Small Craft Advisory 12, NWS JSJ

Area Forecast Discussion
National Weather Service San Juan PR
325 PM AST Fri Apr 19 2019

.SYNOPSIS...An upper level omega blocking pattern continues over
the western Atlantic with a large amplitude upper level trough/low
over the central Atlantic, another upper level trough/low across
the eastern third of U.S. and an upper ridge of high pressure
sandwiched in between them. This upper level ridge is expected to
continue to build across the central and eastern Caribbean. At the
surface...a frontal boundary extending from the closed low over
the central Atlantic southwestward to north of the islands will
slowly drift southward and may have an impact on the local weather
conditions by the start of next week.

&&

.SHORT TERM...Tonight through Sunday Night...Upper ridge mentioned
before, and associated strong mid/upper level subsidence will
tend to limit shower activity across the local area. Still, local
effects, combined with any available moisture, will definitely
play a role in the resultant weather conditions. Therefore,
isolated to widely scattered nighttime and early morning showers
could still be possible over the USVI and eastern PR during this
period. Scattered afternoon showers could also occur over the
west-central portions and west coast of the big island of Puerto
Rico. The upper low over the central Atlantic, and associated
frontal boundary, will continue to drift southward through this
period. Strong wind flow associated with a surface high pressure
ridge north of the front will help advect patches of moisture over
the local area. This, coupled with enhanced low level convergence,
could result in an increased in the shower activity over the USVI
and eastern PR especially Saturday through Sunday Night.

.LONG TERM...Sunday through Friday...Models still indicate that
the low and associated frontal boundary north of the area will
continue to move south with the front moving across the local
islands as a "backdoor front" i.e. from the northeast Monday and
Monday night. Decided to keep scattered to numerous
showers...especially over the eastern half of the forecast area
(eastern PR/USVI) to account for this. Too early to have a clear
idea as to the amount of precip we could expect with this system,
but uncertainty should diminish as the time progresses. Models
also now show that there will be a frontal passage with the
boundary moving to our south before dissipating Monday night. By
Tuesday...the low begins to lift northward away from the northeast
Caribbean. A return to a mostly easterly flow is expected which
will continue to advect small patches of low level moisture from
time to time.

&&

.AVIATION...VFR conditions will prevailed across the local
flying area through the fcst prd. SHRA development are expected
in the vicinity of Mayaguez between 19/18z-23z, possibly affecting
TJMZ/TJBQ. Brief passing SHRA cannot be ruled out across E-PR/USVI
and Leeward Islands terminals at times. Winds will be from the E
at 15 to 20 knots with higher gusts and sea breeze variations
dropping at 10 knots or less aft 19/23z.

&&

.MARINE...A tight pressure gradient will continue across the
northeast Caribbean at least through Sunday. This will keep
marine conditions on the rough side with seas up to 6 feet and
winds in the 15 to 20 knots range. Although there is no a small
craft advisory in effect at this time...small craft operators are
advised to exercise caution while navigating over the coastal
waters. The risk of rip currents remains up to moderate for many
beaches in PR and USVI. Nevertheless, even if the risk is low...beachgoers
are also urged to exercise caution when entering the water as rip
currents could develop unexpectedly.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  75  87  75  85 /  20  30  40  40
STT  75  87  75  86 /  20  30  40  30

&&

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

SHORT TERM...RGH
LONG TERM....RGH

Perspectivas sobre Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia San Juan PR
456 AM AST viernes 19 de abril de 2019

AMZ710>745-PRZ001>013-201000-
San Juan y Vecindad-Noreste-Sureste-
Este Interior- Norte Central-Interior Central-Ponce y Vecindad-
Noroeste- Oeste Interior-Mayaguez y Vecindad-Suroeste-Culebra-
Vieques-Aguas cercanas y mar afuera del Atlantico y Caribe-
456 AM AST viernes 19 de abril de 2019

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

.Inundaciones...Lluvias fuertes pudieran resultar en acumulacion de
agua en carreteras y en areas bajas en el oeste de Puerto Rico.

.Viento... Se esperan vientos sostenidos en exceso de 20 mph /17
nudos a traves de las aguas cercanas a las costas norte y sur de
Puerto Rico, las aguas adyacentes y las costas.

.Oleaje...Se espera oleaje picado hasta 6 pies a traves de las aguas
locales del Atlantico y del Caribe, excepto al oeste de PR.

.Corrientes marinas...Existe riesgo moderado de corrientes marinas
para la mayor parte de las playas de Puerto Rico incluyendo a
Culebra y a Vieques.

.Dia dos a siete...sabado hasta jueves

El riesgo de corrientes marinas sera alto para el domingo a lo largo
de la costa noroeste de Puerto Rico el domingo en la noche y lunes.
Oleaje hasta 7 pies sera posible el lunes y martes en las aguas mar
afuera del Atlantico. Inundaciones urbanas localizadas y de
riachuelos son posibles en el oeste e interior de Puerto Rico el
lunes en la tarde.

.Comunicado sobre informacion reportada por observadores...

No se anticipa activacion amplia de observadores, sin embargo, se
les exhorta a los observadores individuales a reportar inundaciones
y corrientes marinas al Servicio Nacional de Meteorologia en San
Juan.

AMZ715-725-VIZ001-002-201000-
San Tomas, San John y Islas Adyacentes-
Santa Cruz-Aguas cercanas del Atlantico y aguas costeras adyacentes
del Caribe-
456 AM AST viernes 19 de abril de 2019

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

.Dia Uno...hoy y esta Noche

.Oleaje... Se espera oleaje picado hasta 6 pies a traves de las
aguas locales mar afuera del Atlantico y el Pasaje de Anegada.

.Corrientes marinas...Existe riesgo moderado de corrientes marinas
para las playas de Santa Cruz y el noroeste de San Thomas.

.Dia dos a siete...sabado a jueves

Riesgo alto de corrientes marinas es probable para el extremo este
de Santa Cruz el martes en la noche y miercoles. El oleaje hasta 7
pies sera posible el lunes y martes en la noche en las aguas mar
afuera del Atlantico.

.Comunicado sobre informacion reportada por observadores...

No se anticipa activacion amplia de observadores, sin embargo, se
les exhorta a los observadores individuales a reportar corrientes
marinas al Servicio Nacional de Meteorologia en San Juan.