Marine Weather and Tide Forecast for Culebra, PR

SHORT TERM
Tonight through Saturday...

Fair weather conditions were observed across the region during the morning hours, under clear to partly cloudy skies. The "San Juan" streamer started to develop around noon, promoting shower activity along the San Juan metropolitan area and surrounding municipalities.
Doppler radar estimated rainfall accumulations of less than 0.10 inches, however, additional accumulations are possible later this afternoon. Warm temperatures were observed too, mainly over potions of southern, northern and western Puerto Rico, and the U.S. Virgin Islands with temperatures reaching the upper 80s to low 90s.

Clouds began to develop along the Central Mountain Range early in the afternoon. Strong showers and thunderstorms are likely across these areas and northwestern Puerto Rico through early this evening due to additional moisture coming into the area, local orographic effects and diurnal heating.

Slightly drier conditions are anticipated to persist throughout this weekend as a mid-level ridge continues to move eastwards towards the central Atlantic. The precipitable water content will remain within normal climatological values for the next several days (1.5 to 1.7inches), with below normal values on Saturday into Sunday (around 1.3 to 1.4 inches). Therefore, limited showers and thunderstorm activity are expected during the next coming days.
However, sufficient moisture content, diurnal heating, sea breeze convergence, and orographic effects will support the development for showers and thunderstorms along portions of western and northwestern Puerto Rico each afternoon.

Steering winds are expected to strengthen this weekend, as a surface high pressure continues to build over the central Atlantic. Therefore, increasing the pressure gradient over the region. Light to moderate winds will prevail today across the region, becoming moderate to locally fresh from Friday onward. The 925 mb temperatures will remain at normal to above normal climatological values through early next week. Highs will remain in the range from the mid to upper 80s across the coastal and urban areas, and in the upper 70s to low 80s in the higher elevations.

LONG TERM
Sunday through Thursday...

The long-term forecast remains on track, with a variable pattern ahead. Another surface high pressure in the western Atlantic is likely to migrate eastward and build over Central Atlantic, promoting easterly trades through most of the period. The weather conditions for early next week will most likely be seasonal, with Precipitable Water (PWAT) values around 1.7 - 1.8 inches and 500 mb temperatures between -7.5 and -8.0 Celsius. With increasing winds, deep convection activity is expected to develop in the afternoon mainly over portions of western Puerto Rico. Streamers created by the local islands may also move into portions of eastern Puerto Rico as well.

The deep upper-level trough northwest of the CWA is still expected to approach the local area by Monday into Tuesday. Additionally, a tropical wave located at approximately 32W is also anticipated to approach the forecast area now on Monday evening into Tuesday. Based on deterministic guidance from the GFS and ECMWF, the combination of moisture associated to the tropical wave and the upper-level trough will increase PWAT values to above climatological normal.
Additionally, colder 500 mb temperatures will enhance deep convection activity. Hence, moderate to locally heavy rainfall and thunderstorms mainly over the windward sections during the night and early morning and into western portions of Puerto Rico in the afternoon. The flooding potential will remain elevated for the aforementioned areas.

Ensemble members agree that a less wet pattern for the second part of the workweek is the most likely scenario due to the approach of a Saharan Dust layer. From the latest guidance, the highest concentrations should remain south of the region, but uncertainty remains high. Under that scenario, deep convection activity should remain limited with isolated thunderstorms in the afternoon. However, the combination of daytime heating, local effects, and available moisture may trigger showers in the early morning over windward sections and western/northwestern Puerto Rico in the afternoons.

By Thursday, decreasing winds from the southeast will pool warmer and humid air into the local area. This is also reflected in the 925 mb temperatures, which will increase to above climatological normal again. Hence, a limited risk of excessive heat is likely and may affect most individuals sensitive to heat.



AVIATION

Mainly VFR conds are expected across all terminals during the next 24 hrs. However, SHRA/TSRA will develop along the central mountain range, creating mountain obsc and brief MVFR conds at TJBQ thru 22/23Z. Winds will continue from the E at 12-16 kts but locally higher near TSRA/SHRA, and with sea breeze variations. Winds will become calm to light and variable after 22/23Z, returning from the E at around 13-16 kts tomorrow after 23/13-14Z.

MARINE

A building surface high pressure over the central Atlantic will promote gentle to moderate easterly trades today, becoming moderate to locally fresh by Friday. Isolated thunderstorms will continue to develop across the regional waters, particularly across the northern and western coastal waters of Puerto Rico each afternoon.

BEACH FORECAST

Beachgoers, the risk for rip currents is low tonight and throughout the rest of the week. However, please exercise caution as life-threatening rip currents often occur in the vicinity of groins, jetties, reefs, and piers.

SJU WATCHES/WARNINGS/ADVISORIES
PR...Heat Advisory until 4 PM AST this afternoon for PRZ001-005-008- 010.

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