Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 301741

Area Forecast Discussion
National Weather Service San Juan PR
141 PM AST MON MAY 30 2016

.SYNOPSIS...High pressure ridge north of the region and broad surface
trough spread across the central and eastern caribbean...will
maintain a moist southeasterly wind flow across the forecast area
through most of the work week. High amplitude trough across the
west Atlantic extending southwards into the Western Caribbean will
hold through the end of the week. Meanwhile upper level ridge will
remain positioned over the Northeastern Caribbean through the end
of the week. The present overall pattern aloft will maintain a west
southwest flow and diffluence aloft along with good ventilation for
convective development most of the week.


.DISCUSSION...The combination of the upper trough just west of
the region along with a significant moist environment...local and
diurnal effects will continue to support rapid development of showers
and thunderstorm activity across portions of the islands and coastal
waters today and at least until Wednesday. Some of the showers and
thunderstorms will continue to produce periods of locally heavy rainfall
and gusty winds which will eventually lead to minor flooding of urban
areas... rivers and small streams especially along portions of the
northern half of Puerto Rico including parts of the San Juan metro

The activity over land should taper off and diminish just after
sunset leaving variably cloudy skies over land. Another round of
showers an isolated thunderstorms will develop across the coastal
waters during the late evening and overnight hours. The persistent
southeasterly flow will steer these showers across portion of the
east and south coastal sections of the islands during the morning
hours. On Tuesday and possibly into Wednesday...expect showers
and thunderstorm activity to quickly develop once again over the
interior and west sections of Puerto Rico. This will again increase
the potential for urban and small stream flooding mainly across
Puerto Rico.

One note of concern is that although there may be periods of lesser
shower activity in some areas during the next few days...the soil
remain very saturated across portions of the northern half and
east sections of Puerto Rico. Some rivers and streams will continue
to run just above their normal levels especially in parts of the
east interior and west sections of Puerto Rico. Mudslides will
also remain possible in areas of steep terrain. For this reason...
residents...motorists and visitors in these areas should remain
alert and continue to monitor for any statements and bulletins
issued by the National Weather Service San Juan Puerto Rico.

For the long term ...By the end of the work week model guidance
suggest slight decrease in moisture transport and weakening of the
ridge the upper trough west of the region fills and a
short wave trough moves just north of the area. Although lesser
dynamics and upper level support is expected by then...they will
still be sufficient low level moisture to allow daytime heating
and local terrain effects to lead to afternoon convection each


.AVIATION...SHRA/-TSRA still possible across mainland PR thru 22z.
Impacting mainly JSJ/JBQ/JMZ with at least periods of MVFR cigs.
Mountain top obscd likely at el Yunque and the Cordillera Central of
PR. Tops around Fl250-300 will continue over the waters between the
USVI and eastern PR terminals during the overnight hours...creating
mainly VCSH but -RA over the terminals at times. Low level winds
will continue ESE around 10-15 knots...but sfc winds will be light
and variable overnight.


.MARINE...Seas expected to remain below 4 feet and southeast
winds will continue between 10-15 knots. However higher wind gusts
can be expected near enhanced shower and thunderstorm activity
which is expected to continue overnight through Tuesday. Dangerous
lightning strikes will also be likely with thunderstorms that develop
over the coastal waters surrounding Puerto Rico and the U.S Virgin


SJU  77  87  78  89 /  30  40  40  40
STT  80  87  81  86 /  50  50  50  50


.SJU Watches/Warnings/Advisories...


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