Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 220930
Area Forecast Discussion
National Weather Service San Juan PR
530 AM AST Sun Jan 22 2017
.SYNOPSIS...A mid level ridge will prevail through much of the
forecast period, with a brief weakening expected on Tuesday as
a mid to upper level trough moves north of the area. The mid to
upper level trough and associated surface boundary will result in
moisture advection Tuesday-early Wednesday. Therefore, continue
to expect a seasonable weather pattern across Puerto Rico and the
U.S. Virgin Islands with an increase in passing showers on Tuesday.
.DISCUSSION...As the mid level ridge holds across the forecast
area, a generally fair and mainly stable weather pattern will
continue to prevail with a few passing showers possible across
windward areas. The ridge will briefly erode as a broad mid to
upper level trough moves north of the area. The aforementioned
mid to upper level trough and associated surface boundary will
result in moisture advection Tuesday and possibly Wednesday.
However, the bulk of moisture is expected to remain over waters
and east of the forecast area. At lower levels, a high pressure
north of the area will continue to promote a gentle east northeast
wind flow today. Surface winds are expected to become southerly on
Monday as the surface high pressure moves into the central
Atlantic and the boundary approaches from the west. Therefore,
continue to expect a seasonable weather pattern across Puerto Rico
and the U.S. Virgin Islands with limited shower activity through
the forecast period. The chance of passing showers will slightly
increase on Tuesday. Temperatures may increase Monday and Tuesday
under the southerly wind flow.
.AVIATION...VFR conds will prevail thru the forecast period.
SCT SHRA expected across central/western PR after 22/16Z which
could cause VCSH at TJBQ, TJPS, and TJMZ. SCT SHRA also expected
over the waters and near TISX after 22/16Z. Winds from the ENE at
5- 10 KT with sea breeze variations today.
.MARINE...Seas will remain to 3-5 feet today. However...a northwest
swell will reach the local waters...with seas building to 4-6
feet by midweek. There is a high risk of rip currents along the
Atlantic shorelines of Puerto Rico. The high risk of rip currents
will continue to prevail during the next few days.
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 85 74 / 20 20 30 20
STT 83 72 84 75 / 20 40 40 40
PR...High Rip Current Risk through late tonight for Mayaguez and
Vicinity-North Central-Northeast-Northwest-San Juan and