Monday, June25, 2018

Marine Weather and Tides
Arroyo, PR

Version 3.4
What's New / NOTES
5/20/2018 -- NOAA is having problems with the data feed that I use to draw the graphs. They are aware of the issue and working to resolve it. Sometimes changing the location by about a mile will give a correct graph. 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.

Sunrise 5:19AMSunset 6:07PM Monday June 25, 2018 1:41 AM CST (07:41 UTC) Moonrise 4:14PMMoonset 5:28AM Illumination 90% Phase: Waxing Gibbous; Moon at 12 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 250030
area forecast discussion
national weather service san juan pr
830 pm ast Sun jun 24 2018

Showers developed late this afternoon over portions of eastern,
interior and western puerto rico as a result of left over
moisture at 1000 to 850 mb. Dry saharan air will continue to work
in from the east over the next several days which will help to
limit shower development across the region. Although, drier air
is in place showers are still expected to form over the northwest
and western areas of puerto rico during the afternoon hours. A
strong surface ridge of high pressure to the north will continue
to promote easterly winds of 10 to 15 mph with higher gusts
through Wednesday.

Vrf conds will continue across all terminal sites through 25 18z.

Shra tsra are possible around 25 18z across terminals tjbq and
tjmz which could cause brief MVFR conds. Shra will diminish across
the western areas of puerto rico by 25 22z. Sfc winds out of the
east southeast at 10 to 15 kts with higher gusts.

Seas have built up to 7 feet across the atlantic and caribbean
waters with 8 feet seas possible later tonight and into the
beginning of the week. Small craft advisories are in effect
through at least Tuesday morning due to choppy seas. Fresh trades
between 15 to 20 knots with higher gusts. There is a high risk of
rip currents for the southeastern beaches of puerto rico tonight
and a high risk for northwestern and southwestern beaches of
puerto rico on Monday.

Prev discussion issued 423 pm ast Sun jun 24 2018
synopsis... Drier air mass and saharan dust are moving into the
area, limiting shower activity during the next few days. Also, due
to moderate to fresh east southeast winds, sea breeze will not be
as dominant across the coasts. This will help limit some of the
shower development across the islands. Most of the activity
should be focused across western and interior pr during the
afternoons. Shower activity is expected to increase latter in the
week as a tropical wave approaches the region.

Short term... Tonight through Wednesday...

surface high pressure will continue across the central atlantic
through at least Tuesday, producing moderate to fresh east to east
southeast winds across the region. As drier air mass continues to
move into the area tonight, shower activity will continue to

During the rest of the short term forecast period... Drier a air
mass will prevail across the area, along with saharan dust particles
suspended in the air. Also, the moderate to fresh winds will not
allow for much sea breeze convection later in the afternoon. Lower
precipital water is expected as well, with low relative humidity
values extending across the mid to upper levels. This combination
will generally limit the shower and thunderstorm development
across the islands. However, shower and isolated thunderstorms
are still expected to develop due to the diurnal and local
effects, but not as strong and lengthy as the previous days and
should be focused mainly across the western and interior portions
of puerto rico during the afternoon hours each day.

Long term... Thursday through Monday...

prev discussion... Issued 500 am ast Sun jun 24 2018
although trofiness will prevail across the eastern caribbean
through the forecast cycle, the available moisture will determine
if organized convection develops. At this time, low level moisture
is still expected to remain below the normal range much of the
cycle except Friday and Monday when tropical waves are expected to
move across the eastern caribbean. Expect temperatures near or
slightly above the normal values as a broad surface high pressure
across the central atlantic yields easterly winds.

As a result, continue to expect a fair weather pattern across the
local islands with locally induced afternoon showers and thunderstorms
across western areas of puerto rico each day. However, on Friday
as the tropical wave interacts with the upper level trough, an
increase in intensity and areal coverage of showers and thunderstorms
is expected. Similar conditions on Monday as another tropical
wave moves across the area.


vfr conds across the local termimals. Vcsh possible
across tjmz and tjbq this afternoon, but drier air is moving in so
shra activity is expected to be minimal. Winds are expected to
continue from the east at 15-20 knots with sea breeze variations
this afternoon, decreasing after 25 00z to 5-15 knots. Saharan dust
is moving in, but visibilities are expected to be p6sm.

Marine... Moderate to fresh east southeast winds will continue
across the regional waters as a surface high pressure across the
west-central atlantic tightens the local pressure gradient.

Hazardous marine conditions will continue across the outer
atlantic and caribbean waters and the nearshore caribbean waters
of puerto rico. Mariners should expect seas up to 7 feet across
the atlantic waters and increasing up to 8 feet across the caribbean
waters and the mona passage. Small craft advisories are in effect
for most of the waters through at least Tuesday.

Preliminary point temps pops
Sju 78 88 78 87 30 10 20 20
stt 78 88 78 89 40 20 20 20

Sju watches warnings advisories
Pr... High rip current risk through late Monday night for central

Small craft advisory until 2 am ast Tuesday for southeast.

High rip current risk from 6 am ast Monday through late Monday
night for southwest.

Vi... High rip current risk through late Monday night for st croix.

Small craft advisory from 2 am to 2 pm ast Monday for
st.Thomas... St. John... And adjacent islands.

Am... High rip current risk through late Monday night for coastal
waters of southern puerto rico out 10 nm.

Small craft advisory until 8 pm ast Monday for anegada passage
southward to 17n-atlantic waters of puerto rico and usvi
from 10 nm to 19.5n.

Small craft advisory until 2 am ast Tuesday for coastal waters
of southern puerto rico out 10 nm.

Small craft advisory from 2 am to 2 pm ast Monday for coastal
waters of southern usvi vieques and eastern puerto rico out
10 nm.

Small craft advisory until 8 am ast Tuesday for caribbean waters
of puerto rico from 10 nm to 17n-mona passage southward to

High rip current risk from 6 am ast Monday through late Monday
night for coastal waters of southwestern puerto rico out 10

Short term... Tw
long term... .Tw

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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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Wind Forecast for (3,6,7,8)
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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.