Advisory NPW Special Advisory — Mon Sep 30, 2024 11:57 AM

NPWSJU) is in effect for
portions of northern and western PR, and St. Croix.

The precipitable water (PWAT) content is expected to peak today
between 2.00-2.20 inches, with a drying trend expected from late
Tuesday and Wednesday as the layered ridge over Bahamas sinks
southwards over Hispaniola and into the local area. PWAT is expected
to bottom out between 1.40-1.70 inches by early Wednesday morning.

LONG TERM...Thursday through Monday...

On Thursday, a weak mid-level high pressure over the western
Atlantic will sink further into the north-central Caribbean.
Additionally, 500 mb temperatures will warm between -3 and -4
degrees. This could potentially inhibit convective activity across
the forecast area. However, moisture content is expected to
increase. Model guidance suggests precipitable water content will
surge above 2.0 inches, even reaching up to 2.2 inches, which is
near to above the climatological normal. Therefore, expect shower
activity across interior Puerto Rico with a few very isolated
thunderstorms.

Afterwards, winds at the surface will remain light from ENE until
Saturday due to a ridge to our west/northwest and a tropical cyclone
over the far Tropical Atlantic, becoming variable by Sunday onwards.
With a surge in low-level moisture and a mid-to-high level trough
moving into the northeastern Caribbean by the end of this week into
the weekend, shower and thunderstorm activity will increase once
again mainly over the interior and southern sections of the islands
for the forecast period. Slow moving showers will enhance rainfall
accumulations across the area. Hence, a limited to elevated flooding
risk can be anticipated. Ponding of water in roadways and poorly
drained areas are likely, with urban and small stream flooding
across interior Puerto Rico during the afternoon hours.

Then, a mid-level ridge will move eastward and settles over the
forecast area by Monday inhibiting shower activity for the most
part. The combination of limited shower activity, clear skies, and
subsidence aloft will promote hot temperatures for early next
week. Limited to elevated heat risk will prevail for coastal and
urban areas of PR and USVI.

AVIATION...
(06Z TAFS)

Mainly VFR conditions expected across all terminals through the
forecast period. However, diurnally induced afternoon SHRA/TSRA
could lead to tempo MVFR to brief IFR conds at TJPS/TJBQ btw 30/18z-
22z. VCTS is possible across the rest of the terminals. Easterly
winds expected up to 12 kt with sea breeze variations aft 30/14z.

MARINE...

A high pressure system over the western Atlantic will maintain
light to gentle northeast to easterly winds. Seas will remain around
3 to 5 feet over the next few days. Showers and thunderstorms remain
possible across the regional waters through the week.

BEACH FORECAST...

Nearshore buoys are indicating breaking waves of 6-8 feet with
swell action continuing through at least this afternoon.
Therefore, a High Rip Current Risk (CFWSJU) is in effect for the
northeast to northwestern beaches of Puerto Rico, including
Culebra.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk until 6 PM AST this evening for PRZ001-002-
     005-008-010-012.

     Heat Advisory until 5 PM AST this afternoon for PRZ001-005-008-
     010.

VI...Heat Advisory until 5 PM AST this afternoon for VIZ002.

AM...None.

&&

$$