Marine Weather Net

Northern Puerto Rico out 10NM Marine Forecast


REST OF TODAY

E
WINDS
10 - 15
KNOTS

TONIGHT

E
WINDS
10 - 15
KNOTS

WEDNESDAY

NE
WINDS
5 - 10
KNOTS

WEDNESDAY NIGHT

NE
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
AMZ712 Forecast Issued: 1128 AM AST Tue Apr 16 2024

Rest Of Today...East Winds 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 9 Seconds. Showers With Isolated Thunderstorms.
Tonight...East Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 8 Seconds. Numerous Showers With Isolated Thunderstorms.
Wednesday...Northeast Winds 5 To 10 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 8 Seconds. Numerous Showers With Isolated Thunderstorms.
Wednesday Night...Northeast Winds 5 To 10 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 9 Seconds. Numerous Showers With Isolated Thunderstorms.
Thursday...Northeast Winds 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 11 Seconds. Isolated Showers.
Friday...Northeast Winds 5 To 10 Knots. Seas 2 To 4 Feet With Occasional Seas Around 5 Feet. Dominant Period 11 Seconds. Isolated Showers.
Saturday...East Winds 10 To 15 Knots. Seas 2 To 4 Feet With Occasional Seas Around 5 Feet. Dominant Period 10 Seconds. Isolated Showers.
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Area Forecast Discussion
National Weather Service San Juan PR
452am AST Tuesday April 16 2024

Synopsis
Wet and unstable conditions continue through at least tomorrow with favorable conditions for heavy shower and thunderstorm development. Quick river rises and water surges with flash flooding, and landslides are possible. Conditions should improve by the latter half of the week. Small Craft Advisories are in effect through late tonight. A wet pattern is forecast for next week.

.SHORT TERM...Today through Thursday... An unstable and very moist pattern continued across the region overnight and will persist today through Wednesday. A surge of tropical moisture trailing a surface trough with axis now crossing Hispaniola and the Mona passage will merge with the moisture and instability associated with the deep layered trough and frontal boundary approaching from the northwest. Recent satellite imagery and doppler weather radar showed strong thunderstorms developing over the offshore Atlantic waters, while shower activity continued to increase across the Caribbean waters and areas between eastern Puerto Rico and the U.S. Virgin Islands. These showers and thunderstorms continued to produced areas of locally heavy rains and frequent lightning mainly over the coastal waters. Showers are however expected to reach the U.S. Virgin islands and portions of east and southeastern Puerto Rico during the rest of the morning hours, then spread and redevelop across the remainder of the islands throughout the day. Early morning low temperatures were in mid to upper 70s along the coastal areas and in the upper 60s to low 70s in higher elevations. Winds were generally light and variable but occasionally higher with the passing showers.

Through the rest of the period, especially until Wednesday afternoon, active and unstable weather conditions are forecast to continue due to the meandering upper trough and good moisture convergence. Recent model guidance as well as recent satelite derived Precipitable water products and analyses all suggest precipitable water (PWAT) values to range between 1.70-2.00 inches across the region today into Wednesday then diminishing by late Wednesday and on Thursday. This pattern will favor good potential for continued scattered to numerous showers and isolated thunderstorm development across portions of the islands and coastal waters at least through early Wednesday. By Wednesday afternoon and on Thursday, with still lingering moisture availability along with diurnal and local effects expect some additional convective development particularly during the early morning and late afternoon hours. By then prevailing winds will become more east northeast with drier air filtering in by the latter part of the period. Due to the unsettled weather pattern and saturated soils, additional heavy rains will lead to quick river rises and water surges with flash flooding, and landslides, especially through early Wednesday. Consequently, today through Wednesday there will be moderate to high potential for showers and thunderstorm development across most of the islands, with periods of excessive rainfall impacts and urban flooding along with mudslides in areas of steep terrain likely. Thereafter, by late Wednesday and on Thursday, improving conditions expected so far, but localized showers and isolated thunderstorms cannot be ruled out with periods of locally heavy rains still possible as well as the potential for additional minor urban and small stream flooding in isolated areas along with mudslides and rockfall in areas of steep terrain.

Long Term
Friday through Tuesday... Areas of low pressure spread across the western to central Atlantic basin will maintain moderate NE winds through the weekend along with enough water content in a lingering airmass to allow passing showers and afternoon convection to fire up during the afternoon due to local effects. By Sunday, the location of a surface high in the western Atlantic will assist the lifting of a moist airmass from the eastern Caribbean. This in combination with a mid to upper-level trough, with the jet max over the region by Saturday through late Sunday, will allow an increase of passing showers and afternoon convection mainly across western Puerto Rico. Winds begin to strengthen and veer, becoming more easterly to southeasterly Monday to Tuesday, respectively, as the aforementioned surface high moves into the central Atlantic. Elevated Precipitable water values and breezy conditions will allow a wet pattern to prevail.

Marine
A surface ridge over the north-central Atlantic and broad surface trough across the eastern Caribbean will generate moderate to locally fresh east-southeasterly winds. A fading northerly swell and choppy wind driven seas will continue to promote choppy seas across the Atlantic waters. An upper level trough and induced surface trough will continue to promote inclement weather across the local waters for the next few days, with squally weather and thunderstorms possible at times. Another northeasterly swell is forecast to arrive by Thursday.

.SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...Small Craft Advisory until 6am AST Wednesday for AMZ711.