045
FXCA62 TJSJ 010124
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
924 PM AST Sun Jun 30 2024

.UPDATE...Up to 2.5 inches of precipitation were seen across
Anasco this afternoon accompanied by frequent lightning and 50 Kft
tops. Rainfall was limited to less than 0.75 inches just southwest
of the Greater san Juan Metropolitan area.

Showers have cleared off of the land areas as a patch of
drier air moves through. A few showers were seen along the slopes
of El Yunque nevertheless. Another patch of moisture is expected
later tonight and during the early morning hours with most showers
confined to the local waters and eastern Puerto Rico. Dust has
reduced some visibilities to as little as 8 SM as Saharan air
flows north around Major Hurricane Beryl. This Saharan airmass has
been particularly brutal on Saint Croix where another record high
temperature for the date (92 degrees) was set. Warm temperatures
are expected to persist through Monday before some showers and
moisture from Major Hurricane Beryl bring some relief.

No changes to the forecast were introduced.

&&

.PREV DISCUSSION... /issued 503 PM AST Sun Jun 30 2024/

SYNOPSIS...

A dry air mass and subsidence ahead of Major Hurricane Beryl will
limit rain activity through Monday afternoon. The most outer bands
of Beryl could bring squally weather across the U.S. Virgin
Islands and Puerto Rico from late Monday night into Tuesday.
Marine and coastal conditions will gradually deteriorate across
the Caribbean and local passages as Major Hurricane Beryl moves
far to the south across the Caribbean Sea. Stay tuned for updates
on this storm and the Invest 96L, which the National Hurricane
Center monitors.

SHORT TERM...Tonight through Tuesday...

A breezy trade wind pattern will continue as a robust surface high
across the Atlantic Basin and Hurricane Beryl stream trade winds
across the region. Due to this passing showers remain possible
across eastern Puerto Rico and the USVI during the night. By
tomorrow a dry air mass that is preceding the moisture field of
Beryl and strong subsidence ahead of the strong will be present
across the area, limiting rainfall to brief passing showers and
causing hot, muggy conditions. However by the evening hours into the
night, conditions are expected to deteriorate as the hurricane moves
into the eastern Caribbean basin.

An increase of wind speeds and passing showers will focus heavy
rainfall at times across the southern to eastern half of Puerto Rico
including the USVI as Beryl moves well south of the region,
currently projected to be over 200 miles south of islands by Tuesday
morning. Squally weather is possible and could bring impressive
thunderstorm activity that could cause flooding and wind impacts.
This pattern will last through Tuesday evening as the system moves
westward further away from the area. Following this, drier air fills
in behind the storm by Tuesday night causing a dry pattern to
prevail before the next system later in the week.

The greatest impacts to our islands from Beryl will be across the
southern and eastern coastal waters that will experience chaotic
seas due to a strong swell on Tuesday. This will cause very
hazardous coastal conditions with strong breaking waves in excess of
10 feet at times. Strong winds will also be present throughout this
time and as mentioned, thunderstorms and heavy rain will likely be
present as well. Stay vigilant as we approach Tuesday and stay
informed with the latest forecast.

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 cyclone
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...
(00Z TAFS)

VFR conds will prevail across terminals during the next 24 hrs.
Convection will develop tomorrow, btwn 01/15z-22z, due to local
effects and stronger than usual wind flow. The earliest that the
most-outer bands of Beryl may reach the local flying area is aft
01/23z. Land breezes of less than 10 will prevail overnight but
not all locations will be free from increasing easterly flow.
Expect E winds at 15-20 kt with gusts up to 30 kt possible and sea
breeze variations after 01/13z.

MARINE...

The strong surface high pressure across the Central Atlantic will
continue to promote moderate to locally fresh easterly winds over the
islands. The latest National Hurricane Forecast trajectory moves
Major Hurricane Beryl far to the south of the regional waters late
Monday night into Tuesday, deteriorating marine and coastal
conditions considerably, especially for the Caribbean Waters and
Passages. The outer bands of Beryl may produce squally weather during
that time.

BEACH FORECAST...

Swells from Beryl will create life-threatening rip currents along
the south-facing beaches of Puerto Rico and the U.S. Virgin
Islands from Monday afternoon onward. High surf along coasts with
southern exposure is possible beginning on Tuesday.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory from 6 PM Monday to 6 PM AST Tuesday for
     AMZ711-735.

     Small Craft Advisory from 6 AM Monday to 6 PM AST Tuesday for
     AMZ723-733-741.

&&

$$

SHORT TERM/MARINE...WS
LONG TERM....RC
UPPER AIR...MMC
PUBLIC...GRS