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Area forecast discussion 
National Weather Service San Juan PR
211 PM AST Thursday Jul 28 2016

a dry air mass with Saharan dust particles moved across the local
islands today. A weak tropical wave is expected to pass by the
region on Friday. Model guidance forecast the arrival of a strong
tropical wave by Sunday afternoon and into Monday. At the
surface, a broad surface high pressure across the northeast
Atlantic will continue to produce a moderate east wind flow across
the region for the next several days. At upper levels, a TUTT low
will move over the region today and Friday.


fair weather conditions with Saharan dust particles and hot
temperatures prevailed during most of the morning hours and into
the afternoon. However, showers and thunderstorms are expected
over the interior and western sections of Puerto Rico mainly due
to the proximity of a TUTT low and it interaction with the diurnal
heating and local effects. Some of this activity could produce
gusty winds, frequent lightning, small hail and Urban and Small
Stream flooding.

A weak tropical wave is forecast to arrive by Friday. As a result,
another round of showers and thunderstorm could be expected for
tomorrow afternoon. Fair weather conditions should prevailed on
Saturday as a dry air mass is forecast to move over the islands.

A strong tropical wave is forecast to reach the County Warning Area Sunday
afternoon and Monday. If the models are correct, this will
significantly enhance the development of showers, thunderstorms
and flooding across the islands. Please stay tuned and monitor
the evolution of this system.


mostly VFR cond thru the rest of the forecast period. Rain showers/thunderstorms and rain
with mtn obscuration expected across interior and western
portions of PR from 16z-22z, possibly affecting tjmz and tjbq.
Rain showers/thunderstorms in the vicinity possible for tjsj and tjps. Low level winds mainly from
the east at 10-15 kts with higher gusts and sea breeze variations.


tranquil marine weather conditions are expected during the rest
of today, however rough seas and gusty winds can be expected in
and around showers and thunderstorms. Mariners should monitor the
evolution of a strong tropical wave, which is forecast to move
across the region Sunday and Monday.


Preliminary point temps/pops...
sju 79 89 80 90 / 30 30 20 20
stt 79 89 81 92 / 30 30 20 20


Sju watches/warnings/advisories...



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