985
FXCA62 TJSJ 271502 CCA
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
418 AM AST Thu Jun 27 2024

.SYNOPSIS...
A low to mid -level trough will enhance moisture
levels, leading to increased shower coverage across the local
area. this will result in a few showers affecting the coastal
region of Puerto Rico and the U.S. Virgin islands. On Thursday
night, a high pressure system over the mid -Atlantic will
strengthen over the local region, creating dry and stable
conditions across the area through at least Saturday, until the
next Wave moves in. Moisture associated to this tropical wave
will increase the shower and cloud coverage through Sunday. At
this moment the National Hurricane Center is monitoring a vigorous
tropical wave with a moderate to high chance chance of formation
in the long term. Residents in Puerto Rico and the U.S. Virgin
Islands should always stay tuned with the latest information using
official sources.

&&

.SHORT TERM...Today through Saturday...

Passing showers were noted across portions of the islands during the
overnight hours. Minimum temperatures were from the upper 60s to mid
70s across the higher elevations, and from the upper 70s to low 80s
across coastal areas. Winds were light from the east to northeast.
Scattered showers and isolated thunderstorms were increasing over
the offshore Atlantic waters after 3 AM.

A gradual increase in moisture content is expected through the short-
term period as a low-to mid-level trough moves across the
northeastern Caribbean today and a tropical wave on Saturday. A 700-
500MB ridge north of the region will promote northeasterly steering
winds, while mainly easterly trades prevail at the surface due to
the broad surface high pressure over the central Atlantic. This will
cause showers and thunderstorms to develop mainly over the interior
and south/southwestern sections of Puerto Rico through Friday, and
an advective pattern will prevail with passing showers across the
USVI and the east/northeast sections of PR each day, with increasing
shower and thunderstorm activity on Saturday. Urban and small stream
flooding is possible each afternoon over western PR.

Saharan dust will diminish today across the area, but hazy skies can
still be expected. It will be hot again across the islands and a
Heat Advisory (NPWSJU) was issued for Puerto Rico and the U.S.
Virgin Islands once again. Maximum temperatures should reach the low
90s across most coastal municipalities with heat indices reaching or
exceeding 110F. Easterly winds around 15 mph with stronger gusts are
expected during the day.

&&

.LONG TERM...Sunday through Thursday...

The long term forecast is based on the forecast trajectory of a
couple of tropical disturbance that area expected to move south
of the local area. We are currently monitoring two tropical weather
systems. The first system has a higher potential for development,
however, a high pressure area will keep it positioned well to the
south of our region. The second tropical wave is not forecasted
to develop as significantly,but models suggest it will be located
somewhat closer to the local region. While it might initially
appear that neither of these systems will have a direct impact on
our area, they will indeed indirectly affect us. Both systems
will lead to increased cloudiness and higher likelihood of rain.
Our primary concern, however, is the hazardous marine conditions
anticipated, particularly in the Caribbean Sea, due to the
forecasttrack of both systems. The first wave now Invest 95L is
forecast between late Monday and Tuesday and the second wave is
forecast to move south of the area between Wednesday and Thursday.


&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, MVFR conds are possible across
the area terminals btw 27/15z-22z as a trough streams over the area
from the east. East winds expected at 12-16 kt with stronger gusts
and sea breeze variations aft 27/14z.

&&

.MARINE...

A surface high pressure over the central Atlantic, extending all
the way to the Caribbean, will hold a moderate easterly wind
pattern across the region. Therefore, seas will remain between 3
and 4 feet, even less for the coastal waters. By the beginning of
the upcoming workweek, building seas are forecast as a vigorous
tropical wave, now monitored by the National Hurricane Center,
moving over the Caribbean Waters, increasing the seas to 8 feet.
Mariners should keep track of the tropical forecast for further
updates on the expected conditions. Also, regarding the moisture
field that accompanied the tropical wave, the forecast calls for
thunderstorm activity, which could lead to even more localized
hazardous conditions. For the coastal areas, the risk of rip
currents will continue to moderate for some areas and low for the
rest of the areas.



&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

$$

SHORT TERM...DS
LONG TERM....EM
AVIATION...DS