Rip Current in U.S. Virgin Islands, September 7, 2021

Area Forecast Discussion
National Weather Service San Juan PR
1055 AM AST Tue Sep 7 2021

.UPDATE...Fair weather has prevailed across the local area this
morning. Only isolated and brief showers affected a few areas of
eastern PR, while the USVI remained dry. There has been no updates
to the inherited forecast, except a small correction on the Rip
Current Hazard, to include the northeastern beaches, as the
Pinones beach has a high risk of rip currents today. Afternoon
showers and thunderstorms are still expected, mainly affecting
portions of central to western and southwestern PR, while the
rest of PR and the USVI should remain mostly dry, with a slight
chance of brief showers. Temperatures will be warm to hot once
again. Daytime highs in the 90s across the lower elevations, with
heat index values surpassing 100 degrees in many lower elevations
of PR and the USVI.

&&

.AVIATION...VFR conds expected across the local terminals today.
SHRA/TSRA after 07/17Z could affect the vicinity of TJPS. E-NE
winds at 10-15KT with occasional gusts expected today, with a SE
variation at TJPS. Winds to decrease overnight, remaining easterly.

&&

.MARINE...Small craft advisory, and a high risk of rip currents
are in effect. Seas up to 8 feet expected today, increasing up to
10 feet by tonight. No changes in the marine forecast. Surf zone
and marine conditions are hazardous today, and will continue to be
hazardous through Thursday.

&&

.PREV DISCUSSION... /issued 437 AM AST Tue Sep 7 2021/

SYNOPSIS...

Once again, the typical weather pattern is expected, with the
advection of patches of moisture at times and afternoon convection
enhanced by sea breeze variations. Warm to hot temperatures will
persist across Puerto Rico and the U.S. Virgin Islands. A swell
produced by Hurricane Larry will result in a high risk of rip
currents for the north and some of the east-facing beaches.

SHORT TERM...Tuesday through Thursday...

Short term forecast is still on track...A weakening TUTT low will
continue to meander north of the islands through early Wednesday. At
lower levels, as Hurricane Larry continues to lift towards the
Central Atlantic, the steering winds will continue to prevail from
the east northeast. However, on Wednesday, as Larry moves to a
position well north-northeast of the area, the low-level flow will
become east-southeast. The aforementioned wind pattern will enhance
somewhat low level moisture convergence across the local islands.
Nevertheless, precipitable water values over the region are expected
to remain between 1.6 and 1.8 inches which is near normal. As a
result, continue to expect a seasonable weather pattern with locally
induced afternoon showers and thunderstorms across west areas of
Puerto Rico each day. A higher incidence of early morning showers
affecting the USVI and Atlantic coastal areas of Puerto Rico is
possible under the east northeast wind flow throughout the day
today. Some haziness due to Saharan dust particles is possible on
Thursday. Heat indices will again push into the 100s with
temperatures in many areas ranging from the upper 80s to lower 90s.

LONG TERM...Friday through Tuesday

The arrival of a Saharan Air Layer combined with an east to
southeast wind flow will promote warm to hot temperatures across
the islands, with maximum temperatures in the 90s and heat indices
in the 100s Friday and even Saturday. The SAL will remain over
the region through early Saturday, resulting in hazy skies. As the
dry air exit the area, a retrograding TUTT-Low moving across the
Northeast Caribbean will induce surface perturbation through the
weekend, increasing instability and convective activity.
Atmospheric conditions will remain favorable for the development
of rain showers and thunderstorms with the arrival of a negative
tilted tropical wave late Sunday afternoon, with its moisture
lingering through Monday. GFS suggested Total Precipitable Water
ranging between 1.90 and 2.30 inches through Tuesday, but the best
moisture pooling over the islands on Monday.

AVIATION...

VFR conditions are expected at all TAF sites during the forecast
cycle. Northeasterly winds at 10 to 15 knots with higher gusts and
sea breeze variations aft 07/13z.

MARINE...

A swell generated by Hurricane Larry is moving across the local
Atlantic Waters and Anegada Passage. Seas will range between 6 and
10 feet across the Atlantic Offshore Waters and between 3 and 7
across the coastal waters. However, swell periods between 12 and
15 seconds will create breaking waves between 6 and 9 feet across
the north-facing beaches from the northwest coast to San Juan and
vicinity area and the north and eastern shores in St Croix.
Breaking waves will peak by Wednesday when swells between 5 and 7
feet (or even higher) hit the Atlantic shoreline of Puerto Rico
and the northern and eastern shoreline of St Croix.

Small Craft Advisories are in effect for the Atlantic Waters and
local passage through at least mid-week. Then, marine conditions
are forecast to improve Thursday into the weekend.

Beachgoers, Larry's swell is producing dangerous breaking waves,
resulting in a high risk of rip current across the northern
shoreline of Puerto Rico and the north and eastern coast in St
Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  90  80  93  79 /  20  40  40  20
STT  89  79  90  80 /  20  40  20  20

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Thursday afternoon for North
     Central-Northeast-Northwest-San Juan and Vicinity-Southeast.

VI...High Rip Current Risk through Thursday afternoon for St Croix.

AM...Small Craft Advisory until 8 AM AST Wednesday for Anegada
     Passage Southward to 17N-Coastal Waters of Northern USVI
     and Culebra out 10 NM-Coastal Waters of Southern USVI
     Vieques and Eastern Puerto Rico out 10 NM.

     Small Craft Advisory from 8 AM Wednesday to 2 AM AST Thursday
     for Coastal Waters of Northern Puerto Rico out 10 NM.

     Small Craft Advisory until 2 AM AST Thursday for Atlantic Waters
     of Puerto Rico and USVI from 10 NM to 19.5N.

&&

SHORT TERM...JA
LONG TERM....ERG
PUBLIC DESK...FRG

Perspectivas sobre las Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia en San Juan PR
508 AM AST martes 7 de septiembre de 2021

AMZ710>745-PRZ001>013-080900-
San Juan y Vecindad-Noreste-Sureste-Este Interior-Norte Central-
Interior Central-Ponce y Vecindad-Noroeste-Oeste Interior-
Mayaguez y Vecindad-Suroeste-Culebra-Vieques-Las aguas costeras
cercanas y lejanas a la costa del Atlantico y Caribe-
508 AM AST martes 7 de septiembre de 2021

Esta Perspectiva sobre las Condiciones Peligrosas del Tiempo es para
Puerto Rico y las aguas costeras adyacentes del Atlantico.

.Dia Uno...Hoy y esta noche

.Tronadas...Existe el potencial de tronadas con lluvia fuerte y
rafagas de vientos breves esta tarde a traves de sectores del interior,
oeste y suroeste de Puerto Rico.

.Inundaciones...Lluvias fuertes podrian resultar en inundaciones
urbanas y de riachuelos a traves de porciones del oeste, suroeste
e interior de Puerto Rico.

.Olas...Se espera oleaje hasta 8 pies mayormente a traves de las
aguas mar afuera del Atlantico. El oleaje aumentara a 10 pies en estas
aguas.

.Corrientes marinas...Existe riesgo alto de corrientes marinas
para las playas del norte de Puerto Rico. Esta noche el riego
aumenta a alto para las playas del este de Puerto Rico.

.Calor...Se esperan indices de calor entre 102 y 107 grados en las
areas costeras.

.Dias dos hasta el siete...miercoles a lunes

Se esperan indices de calor por encima de lo normal durante los
proximos dias. Riesgo alto de corrientes marinas para el norte y este
de Puerto Rico hasta el jueves. Las condiciones maritimas continuaran
peligrosas a traves de las aguas costeras hasta miercoles debido a
una marejada de Larry. Un patron de temporada persistira durante la semana.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Favor de reportar
cualquier informacion sobre vientos, oleaje y corrientes marinas al
Servicio Nacional de Meteorologia en San Juan mientras siguen las
indicaciones de las autoridades locales y estatales.

AMZ715-725-VIZ001-002-080900-
San Tomas, San John e Islas Adyacentes-Santa Cruz-Aguas cercanas
del Atlantico y aguas costeras adyacentes del Caribe-
508 AM AST martes 7 de septiembre de 2021

Esta perspectiva sobre las condiciones peligrosas del tiempo es para
Islas Virgenes Estadounidenses y las aguas costeras adyacentes.

.Dia Uno...Hoy y esta noche.

.Olas...Se esperan olas de hasta 7 pies a traves de las aguas
costeras del las Islas Virgenes y el pasaje de Anegada.

.Corrientes marinas...Hay un riesgo alto de corrientes marinas para las
playas del norte y este de las playas locales.

.Dias dos hasta el siete...miercoles a lunes

Se esperan indices de calor por encima de lo normal durante los
proximos dias. El riesgo de corrientes marinas aumentara
a alto a traves de la mayoria de las Islas Virgenes el miercoles.
Las condiciones maritimas continuaran peligrosas a traves de las
aguas costeras hasta el miercoles debido a una marejada de
Larry. Un patron de temporada persistira durante la semana.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Favor de reportar
cualquier informacion sobre vientos, oleaje y corrientes marinas al
Servicio Nacional de Meteorologia en San Juan mientras siguen las
indicaciones de las autoridades locales y estatales.