916
FXCA62 TJSJ 231329
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
929 AM AST Sun Feb 23 2025

.UPDATE...
Minor changes were introduced to the forecast. The Small Craft
Advisory starting time was moved 6 hours earlier for the coastal
waters of northern Puerto Rico based on current observations from
the offshore Atlantic buoys. So far, seas of 8 to 9 feet were
observed offshore, and up to 6 feet nearshore. These conditions
will also result in dangerous breaking waves across the north-
facing beaches of Puerto Rico. Conditions are not favorable for
beach-goers in these areas, and also for Culebra, St. Thomas and
St. John, where a High Rip Current Risk statement is in effect.

Additionally, a Fire Danger Statement was issued for the southern
hills, plains, and west coast of Puerto Rico. With stronger winds
and low relative humidities, conditions will be more favorable
for fire spreading.

&&

.PREV DISCUSSION... /issued 659 AM AST Sun Feb 23 2025/

.SYNOPSIS...

A northerly swell will produce life-threatening rip currents
along the north-facing beaches of Puerto Rico today and Monday.
Also, large breaking waves of around 8 to 10 feet are possible
today along northern Puerto Rico. For that reason, a High Surf
Advisory is in effect until this afternoon. Southeasterly winds
return next week, promoting warmer than normal temperatures across
the lower elevations of the islands. Model guidance suggests an
better rain chances by the end of next week, as moisture content
increase with the proximity pre-frontal trough.

.SHORT TERM...Today through Tuesday...

A variable weather pattern persisted during the overnight hours,
with isolated to scattered showers observed across the southeastern
coastal areas of Puerto Rico. Most frequent showers were observed
across the coastal local waters, briefly brushing some coastal areas
and leaving minimal rainfall accumulations. Overnight temperatures
were in the seasonal range, with the mid 70s across the coastal
areas and slightly cooler across the interior and mountains. Winds
remained from the east at 10 mph or less, with some gusty winds near
the strongest showers.

Although some moisture is moving at the northern over the Atlantic
waters, resulting in some showers during the morning, the rest of
the islands will continue to observe mostly sunny skies and limited
rainfall due to the lack of moisture, as suggested by the GOES
satellite-derived PWAT. In the afternoon hours, some showers cannot
be ruled out across the western interior due to the local and
diurnal effects, with minimal rainfall accumulations. For Tuesday,
winds will remain easterly, with mostly brief shallow patches of
moisture leaving the islands under a stable weather pattern. On
Tuesday, a building surface low over the western Atlantic will
enhance East-southeasterly winds across the islands, increasing low-
level moisture. While overall moisture content will remain shallow,
the frequency of trade wind showers will increase, particularly
across eastern Puerto Rico, the U.S. Virgin Islands, and surrounding
waters during the morning, followed by afternoon activity over the
northwestern and interior sections of Puerto Rico. No significant
weather disturbances are expected, but isolated moderate showers may
develop in areas of enhanced convergence.

.LONG TERM...Wednesday through Sunday...

Around midweek, variable conditions are expected, with patches of
moisture leading to rainy periods at times. Global models show
some discrepancies in terms of timing, but overall precipitable
water values are expected to range from seasonal to above normal
for this time of year, between 1.3 and 1.7 inches. Moderate
southeasterly winds (10-15 kt) will persist through the long-term
period, due to a front stretching from the southwestern Atlantic
into the north-central Atlantic, along with a surface high over
the central Atlantic. This shift in winds will likely lead to
warmer temperatures. By the end of the week into the weekend, a
wetter weather pattern is anticipated for Puerto Rico and the U.S.
Virgin Islands due to the influence of an upper-level trough.
Additionally, a pre-frontal trough associated with another
frontal boundary moving from the western Atlantic will increase
moisture over the area, with precipitable water values expected to
range in the above normal levels.

.AVIATION...
(06Z TAFs)

Stable VFR conditions will persist across all TAF
sites during the period, providing a reliable basis for flight
planning. Winds will continue light and VRB until 23/15Z, before
shifting from the E at speeds of up to 15 knots, with sea breeze
variation and occasional gusts. VCSH & SHRA are forecasted near TJBQ
at 23/19Z due to aft conv, leading to lower ceilings and reduced VIS
along the mountains.

.MARINE...

Easterly winds will prevail today while a frontal boundary moves
eastward across the western Atlantic. A long period northerly swell
will deteriorate seas today with Small Craft Advisories in effect
for the Atlantic waters through at least tonight. A surface high
pressure building across the central Atlantic will tighten the local
pressure gradient, promoting moderate to locally fresh winds early
this upcoming week.

.BEACH FORECAST...

A long-period northerly-northwesterly swell will be reaching the
local area today, Therefore, the is a High Risk of Rip Currents
along the northwestern, northern, and east-facing beaches of
Puerto Rico and the northern USVI, Also, High Surf Advisory is in
effect until this afternoon for the same area as large breaking
waves up to 10 feet are possible in the local area today, peaking
at around noon.

&&

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

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

     High Rip Current Risk through late tonight for PRZ010-012.

VI...High Rip Current Risk through late tonight for VIZ001.

AM...Small Craft Advisory until 6 AM AST Monday for AMZ711.

     Small Craft Advisory until 6 AM AST Monday for AMZ712.

&&

$$

ERG/MRR