678
FXCA62 TJSJ 300909
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Sun Jun 30 2024

.SYNOPSIS...

Lingering moisture from a tropical wave combined with Saharan Dust
will promote thunderstorm activity over western Puerto Rico during
the afternoon hours. Hurricane Beryl is forecast to rapidly
intensify today as it approaches the Caribbean waters. Marine and
coastal conditions will start to gradually deteriorate across the
Caribbean and local passages as Beryl approaches the area. Stay
tuned for updates associated with this storm.

&&

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

Scattered showers and isolated thunderstorms were noted across the
local waters and over portions of the islands during the night. The
Doppler radar estimated around half an inch of rain over Juncos and
Las Piedras and around a quarter of an inch across St. Thomas and
St. John. Minimum temperatures ranged from the upper 60s to mid-70s
across the higher elevations and from the upper 70s to low 80s
across coastal municipalities. Winds were up to 15 mph from the
east, with gusts around 25 mph across coastal areas.

For today, the lingering moisture from a tropical wave, combined
with the influence of a Saharan Air Layer carrying moderate amounts
of Saharan dust, will promote shower and thunderstorm activity,
mainly across PR throughout the day, with drier conditions expected
across the USVI. The hazy skies and low-level southeasterly winds
will also contribute to hot temperatures across the islands, and a
Heat Advisory (NPWSJU) is in effect for the west, north, and eastern
coastal municipalities of PR and St. Croix. Maximum temperatures should
reach the low 90s across the lower elevations, with general heat indices
ranging between 106F and 112F.

There haven`t been significant changes in the forecast track for
Beryl, which is expected to pass about 200 miles south of the
islands. However, weather conditions will quickly deteriorate
between Monday afternoon and Tuesday as the outer bands from
Tropical Cyclone Beryl bring showers and thunderstorms to the local
area. Squally weather with strong gusty winds is possible across
portions of the Caribbean waters, the US Virgin Islands, and
eastern/southern Puerto Rico through Tuesday.

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

After the passage of Hurricane Beryl south of the local area, a
drier airmass will quickly move over the islands. This drier airmass
will promote stable conditions on Wednesday with limited shower
activity. However, by Thursday onwards tropical activity is expected
once again.

The National Hurricane Center (NHC) is currently monitoring an area
of low pressure located over the eastern Atlantic with a medium to
high formation chance over the next 7 days. Latest model guidance
suggest that this system will develop as a tropical storm or
hurricane before reaching the Lesser Antilles. Nonetheless, this
system should remain south of the islands and over the Caribbean
waters. At this moment some of the potential indirect impacts
associated to this low are: localized flooding, gusty winds,
squally weather, and deteriorated marine and coastal conditions.
It is too early at this moment to determine the amount of expected
rain. Therefore, residents and visitors of Puerto Rico and the
U.S. Virgin Islands may continue to monitor the progress of this
system as it moves towards the Caribbean. A vast moisture field of
this low will persist across the region once it departs on
Saturday, promoting afternoon convective activity across the
western portions of Puerto Rico. Following the system, more drier
air and Saharan Dust particles will take over, enhancing stable
and dry conditions for few days. Despite of the expected weather,
high temperatures will remain between the upper 80s to low 90s
across the islands with heat indices surpassing the mid 100s.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions expected across all terminals. However,
SHRA/TSRA expected to develop due to a departing tropical wave may
cause tempo MVFR conds at TJSJ/TJBQ btw 30/16-22z. HZ due to Saharan
dust expected but VSBY should remain P6SM. East winds at 12-16 kt
with stronger gusts and sea breeze variations aft 30/14z.

&&

.MARINE...

A surface high pressure over the central Atlantic will promote
moderate to locally fresh easterly winds over the next few days,
bringing trade wind showers. Hurricane Beryl is forecast to
strengthen as it approaches the Caribbean waters late Monday night
into Tuesday, deteriorating marine and coastal conditions
considerably for the Caribbean and local passages.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon
     for PRZ001-002-005-008-010-012-013.

VI...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon
     for VIZ002.

AM...None.
&&

$$

SHORT TERM...DSR
LONG TERM....GRS