National Weather Service San Juan PR
532 AM AST Fri Aug 4 2017
.SYNOPSIS...Fairly drier airmass and hazy skies with limited shower
activity expected as Saharan dust will linger across the region today
through Saturday. However, a few early morning trade wind showers are
expected to affect the east sections of Puerto Rico and the surrounding
waters. The next tropical wave will move across the region Tuesday
though Wednesday of next week with a Tutt and associated low to develop
north and west of the region.
&&
.SHORT TERM...Today through Sunday...Trade wind showers moved over
the southeastern interior sections of Puerto Rico during the
overnight hours under a 25-35 knot steering wind flow. The doppler
radar estimated rainfall accumulations between half to one inch of
rain. Dry mid levels and Saharan air layer will continue to create
hazy skies across the islands at least until today. Tropical wave
across the Caribbean Sea will continue to exit the local area.
However, lingering moisture associated to the wave will combine with
local effects to induce afternoon showers and isolated thunderstorms
across the western portions of Puerto Rico.
TUTT pattern is forecast to establish across the Atlantic waters and
over the Hispaniola through the weekend. This will aid in the development
of showers and thunderstorms, mainly over west/northwest PR on Saturday
afternoon were urban and small stream flooding is possible. Enough
low level moisture will continue through the weekend resulting in
trade wind showers across the local waters, with showers moving inland
over portions of the USVI and the eastern half of Puerto Rico during
the overnight/early morning hours.
.LONG TERM...Monday through Saturday...Several tropical waves are
forecast to approach the local region area during the period. Based
on the most recent model guidance, the first tropical wave is expected
to enter and move across the region Tuesday through Wednesday. This
wave wave is expected to bring significant amounts of moisture to the
region allowing good low level moisture across the islands. This along
with the developing tutt and associated low north and west of the region
will support enhanced convection across the forecast area and therefore
increase the potential for enhanced and widespread showers and thunderstorm
activity due to the instability/strong divergence aloft. After Wednesday,
there is still much uncertainty in the extended long term forecast
due to model guidance discrepancies at this time. The National Hurricane
Center is however monitoring a strong tropical wave located several
hundred Miles southeast of the Cape Verde Islands. This system is forecast
to move west or west northwest during the next several days. As mentioned
at this time this feature is still too far away from the local region
and therefore there remains much uncertainty in the future impacts
that it will have across the local area. We will continue to closely
monitor and make any necessary adjustment to the long tern forecast
package as model guidance adjusts with time and becomes more consistent.
&&
.AVIATION...Tropical wave moving across the Caribbean Sea is forecast
to exit the area today. SHRA and isolated TSRA across the Caribbean
waters could affect briefly the flying area of the Leeward terminals
and TISX today. Afternoon SHRA/TSRA expected to develop over west
PR impacting mainly the flying area of TJMZ/TJBQ. VFR expected to
prevail elsewhere. Low level winds will continue E-ESE at 15-25 kts.
&&
.MARINE...Small craft advisory portions of the local waters due to
the moderate to fresh trade winds. Mariners can expect choppy seas
between 5 And 8 feet and winds around 20 knots and locally higher
in and around showers. Marine conditions are forecast to slowly
improve today and into the upcoming weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 80 90 79 / 30 20 20 20
STT 91 81 90 79 / 30 30 30 30