Marine Weather and Tides
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen
|Sunrise 5:47AM||Sunset 5:19PM||Wednesday December 11, 2019 5:13 AM CST (11:13 UTC)||Moonrise 6:58PM||Moonset 4:03AM||Illumination 100%|
7 Day Forecast for Marine Location Near Pole Ojea, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXCA62 TJSJ 110943 AFDSJU
Area Forecast Discussion National Weather Service San Juan PR 543 AM AST Wed Dec 11 2019
Showers will increase across the region over the next few days as moisture works in from the east, with a slight chance of thunderstorms for today. Breezy easterly trade winds continue for the next several days, driving hazardous seas and a high risk for rip currents. A trend to drier weather will ensue for next week.
SHORT TERM. Today through Friday .
A cut-off low has formed in the passing upper level trough and it will hold about 400 miles east northeast of San Juan through tonight before receding northeastward. Upper level winds will be northwest and subside through the period. 500 mb temperatures will be around minus 8 to minus 9 degrees today to create a slight chance of thunderstorms. Chances will decrease on Thursday and Friday.
At the surface, high pressure of around 1042 mb will be just west of the Azores today. It will continue to drift east and fade as another high moves out of the eastern United States and into the western Atlantic north of 40 degrees north latitude Thursday and Friday. This will drive surface winds over the local waters of 15 to 20 knots that will last beyond Friday. Pockets of moisture are interspersed in the flow over the western tropical Atlantic with areas of drier air between. One of those pockets is moving across the Leeward Islands this morning. Although precipitable water values are modest, they will increase through Friday, and the lowest levels of the atmosphere will remain quite moist bringing periods of showers to most of the forecast area-- but especially the windward slopes of higher terrain in Puerto Rico.
Moisture is rich below 850 mb throughout the period and well beyond, but little is seen above 500 mb. Moisture between 850 mb and 500 mb will increase Thursday and Friday and will generate better showers. Winds will keep these moving quickly so excessive rainfall amounts are not expected. Rainfall amounts over the next 3 days should not exceed 1.5 to 3.0 inches even in the wettest areas.
LONG TERM. Saturday through Thursday .
A fairly wet weather pattern continues into the weekend as moisture gets pulled up from the southeast into our region. For the weekend, Sunday looks to be the wetter of the two days. Under the direction of the forecasted wind flow, southern and eastern Puerto Rico will see the bulk of the shower activity, with a second maximum in rainfall for northwestern Puerto Rico in the afternoon under the convergent windflow around the island. The atmosphere looks to be more stable for the weekend compared to the short term period, so the thunderstorm threat will be minimal. Low level winds are expected to slow down a little bit, but still have decent speed to keep showers moving along. Thus the threat for local flooding should be rather low.
As has been discussed over the past few days, a strong area of high pressure in the Atlantic has been driving stronger than normal easterly trade winds across the region. These winds are expected to subside a bit as this high moves off to the east over the weekend. However, another area of high pressure will move out over the Atlantic for Monday, and this will once again enhance the low level wind flow. This will impact marine conditions once again, and will keep fairly breezy winds in the forecast. Along with that area of high pressure, drier and more stable air is expected to move in for next week. Long range models are even hinting at some Saharan dust that could work in for the middle of next week. Shower activity is of course possible, but these showers will be less prevalent than what we have seen over the past few days.
VFR conditions are expected to prevail across all terminals. Sct SHRA will continue over the area and spread into SW PR aft 11/15Z. Hir trrn will be obscured. Isold TSRA are psbl. Sfc winds increasing to 10-20 kt with gusts to 26 kt on nrn coasts. Max winds WNW 50-60 knots btwn FL430-480 and diminishing during the day.
Hazardous seas continue across the region. As such, a Small Craft Advisory is in effect for all the local and outer waters except for the southern nearshore waters of Puerto Rico. Seas will range from 6 to 10 feet with seas occasionally reaching 11 feet. Seas are forecast to remain choppy into the weekend. Though the hazardous conditions will subside a bit for the beginning of next week, it appears another area of high pressure to our north will drive windy conditions producing more rough seas for next week. There is a high risk of rip currents for the northern beaches of Puerto Rico and the eastern beaches of Culebra. In addition, there is a high risk of rip currents for the northeastern beach of the U.S. Virgin Islands, and the northwestern beach of Saint Thomas.
PRELIMINARY POINT TEMPS/POPS. SJU 85 76 84 74 / 80 80 80 80 STT 87 76 85 74 / 60 60 50 70
SJU WATCHES/WARNINGS/ADVISORIES. PR . High Rip Current Risk through Saturday morning for Culebra-North Central-Northeast-Northwest-San Juan and Vicinity-Southeast.
High Rip Current Risk through late Thursday night for Mayaguez and Vicinity.
VI . High Rip Current Risk through Saturday morning for St Croix- St Thomas. St John. and Adjacent Islands.
AM . Small Craft Advisory until 8 AM AST Saturday for Anegada Passage Southward to 17N-Atlantic Waters of Puerto Rico and USVI from 10 NM to 19.5N-Caribbean Waters of Puerto Rico from 10 NM to 17N-Coastal Waters OF Northwestern Puerto Rico out 10 NM-Coastal Waters of Northern Puerto Rico out 10 NM-Coastal Waters of Northern USVI and Culebra out 10 NM-Coastal Waters of Southern USVI Vieques and Eastern Puerto Rico out 10 NM-Mona Passage Southward to 17N.
SHORT TERM . WS LONG TERM . mb
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