Marine Weather and Tides
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
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.
|Sunrise 6:04AM||Sunset 6:45PM||Saturday April 21, 2018 3:31 AM AST (07:31 UTC)||Moonrise 11:03AM||Moonset 12:00AM||Illumination 34%|
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|AMZ735 Coastal Waters Of Southern Puerto Rico Out 10 Nm- 902 Pm Ast Fri Apr 20 2018 |
.small craft should exercise caution...
Rest of tonight..East winds 15 to 20 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 7 seconds. Scattered showers through the night.
Saturday..East winds 15 to 20 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 7 seconds. Isolated showers.
Saturday night..East winds 15 to 20 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers through the night.
Sunday..East winds 15 to 20 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers.
Sunday night..East winds 15 to 20 knots. Seas 2 to 4 feet with occasional seas up to 5 feet. Dominant period 7 seconds. Isolated showers.
Monday..East winds 15 to 20 knots. Seas 1 to 3 feet. Dominant period 8 seconds. Isolated showers.
Tuesday..East winds 10 to 15 knots. Seas 1 to 3 feet. Dominant period 7 seconds. Scattered showers.
Wednesday..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 902 Pm Ast Fri Apr 20 2018 |
Synopsis for puerto rico and the uS. Virgin islands waters... A moderate to locally fresh wind flow will prevail across the regional waters through early next week. A long period northeast swell will continue to affect the local waters tonight. Seas will gradually subside through the weekend.
7 Day Forecast for Marine Location Near Ponce, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxca62 tjsj 210055|
area forecast discussion
national weather service san juan pr
855 pm ast Fri apr 20 2018
Update The san juan sounding was wetter overall compared to 12
and 24 hours ago with precipitable water coming in at 1.67 inches.
Nevertheless radar shows that skies are mostly rain-free and an
inversion is setting up over nearby land areas, making any
showers--at least for the next 3 to 4 hours or so--unlikely. With
flow continuing to be east southeast and a weak cap at around 8600
feet only scattered clouds are expected overnight. Some showers
may develop over the local waters and move inland over eastern
puerto rico later tonight and so have left pops there at 40
percent. By mid afternoon, sea breezes should also limit afternoon
temperatures, which would otherwise be susceptible to being above
normal, owing to the east southeast flow, and will also keep
significant precipitation and cloudiness inland from the coast
near the greater san juan metropolitan area Saturday afternoon.
The GFS seemed to be very wet at 850 mb until the mass of dry air
moves in from 21 18-22 00z, but satellite pictures suggest that
this relative humidity--also confirmed in the sounding--is not
producing as much cloudiness or showers as might be expected.
Therefore, have lowered expectations overnight somewhat.
Minor tweaks were made to near-term grids, but overall
expectations are as below.
Aviation Vfr conds are expected at all TAF sites except as
noted: aft 21 16z shra and MVFR CIGS with mtn obscurations will
devlp ovr western and interior pr and down stream from higher
trrn. Isold tsra are expected--mainly in the west half of pr.
Conds clrg aft 21 23z. Sfc winds E 5-10 kt bcmg 10-20 kt with
land sea breeze influences. MAX winds W 50-60 kt btwn fl370-450
bcmg up to 80 kt aft 22 00z at fl410.
Marine Seas will slowly diminish and most areas will come below
7 feet before 6 am ast Saturday morning. Small craft advisories
are not expected again until aft 28 apr 2018. Thunderstorms over
local waters are only expected immediately downstream from puerto
rico during the late afternoons and early evenings.
Prev discussion issued 426 pm ast Fri apr 20 2018
synopsis... Broad surface high pressure will continue across the
eastern atlantic through early next week. Patches of moisture
embedded in the trades will move occasionally across the region
for the next several days, inducing the development of showers and
thunderstorms each afternoon across interior and western puerto
rico with isolated to scattered showers across the u.S. Virgin
islands and eastern puerto rico during the nights and early
Short term... Tonight through Sunday...
a patch of moisture embedded in the trades moved across the u.S.
Virgin islands, vieques, culebra as well as across the eastern
sections of puerto rico this morning inducing the development of
scattered to numerous passing showers over those sectors. This
moisture in combination with daytime heating and local effects
will continue to produce showers and thunderstorms over western
and interior sections of puerto rico until late this afternoon.
Drier air will continue to move across the region tonight and
Saturday. However... Patches of moisture embedded in the trades
will move occasionally across the region during the next several
days. This moisture will induce the development of isolated to
scattered showers across the u.S. Virgin islands, vieques, culebra
as well as across the eastern sections of puerto rico during the
night and early morning hours followed by scattered showers and
isolated thunderstorms across western and interior sections of
puerto rico each afternoon. Latest satellites images depicted
another patch of moisture to the east of the region. This feature
is expected to produce scattered showers tonight and early
Saturday morning across the local waters, usvi and eastern pr.
By Sunday, drier air is expected to dominate the region. Not
significant changes are expected in the present weather pattern
during the forecast period.
Long term... Monday through Friday... From previous reasoning...
moisture peaks on Monday and Tuesday and an upper level trough
will support thunderstorm development each day. But overall the
same weather pattern is expected to prevail each day. Shower and
thunderstorm development is expected to develop each afternoon
over portions of western puerto rico. Trade wind showers will
persist across the usvi and eastern portions of pr during the
overnight and early morning hours. Drier air is expected to move
once again from the east by Friday. Day time maximum temperatures
are expected to reach the high 80s to low 90s across the lower
elevations and overnight minimum temperatures are expected to
range from the low 60s across the higher elevations to low 70s
along the lower elevations.
Aviation... Periods of MVFR conds likely in and around jmz jbq and
possibly jsj in shra tsra through 20 22z. Expect vcsh at the leeward
and usvi terminals this afternoon and early tonight. Ese winds
around 10-15 knots with some sea breeze variations, becoming at 10
knots or less overnight.
Marine... A long period northeast swell will continue to result
in life threatening rip currents across the north, east and
southeast facing beaches of puerto rico, culebra, vieques and st.
Croix. Small craft advisories are in effect for the offshore
waters and passages due to seas up to 7 feet. East winds will
continue at 15 to 20 knots across the region through the weekend.
Preliminary point temps pops
Sju 75 86 75 85 40 40 20 10
stt 76 86 75 87 30 20 20 20
Sju watches warnings advisories
Pr... High rip current risk until 6 am ast Saturday for central
interior-culebra-north central-northeast-northwest-san juan
and vicinity-southeast-vieques-western interior.
High rip current risk until 6 am ast Saturday for coastal
waters of southern puerto rico out 10 nm.
Vi... High rip current risk through late Saturday night for st croix.
Am... Small craft advisory until 6 pm ast Saturday for atlantic
waters of puerto rico and usvi from 10 nm to 19.5n.
Short term... Jf
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|
|JOXP4 - Jobos Bay Reserve, Puerto Rico||21 mi||107 min||NNE 2.9||75°F||1017 hPa||70°F|
|MGIP4 - 9759110 - Magueyes Islands, PR||23 mi||50 min||NE 2.9 G 4.1||81°F||1016.2 hPa|
|AROP4 - 9757809 - Arecibo, PR||36 mi||44 min||E 7 G 13|
|YABP4 - 9754228 - Yabucoa Harbor, PR||42 mi||62 min||76°F|
|SJNP4 - 9755371 - San Juan, PR||43 mi||50 min||80°F||1017 hPa|
|PTRP4||43 mi||37 min||E 6 G 8.9||74°F|
|41053 - San Juan, PR||44 mi||62 min||S 3.9 G 7.8||75°F||1016.2 hPa|
|41115 - Rincon, Puerto Rico (181)||45 mi||32 min||81°F||2 ft|
Wind History for Penuelas (Punta Guayanilla), PR(wind in knots) EDIT (on/off)  Help
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports
Wind History from JPS (wind in knots)
|1 day ago|
|2 days ago|
EDIT RT Ports Option Weekend mode (on/off) (on/off)  Help One Week of Data
|Playa de Ponce |
Click for Map
Sat -- 02:41 AM AST 0.66 feet High Tide
Sat -- 06:05 AM AST Sunrise
Sat -- 11:03 AM AST Moonrise
Sat -- 03:09 PM AST -0.28 feet Low Tide
Sat -- 06:44 PM AST Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
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|Punta Guayanilla |
Click for Map
Sat -- 04:00 AM AST 0.62 feet High Tide
Sat -- 06:06 AM AST Sunrise
Sat -- 11:03 AM AST Moonrise
Sat -- 03:10 PM AST -0.17 feet Low Tide
Sat -- 06:45 PM AST Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Weather Map and Satellite Images(on/off)  HelpWeather Map
GOES Local Image of Puerto Rico 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.
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Other links: Northern Pacific Contential US Full GOES-East
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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.