National Weather Service San Juan PR
414 AM AST Tue May 12 2020
.SYNOPSIS...Surface high pressure over the Atlantic will continue
to promote an east to southeast wind flow for the next several
days. Near or below normal moisture is expected for the next
several days, but brief patches of moisture will move in
occasionally. Mid and upper level ridge is expected to prevail
through the rest of the workweek as well. Mostly stable
conditions are expected for the rest of this week, but brief
isolated to scattered showers in the mornings and overnight hours
can be expected across the local waters, eastern Puerto Rico and
the USVI. Locally induced afternoon showers can be expected across
western to northwestern Puerto Rico. Temperatures are expected to
be slightly above normal, in the upper 80s to low 90s across the
lower elevations for the next several days.
&&
.SHORT TERM...Today through Thursday.
Surface high pressure to the northeast of the local area will
continue to cause east to southeasterly winds over the region. As
a result, warm temperatures are expected today and Wednesday over
the lower elevations of the local islands. Also, passing showers
will move into the eastern sections of Puerto Rico and over the
U.S. Virgin Islands from time to time this morning. Afternoon
convection will be focused over the northwestern and interior
sections of Puerto Rico. On Wednesday, drier air is expected to
filter over the region, providing fair weather conditions,
especially in the nighttime hours. A slight increase in moisture
is expected once again on Thursday, increasing the probability of
shower activity in the morning and evening hours over the local
waters, eastern sections of Puerto Rico and the U.S. Virgin
Islands. Also, locally induced afternoon shower activity over the
western sections of Puerto Rico is expected.
.LONG TERM...Friday through Wednesday...
Near or below normal moisture is expected in the long term. The
long range guidance has been consistent in showing that mainly
stable conditions will continue through the weekend. However, the
latest model run is showing an upper level low to the north of the
local area on Monday, moving south and causing divergence and
increasing instability for the first half of next week, which
would translate to more significant shower activity, especially
across the northern sectors of our local area. That said,
confidence is low and more consistency between the different model
runs should be achieved before confidence increases.
Nevertheless, brief isolated to scattered showers are expected
across the local waters, eastern Puerto Rico and the USVI, with
locally induced showers developing across western Puerto Rico in
the afternoons. The days with higher moisture are expected to be
on Friday, but the mid to upper levels are not conducive for
widespread heavy showers. Therefore, any significant showers
should be somewhat limited with moderate showers having more
coverage. The drier than normal conditions and the east to
southeast winds will cause the high temperatures to also be above
normal, reaching the upper 80s to low 90s across the lower
elevations.
&&
.AVIATION...VFR conditions will continue to prevail at all TAF sites.
Some Brief -SHRA to Isolated SHRA are possible in and around
TJSJ, TJMZ and TJBQ between 12/14z and 12/20z. ESE winds to
continue at around 15 knots with some wind gusts up to 25kt and
sea breeze variations.
&&
.MARINE...Small craft operators are urged to exercise caution
today due to choppy seas up to 6 feet and winds up to 20 knots.
The local seas are expected to improve slightly on Wednesday, with
seas up to 5 feet, but the local winds will still be up to 20
knots. There is a moderate risk of rip currents for most of the
local beaches today.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 90 76 89 75 / 30 20 30 40
STT 87 77 87 76 / 10 20 30 30