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 6:57AM||Sunset 6:12PM||Saturday January 20, 2018 10:39 PM AST (02:39 UTC)||Moonrise 9:23AM||Moonset 9:19PM||Illumination 19%|
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|AMZ712 Coastal Waters Of Northern Puerto Rico Out 10 Nm- 914 Pm Ast Sat Jan 20 2018 |
.small craft advisory in effect through late Sunday night...
Rest of tonight..East winds 10 to 15 knots. Seas 6 to 8 feet with occasional seas up to 10 feet. Dominant period 11 seconds. North swell 6 to 8 feet. Scattered showers.
Sunday..East winds 15 to 20 knots. Seas 6 to 8 feet with occasional seas up to 10 feet. Dominant period 10 seconds. North swell 5 to 7 feet. Scattered showers.
Sunday night..East winds 15 to 20 knots. Seas 5 to 7 feet with occasional seas up to 9 feet. Dominant period 10 seconds. North swell 4 to 7 feet. Scattered showers through the night.
Monday..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 9 seconds. Scattered showers.
Monday 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.
Tuesday..East winds 10 to 15 knots. Seas 4 to 6 feet with occasional seas up to 8 feet. Dominant period 8 seconds. Scattered 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.
Thursday..East winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 11 seconds. Northeast swell around 4 feet. Scattered showers.
|AMZ700 914 Pm Ast Sat Jan 20 2018 |
Synopsis for puerto rico and the uS. Virgin islands waters... A frontal boundary will weaken and linger north of the region. Surface high pressure moves into the west and central atlantic. Moderate to locally fresh trade winds are expected as the local pressure gradient tightens across the region and increases the trade wind flow. A long dominant period northerly swell will continue to spread across the atlantic waters and passages through the rest of weekend.
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 210133|
area forecast discussion
national weather service san juan pr
933 pm ast Sat jan 20 2018
Update The showers that affected the western and southwestern
portions of pr dissipated late in the afternoon, the rest of the
local islands remained with fair weather. Slightly drier air is
moving in, so only brief isolated to scattered showers are to be
expected. These showers may affect the usvi and the eastern
portions of pr tonight into the early morning hours. Then, locally
induced showers are expected to develop in the afternoon across
the western interior and western sections of pr with isolated and
brief showers expected for the rest of the local islands.
Aviation Vfr conds expected overnight across the local
terminals with possible vcsh at tist, tisx, and tjsj. Overnight
winds will be mainly from the east at 5-10kt with tjps and tjmz
observing light and variable winds. Isold sct shra activity
possible after 21 15z may cause vcsh at tjbq and tjmz in the
afternoon. Winds will be from the east at 10-15kt with sea breeze
variations after 21 14z.
Marine Seas have become hazardous. Small craft advisory and
high surf advisory are both in effect. There is also a high risk
of rip currents for the northern coasts of the local islands,
except for saint john with has a moderate risk. The northwestern
and northeastern facing beaches of pr also has a high risk of rip
currents. Seas will be up to 8 feet and breaking wave heights in
the surf zine could be 8-12 feet tonight.
Prev discussion issued 511 pm ast Sat jan 20 2018
synopsis... Frontal boundary will remain north of the region. Mid
to upper level ridge will continue to build and hold for the next
several days. Surface ridge to the northwest of the region will
merge with another surface high by early next week and continue
through the end of the week. Moderate to fresh trades will
continue to carry passing showers across the region through next
Short term... Tonight through Tuesday...
the cold front continues about 240 miles north of san juan, but is
now denoted by a rope cloud more than a solid deck of clouds. As of
20 1730z showers were just beginning to form under partly cloudy
skies over the interior portion of puerto rico. Early indications
suggest less rain coverage than yesterday. The front is expected to
undergo frontolysis as it lays more east west over the waters to the
north of us. High pressure at the surface is moving east out of the
western atlantic and the southeastern u.S. And is reinforcing the
trade wind flow now through Sunday. This high pressure will merge
with a high in the northwest atlantic Tuesday before moving east
into the northeast atlantic, but trade wind flow will persist just
the same. Patches of moisture will continue to pass in that flow,
but GFS is showing less pronounced peaks to the precipitable water
than in previous forecasts and more general fluctuations. The most
pronounced is from 1.04 inches at 21 12z to 1.61 inches 23 12z. All
fluctuations between Tuesday and the following Monday remain within
these bounds. Scattered trade wind showers will continue--minimally
tonight and Sunday, but increasing somewhat Monday and Tuesday.
Long term... Tuesday through Sunday... From previous
discussion... Low level moisture will periodically pass over
puerto rico and the u.S. Virgin islands during the long term
period. Several short wave troughs will move north of the region
with little to no effect on the area due to the troughs energy
remaining north of puerto rico. Therefore, the long term weather
will be influenced by the mid to upper level ridge and low level
moisture moving in from the east. The ridge of high pressure will
feel the effects of the the troughs and become elongated from east
to west. The weakening high will allow low level moisture to
sneak in from the south which will induce showers across the|
windward islands and eastern puerto rico during the night and
morning hours. Also, low level moisture combined with daytime
heating along with orographic effects and sea breeze variations
will produce showers over portions of the interior and western pr
during the afternoon.
Aviation... Limited mtn obscurations over the highest trrn,
otherwise WRN pr btwn 20 18-22z. Sfc winds easterly 10 to 15 kt with
sea breeze influences til 20 21z. Maximum winds 30-35 kt from fl410-
480 diminishing durg the next 24 hrs.
Marine... Long period northwest swell will continue to affect the
regional waters through the weekend with seas ranging between 6-8
feet. Moderate to locally fresh easterly trades will continue
through the next several days. Hazardous seas will continue
through early next week. Small craft advisories are in effect for
the atlantic waters and passages as well across portions of the
offshore caribbean waters. High surf advisory is in effect for the
atlantic beaches of puerto rico. High rip current risk continues
in effect for the northern beaches of the islands.
Preliminary point temps pops
Sju 74 85 75 85 30 40 50 50
stt 76 85 76 79 20 20 40 30
Sju watches warnings advisories
Pr... High rip current risk through late Sunday night for culebra-
mayaguez and vicinity-north central-northeast-northwest-san
juan and vicinity-southeast-western interior.
High surf advisory until 6 pm ast Sunday for mayaguez and
vicinity-north central-northeast-northwest-san juan and
High rip current risk through Sunday afternoon for vieques.
Vi... High rip current risk through late Sunday night for
st.Thomas... St. John... And adjacent islands.
High rip current risk through Sunday afternoon for st croix.
Small craft advisory until 8 pm ast Sunday for st.Thomas... St.
John... And adjacent islands.
Am... High rip current risk through late Sunday night for coastal
waters of northern usvi and culebra out 10 nm-coastal
waters of southern usvi vieques and eastern puerto rico out
Small craft advisory from 2 am to 8 pm ast Sunday for caribbean
waters of puerto rico from 10 nm to 17n.
Small craft advisory until 8 pm ast Sunday for coastal waters of
northwestern puerto rico out 10 nm-coastal waters of
northern usvi and culebra out 10 nm.
Small craft advisory until 2 am ast Monday for coastal waters of
northern puerto rico out 10 nm.
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 from 2 am Sunday to 2 pm ast Monday for
anegada passage southward to 17n.
Small craft advisory until 8 am ast Monday for mona passage
southward to 17n.
Short term... Ja
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||70 min||E 14 G 16||80°F||1017.8 hPa|
|SJNP4 - 9755371 - San Juan, PR||7 mi||58 min||82°F||1018.8 hPa|
|YABP4 - 9754228 - Yabucoa Harbor, PR||29 mi||52 min||78°F|
|41056||31 mi||100 min||ENE 9.7 G 14||79°F||5 ft||1018.3 hPa (+1.6)|
|AROP4 - 9757809 - Arecibo, PR||38 mi||52 min||E 5.1 G 7|
|CLBP4 - 9752235 - Culebra, PR||38 mi||52 min||81°F||1018.8 hPa|
Wind History for San Juan, PR(wind in knots) EDIT (on/off)  Help
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|Boca De Cangrejos |
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Sat -- 04:59 AM AST 0.06 feet Low Tide
Sat -- 06:59 AM AST Sunrise
Sat -- 09:23 AM AST Moonrise
Sat -- 11:57 AM AST 1.36 feet High Tide
Sat -- 06:10 PM AST Sunset
Sat -- 06:24 PM AST 0.36 feet Low Tide
Sat -- 09:18 PM AST Moonset
Sat -- 11:43 PM AST 0.91 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
EDIT (on/off)  Help One Week of Data
|San Juan |
Click for Map
Sat -- 04:27 AM AST -0.03 feet Low Tide
Sat -- 06:59 AM AST Sunrise
Sat -- 09:23 AM AST Moonrise
Sat -- 11:30 AM AST 1.45 feet High Tide
Sat -- 06:03 PM AST 0.30 feet Low Tide
Sat -- 06:11 PM AST Sunset
Sat -- 09:19 PM AST Moonset
Sat -- 11:16 PM AST 0.87 feet High Tide
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 (21,6,7,8)(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.