559
FXCA62 TJSJ 052017
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
417 PM AST Wed Feb 5 2025

.SYNOPSIS...

As mentioned in previous discussion, variable weather conditions
will persist during the next several days with passing showers
moving from time to time over windward areas. Breezy conditions
are expected from tomorrow onwards. Localized afternoon
convection is possible across the interior to W-SW PR. Small craft
operators should take action to avoid hazardous seas caused by
breezy conditions, which will continue through the week and into
the weekend. Life- threatening rip currents are possible,
especially along northwestern, northern and eastern Puerto Rico,
Vieques, Culebra and the U.S. Virgin Islands.

&&

.SHORT TERM...Today through Friday...

Variably cloudy skies were observed across the U.S. Virgin Islands
and Puerto Rico today. Trade wind showers were noted this morning
mainly across the eastern and northern sections of PR, where the
Doppler radar estimated between three quarters and an inch of rain
between Isabela and Camuy In the afternoon, quick showers developed
over the interior and western PR, with radar estimates of less than
half an inch of rain. In general, maximum temperatures were in the
low to mid 80s across the lower elevations, to the upper 70s and low
80s across the higher elevations.

For the rest of this afternoon and tonight, the low-level surge of
moisture that brought showers across the islands will be replaced
briefly by a drier air mass from the east. However, cooler air due
to the prevailing ENE trades will promote an advective weather
pattern with showers developing over the coastal waters and moving
at times across portions of the USVI and eastern/northern PR.
Seasonal temperatures will continue under the prevailing east to
northeasterly trades.

A similar weather pattern can be expected for the rest of the
workweek as a building surface high pressure over the western
Atlantic tightens the pressure gradient and brings stronger ENE
trades across the northeastern Caribbean. However, another drier air
mass with minor Saharan dust concentrations will reach the islands
by Thursday night, but this will be followed by a low-level
perturbation on Friday that will increase the areal coverage of
showers across the islands in general.

&&

.LONG TERM...Saturday through Wednesday...
//FROM PREVIOUS DISCUSSION//

A surface high pressure system will be centered northeast of the
area during the weekend, but will extend north of the area early
next week. This will maintain a tight pressure gradient, with breezy
east-northeasterly winds during the weekend, and breezy to locally
windy conditions but with a more easterly component during the first
half of next week. These winds will keep an advective pattern with
patches of moisture reaching our area from time to time, increasing
the frequency of passing showers across the windward sections of the
islands. A series of weak mid to upper level troughs will maintain
some instability aloft during the weekend, allowing the moisture
layer to extend from the surface up to just under 500mb.
Precipitable Water (PWAT) values will fluctuate between 1.1 and 1.6
inches during the weekend, with the passage of the moisture patches.
This will help boost the rainfall pattern during the afternoons,
with an increase in convective activity.

Relatively drier conditions will follow early next week as a mid
level ridge builds just north of our area. However, patches of
moisture will continue to stream across the area from time to time.
Precipitable Water (PWAT) will range from 1.1 to 1.4. Temperatures
will continue near seasonal levels during the period with highs
ranging from the low to mid 80s across lower elevations (locally
higher over W-SW-S PR). Minimum temperatures can reach the upper 50s
to 60s across higher elevations, and from the low to mid 70s across
lower elevation of the islands. Patchy fog are possible during the
overnight to early morning hours across the interior valleys of
Puerto Rico.

&&

.AVIATION...
(18Z TAFS)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, trade wind SHRA could move at
times across the USVI/eastern PR terminals through 06/13z. The
05/12z TJSJ sounding indicated ENE winds at 9-18 kt blo FL050.

&&

.MARINE...

A surface high pressure over the western Atlantic migrating eastward,
will maintain moderate to fresh east-northeast winds. As this high
builds, winds will become stronger by the latter part of the workweek
and the upcoming weekend. As a result,choppy seas and hazardous
conditions for small crafts are expected across the offshore
Atlantic, while choppy seas will persist elsewhere.

&&

.BEACH FORECAST...

A moderate rip current risk will continue for the rest of the week
in most exposed beaches. Specific north-facing beaches, and other
less sheltered coastal areas may present a higher danger to
swimmers and beachgoers. Beachgoers must stay alert and avoid
dangerous waters. For more information please refer to the latest
Surf Zone Forecast (SRFSJU).

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory until midnight AST Sunday night for AMZ711.

     Small Craft Advisory from 6 AM Thursday to midnight AST Sunday
     night for AMZ723.

     Small Craft Advisory from 6 PM Thursday to noon AST Friday for
     AMZ733-741.

&&

$$

SHORT TERM...DSR/MMC
LONG TERM...ICP/KML
AVIATION...DSR
MARINE...LIS
BEACH FORECAST...MMC