Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 050920
Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Mon Dec 5 2016
.SYNOPSIS...Showers embedded in the trades at times as well as
locally induced afternoon showers across west Puerto Rico still
expected each day under a mid level ridge and available low level
.DISCUSSION...Partly cloudy skies prevailed across the local
islands during the overnight and early morning hours. Isolated to
scattered showers were observed across northern and eastern
Puerto Rico but the accumulations were minimal. Overnight minimum
temperatures ranged from the low 70s to the upper 70s across the
lower elevations and in the mid to upper 60s across the higher
elevations. Winds over land were mainly light and variable.
Although a developing upper level trough will prevail much of
this week across the eastern Caribbean, a seasonable weather
pattern will continue to prevail under a mid level ridge which
is expected to hold during the next several days. Moisture
advection will continue at times as a building surface high north
of the area brings remnants of old frontal boundaries over the
Therefore, showers embedded in the trades are expected at times
each day with the potential for locally induced afternoon convection.
Due to the lack of forcing associated with the mid level ridge
and building high north of the area, afternoon showers are expected
to be shallow and focused across west and southwest Puerto Rico
each day. The aforementioned weather pattern is expected to prevail
much of this week. Due to already saturated soils, sharp raises
along small streams and rivers still possible. A wet pattern could
be expected Friday and into the upcoming weekend as a surge of low
to mid level moisture moves across the eastern Caribbean.
.AVIATION...VFR conditions are expected across all terminals for
the next 24 hours. VCSH possible at TJSJ and TIST through
05/13Z.SHRA developing across interior, Western and SW-PR causing
VCSH at TJMZ, TJBQ and TJPS after 05/17Z. East winds of around 10
kt expected with sea breeze variations developing after 05/13Z.
.MARINE...Tranquil marine conditions will continue to prevail across
the regional waters today. Mariners can expected winds 10-15 kt
and seas of 3-5 feet across Atlantic waters. Elsewhere, seas will
remain below 4 feet. A northerly swell is expected to invade the
Atlantic waters and Caribbean passages tonight into Tuesday,
increasing seas up to 6 feet.
.PRELIMINARY POINT TEMPS/POPS...
SJU 86 77 86 76 / 20 40 40 30
STT 86 76 86 76 / 20 20 20 30