393
FXCA62 TJSJ 030912
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Wed Jul 3 2024

.SYNOPSIS...

Dry weather conditions and the presence Saharan Dust will promote
hazy skies and hot conditions today. Above-normal temperatures in
combination with the available moisture will result in warm to
hot heat indices. Therefore, a Heat Advisory will be in effect for
portions of Puerto Rico and St. Croix. A tropical wave (Invest
96L) is expected to approach the area tonight, enhancing the
potential for showers and isolated thunderstorms across the
region.

&&

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

Calm weather conditions prevailed overnight, with warmer-than-normal
low temperatures across Puerto Rico and the U.S. Virgin Islands.
Additionally, we had variably cloudy skies due to a mid- to upper-
level cloud deck associated with Major Hurricane Beryl, located
south of Hispaniola. The winds were mainly from the east to east-
northeast at 10 mph or less. Additionally, a drier air mass with
suspended Saharan dust particles began producing hazy skies and
limiting rain activity across the region.

The mid to upper-level clouds and the suspended dust particles limit
the nighttime cooling, resulting in warmer-than-normal low
temperatures. Thus, we can expect maximum temperatures to rise to
near or above-normal values today. The arrival of a Saharan Air
Layer will reduce the available moisture, but the lingering moisture
will still lead to warm and hot heat indices. This has prompted a
Heat Advisory for most of the coastal areas and western sections of
Puerto Rico and St Croix. Virgin Islands. However, expect a few
trade wind showers across the windward sections and isolated to
scattered afternoon showers across the interior and western PR.

A tropical wave, the Invest 96L, will cross the Lesser Antilles
later today, with its leading moisture arriving late tonight across
the local islands. The wave`s axis should cross the region around
early Thursday morning, promoting an unstable weather pattern
through the 4th of July. This wave may bring strong thunderstorms,
producing downpours and frequent lightning, especially during the
day and afternoon of the 4th. Urban and small stream flooding may
also be observed. Residents and visitors should monitor the weather
conditions for additional updates.

The wave`s trailing moisture will linger across the regions through
Friday morning, when additional suspended dust particles from the
African deserts will arrive, creating hazy skies once more. However,
the interaction of the available moisture and the dust particles
will enhance the formation of afternoon and evening convection,
especially across western PR and the surrounding waters.  A drier
air mass with Saharan Dust Particles will result in hazy skies
affecting visibilities, lowering them around 6 SMi. SHRA/TSRA could
develop across the interior and western PR between 03/17-21z. A
tropical wave will deteriorate weather conditions after 04/06z
onward. The winds will remain calm to light and variable through
12z, returning from the E to ENE at 15-20 kt with gusts between 20
and 30 kt and sea breeze variations.

LONG TERM...Saturday through Wednesday...

A strong high pressure located in the central Atlantic will maintain
the wind flow from the east southeast for most of the long-term
period. Dry conditions are expected to prevail for the first half
of the period as a drier airmass moves into the region with
moderate to high concetrations of Saharan Air Layer (SAL). Hazy
skies will dominate until at least Monday, resulting in lower
visibilities. Very hot conditions are expected too, with
temperatures rising to the 90s along the coastal and urban
portions of the islands. This in combination with the available
moisture will result in higher heat indices across the region
surpassing the mid 100s. By the second half of the period a
vigorous tropical wave is anticipated to approach the local
islands. The precipitable water content analysis suggest values
between 1.90 to 2.15 inches from Tuesday to Wednesday. This wave
will move relatively fast across the region on Tuesday. Moderate
to heavy showers and isolated thunderstorms are expected across
the western and northwestern portions of Puerto Rico during the
afternoon hours. The US Virgin Islands can expect passing showers
throughout the morning hours and isolated shower activity during
the afternoon. After wave passage, a drier pattern will establish
and will persist through the week.

&&

.AVIATION...

(06Z TAFS)

A drier air mass with Saharan Dust Particles will result in hazy
skies affecting visibilities, lowering them around 6 SMi. SHRA/TSRA
could develop across the interior and western PR between 03/17-21z.
A tropical wave will deteriorate weather conditions after 04/06z
onward. The winds will remain calm to light and variable through
12z, returning from the E to ENE at 15-20 kt with gusts between 20
and 30 kt and sea breeze variations.

&&

.MARINE...

Fresh to locally strong easterly winds will continue today as Major
Hurricane Beryl continues moving westward across the Caribbean Basin
south of Hispaniola. This will cause hazardous marine and coastal
conditions to prevail especially for the Caribbean Waters and
Passages. A tropical wave will move across the Eastern Caribbean
later today, deteriorating the local weather and marine conditions
late tonight into Thursday.

&&

.BEACH FORECAST...

Coastal condtions will gradually improve as Hurricane Beryl
continues to move westward. A high risk of life-threatening rip
currents remain in effect until this afternoon for southern Puerto
Rico. Elsewhere, a moderate risk of rip currents is in effect.

&&

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

     High Rip Current Risk through this afternoon for PRZ003-007-011.

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

AM...Small Craft Advisory until 6 AM AST early this morning for
     AMZ711.

     Small Craft Advisory until 6 AM AST Thursday for AMZ723-733-735-
     741.

&&

$$

SHORT TERM...CAM
LONG TERM....GRS
AVIATION...CAM