Sunday, January21, 2018

Marine Weather and Tides
Arroyo, PR

Version 3.4
What's New / NOTES
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 6:03AMSunset 5:41PM Sunday January 21, 2018 11:59 AM CST (17:59 UTC) Moonrise 10:03AMMoonset 10:55PM Illumination 24% Phase: Waxing Crescent; Moon at 5 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Arroyo, PR
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location: -34.81, -58.22     debug

Area Discussion for - San Juan, PR
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Fxca62 tjsj 211455 aaa
area forecast discussion... Updated
national weather service san juan pr
1055 am ast Sun jan 21 2018

Update Sounding this morning came out slightly drier than
forecast at 1.26 inches. Marine layer is also very attenuated and
moisture begins to drop off just a few thousand feet above the
surface. This will lead to mostly fair weather cumulus except in
very isolated areas and mainly afternoon in western puerto rico.

Visible satellite picture reveals unstable cumulus to the north
of puerto rico and the u.S. Virgin islands as well as speckled
smaller cumulus south of the islands with a weak streamer off of
saint croix. With east northeast flow, this will prolong the
relatively dry period through the day and into tonight. The gfs
has a plume of moisture entering the southeast portion of the
forecast area later tonight, crossing saint croix and then
entering eastern puerto rico tomorrow. Not certain what will bring
this, as it is not presently evident, so will give it fairly low
confidence matched with pops less than 40% everywhere through noon

Aviation Vfr conds to prevail through 22 04z. Some clouds will
top LCL mtns aft 21 17z till 22 02z. Sfc winds east 10 - 15 kt
with gusts to 20 to 25 kt along the north coast of pr til 21 21z.

Sfc winds east less than 15 kt aft 22 00z. MAX winds west 30-40
kt from fl410-510.

Marine Seas at the outer buoy, 41043, were still 7.5-8.5 feet
but falling. Seas at the inner buoy, 41053, were less than 6 feet
last 4 hours. Periods have been around 12 seconds. This is enough
to give 10 foot breakers at the most favored locations on the
northern puerto rico coast even if not at some of the most popular
beaches. Therefore have decided to carry the high surf advisory
through to its expiration, but will not seek to extend it. The
high risk of rip currents will continue along coasts exposed to
the northerly swell through at least Monday afternoon, but at this
time may drop down to moderate for saint croix and vieques by
Monday morning. Model is still slightly underestimating the seas
across the area so have used a plus 10 percent correction to
arrive at forecast. Even so, small craft advisories begin to drop
out on Monday and swell slowly veers slightly east of north by
Tuesday. Should be able to take all small craft advisories down by
Tuesday unless east trade winds are higher than forecast.

Prev discussion issued 713 am ast Sun jan 21 2018
synopsis... Surface ridge and upper level ridge of high pressure
will create mostly fair weather conditions for puerto rico and the
u.S. Virgin islands through Friday. Moderate to fresh trades winds
will cause isolated showers for most of the forecast area through
late next week. Friday, a trough of low pressure will move across
the atlantic waters and possibly increase showers activity for
puerto rico and the u.S. Virgin islands on Saturday.

Short term... Today through Tuesday... Partly cloudy skies prevailed
across puerto rico and the u.S. Virgin islands overnight. Latest
satellite images depicted an area of low level moisture over the
u.S. Virgin islands early this morning. This area of moisture will
spread across puerto rico this morning, bringing with it some
isolated passing showers. These showers will move quickly
westward. For this afternoon, some cloudiness with showers are
expected to develop across the western interior and west sections
of puerto rico.

High pressure system located north of the area will continue in
control of the weather locally. 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.

Long term... Wednesday through Monday...

easterly trade winds will bring patches of low level moisture
periodically over the region through the long term period thus
scattered showers are possible during the morning and afternoon
hours. Strong brisk easterly winds can be expected through
Wednesday due to the strengthening surface high pressure system
to north of puerto rico. Otherwise, mostly fair weather conditions
across the forecast area until the end of next week when a trough
of low pressure moves into the atlantic waters with some guidance
showing a frontal passage on Saturday.

Aviation...VFR conditions are expected to prevail across all
terminals through at least 21 22z. Some light to moderate showers
can be expected in the vicinity of tist, tisx and tjsj throughout
the forecast period. Low level winds will continue mainly from the
east at 10 to 15 kts with higher gusts.

Marine... Hazards weather conditions will prevail through Tuesday.

A long period northerly swell will cause seas to rise to 6 to 8
feet through Tuesday. Small craft advisories are in effect for
the atlantic waters and passages as well across portions of the
offshore caribbean waters. High rip current risk continues in
effect for the northern coast of the local islands, excluding st.

John with moderate risk. High surf advisory is in effect for the
atlantic beaches of puerto rico.

Preliminary point temps pops
Sju 85 74 85 74 10 30 30 30
stt 78 77 79 78 10 30 20 20

Sju watches warnings advisories
Pr... High rip current risk through Monday afternoon for culebra-
mayaguez and vicinity-north central-northeast-northwest-san
juan and vicinity-southeast-western interior.

High surf advisory until 6 pm ast this evening for mayaguez and
vicinity-north central-northeast-northwest-san juan and
vicinity-southeast-western interior.

High rip current risk through late tonight for vieques.

Vi... High rip current risk through Monday afternoon for
st.Thomas... St. John... And adjacent islands.

High rip current risk through late tonight for st croix.

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-
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 from 8 pm this evening to 2 am ast Tuesday
for coastal waters of southern usvi vieques and eastern
puerto rico out 10 nm.

Small craft advisory until 2 pm ast Monday for coastal waters of
northern usvi and culebra out 10 nm.

Small craft advisory until 6 am ast Monday for coastal waters of
northwestern puerto rico out 10 nm.

Short term... Ws
long term... .Ws

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Weather Map and Satellite Images
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Weather Map
IR Satellite Image from GEOS

GOES Local Image of Puerto Rico    EDIT

Wind Forecast for (12,3,4,5)
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Ground Weather Radar Station Puerto Rico,Virgin Islands
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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 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 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.