Scientific Forecaster Discussion
fxca62 tjsj 270855
Area forecast discussion
National Weather Service San Juan PR
455 am AST Sat may 27 2017
Synopsis...TUTT low and associated trough across the Lesser
Antilles will lift northwards across the region over the weekend.
Broad high pressure ridge across the central Atlantic will hold
and allow better transport of trade wind moisture across the
forecast areas overnight and through the weekend. A tropical wave
will approach the local area Monday into Tuesday next week.
Short term...today through Tuesday morning...
Clear to partly cloudy skies prevailed across the local islands
overnight and early this morning with a few passing showers noted
across the surrounding waters, USVI and east PR. Rainfall accumulations
associated with these showers were minimal. Overnight temperatures
were in the upper 70s to low 80s across the lower elevations and in
the low 70s across the higher elevations. Winds were mostly light
Although a TUTT low to the northeast of the forecast area will
continue to move away while weakening, trofiness will return to the
northeast Caribbean late Monday into Tuesday. This feature will
interact with an approaching tropical wave to result in a better
chance for showers and thunderstorms Monday afternoon into Tuesday.
Meanwhile, during the weekend as well as Monday continue to expect
trade wind showers across windward areas in the morning hours
followed by locally induced afternoon showers and thunderstorms
across west and north portions of Puerto Rico. Elsewhere, mainly
fair weather will continue to prevail with a few passing showers
possible. With the heaviest showers during the afternoon hours,
minor urban flooding likely.
Long term...Tuesday afternoon through Sunday...
For Tuesday, a tropical wave is expected to affect the region
with an increase in showers and thunderstorms activity. A moist
weather pattern is forecast to prevail across the northeast
Caribbean next work week as a series of tropical waves and
trofiness aloft affect the region.
Aviation...VFR conds expected at all taf sites through the morning
hours with vcsh possible at the leeward and USVI terminals as well
as jsj. Aft 27/16z rain showers/thunderstorms and rain expected over NE PR and this may result
in MVFR conds in and around jmz/jbq. Vcsh at jsj also possible this
afternoon. Easterly winds 10-15 knots with some sea breeze
variations after 27/12z.
Marine...seas between 3 to 5 feet and east winds at 5 to 15 knots are
expected across much of the local waters and passages. There is
a moderate risk of rip currents across the north facing beaches
of Puerto Rico and Culebra and Saint Croix in the U.S. Virgin
Preliminary point temps/pops...
sju 90 78 89 77 / 40 20 20 20
stt 88 78 89 78 / 30 30 20 30