Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 280809
Area Forecast Discussion
National Weather Service San Juan PR
409 AM AST Tue Mar 28 2017
.SYNOPSIS...A surface low pressure system north of Puerto Rico
will continue to bring a light and moist southerly wind flow
across the region today. A surface trough is forecast move across
the local islands today aiding in the development of showers and
thunderstorms along and to the north of Cordillera Central,
including the San Juan metropolitan through at least tonight.
A drier air mass is expected to encompass the region by mid week.
.SHORT TERM...Today through Thursday...
A surface low pressure system located around 300 miles north of
Puerto Rico early this morning will continue to induce a moist
south to southwesterly flow which in combination with daytime
heating and local effects, will aid in the development of showers
and possible thunderstorms across the northern slopes of Puerto
Rico this afternoon. As has been the last couple of days, the
afternoon activity will be focus mainly across the north and
northeast sections of Puerto Rico including in the vicinity of San
The surface low is expected to move northeast away from the area by
late Wednesday. As it move away from the area, a high pressure
system is expected to take control of the weather locally. As a
result, drier and stable weather conditions are expected to return
to the local area by Thursday.
LONG TERM...Friday through Tuesday...
As the surface low just to the north of Puerto Rico and
Hispaniola continues to move further northeastward into the north
central Atlantic, a ridge will begin to build across the region
late in the work week and during the upcoming weekend. This
feature will bring a northeasterly wind flow and a general dry and
stable weather pattern across the local islands through early in
the weekend. The northeasterly wind flow is expected to produce
seasonable temperatures during this period. An east to east
southeast winds will return to the region from late Saturday
through early next week with more moisture transport to produce an
slight increase in cloudiness and showers across the region and
warmer than normal temperatures across the northern coastal
municipalities of Puerto Rico. No widespread or significant shower
activity is expected at in the foreseeable future.
.AVIATION...Mainly VFR conditions are expected to prevail across all
TAF sites through at least 28/16z. Periods of MVFR conditions can be
expected across TJSJ and TJBQ between 28/16z through 28/22z in SHRA.
Low level winds will continue mainly south at 10 kts or less.
.MARINE...Seas of 3 to 5 feet will continue to prevail across
the Atlantic waters, with seas 2 to 4 feet across the Caribbean
waters. A moderate risk of rip current will continue across the
Atlantic shoreline of Puerto Rico during the next few days. A
northerly swell will arrive across the local waters Wednesday
into Thursday with seas increasing up to 6 feet.
.PRELIMINARY POINT TEMPS/POPS...
SJU 87 77 85 75 / 60 20 20 10
STT 83 74 85 73 / 40 20 40 20