

BEACH FORECAST
Moderate easterly winds will raise the risk of rip currents along most north- and east-facing beaches of Puerto Rico and St. Croix.
Deteriorating seas over the weekend are expected to elevate the rip current risk once again. Beachgoers should also remain alert to the threat of afternoon thunderstorms on Friday, particularly along the western and southwestern shores of Puerto Rico, which may produce dangerous lightning.

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