Wednesday, April25, 2018 L-36.com


Marine Weather and Tides
Arroyo, PR

Version 3.4
What's New / NOTES
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 5:23AMSunset 5:53PM Wednesday April 25, 2018 12:40 AM CST (06:40 UTC) Moonrise 4:05PMMoonset 2:37AM Illumination 75% Phase: Waxing Gibbous; Moon at 10 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 250201 cca
afdsju
area forecast discussion... Corrected
national weather service san juan pr
1001 pm ast Tue apr 24 2018

Update Only the lightest showers are seen on the local radars.

The 25 00z sounding showed 1.47 inches of precipitable water
which is down almost one half inch from yesterday at this time.

The dry slot that has caused all the precipitation to dissipate is
now working its way through the forecast area. Saint martin
(tncm) is also seeing the back edge of that dry slot with showers
and ceilings below fl035. This area of cloudiness is expected to
dissipate before reaching saint croix 25 08z or puerto rico at
25 11z as indicated by the GFS however moisture at 850 mb does
come through the area and there may be enough moisture for
isolated showers as in the current forecast.

Aviation Lower CIGS are now encroaching on tncm tkpk with
shra, but so far CIGS are above fl030. Some brief MVFR is
possible thru 26 00z. Isold shra are psbl in ene flow onto pr and
arnd the usvi otherwiseVFR is indicated thru 25 16z. Btwn
25 16-18z areas of cigs AOB fl050 will dvlp over WRN and interior
pr with shra and mtn obscurations. Brief MVFR psbl in tjmz. Sfc
winds E 5-10 kt with land sea breezes bcmg 10 to 15 kt aft
25 14z. MAX winds W 60 kt at fl470.

Marine Showers will increase beginning Wednesday night, but
small craft advisories are not expected during the next 7 days.

Prev discussion issued 336 pm ast Tue apr 24 2018
synopsis...

although satellite imagery detected dry air filtering from the
east over the islands, the lingering moisture combined with
diurnal and local effect will result in shower activity to the
west of the cordillera central through the evening hours. A fair
weather pattern with an easterly wind flow and little or no shower
activity is expected overnight and early Wednesday morning.

Short term... Tonight through Thursday...

showers were detected across the western municipalities of puerto
rico, and the eastern section of puerto rico and the u.S. Virgin
islands have mostly clear skies with no shower activity. As the
short wave trough axis exit the region an upper level ridge will
build aloft. A dry air mass already filtered over the islands,
which will limit shower activity through late Wednesday night.

However, the lingering moisture will interact with diurnal and
local effect to produce a few showers across the northwest
quadrant of puerto rico.

A ridge aloft will continues in place through at least Friday,
but a surge of moisture is expected to bring shallow passing
showers across the u.S. Virgin islands and southeast puerto rico
early Thursday morning into mid-day followed by afternoon
convection across the northern half of pr on Thursday.

Long term... Friday through Wednesday...

near normal moisture and upper ridge will cause a weather pattern
of some isolated to scattered brief showers across the local
waters, usvi and eastern pr during the overnight and early morning
hours. Afternoon shower and possible thunderstorm development will
be mainly due to local effects over pr. Therefore, the available
moisture will combine with the diurnal heating and sea breeze
convergence to cause some showers and possible thunderstorms. This
weather pattern can be expected through the weekend and into
early next week.

The very long range models started hinting at a significant
increase in moisture and in shower activity by next Wednesday as
a frontal boundary settles north of the local islands. This is way
too far into the forecast period and the confidence is very low.

We will continue to monitor but it would not be surprising if the
model guidance varies widely from today until that date arrives.

Aviation...

shra tsra over western pr should end by 22z, impacting
the flying area of tjmz tjps tjbq. However, mainlyVFR conditions
are expected to prevail across all the terminals through the
forecast period. Low level winds will continue from the ene at 10-20
kt... Turning ese after 25 08z.

Marine...

mariners can expect tranquil marine conditions with seas between 2
and 4 feet across the coastal waters of the islands and up to 6
feet across the atlantic offshore waters through tonight. Winds
are forecast to continue from the east at 10 to 20 knots but are
expected to veer from the east-southeast after Wednesday.

Preliminary point temps pops
Sju 75 89 76 88 20 20 40 50
stt 75 86 77 86 20 40 40 40

Sju watches warnings advisories
Pr... None.

Vi... None.

Am... None.

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


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Weather Map and Satellite Images
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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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Wind Forecast for (2,6,7,8)
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Ground Weather Radar Station Puerto Rico,Virgin Islands
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Disclaimer:
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.