Marine Weather and Tides
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.
|Sunrise 6:31AM||Sunset 5:45PM||Tuesday November 21, 2017 6:18 AM AST (10:18 UTC)||Moonrise 8:59AM||Moonset 8:25PM||Illumination 8%|
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|AMZ725 Coastal Waters Of Southern Usvi Vieques And Eastern Puerto Rico Out 10 Nm- 411 Am Ast Tue Nov 21 2017 |
Today..East winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 8 seconds. Isolated showers.
Tonight..East winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers.
Wednesday..East winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 8 seconds. Scattered showers.
Wednesday night..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 10 seconds. Scattered showers.
Thursday..East winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 8 seconds. Scattered showers.
Friday..East winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 8 seconds. Scattered showers.
Saturday..East winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 10 seconds. Scattered showers.
|AMZ700 411 Am Ast Tue Nov 21 2017 |
Synopsis for puerto rico and the uS. Virgin islands waters... Easterly winds and a more stable air mass are expected across the local waters today. Seas will increase briefly up to 7 feet on Wednesday and Wednesday night across the atlantic waters and the anegada passage from a cold front now pushing south into the tropical atlantic.
7 Day Forecast for Marine Location Near Vieques, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxca62 tjsj 210857|
area forecast discussion
national weather service san juan pr
457 am ast Tue nov 21 2017
Synopsis Drier air will reduce showers and thunderstorms today,
but moisture will return Thursday and Friday. Another break over
the weekend will occur before moisture returns from the south on
Monday. Cold fronts are still being restrained from reaching the
area by local trade winds during the next 7 to 10 days.
Short term Today through Thursday...
mostly clear skies prevailed across the forecast area overnight and
early this morning. A few passing showers were observed across the
local waters but none over land areas. Coastal temperatures were in
the mid to upper 70s under east southeast winds at 10 mph or
Although a mid to upper level ridge will continue to build across
the forecast area today and hold through much of the week, easterly
winds will continue to bring patches of low level moisture at
The GFS is showing a drop in precipitable water to as
little as 1.1 inches tonight. Environmental conditions are
rapidly becoming hostile for organized deep convection under the
building ridge, but there will still be enough low level moisture
to assure shower activity, particularly late Wednesday into
Thursday. In fact, based on the latest guidance, today through
Wednesday afternoon is the driest period with precipitable water
increasing to near two inches Wednesday night into Thursday.
Therefore, expect a fair and generally stable weather pattern
today and Wednesday with morning passing showers across usvi and
east pr followed by some afternoon showers across west puerto
rico. The chance for shower activity will increase Wednesday night
into Thursday as low level moisture increases across the eastern
The flash flood watch in northwest puerto rico is for the
downstream portion of rio guajataca below the lake. Recent rains
have raised the lake levels several feet and local authorities
want to maintain vigilance regarding the unstable condition of
Long term Friday through Wednesday... High pressure that forms
just north of the mona channel Wednesday night will bring in|
moisture on Thursday from the northeast that will linger until
early Saturday morning. This and the easterly wave that will move
through on Friday will continue the good chances for both night
and early morning showers in eastern puerto rico and the u.S.
Virgin islands and showers and isolated thunderstorms in western
puerto rico in the afternoon. A break in the moisture will occur
over the weekend. As a cold front sweeps down through the last of
the bahama islands on Monday a new surge of tropical moisture
invades the area from the caribbean sea to the south. Lower levels
will then see wet and dry periods during the first part of next
week and the front will lift to the north mid week next week before
reaching the area.
The ridge of high pressure at upper levels will continue just
east of the area and keep convection limited. The deep long wave
trough invading the western atlantic on Sunday will weaken in the
process of flattening that ridge in its passage through the area
on Wednesday of next week. Although good moisture will be
available during the week next week it will not be as strong as
has occurred in the last few days.
Aviation MostlyVFR conds are expected to prevail at all taf
sites throughout the day. Brief MVFR conds will remain possible in
and around jmz jbq due to shra btw 21 16-22z. Ese winds at around 10
knots with some sea breeze variation to continue.
Marine East northeast winds behind a front dipping toward the
tropical atlantic today will drive swell into the outer atlantic
waters late Wednesday. Seas will approach small craft advisory
conditions then. Small craft advisories are not expected through
the middle of next week after that.
Preliminary point temps pops
Sju 87 77 88 77 20 20 30 30
stt 86 77 85 76 20 30 30 50
Sju watches warnings advisories
Pr... Flash flood watch until 2 pm ast this afternoon for northwest-
Short term... Om
long term... .Ws
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
|Stations||Dist||Age||Wind||Air Temp||Water Temp||Waves||Pressure||DewPt|
|41056||8 mi||78 min||ESE 12 G 14||82°F||3 ft||1011.1 hPa (-1.0)|
|CLBP4 - 9752235 - Culebra, PR||12 mi||48 min||79°F||83°F||1011.7 hPa|
|YABP4 - 9754228 - Yabucoa Harbor, PR||22 mi||48 min||76°F|
|41052 - South of St. John, Virgin Islands||36 mi||48 min||E 12 G 14||82°F||1009.6 hPa|
|LAMV3||39 mi||48 min||80°F||84°F|
|41053 - San Juan, PR||42 mi||48 min||S 1.9 G 3.9||79°F||1010.8 hPa|
|SJNP4 - 9755371 - San Juan, PR||42 mi||48 min||83°F||1011.8 hPa|
Wind History for Isabel Segunda, Vieques Island, PR(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
|San Juan, Luis Munoz Marin International Airport, PR||36 mi||22 min||N 0||10.00 mi||A Few Clouds||75°F||75°F||100%||1011.9 hPa|
Wind History from JSJ (wind in knots)
|1 day ago||SE||Calm||Calm||NE||NE||NE||Calm||NW||Calm||SW||SE||Calm||Calm||SE||SE||SE||S||E||E||W||Calm||N||SE|
|2 days ago||Calm||Calm||Calm||SE||E||E||SE||S||Calm||N||NE||S||Calm||Calm||Calm||Calm||Calm||SE||SE||Calm||SW||Calm||SW||Calm|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
|Punta Mulas |
Click for Map
Tue -- 03:37 AM AST 0.05 feet Low Tide
Tue -- 06:31 AM AST Sunrise
Tue -- 08:58 AM AST Moonrise
Tue -- 10:57 AM AST 1.24 feet High Tide
Tue -- 05:40 PM AST 0.38 feet Low Tide
Tue -- 05:43 PM AST Sunset
Tue -- 08:25 PM AST Moonset
Tue -- 10:17 PM AST 0.65 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Vieques Passage |
Click for Map
Tue -- 01:12 AM AST 0.45 knots Max Flood
Tue -- 04:08 AM AST -0.00 knots Slack
Tue -- 06:32 AM AST Sunrise
Tue -- 06:40 AM AST -0.35 knots Max Ebb
Tue -- 08:59 AM AST Moonrise
Tue -- 09:05 AM AST 0.00 knots Slack
Tue -- 12:36 PM AST 0.66 knots Max Flood
Tue -- 03:44 PM AST -0.00 knots Slack
Tue -- 05:44 PM AST Sunset
Tue -- 07:22 PM AST -0.87 knots Max Ebb
Tue -- 08:25 PM AST Moonset
Tue -- 11:12 PM AST 0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  Help
|Weather Map ||IR Satellite Image from GEOS|
GOES Local Image of Puerto Rico EDIT
Wind Forecast for (5,6,7,8)(on/off)  Help
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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 numerious 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.