Tuesday, May21, 2019 L-36.com

Marine Weather and Tides
Arroyo, PR

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 5:16AMSunset 5:58PM Tuesday May 21, 2019 8:35 PM CST (02:35 UTC) Moonrise 8:25PMMoonset 10:14AM Illumination 90% Phase: Waning Gibbous; Moon at 18 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
    EDIT      (on/off)   Help

7 Day Forecast for Marine Location Near Arroyo, PR
   Hourly   EDIT   Help
location: -34.81, -58.22     debug

Area Discussion for - San Juan, PR
      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
Fxca62 tjsj 220120
area forecast discussion
national weather service san juan pr
920 pm ast Tue may 21 2019

Showers and isolated thunderstorms dissipated across the
northwestern areas of puerto rico before sunset today. Tonight
partly cloudy skies are expected for most of the area with east to
southeast winds of 5 to 10 kts. Tonight partly cloudy skies with
east to southeast winds of 5 to 10 mph are expected over the area.

Overnight low temperatures are forecast to be near the lower to
middle 70s near coastal locations, and middle to upper 60s in
higher elevations.

Tomorrow scattered showers and thunderstorms are forecast to
develop across the northwest and interior areas of the island
during the afternoon. These showers and thunderstorms will produce
locally heavy to moderate rainfall which could lead to urban and
small stream flooding. Also, showers are forecast to develop
across the interior and northeastern areas of the island during
the early morning, and afternoon. Showers and thunderstorms will
be induce by mid to upper-level instability, diurnal heating, and
local effects.

Vrf conds will continue across all terminal sites until 22 18z.

Then shra vcts are forecast to develop across tjbq and tjmz which
could cause mvrf conds until 23 01z. The other terminal sites
shra vcsh could develop until 23 01z. Sfc winds out of the east to
south at 5 to 10 kts tonight, then winds will increase to 10 to
15 with higher gusts by 22 12z.

Across the regional waters and local passages, seas are expected
to remain at 5 feet or below. East to southeast winds will
continue between 10 to 15 knots. There is a moderate risk of rip
currents for the north facing beaches of puerto rico.

Prev discussion issued 440 pm ast Tue may 21 2019
synopsis... The chance for shower and thunderstorm activity will
continue to increase as a mid to upper level trough moves closer
to the forecast area. Although this feature is expected to weaken
by the end of the week, trofiness and plenty of moisture will
persist much of the upcoming week.

Short term... .Tonight thru thu...

heights will continue to fall as a mid to upper level trough
-now located in the vicinity of the bahamas- shifts southeast;
reaching the northeast caribbean by Thursday. This feature will
also induce a surface trough enhancing moisture advection across
the local islands with precipitable water near 2 inches by
Thursday morning.

Under plenty of moisture and favorable upper level conditions,
the chance for showers and thunderstorms will continue to increase
through the forecast period. Expect shower and thunderstorm
development across central and western puerto rico Wednesday
afternoon. The intensity and areal coverage of showers and
thunderstorms will increase on Thursday as the aformentioned
trough moves closer to the forecast area. The best chance for
shower and thunderstorm development across the usvi is on
Thursday, as well. As a result, there is an increasing potential
for urban and small streams flooding, particularly Thursday.

Meanwhile, shower activity over western areas of puerto rico will
diminish late this afternoon, leaving partly cloudy skies.

Passing showers will remain possible across the eastern third of
puerto rico and the outlying islands overnight.

Long term... Fri thru Tue issued 504 am ast Tue may 21 2019
a trof pattern will maintain unstable weather conditions across
the area throughout the week. Model guidance continues to suggest
precipitable water values ranging between 1.7 and 2.20 inches
through the long term period. Therefore, the combination of
abundant tropical moisture with good instability will result in
periods of enhanced shower and thunderstorm activity, especially
across along and north of the cordillera central of puerto rico
each afternoon. Showers and isolated thunderstorms should not be
ruled out across portions of eastern pr and the usvi, especially
during the overnight hours.

Global models continues to suggest an amplifying trough
interacting with deep tropical moisture early next week, between
Sunday or Monday. If these solutions are correct, unsettle weather
conditions could be expected the first part of the upcoming week.

In addition, a tropical wave will reach the local islands around
Wednesday of the upcoming week. At this time, confidence is low to
moderate because this solutions are to far in time. However,
please continue to monitor the latest forecast updates during the
next several days as the picture becomes clearer.

Aviation... Shra tsra across nw-pr to continue through 20 22z,
possibly causing tempo MVFR conds at tjbq tjmz. -shra at tjsj
through 21 18z. The rest of the local terminals will observeVFR
conds. After 21 23z, all of the local terminals are expected to
observeVFR conds, with only brief vcsh possible at tist and tisx
during the overnight hours. Local winds from the ese at 10-15kt
expected through 21 23z with sea breeze variations and occasional
gusts, gradually decreasing thereafter through the night.

Marine... Seas below 5 feet and winds 15 to 20 knots to continue
during the forecast period. Along the coastal areas, a low to
moderate risk of rip currents is expected to continue through
much of the week. Criteria for scas are not expected to be

Preliminary point temps pops
Sju 79 90 76 87 20 40 40 70
stt 78 86 76 86 30 50 50 40

Sju watches warnings advisories
Pr... None.

Vi... None.

Am... None.

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

Weather Reporting Stations
   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map

Airport Reports
    EDIT      (on/off)   Help   Click EDIT to display multiple airports
Click EDIT to select an airport
Tide / Current Tables for
   EDIT   Weekend mode (on/off)   (on/off)   Help
Tide / Current Tables for
   EDIT      (on/off)   Help
Weather Map and Satellite Images
       (on/off)   HelpWeather Map
GOES Local Image of    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.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for (22,6,7,8)
      (on/off)   Help

Ground Weather Radar Station Puerto Rico,Virgin Islands
   (on/off)   Help
weather_mapweather_map weather_map

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.