Marine Weather and Tide Forecast for Arroyo, PR
May 12, 2024 8:41 AM CST (14:41 UTC) Change Location
 | Sunrise 5:17 AM Sunset 5:56 PM Moonrise 12:22 PM Moonset 9:59 PM |
FXCA62 TJSJ 120901 AFDSJU
Area Forecast Discussion National Weather Service San Juan PR 501 AM AST Sun May 12 2024
SYNOPSIS
A more seasonal weather pattern is forecast through the period.
A limited to elevated excessive rainfall risk is present today for mainly the NW quadrant of Puerto Rico during the afternoon under south to southeast winds. As winds become more easterly, the focus of the afternoon activity during the workweek will shift to portions of the western interior to western Puerto Rico.
Temperatures along the coast and in urban areas today can reach the upper 80s to mid 90s today, with heat indices that may exceed 102 degrees Fahrenheit (localized areas possibly experiencing 108-110 degrees).
SHORT TERM
Today through Tuesday...
Overnight observations from satellite and radar have indicated isolated showers and an isolated thunderstorm over the local waters.
Some moved across southern Puerto Rico and Saint Croix, leaving minimal rainfall accumulations. Most showers dissipated after 2 AM AST, with skies clearing afterward. However, from around 11 PM AST, satellite-derived data has also indicated persistent foggy conditions along the Cordillera Central eastward to Sierra de Cayey.
Overnight low temperatures ranged from the upper 60s across higher elevations to the lower 80s across eastern Puerto Rico and the local islands. Winds were generally light and variable, influenced by land breezes.
During the short-term forecast period, expect a typical seasonal weather pattern characterized by significant rainfall accumulation resulting from afternoon convective activity. With an upper-level jet streak (70-90 knots) situated to the north, today's conditions will remain marginally favorable, with diurnal heating being the primary triggering factor. Moisture levels are expected to remain high, with precipitable water values ranging from 1.7 to 1.9 inches, leading to scattered showers and isolated thunderstorm development, particularly after the peak diurnal heating around 2 PM AST. Surface south-to-southeast winds at 5 to 15 mph and south-southwesterly winds at the 700 mbar level suggest that today's activity will spread northward again, affecting municipalities of the northern half of Puerto Rico, including portions of the San Juan metropolitan area and northeastern Puerto Rico. Due to the persistent weak steering flow, the expected moderate to locally heavy rainfall from slow-moving showers will likely pose a limited to elevated excessive rainfall hazard risk today, with the highest risk likely across the northwestern quadrant of Puerto Rico.
As the jet streak gradually moves northward early next week, a mid- level high pressure will extend into the northeastern Caribbean, establishing a trade wind cap inversion and bringing drier conditions aloft. Consequently, precipitable water values will decrease, eventually falling to the lower end of typical thresholds as moisture becomes confined below the 700 mb layers. Despite conditions becoming less conducive to convective development and a gradual decrease in moisture, afternoon showers with possible isolated thunderstorms on Monday and Tuesday are still likely, with less area coverage and intensity each passing day, possibly generating limited flooding risk. As winds become more from the easterly and increase to 10-15 mph early next week, the focus of the afternoon activity will shift to portions of the western interior to western Puerto Rico.
Due to consistent southerly winds, temperatures along the coast and in urban areas today may rise to the upper 80s to mid-90s, while higher elevations could experience highs in the upper 70s to mid- 80s. With abundant moisture throughout the region, heat indices may exceed 102 degrees Fahrenheit, with localized areas possibly experiencing 108-110 degrees. Although slightly cooler temperatures are likely early next week, warmer conditions will persist.
Lingering saharan dust is present in the area.
LONG TERM
Wednesday through Sunday...
Precipitable water (PWAT) values should remain at normal values for this time of the year, between 1.5 to near 2.0 inches, during the period, as patches of moisture advect into the region. Model guidance seems to have backed off on moisture significantly increasing by the end of the workweek, now showing only patches of high end seasonal PWAT reaching the islands. For at least the start of the period, NASA aerosol optical thickness (AOT) suggests lingering Saharan dust particles to start the period. A mid-level ridge will exert its influence over the region to start the period, promoting more typical weather with afternoon convection due to diurnal and local effects. Model guidance now suggests an upper trough moving north of the islands from the northwest by Friday and Saturday. Most available moisture should reach up to 850 to 800 mb for the period. Light to moderate easterlies are forecast through the period as a surface high moves into the western to central Atlantic. Limited to possibly elevated Heat Risk, especially during the daily maximum heating, will persist across several lower elevation sectors of the islands where no significant rain is observed. This diurnal heating, along with local effects and sea breeze convergence will continue to promote up to strong afternoon convection, steered by easterly winds. This will promote convective activity mainly over sectors of the interior to western half of the Puerto Rico and downwind of the local islands. Early morning and overnight passing showers are also forecast across windward sectors of the islands along with patchy fog over areas of the interior.
AVIATION
(06Z TAFS)
Mainly VFR conditions across most local terminals during the next 24 hours. Afternoon SHRA/TSRA may result in brief MVFR conditions, with periods of reduced visibility and lower ceilings, across TJSJ/TJBQ between 12/16-23Z. VCSH may also affect TJSJ and USVI terminals after 12/23Z, with minimal impacts to operations. Light to calm and variable winds increasing to 8-12 knots and turning more from the east with sea breeze variations between 12/13-23Z.
MARINE
Seas will be favorable for small craft through at least Thursday. A surface high pressure across the central Atlantic and a low in the western Atlantic will allow southeasterly winds to prevail today. As another high moves into the western Atlantic winds will be light to moderate easterlies through the rest of the period. A weak northerly swell will continue to fade across the Atlantic waters and passages.
Afternoon convective activity could move from the islands towards nearby waters.
BEACH FORECAST
Weak pulses of northeasterly swell will continue to fade across the Atlantic waters and Caribbean Passages. Low Risk of Rip Currents today and tonight. However, they occur most often at low spots or breaks in the sandbar and in the vicinity of structures such as groins, jetties and piers.
SJU WATCHES/WARNINGS/ADVISORIES
PR...None.
VI...None.
AM...None.
Area Forecast Discussion National Weather Service San Juan PR 501 AM AST Sun May 12 2024
SYNOPSIS
A more seasonal weather pattern is forecast through the period.
A limited to elevated excessive rainfall risk is present today for mainly the NW quadrant of Puerto Rico during the afternoon under south to southeast winds. As winds become more easterly, the focus of the afternoon activity during the workweek will shift to portions of the western interior to western Puerto Rico.
Temperatures along the coast and in urban areas today can reach the upper 80s to mid 90s today, with heat indices that may exceed 102 degrees Fahrenheit (localized areas possibly experiencing 108-110 degrees).
SHORT TERM
Today through Tuesday...
Overnight observations from satellite and radar have indicated isolated showers and an isolated thunderstorm over the local waters.
Some moved across southern Puerto Rico and Saint Croix, leaving minimal rainfall accumulations. Most showers dissipated after 2 AM AST, with skies clearing afterward. However, from around 11 PM AST, satellite-derived data has also indicated persistent foggy conditions along the Cordillera Central eastward to Sierra de Cayey.
Overnight low temperatures ranged from the upper 60s across higher elevations to the lower 80s across eastern Puerto Rico and the local islands. Winds were generally light and variable, influenced by land breezes.
During the short-term forecast period, expect a typical seasonal weather pattern characterized by significant rainfall accumulation resulting from afternoon convective activity. With an upper-level jet streak (70-90 knots) situated to the north, today's conditions will remain marginally favorable, with diurnal heating being the primary triggering factor. Moisture levels are expected to remain high, with precipitable water values ranging from 1.7 to 1.9 inches, leading to scattered showers and isolated thunderstorm development, particularly after the peak diurnal heating around 2 PM AST. Surface south-to-southeast winds at 5 to 15 mph and south-southwesterly winds at the 700 mbar level suggest that today's activity will spread northward again, affecting municipalities of the northern half of Puerto Rico, including portions of the San Juan metropolitan area and northeastern Puerto Rico. Due to the persistent weak steering flow, the expected moderate to locally heavy rainfall from slow-moving showers will likely pose a limited to elevated excessive rainfall hazard risk today, with the highest risk likely across the northwestern quadrant of Puerto Rico.
As the jet streak gradually moves northward early next week, a mid- level high pressure will extend into the northeastern Caribbean, establishing a trade wind cap inversion and bringing drier conditions aloft. Consequently, precipitable water values will decrease, eventually falling to the lower end of typical thresholds as moisture becomes confined below the 700 mb layers. Despite conditions becoming less conducive to convective development and a gradual decrease in moisture, afternoon showers with possible isolated thunderstorms on Monday and Tuesday are still likely, with less area coverage and intensity each passing day, possibly generating limited flooding risk. As winds become more from the easterly and increase to 10-15 mph early next week, the focus of the afternoon activity will shift to portions of the western interior to western Puerto Rico.
Due to consistent southerly winds, temperatures along the coast and in urban areas today may rise to the upper 80s to mid-90s, while higher elevations could experience highs in the upper 70s to mid- 80s. With abundant moisture throughout the region, heat indices may exceed 102 degrees Fahrenheit, with localized areas possibly experiencing 108-110 degrees. Although slightly cooler temperatures are likely early next week, warmer conditions will persist.
Lingering saharan dust is present in the area.
LONG TERM
Wednesday through Sunday...
Precipitable water (PWAT) values should remain at normal values for this time of the year, between 1.5 to near 2.0 inches, during the period, as patches of moisture advect into the region. Model guidance seems to have backed off on moisture significantly increasing by the end of the workweek, now showing only patches of high end seasonal PWAT reaching the islands. For at least the start of the period, NASA aerosol optical thickness (AOT) suggests lingering Saharan dust particles to start the period. A mid-level ridge will exert its influence over the region to start the period, promoting more typical weather with afternoon convection due to diurnal and local effects. Model guidance now suggests an upper trough moving north of the islands from the northwest by Friday and Saturday. Most available moisture should reach up to 850 to 800 mb for the period. Light to moderate easterlies are forecast through the period as a surface high moves into the western to central Atlantic. Limited to possibly elevated Heat Risk, especially during the daily maximum heating, will persist across several lower elevation sectors of the islands where no significant rain is observed. This diurnal heating, along with local effects and sea breeze convergence will continue to promote up to strong afternoon convection, steered by easterly winds. This will promote convective activity mainly over sectors of the interior to western half of the Puerto Rico and downwind of the local islands. Early morning and overnight passing showers are also forecast across windward sectors of the islands along with patchy fog over areas of the interior.
AVIATION
(06Z TAFS)
Mainly VFR conditions across most local terminals during the next 24 hours. Afternoon SHRA/TSRA may result in brief MVFR conditions, with periods of reduced visibility and lower ceilings, across TJSJ/TJBQ between 12/16-23Z. VCSH may also affect TJSJ and USVI terminals after 12/23Z, with minimal impacts to operations. Light to calm and variable winds increasing to 8-12 knots and turning more from the east with sea breeze variations between 12/13-23Z.
MARINE
Seas will be favorable for small craft through at least Thursday. A surface high pressure across the central Atlantic and a low in the western Atlantic will allow southeasterly winds to prevail today. As another high moves into the western Atlantic winds will be light to moderate easterlies through the rest of the period. A weak northerly swell will continue to fade across the Atlantic waters and passages.
Afternoon convective activity could move from the islands towards nearby waters.
BEACH FORECAST
Weak pulses of northeasterly swell will continue to fade across the Atlantic waters and Caribbean Passages. Low Risk of Rip Currents today and tonight. However, they occur most often at low spots or breaks in the sandbar and in the vicinity of structures such as groins, jetties and piers.
SJU WATCHES/WARNINGS/ADVISORIES
PR...None.
VI...None.
AM...None.
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Virgin,Islands/San,Juan/Cayey,PR
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