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 5:59AM||Sunset 7:01PM||Friday July 28, 2017 12:59 PM AST (16:59 UTC)||Moonrise 10:52AM||Moonset 11:07PM||Illumination 26%|
EDIT (on/off)  Help
|AMZ712 Coastal Waters Of Northern Puerto Rico Out 10 Nm- 1011 Am Ast Fri Jul 28 2017 |
Rest of today..East winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Scattered showers through the day. Isolated Thunderstorms in the afternoon.
Tonight..Southeast winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers.
Saturday..East winds 15 to 20 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers.
Saturday night..Southeast winds 10 to 15 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Scattered showers and isolated Thunderstorms.
Sunday..East winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 7 seconds. Isolated Thunderstorms. Scattered showers.
Monday..East winds 15 to 20 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 10 seconds. Northeast swell around 4 feet. Isolated showers.
Tuesday..East winds 15 to 20 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 11 seconds. Northeast swell 4 to 5 feet. Isolated showers.
|AMZ700 1011 Am Ast Fri Jul 28 2017 |
Synopsis for puerto rico and the uS. Virgin islands waters... A weak tropical wave is moving across the local islands today. This will produce an increase in showers and Thunderstorms across the regional waters this afternoon and tonight. A surface high pressure across the central atlantic will continue to yield moderate east to southeasterly winds into the upcoming weekend. Seas and winds are forecast to increase early next week.
7 Day Forecast for Marine Location Near Carolina, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxca62 tjsj 281426|
area forecast discussion
national weather service san juan pr
1026 am ast Fri jul 28 2017
Update A weak tropical wave will continue to move across the
region this afternoon and tonight. A persistent upper level trough
remain to the northeast of the region until at least Saturday.
Doppler weather radar indicated only isolated shower activity
mostly across the surrounding coastal waters this morning with few
of them affecting the eastern sections of puerto rico. Not
precipitation was observed elsewhere over land areas so far this
The limited moisture provided by the weak tropical wave in
combination with the upper trough, strong daytime heating and
local effects will be sufficient to produce the development of
another round of scattered showers and isolated thunderstorms
along, north and northwest of cordillera central this afternoon.
Due to previous days rainfall, urban and small stream flooding is
possible this afternoon mostly across northwestern puerto rico.
The shower and thunderstorm activity is expected to diminish
rapidly after sunset.
Aviation MostlyVFR conditions will prevail over all TAF sites
during the rest of the morning hours. Aft 28 16z areas of
convection will form due to an induced tropical wave and
instability mainly over western and central pr and downstream from
the usvi. After 28 16z MVFR ifr conds with mtn obscurations are
psbl in these areas and vcty or over tjmz tjbq tjsj tjps in
shra tsra. Low level SE winds of 5-15 kt expected to diminish
after 28 22z.
Marine Relatively tranquil marine conditions expected to
continue across the local coastal waters through the upcoming
weekend. Mariners can expect seas up to 4 feet and winds up to 15
knots. Showers and possible thunderstorms expected this afternoon
and mariners should exercise caution due to this activity. Seas
and winds are forecast to increase by the upcoming week.
Prev discussion issued 520 am ast Fri jul 28 2017
a weak tropical wave will move across the region today. After this
wave a relative dry air mass is expected to filters tonight into
Saturday morning. A tutt low will continue to meander northeast
of the islands through at least early Saturday morning. This
feature is forecast to weakens as a high pressure ridge builds at
mid levels and hold into the upcoming week. A broad surface high
pressure will continue over the central atlantic ocean.
Short term... Today through Sunday...
columnar moisture reached a minimum of 1.61 inches at 28 06z and
will increase to almost 2 inches by 29 06z as the moisture centered
over the leeward islands moves over the local area today and
tonight. During this time clouds and showers will increase. The gfs
suggest that the lifted index for the surface based parcel will
reach minus 9 this afternoon so expect some isolated thunderstorms
before the best moisture arrives. Showers will continue through most
of the night--but mainly over the local waters, the usvi and the
southeast third of puerto rico. Thunderstorms will likely end
after 29 04z. Although drier air follows the wave, another band of
moisture moves through on Saturday night and this will increase
showers on the southeastern side of puerto rico and around the u.S.
Virgin islands then. This moisture will not have completely exited
puerto rico by 30 18z and this will trigger another round of strong
thunderstorms with heavy rain.
Moisture will be better today than Saturday and this will mean many
more showers and thunderstorms will develop today with areas of
urban and small stream flooding developing later this afternoon.
Then, not as much flooding on Saturday will occur, although some|
local areas of flooding are expected, then on Sunday more urban and
small stream flooding is expected to develop.
For the north coast of puerto rico temperatures will drive into the
low to mid 90s owing to the drier air just ahead of the wave and the
southeast flow setting up over the island. The forecast is for 93
degrees in san juan and this would be a record, since the high for
july 28 was 92 degrees set in 1981. Temperatures will not be far
behind on the south coast. Fortunately, although southeast flow
continues, moisture and clouds will keep temperatures a little below
the record tomorrow, which, for san juan, is 93 degrees.
Long term... Monday through Saturday...
a mid level ridge is expected to hold across the area through at
least the end of the work week, turning the atmosphere unfavorable
for organize convection. However, a tropical wave accompanied by a
wind surge is expected to swing by the region on Monday or Tuesday.
At lower levels, a broad high pressure across the central atlantic
will result in east to east-southeast winds through Tuesday. Under
this wind flow, above normal temperatures are possible mainly
along the coastal sections of puerto rico. Then, winds are
expected to increase and shift from the east northeast after
Although upper level dynamic is not favorable next week, moisture
advection with a moderate to strong northeast wind flow will
result in a seasonable weather pattern each day across the region.
As a result expect trade wind showers across the u.S. Virgin
islands and east puerto rico overnight into the early morning
hours. Followed by afternoon convection along and to the west of
the cordillera central of puerto rico. A surface disturbance is
forecast to move in Wednesday into Thursday providing moisture
pooling and increasing the chance of showers and thunderstorms
across the region. After the passage of this disturbance a dry air
mass with saharan dust particles is forecast to filters over the
region Friday into the weekend.
vfr conditions will prevail over all TAF sites til arnd
28 14z. Aft 28 14z areas of convection will form due to an induced
tropical wave and instability mainly over western and central pr and
downstream from the usvi. Aft 28 16z MVFR ifr conds with mtn
obscurations are psbl in these areas and vcty or over
tjmz tjbq tjsj tjps in shra tsra. Winds bcmg SE 5-15 kt aft 28 12z
up thru fl140. Winds abv fl140 are less than 15 kt.
tranquil marine conditions expected to prevail across the regional
waters through the upcoming weekend. Mariners can expect seas
below 5 feet and winds below 18 knots. The potential for showers
and thunderstorms is expected to increase during the afternoon
hours and mariners should exercise caution due to this activity.
Seas and winds are forecast to increase by the upcoming week.
If model are right, this weather pattern would require small
Preliminary point temps pops
Sju 93 79 91 79 50 30 40 40
stt 88 81 90 79 30 30 50 50
Sju watches warnings advisories
Short term... Jf
long term... .99
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|
|41053 - San Juan, PR||6 mi||59 min||ENE 14 G 16||85°F||85°F||3 ft||1014.1 hPa (-1.1)|
|SJNP4 - 9755371 - San Juan, PR||7 mi||47 min||ENE 13 G 18||87°F||86°F||1014.8 hPa|
|FRDP4 - 9753216 - Fajardo, PR||21 mi||41 min||E 8 G 9.9||85°F||77°F|
|YABP4 - 9754228 - Yabucoa Harbor, PR||29 mi||41 min||E 6 G 8||89°F|
|41056||31 mi||59 min||ESE 9.7 G 12||84°F||2 ft||1015.1 hPa (-0.5)|
|VQSP4 - 9752619 - Isabel Segunda, Vieques, PR||36 mi||41 min||ESE 5.1 G 8.9||88°F|
|ESPP4 - 9752695 - Esperanza, PR||37 mi||47 min||SSE 7 G 11||84°F||87°F||1015.1 hPa|
|JOXP4 - Jobos Bay Reserve, Puerto Rico||37 mi||74 min||E 7||90°F||1016 hPa||75°F|
|AROP4 - 9757809 - Arecibo, PR||38 mi||41 min||NE 9.9 G 14|
|CLBP4 - 9752235 - Culebra, PR||38 mi||41 min||91°F||86°F||1015.2 hPa|
Wind History for San Juan, PR(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
Click EDIT to select an airport
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
|Boca De Cangrejos |
Click for Map
Fri -- 12:43 AM AST 1.30 feet High Tide
Fri -- 06:00 AM AST Sunrise
Fri -- 07:09 AM AST 0.15 feet Low Tide
Fri -- 10:52 AM AST Moonrise
Fri -- 01:18 PM AST 1.10 feet High Tide
Fri -- 07:00 PM AST Sunset
Fri -- 07:14 PM AST 0.27 feet Low Tide
Fri -- 11:07 PM AST Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|San Juan |
Click for Map
Fri -- 12:35 AM AST 1.52 feet High Tide
Fri -- 06:01 AM AST Sunrise
Fri -- 07:01 AM AST 0.21 feet Low Tide
Fri -- 10:52 AM AST Moonrise
Fri -- 01:11 PM AST 1.31 feet High Tide
Fri -- 07:00 PM AST Sunset
Fri -- 07:09 PM AST 0.35 feet Low Tide
Fri -- 11:08 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 (12,3,4,5)(on/off)  Help
Ad by Google
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.