Atlantic Hurricane Season 2024 Storm Names

575
FXCA62 TJSJ 172041
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
441 PM AST Fri Jan 17 2025

.SYNOPSIS...

The remnants of an old frontal boundary will arrive this evening
into Saturday, promoting instability and wetter conditions across
Puerto Rico and the U.S. Virgin Islands. Periods of with moderate
to locally heavy showers are likely mainly over portions of
northern and northeastern Puerto Rico. Pulses of a long-period
northerly swell will promote hazardous marine conditions and life-
threatening rip currents over the next few days. A High Surf Advisory
is now in effect through at least 6 AM AST Saturday due to large
breaking waves between 10 and 13 feet.

&&

.SHORT TERM...Tonight through Sunday...

A dry air mass promoted a sunny day with minimal rain activity
across PR and the US Virgin Islands due to less-than-normal
moisture content. Winds were mainly from the northeast at 10 to 20
mph in windward areas and 5 to 15 mph in leeward locations.
Maximum temperatures ranged from the mid-80s along the coast to
the upper 70s in mountains and valleys. We detected a rope cloud
with the GOES-E visible channel approaching the region and
generating gusty winds across St Croix, St John, and St Thomas.

From now into early Saturday morning, dangerous breaking waves will
create life-threatening rip currents and localized beach erosion
along the north-facing beaches in PR and the Northern USVI.

Sea breeze and local effects will enhance late afternoon convection
across the southwest quadrant of PR. Also, the remnants of the
frontal boundary advected by the prevailing trade winds will
increase shower activity across the islands late this afternoon
into the evening, enhanced by low-level convergence. Under the
weather pattern mentioned above, we expect periods of moderate to
locally heavy rain, producing ponding of water in roads and poorly
drained areas, especially across windward locations. As a result,
the wettest period will prevail between late tonight through
early Saturday morning.

Due to local effects, additional shower development may occur over
the interior and western regions of Puerto Rico by Saturday
afternoon. As the mid-level ridge strengthens later in the short-
term forecast period, increased stability in the atmosphere is
expected to reduce the frequency of showers. However, enough low-
level moisture will remain to support isolated to scattered
showers on Sunday morning. These showers will likely have light to
moderate intensity, mainly confined to windward locations. They
are not expected to pose any flooding threat.

&&

.LONG TERM...Monday through Friday...
.PREV DISCUSSION... /issued 402 AM AST Fri Jan 17 2025/

The upcoming workweek will begin with drier and stable weather
conditions across the local islands as pockets of drier air filter
into the region from the east. The latest precipitable water content
analysis suggest values to remain between normal to below-normal
(1.0 to 1.2 inches) throughout the period. However, periods of
isolated to scattered showers are anticipated as small patches of
moisture moves into the area at times.

At the mid-levels, a strong mid-level ridge will establish over the
region promoting drier air and stability aloft. At the surface, a
dominating surface high pressure in the central Atlantic will
promote an easterly wind flow through Wednesday. With the
aforementioned weather scenario, limited showers activity is
expected through the latter part of the week.

As the surface high pressure migrates from the central to eastern
Atlantic, winds will begin to shift from the southeast. Under this
pattern an increase in precipitable water is expected with values up
to 1.6 inches. By late Wednesday into Thursday, an upper-level low
is expected to migrate east of the islands and promoting unstable
conditions through the rest of the period. With this environmental
setting, isolated to scattered showers are likely over eastern
Puerto Rico and the U.S. Virgin Islands during the morning hours
and over the interior in the afternoon.

A warmer trend continues for the long-term weather outlook with
above-than-normal temperatures to remain for several days. Daytime
highs are expected to reach the mid to upper 80s in coastal and
lower elevations, while the mountains will experience highs in the
mid to upper 70s.

&&

.AVIATION...
(18Z TAFs)

VFR conditions will prevail today. However, the remnants of an
old frontal boundary will result in gusty winds and showery
weather, especially at local TAF sites, through this evening. The
SHRA/-SHRA will focus on the eastern third of PR and the USVI,
mainly affecting JSJ/IST/ISX. An occasional brief period of MVFR
conditions cannot be ruled out. Winds will prevail mainly from the
ENE at 10-20 kt with higher gusts and sea breeze variations,
becoming calm to light and VRB after 18/00z but accelerating once
again after 18/13z.

&&

.MARINE...

High pressure building across the western Atlantic will support
moderate to locally fresh east to northeast trades tonight. Winds
will turn more easterly during the weekend. Another pulse of a
northerly swell will continue to spread across the Atlantic waters
and local Caribbean passages tonight, and linger through the
weekend. This swell will promote hazardous seas and small craft
advisory conditions once again.

&&

.BEACH FORECAST...

Pulses of long-period northerly swell will continue to pose
significant risks for coastal activities throughout the weekend.
A High Surf Advisory is now in effect through at least 6 AM AST
Saturday due to large breaking waves between 10 and 13 feet along
the northwest to northeast coast of Puerto Rico, Culebra, and the
northern U.S. Virgin Islands. Residents and visitors in affected
regions should heed warnings, avoid swimming in these waters, and
stay informed about updates from local authorities.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Saturday night for PRZ001-002-
     005-008-010-012-013.

     High Surf Advisory until 6 AM AST Saturday for PRZ001-002-005-
     008-010-012.

VI...High Rip Current Risk through late Saturday night for VIZ001.

     High Surf Advisory until 6 AM AST Saturday for VIZ001.

AM...Small Craft Advisory until 6 AM AST Sunday for AMZ711-712-716-
     723-726-741-742.

&&

$$

SHORT TERM/AVIATION...CAM/ICP
LONG TERM....GRS
MARINE/BEACH FORECAST...ICP/YZR
PUBLIC...YZR

NWS SJU Office Area Forecast Discussion