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 7:07AM||Sunset 6:23PM||Monday January 22, 2018 8:28 AM AST (12:28 UTC)||Moonrise 10:50AM||Moonset 11:09PM||Illumination 32%|
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|AMZ741 Mona Passage Southward To 17n- 431 Am Ast Mon Jan 22 2018 |
.small craft advisory in effect through late tonight...
Today..East winds 15 to 20 knots. Seas 5 to 7 feet with occasional seas up to 9 feet. Dominant period 8 seconds. North swell around 4 feet. Isolated showers.
Tonight..East winds 15 to 20 knots. Seas 5 to 7 feet with occasional seas up to 9 feet. Dominant period 7 seconds. Northeast swell around 4 feet. Scattered showers through the night.
Tuesday..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 7 seconds. Isolated showers.
Tuesday night..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 8 seconds. Isolated showers.
Wednesday..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 8 seconds. Isolated showers.
Thursday..Northeast winds 15 to 20 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 10 seconds. East swell 4 to 5 feet. Scattered showers.
Friday..Northeast winds 15 to 20 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 12 seconds. Northeast swell 4 to 7 feet. Isolated showers.
|AMZ700 431 Am Ast Mon Jan 22 2018 |
Synopsis for puerto rico and the uS. Virgin islands waters... Surface high pressure across the west and central atlantic will maintain moderate to locally fresh trade winds through Tuesday. A long dominant period northerly swell will continue to affect the atlantic waters and local passages today but slowly subsiding through Tuesday.
7 Day Forecast for Marine Location Near El Combate, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxca62 tjsj 220816|
area forecast discussion
national weather service san juan pr
416 am ast Mon jan 22 2018
Synopsis Frontal boundary and associated shear line will remain
north of the region as it dissipates slowly today through Tuesday.
Mid to upper level ridge will hold across the region for the next
several days. Surface high pressure north of the area will maintain
moderate east to northeast trade winds across the forecast areas
through the period. A cold front and associated boundary is forecast
to sink southwards and approach the region by the upcoming weekend.
Short term Today through Wednesday...
clear to partly cloudy skies prevailed across the local islands
overnight. A dissipating frontal boundary remains across the atlantic
waters well northeast of the local islands. Terminal doppler radar
indicated only few showers across the atlantic waters as well as across
the surrounding waters of the northern u.S. Virgin islands. Not precipitation
was detected elsewhere across the region overnight and so far this morning.
A surface high pressure located across the atlantic waters just to the
north of the region will continue as the main weather feature across
the local islands for the next couple of days. Trade winds will continue
to transport patches of low level moisture across the local islands
from time to time during the next couple of days. Small patches of
low level moisture embedded in the trades will continue to produce
brief passing showers across the u.S. Virgin islands and eastern puerto
rico from time to time, especially overnight and early in the mornings
for the next couple of days. These showers will move quickly westward
with minimal rainfall accumulations. During the afternoons, some cloudiness
with showers are expected to develop across the interior and west sections
of puerto rico. The GFS model guidance suggests an increase in low level
moisture by the middle of the week.
Long term Thursday through Tuesday of next week.
The upper level high pressure ridge will hold across the region through
Friday. However the prevailing easterlies will continue to transport
sufficient moisture across the region to support periods of passing
late evening and early morning showers, as well as isolated to scattered
afternoon convection. Saturday through Sunday, a polar trough will amplify
and spread eastward across the west and central atlantic causing a slight
erosion of the upper level ridge. By Monday and Tuesday the mid to upper
level ridge will reestablish over the region and again limit shower
In the meantime, the a cold front is forecast to move across the west
atlantic and reach the local area by the upcoming weekend. Model guidance
continued to suggest a gradual increase in trade winds moisture during
the latter part of the week with more favorable conditions for moisture
convergence and shower development over the weekend, as the cold front
sinks southwards and stalls just north of the region by Sunday. Improving
weather conditions are however expected by Monday and Tuesday with a|
return of more typical passing trade wind showers.
Aviation MainlyVFR conditions are expected across the local
flying area through the forecast period. Little to no shower activity
is expected until 22 15z. Thereafter, shra will begin to develop affecting
mostly tjmz between 22 18z and 22 21z. Easterly winds expected to increase
to about 15 kts with sea breeze variations developing after
Marine A northerly swell and and moderate to locally fresh trades
winds will affect the local waters today but will continue to slowly
subside and diminish today through Tuesday. Due to the rough and
choppy seas, small craft advisories will remain in effect today for
the atlantic, local passages and offshore caribbean waters. Easterly
winds will prevail between 15 to 20 knots. For beach goers, the
high surf advisory has been cancelled as the breaking waves are
now expected to be less than 10 feet. However, high risk of rip
currents will continue for the northwest to north facing beaches
of puerto rico, culebrita beach and also for saint thomas.
Preliminary point temps pops
Sju 85 74 84 75 30 30 30 30
stt 84 75 84 74 30 20 40 20
Sju watches warnings advisories
Pr... High rip current risk through late tonight for culebra-north
central-northeast-northwest-san juan and vicinity-southeast-
Vi... Small craft advisory until 2 am ast Tuesday for st.Thomas... St.
John... And adjacent islands.
High rip current risk through this afternoon for st.Thomas... St.
John... And adjacent islands.
Am... Small craft advisory until 2 am ast Tuesday for anegada passage
southward to 17n-caribbean waters of puerto rico from 10 nm
to 17n-coastal waters of northern puerto rico out 10 nm-
coastal waters of southern usvi vieques and eastern puerto
rico out 10 nm-mona passage southward to 17n.
Small craft advisory until 2 pm ast Tuesday for atlantic waters
of puerto rico and usvi from 10 nm to 19.5n.
Small craft advisory until 2 pm ast this afternoon for coastal
waters of northern usvi and culebra out 10 nm.
Small craft advisory until 8 am ast this morning for coastal
waters of northwestern puerto rico out 10 nm.
Short term... Jf
long term... .Ram
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|
|MISP4 - 9759938 - Mona Island, PR||0 mi||40 min||72°F||80°F||1016.2 hPa|
Wind History for Mayaguez, PR(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
Wind History from JMZ (wind in knots)
|1 day ago|
|2 days ago|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
|Mona Island |
Click for Map
Mon -- 02:59 AM AST 0.12 feet Low Tide
Mon -- 07:06 AM AST Sunrise
Mon -- 10:49 AM AST Moonrise
Mon -- 12:05 PM AST 0.71 feet High Tide
Mon -- 04:41 PM AST 0.42 feet Low Tide
Mon -- 05:59 PM AST 0.43 feet High Tide
Mon -- 06:20 PM AST Sunset
Mon -- 09:25 PM AST 0.26 feet Low Tide
Mon -- 11:09 PM AST Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|Puerto Real |
Click for Map
Mon -- 05:34 AM AST 0.13 feet Low Tide
Mon -- 07:03 AM AST Sunrise
Mon -- 10:46 AM AST Moonrise
Mon -- 12:02 PM AST 0.96 feet High Tide
Mon -- 06:17 PM AST Sunset
Mon -- 06:41 PM AST 0.14 feet Low Tide
Mon -- 11:06 PM AST Moonset
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 (7,2,3,4)(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.