National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXCA62 TJSJ 112022
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
422 PM AST Thu Apr 11 2024

.SYNOPSIS...

Breezy conditions expected through Saturday, bringing passing
showers and gusty winds. Over the next 24 hours remnants of an
old front will move across the region lasting through early
Saturday until a drier air mass arrives, causing drier conditions
through Monday morning. During midweek next week, an upper-level
trough and higher moisture content is expected to increase shower
and thunderstorm activity across the islands. Hazardous seas and
life threatening rip currents will continue for the next few days.

&&

.SHORT TERM....Tonight through Saturday...

Breezy conditions prevailed through the day with plenty of passing
showers that according to radar estimates they provided up to 2
inches of rain near Vega Baja this morning and then during the
afternoon convection brought so far up to an inch and a half to
sections near Moca. Easterly winds remained steady between 15-20
mph throughout the day and temperatures were in the low 80s across
coastal regions and were slightly lower across higher elevations.

A broad surface high pressure over the western-central Atlantic will
continue to drive moderate to strong trades across the islands,
bringing showers throughout the night mainly for coastal sections of
eastern Puerto Rico and the USVI. The arrival of moist airmass
throughout tomorrow morning will enhance the amount of showers,
providing a better chance for ponding of water and minor flooding
across urban coastal areas. Into the afternoon hours showers are
forecast to spread across the interior to western sections of PR,
bringing persistent rain with the assistance of local effects. A
mid to upper- level ridge and trade wind inversion together
centered over the Greater Antilles will help prevent any heavy
convective activity, however isolated areas may receive a
noticeable amount of rain throughout this period.

Tomorrow is appearing to be the wettest day of the short term
with precipitable water values reaching a standard deviation above
normal. However, on Saturday the arrival of drier air from the
east will reduce the amount of posible rainfall. With the
continuation of breezy easterly winds there will still be plenty
of passing showers yet not as much as Friday. Temperatures will be
slightly cooler across coastal regions during these days as windy
conditions keep the air a bit fresher.

&&

LONG TERM...Sunday through Thursday...

Fair weather conditions are expected to prevail on Sunday as a drier
air mass moves briefly over the region. However, diurnally induced
afternoon showers are expected to develop over portions of the
southwestern quadrant of Puerto Rico. Seasonable temperatures are
expected to prevail through early next week. Weakening of the
surface ridge is expected by Monday, and winds speeds will
decrease in general as a front approaches from the northwest, but
remains well north of the region. At the same time and through
midweek, a strong upper level trough is expected to linger over
the region. In response, an induced surface trough is expected to
develop over the eastern Caribbean and promote moisture pooling
over the islands. Therefore, the potential for thunderstorm
activity will increase, as well as for flooding rains as a wetter
and unstable pattern evolves through at least Wednesday night.
Model guidance suggest a quick drying trend from Thursday onwards.

&&

.AVIATION...
(TAFs 18z)

Mainly VFR conditions expected through the forecast cycle. SHRA ovr
ctrl mtn range, spreading to S and SW PR may cause brief MVFR conds
at JPS. Passing SHRA may affect JSJ/IST/ISX. E winds 15 to 20 knots
with higher gusts, becoming at 10 to 15 knots overnight.


&&

.MARINE...

A surface ridge now extending into the central Atlantic
will continue to generate fresh to locally strong east-
northeasterly winds into the weekend. This will bring periods of
passing showers and gusty winds across the regional waters.
Northerly swells will continue to spread across the Atlantic
waters and passages through tonight. The wind and swell
interaction will maintain confused, hazardous seas for small craft
over the next few days.

&&

.BEACH FORECAST...

Breezy winds and a long-period northerly swell is causing
dangerous swimming conditions, due to large breaking waves of up
to 10 feet, higher at times, and strong rip currents. Given these
conditions, a High Surf Advisory and High Rip Current Risk are in
effect for the northwest to northeast beaches of Puerto Rico,
Culebra, and the northern US Virgin Islands, where localized minor
beach erosion is possible. Across Vieques and St. Croix, there is
a High Rip Current Risk in effect. For detailed information,
please refer to the Coastal Hazard Message (CFWSJU) and Surf Zone
Forecast (SRFSJU). The high risk of rip currents will continue
through the weekend across the north-facing beaches of the
islands.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Saturday afternoon for PRZ001-002-
     005-008-010-012.

     High Surf Advisory until 6 PM AST this evening for PRZ001-002-
     005-008-010-012.

     High Rip Current Risk through Friday afternoon for PRZ013.

VI...High Rip Current Risk through Saturday afternoon for VIZ002.

     High Surf Advisory until 6 PM AST this evening for VIZ001.

     High Rip Current Risk through Friday afternoon for VIZ001.

AM...Small Craft Advisory until noon AST Saturday for AMZ711-712-723-
     733-741.

     Small Craft Advisory until 6 AM AST Saturday for AMZ716-726-742.

&&

$$

CAM/YZR/RC