Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 251540
Area Forecast Discussion
National Weather Service San Juan PR
1140 AM AST SUN SEP 25 2016
.UPDATE...Mostly sunny to partly cloudy skies across most of the
islands during the morning hours under a fairly light easterly
trade wind flow. Recent TJSJ upper air sounding suggest precipitable
water still around 1.80 inches or so so local and diurnal effect
may again lead to some afternoon convection mainly over parts of
the interior and west sections of PR and adjacent island. No
changes to inherited shore term forecast package at this time. So
far still expect overall high temperatures to be in the high 80
to low 90s along the north and south coastal areas.
.AVIATION...No chg to previous AVN discussion. VFR conds expected
to prevail durg the entire prd. Except for the isold-sct convection
over portions of the central and west section of PR til 25/22z.
.MARINE...No change in previous marine discussion. Fairly tranquil
marine conditions for the local waters through Monday. However,
Winds and Seas to increase by Tuesday and through the remainder
of the week as a surface trough followed by a strong Tropical wave
is forecast to move across the Eastern Caribbean. Stay Tuned!
.PREV DISCUSSION... /issued 508 AM AST SUN SEP 25 2016/
SYNOPSIS...Upper level trough will linger across the region
through at least tuesday. Tropical wave will move across the
region late Tuesday. A stronger and very active tropical wave
will approach the local region by the end of the week.
DISCUSSION...Surface winds have shifted easterly overnight. These
winds brought with it some passing showers across the local
waters. Some of these showers affected the north and east sections
of Puerto Rico, but were short-lived. Meanwhile, partly cloudy to
clear skies prevailed across the U.S. Virgin Islands. Local area
will remain under the influences of a weak area of surface high
pressure. As a result, local winds will continue light to gentle,
with trade wind showers affecting the local region from time to
time. For this afternoon...another round of showers and
thunderstorms are expected, as daytime heating combines with low
level moisture and local effects.
For Tuesday, a tropical wave located near 58 west longitude early
this morning,will affect the local region. Better moisture it is
expected to encompass the region Tuesday afternoon and lingering
through Tuesday night.
A very strong tropical wave located early this morning between
Africa and the lesser Antilles is expected to approach the local
region Thursday. The National Hurricane Center is closely
monitoring this system for tropical cyclone formation. Stay tuned.
AVIATION...VFR conds expected across the flying area and all
TAF sites during the morning hours. SHRA/TSRA expected to develop
along interior and West PR. MVFR conds possible at TJMZ with MTN
obscurations along interior PR between 25/17-22Z. Winds becoming
more easterly today at around 10 kts.
MARINE...Seas up to 5 feet and winds up to 10 knots are expected
over the coastal waters.
.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 91 79 / 20 10 30 30
STT 90 80 89 80 / 20 30 30 30