Advisory NPW Special Advisory — Tue Aug 27, 2024 5:15 AM

NPWSJU) was issued for portions of the islands. Please refer to the
latest NPWSJU for detailed information.

For Wednesday, a drier air mass will move from the east and across
the islands through midday, the precipitable water content is
expected to drop below normal values around 1 to 1.50 inches with
fair weather conditions prevailing through most of the day. However,
moisture picks up quickly before sunset as a tropical wave streams
across the local area, increasing PWAT values between 2-2.25 inches
through the night. Therefore, a late onset of afternoon showers with
isolated thunderstorms is still expected to develop downwind of the
USVI, and across the eastern interior and western PR. Also, a wind
surge and a weak Saharan Air Layer will accompany the wave passage,
and periods of hazy skies can be expected. On Thursday, moderate to
locally fresh trade winds with a slight ENE wind component from a
700 mb high near 28N are expected to promote passing showers with
light rainfall amounts across the USVI, and favor the development of
diurnally induced afternoon showers with iso thunderstorms over
west/southwest PR.

.LONG TERM...Friday through Tuesday...

A low to mid-level ridge will anchor across the western Atlantic
during the long-term forecast period. The forecast area will remain
on the southern to southwestern edge of this ridge, resulting in
marginal instability aloft. However, a series of tropical waves and
surface perturbations will sustain moisture levels from normal to
above normal, particularly from this weekend onward, with
precipitable water fluctuating between 1.75 inches and nearly 2.20
inches at times. This weather setup will lead to variable conditions
across the region, with the development of showers and thunderstorms
highly dependent on the prevailing wind steering flow. Orographic
factors will also play a significant role, particularly in driving
diurnal convection, which could enhance storm activity in certain
areas.

As a result, localized weather patterns may vary, with some regions
experiencing more frequent and intense showers. Model guidance
suggests the highest rainfall accumulations are expected across
interior and western Puerto Rico. Therefore, a limited to elevated
flood threat is anticipated each day of the long-term forecast. With
frequent showers in some areas, quick river rises, river flooding,
and landslides are likely.

The National Hurricane Center (NHC) is monitoring an active area
across the central tropical Atlantic with a low probability of
tropical cyclone formation in the next seven days. While it`s too
early to determine any potential impact on our forecast area, its
advisable to stay informed, especially as we enter the peak of
hurricane season.


&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, trade wind SHRA could move at
times across the USVI and eastern PR terminals throughout the day.
Afternoon SHRA/TSRA is expected to develop btw 27/18z-22z in the
vcty of TJSJ/TJPS/TJBQ. This may cause tempo MVFR conds and mtn tops
obscd. East winds expected at 8-15 kt with locally higher gusts and
sea breeze variations aft 27/14z.

&&

.MARINE...

Surface high pressure over the Atlantic and a weak surface trough
will promote moderate east winds through most of the work week.
Passing showers will move across the coastal waters, mainly during
the overnight and early morning hours, followed by afternoon shower
development mainly downwind of the local islands each afternoon, with
strongest activity moving over the Mona Passage. The coverage of
showers and thunderstorms across the local waters and passages are
forecast to increase by this afternoon.

&&

.BEACH FORECAST...

Rip current risk has continued to diminish with a moderate risk
of rip currents across the northern and northwestern coast of
Puerto Rico. Low risk elsewhere, however, life- threatening rip
currents often occur in the vicinity of groins, jetties, and
piers.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon
     for PRZ005-007-008-010-011.

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

AM...None.
&&

$$