Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 270934
Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST WED JUL 27 2016
.SYNOPSIS...A generally stable air mass will prevail across the
forecast area today. Saharan Air Layer is still present over the
area...resulting in hazy skies and somewhat reduced visibilities.
Then...upper level trough/TUTT will retrogress across the
forecast area on Thursday...enhancing the development of showers
and thunderstorms across the region. The next tropical wave
expected on Sunday.
.DISCUSSION...Fair weather will prevail across Puerto Rico and
the U.S. Virgin Islands today. Saharan Air Layer will persist
across the area over the next few days...resulting in hazy skies
and somewhat reduced visibilities. Although...relatively dry and
stable pattern will continue across the local islands over the
next 24 hours...diurnal induced showers and a thunderstorm or two
can not ruled out across Northwest Puerto Rico this afternoon.
Elsewhere...little or no shower activity is anticipated today.
Then...a upper trough/TUTT will move over the local region on
Thursday enhancing the shower and thunderstorm activity. Strong
thunderstorms may develop in the afternoon due to the influence
of the TUTT. At the same time...Saharan Dust will be presented
over the area...limiting the coverage of the showers and
thunderstorms. On Thursday...afternoon showers and thunderstorms
will focus mainly over the Central Interior...West and South
portions of Puerto Rico.
For Saturday...Drier and stable air mass is forecast ahead of the
next tropical wave. Moisture associated with the wave will likely
reach the local region on Sunday. This unstable environment will
support the development of scattered to numerous showers across
the regional waters and portions of the islands.
.AVIATION...Mostly VFR conditions are expected to continue this
morning across the local flying area. Only VCSH due to ISOLD SHRA
expected over the Leewards, USVI and Eastern PR taf sites. East
winds will continue at around 10KT or less but increasing to 10-15
knots after 27/13Z with sea breeze variations. VCSH/VCTS likely at
TJBQ and TJMZ after 27/17Z with TSRA possible at TJMZ after 27/19Z.
Saharan dust will reduce visibilities across some of the local taf
sites during the next 24 hours.
.MARINE...Winds of 10-20 knots and seas of 3-5 feet are expected
across the local waters over the next several days. Small craft
operators should exercise caution across the coastal waters of
Puerto Rico this afternoon due to winds around 20 knots. There is
a moderate risk of rip currents mainly across northern Puerto Rico
and some coastal areas of southeastern Puerto Rico including Culebra
.PRELIMINARY POINT TEMPS/POPS...
SJU 90 81 90 80 / 30 40 40 30
STT 90 80 90 79 / 30 40 40 30