Marine Weather and Tides
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
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.
|Sunrise 6:02AM||Sunset 5:39PM||Saturday January 18, 2020 4:52 PM CST (22:52 UTC)||Moonrise 12:04AM||Moonset 1:42PM||Illumination 37%|
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 182213 AAA AFDSJU
Area Forecast Discussion . UPDATED National Weather Service San Juan PR 613 PM AST Sat Jan 18 2020
UPDATE. Marine conditions will deteriorate rapidly and to a greater extent than expected. Please see the details in the marine section below.
Scattered showers are moving into the area as the first bands of the cold front poised near 20 north enter the area. The GFS continues to show the front moving into the area tonight and into Puerto Rico Sunday morning. Satellite imagery however shows no cool tops in the clouds and so anticipate that showers will be generally light to moderate with flooding not anticipated. Moisture at 700 mb begins to return to Puerto Rico and the U.S. Virgin Islands late Sunday afternoon through Monday morning. This is when better shower and better probabilities of rainfall should be expected--focusing mainly on the U.S. Virgin Islands and the eastern half of Puerto Rico. It is during this time also that winds transition to easterly. On Monday winds will be coming more from the southeast. This will likely bring slightly cooler temperatures to the south coast, and two to four degrees warmer temperatures to the north coast both Monday and Tuesday. The GFS model also shows 1000-850 mb temperatures warming during the period.
AVIATION. TAF sites are likely to remain VFR during the next 24 hours, however some mountain obscurations should be expected. An area of moisture is currently moving across TKPK and has brought broken CIGS arnd FL045. A band of moisture associated with the cold front is moving into the FA and is expected to move into PR/USVI btwn 19/06-12Z. Stronger than normal nighttime winds: NE 10-20 kt with gusts to 26 kt near SHRA. Aft 19/14Z sfc winds ENE 10-25 kt with gusts to 30 kt psbl--strongest near the north coast. Max winds WNW 65-75 kt btwn FL400-500.
MARINE. Swell from a storm moving through the western Atlantic have begun moving past buoy 41043. Seas up to 13 feet have been seen but are expected to increase up to 17 feet by 8 AM AST Sunday. Northeast winds are also adding to the confused seas. This will result in considerably higher breaking waves than previously expected. Breaking waves up to 19 feet are expected along the north central coast of Puerto Rico. This will increase the amount of coastal erosion and some salt water intrusion from the Atlantic. The models have been consistently 3 to 5 feet lower than the actual buoy reports and although this may be in part due to the early arrival of the swell from the north, it is still going to bring in much worse conditions. Hazardous seas should begin diminishing by Sunday afternoon, but the last small craft advisories will likely not go down before Tuesday.
PREV DISCUSSION. /issued 200 PM AST Sat Jan 18 2020/
SYNOPSIS . An approaching frontal boundary will increase low- level moisture and instability over the region tonight and early next week. However, with the increasing winds expected, shower activity will be of fast moving nature and therefore no significant accumulations are forecast. The arrival of a long period northerly swell by late tonight, together with wind-driven seas will continue to generate hazardous coastal and marine conditions over most of the local waters. Another frontal boundary will arrive by mid-week, thus producing shower activity across most of the region during the rest of the forecast period.
SHORT TERM . Today through Monday . Dry conditions aloft will prevail through Monday. However, due to low-level moisture associated with an approaching frontal boundary, isolated to scattered showers could be expected from time to time over eastern portions of PR and USVI with the highest activity over the local waters, mainly during the evening hours. However, rainfall estimates are not expected to be significant as shower activity will be of fast moving nature. Starting late Sunday night, a change in wind speeds and direction more to the east will result in breezy conditions and a return of late evening and early morning trade wind shower activity to portions of the local waters and coastal sections of the islands. By Monday afternoon, lingering moisture will combine with local and diurnal effects to produce mostly isolated to scattered showers over parts of the northwestern quadrant of the islands.
LONG TERM . Tuesday through Saturday . From Prev Discussion . The long- term period looks unsettled as a result of several weak frontal boundaries, which will move across the U.S. Virgin Islands and Puerto Rico. The frontal boundaries will increase low- level moisture and instability; this will lead to the development of frequent passing showers.
Tuesday through Wednesday, a surface ridge is progged to slide northeast ahead of an intensifying mid to upper-level trough over the western Atlantic. The shift in the surface to the mid-level ridge will result in low-level convergence and weak upper-level divergence across the region. Also, guidance shows a robust low- level jet with winds ranging from 60 to 90 kts persisting across the region through the end of the week. The above conditions, combined with weak troughiness aloft, increasing instability and moisture will result in unsettled weather conditions. Therefore, expected continuous showers to move across Puerto Rico and the U.S. Virgin Islands during the middle of the week.
Thursday, an area of high pressure is expected to move off the eastern seaboard, this will cause the surface ridge to abate over the region as the frontal boundary strengthens over the Atlantic waters. A cyclonic col is forecast to develop over the region, and this will cause winds to slow and allow moisture to pull over the area from the north/southeast.
Friday, the GFS shows the front boundary across Puerto Rico during the afternoon. The frontal boundary and northerly winds will aid in the development of showers across most of the region on Friday.
Saturday, the GFS shows the boundary draped across the U.S. Virgin Islands and Puerto Rico through the afternoon, before moving the boundary south of the area late Saturday night into Sunday morning.
AVIATION . Fair weather will persist throughout much of the forecast period. However, a few quick passing showers are expected across the local flying area at times. Clouds and showers will increase from the north by 19/02z. The wind will blow from the ENE at 10-20 kts with gust up to 30 kts.
MARINE . Marine conditions will deteriorate throughout the day. A northerly swell combined with wind-driven seas will increase seas up to 15 feet late tonight and continuing through at least Monday. Breaking wave heights between 10 and 17 feet can be expected with the arrival of this swell. Therefore, small craft and high surf advisories and a are in effect for most of the local waters. Also, coastal flood advisories will go in effect late tonight for the northern coasts of the islands. Refer to local marine products for additional information.
PRELIMINARY POINT TEMPS/POPS. SJU 72 84 73 85 / 60 60 80 50 STT 73 85 76 84 / 40 50 70 70
SJU WATCHES/WARNINGS/ADVISORIES. PR . High Rip Current Risk through late Monday night for Culebra- North Central-Northeast-Northwest-San Juan and Vicinity- Southeast.
High Surf Advisory until 6 PM AST Monday for Culebra-Mayaguez and Vicinity-North Central-Northeast-Northwest-San Juan and Vicinity-Southeast-Vieques.
Coastal Flood Advisory until 6 PM AST Sunday for Culebra- Mayaguez and Vicinity-North Central-Northeast-Northwest-San Juan and Vicinity-Southeast.
High Rip Current Risk through late Monday night for Central Interior-Mayaguez and Vicinity-Southwest-Vieques.
High Rip Current Risk from Sunday morning through late Sunday night for Ponce and Vicinity-Western Interior.
VI . High Rip Current Risk through late Monday night for St Croix- St Thomas. St John. and Adjacent Islands.
High Surf Advisory until 6 PM AST Monday for St Thomas. St. John . and Adjacent Islands.
Coastal Flood Advisory until 6 PM AST Sunday for St Thomas. St. John . and Adjacent Islands.
AM . Small Craft Advisory until 8 PM AST Monday for Coastal Waters of Southern Puerto Rico out 10 NM.
Small Craft Advisory until 8 AM AST Tuesday for 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-Mona Passage Southward to 17N.
Small Craft Advisory until 8 AM AST Tuesday for Anegada Passage Southward to 17N-Coastal Waters of Southern USVI Vieques and Eastern Puerto Rico out 10 NM.
Small Craft Advisory from 2 AM Sunday to 8 PM AST Monday for Coastal Waters OF Southwestern Puerto Rico out 10 NM.
SHORT TERM . WS LONG TERM . mb PUBLIC DESK . RVT
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports. Follow links for more data.
Click EDIT to select an airport
EDIT Weekend mode (on/off) (on/off)  Help
EDIT (on/off)  Help
Weather Map(on/off)  Help Weather Map
GEOS Local Image of EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop
Other links: Northern Pacific Contential US Full GOES-East
Wind Forecast for (17,4,5,8)(on/off)  Help
Ad by Google
I do not sell or share any user data or anything else for that matter. The only personal information I save is in the site log which has a line for each page view which includes the IP address your browser sends in the header as well as which page you requested. I use this to block hackers and other bad actors. I do not use this raw data to create profiles on users. I periodically delete the log files. If you are subject to CCPA, Google ads on this site will not be based on your past behavior so you will likely not see an ad for a lawn mower just because you looked for one at a big box website. I do not believe this site is subject to CCPA but I am doing what I can to follow the guidelines anyway.
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.