Marine Weather and Tides
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.
|Sunrise 5:54AM||Sunset 6:55PM||Thursday July 29, 2021 5:18 AM AST (09:18 UTC)||Moonrise 11:02PM||Moonset 10:52AM||Illumination 75%|
7 Day Forecast for Marine Location Near Suï¿½rez, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXCA62 TJSJ 290846 AFDSJU
Area Forecast Discussion National Weather Service San Juan PR 446 AM AST Thu Jul 29 2021
SYNOPSIS. A Tropical Upper Tropospheric Trough (TUTT) currently moving over the local area will continue to result in shower activity over the region. A dry pattern is expected for this weekend, due to an increase in drier air and Saharan dust particles, and a mid to upper level ridge moves over the forecast area.
SHORT TERM. Today through Saturday .
Near normal moisture is expected in the morning, but a patch of drier air with some minor concentrations of Saharan Dust will move in during the late morning into the afternoon hours. However, starting late this afternoon and tonight, a tropical wave will move in and will bring deeper moisture. The overall wind flow will shift to a more SE direction as the day progresses. There is also a TUTT passing through the local area, which could help promote thunderstorm development this afternoon. So given the current and expected pattern, scattered showers are expected in the morning across the local islands, isolated thunderstorms could start developing late in the morning and into the afternoon hours. The northwestern municipalities of PR have the highest chance of thunderstorms this afternoon. Also, showers and thunderstorms expected tonight into Friday morning, as the TUTT interacts with the tropical wave that will cause the increase in moisture. This increase in activity will be generally across the Caribbean waters, south and eastern PR and around the USVI. The SE winds could cause warmer than normal temperatures for the northern sections of PR today.
For Friday and Saturday, the shower activity is expected to be more modest, with locally induced afternoon showers across W/NW PR on Friday, with isolated to scattered showers elsewhere through the day. Even less shower activity is expected on Saturday across the local area. Much drier air is expected to move in with a higher concentration of Saharan dust. For that reason, very limited shower activity is expected. The model guidance also is suggesting daytime temps in the 90s for Saturday.
LONG TERM. Sunday through Friday .
A drier air mass with saharan Dust particles will continue to move over the forecast area on Sunday. As a result, fair weather conditions with hazy skies are expected to prevail for the first day of the long term forecast (Sunday). Tuesday now looks like it has better potential for shower development. First, the surface high pressure across the central Atlantic is expected to induce a southeasterly component in the winds over the forecast area. As a result, this wind flow will drag some patches of moisture with precipitable water above normal. Meanwhile, at the upper levels, the ECMWF and GFS model guidance is suggesting a Tropical Upper Tropospheric Trough (TUTT) moving westward into the local area, which will help increase thunderstorm potential. At this time, the models kind of agree in the timing of the most unstable conditions over the region. That said, expect morning showers over the eastern sections of Puerto Rico and the U.S. Virgin Islands. Then, in the afternoon hours, Galvez- Davison index suggest the possibility of scattered thunderstorms across northwestern quadrant of Puerto Rico. Confidence in the forecast is moderate, but still a few days to follow the dynamics in the upper levels and the moisture content.
For Wednesday onward, a rainy pattern is expected. On Wednesday, several patches of moisture are expected to filter into the region. The combination of the available moisture with the local effects and the upper level dynamics, will result in afternoon convection over the western sections of Puerto Rico, while isolated to scattered showers are expected elsewhere. On Thursday morning, a slot of dry air will move over the area, limiting the shower activity, but after that, in afternoon hours, a tropical wave is expected to increase the potential for shower activity once again through Friday. As a result, shower development is expected, mainly over the northwestern quadrant of Puerto Rico and the San Juan metro area each day.
AVIATION. VCSH expected across the local terminals today as SCT SHRA affect the local area. However, TSRA is expected across NW-PR this afternoon, which could affect the actual TJBQ terminal, but VCTS on TAF due to some uncertainty on exact timing. Winds will be from the east at around 10KT or less through 29/13Z, but will increase to around 15KT with gusts up to 25KT and sea breeze variations thereafter.
MARINE. Across the regional waters, tranquil marine conditions with seas of up to 5 feet will prevail across the regional waters for the next several days. For beachgoers, there is a moderate risk of rip currents for the northern and southeastern beaches of Puerto Rico as well most of the beaches of Culebra, Vieques and Saint Croix.
PRELIMINARY POINT TEMPS/POPS. SJU 91 77 89 79 / 50 50 40 30 STT 88 79 88 80 / 30 50 40 20
SJU WATCHES/WARNINGS/ADVISORIES. PR . None. VI . None. AM . None.
SHORT TERM . JA LONG TERM . LIS PUBLIC DESK . GL
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