NWS San Juan, PR wrote its last area forecast discussion before the first event at Sep 8, 3:46 PM AST, 3 hours 14 minutes earlier.
Area forecast discussion, Sep 8, 3:46 PM AST, 3 hours 14 minutes before
Area Forecast Discussion
National Weather Service San Juan PR
346 PM AST Sun Sep 8 2024
.SYNOPSIS...
Expect shower and thunderstorm activity during the next few days
as the tropical upper tropospheric trough (TUTT) and a broad
tropical wave continues to move across the area. Southeasterly
winds and a high- moisture environment will also contribute to
excessive heat risks. The National Hurricane Center (NHC) is
monitoring an area, currently in the central tropical Atlantic,
with a medium cyclonic formation chance in the next 48 hours and
a high formation chance in the next seven days.
&&
.SHORT TERM...Today through Tuesday...
Doppler radar observed isolated shower activity across eastern
Puerto Rico and the U.S. Virgin Islands in the morning. Around 10
AM, more well-developed showers began streaming across the eastern
sections of Puerto Rico, affecting Luquillo, Rio Grande, and
Fajardo. Afterward, the shower activity started to develop across
most of the eastern sections of Puerto Rico, the interior, and
the northwestern regions. Intense shower activity resulted in
rainfall accumulations between 1 and 3 inches, with the highest
amount observed in San Sebastian, where radar estimates indicated
around 3 inches. Although cloud cover persisted throughout the
morning, maximum temperatures climbed into the upper 80s to lower
90s, with heat indices ranging from 108 to 110 degrees
particularly along the southern coastal areas.
Unsettled and wet weather conditions will prevail for the rest of
the forecast period. The upper-level low will continue to linger
across the islands, resulting in an unstable pattern conducive to
the development of showers. Meanwhile, at the surface, a tropical
wave moving westward into the region will provide abundant moisture,
with PWAT values of 2.1 inches as indicated by derived GOES
satellite images. This combination will trigger active afternoon
showers and variable weather conditions during the late and early
morning hours. Given these expected conditions, the risk of
excessive rainfall will remain elevated, mainly for Puerto Rico.
Saturated soils could lead to localized flash flooding and
mudslides, particularly in small streams, creeks, and areas of steep
terrain. Residents and visitors should exercise caution or avoid
outdoor activities during the afternoon. Across the U.S. Virgin
Islands, minor flooding may occur on roads and in poor drainage
areas as shower activity increases.
Temperature-wise, the islands can expect warmer conditions, with
maximum temperatures in the upper 80s to lower 90s across most urban
and coastal areas. Heat indices could exacerbate health issues,
particularly in vulnerable populations. Given the forecast
conditions, heat advisories and warnings are likely to be issued.
&&
.LONG TERM...Wednesday through Sunday...
//from previous discussion//
An upper level trough will be present northeast of the local islands
to start the period, before gradually weakening throughout the
workweek. By the end of the week, a mid-level ridge will reduce
instability aloft. Precipitable water (PWAT) values will continue
mainly above 2.1 inches for the start of the period, above normal
values for this time of the year. East to east-southeast winds will
aid in providing moisture to the area. Expect variable weather
conditions as local, orographic and diurnal effects generates
afternoon convective activity, increasing the risk of flooding
during the afternoon for sectors of interior and western Puerto
Rico. Lines of convection (showers and thunderstorms) can also
develop from the USVI, Vieques, Culebra, and from El Yunque. Periods
of passing overnight and early morning showers are also forecast
across windward sectors of the islands. With available moisture and
east to east-southeast winds, heat indices in coastal, urban and
lower elevation areas can reach above 108 degrees Fahrenheit. The
Climate Prediction Center's (CPC) Global Tropics Hazards Outlook
indicates a greater than 50% probability of above-average rainfall
across the northeastern Caribbean during the period. The National
Hurricane Center (NHC) is monitoring an area, currently in the
central tropical Atlantic, with a medium cyclonic formation chance
through the next seven days. While it's too early to assess any
potential impact on our forecast area, please continue to remain
vigilant and monitor future forecast updates from the NHC and from
WFO San Juan.
&&
.AVIATION...
(18z)
SHRA and TSRA are resulting in MVFR conditions across
all TAF sites. Winds will continue from the E-SE at up to 15 knots
with gusts. TSRA and SHRA may lead to lower ceilings across the
mountains and reduced visibility. Another round of SHRA with TS is
forecast for all eastern TAF sites from 09/09Z to 09/15Z.
&&
.MARINE...
A surface high pressure across the Atlantic will promote gentle to
moderate easterly winds over the next few days. An upper-level
trough to our north and a broad tropical wave moving in from the east
will boost shower and thunderstorm activity during the next few
days. Thunderstorms will affect the coastal waters of western Puerto
Rico each afternoon.
&&
.BEACH FORECAST...
A moderate rip current risk is present along the northern and
eastern-facing beaches of Puerto Rico and Culebra. Low risk
elsewhere, however, life-threatening rip currents often occur in
the vicinity of groins, jetties, reefs, and piers.
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory until 4 PM AST this afternoon for PRZ011.
VI...None.
AM...None.
&&
SHORT TERM...LIS/WS
LONG TERM...MRR
AVIATION...LIS/WS
PUBLIC DESK...MMC/RVT
Hazardous weather outlook, Sep 8, 5:03 AM AST, 13 hours 57 minutes before
Perspectiva sobre las Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorología San Juan PR
448 AM AST domingo 8 de septiembre de 2024
AMZ711>745-PRZ001>013-091000-
San Juan y Vecindad-Noreste-Sureste-Este Interior-
Norte Central-Central Interior-Ponce y Vecindad-Noroeste-
Oeste Interior-Mayagüez y Vecindad-Suroeste-Culebra-Vieques-
Las aguas cercanas y fuera de la costa del Atlántico y del Caribe-
448 AM AST domingo 8 de septiembre de 2024
Esta perspectiva sobre las condiciones peligrosas del tiempo es para
sectores de Puerto Rico.
.DÍA UNO...Hoy y esta noche
.Rayos...Tormentas eléctricas de aisladas a dispersas son posibles.
Planee detener toda la actividad al aire libre y moverse a refugios.
.Lluvia Excesiva...Inundaciones en áreas urbanas, carreteras,
riachuelos y lavados. Inundaciones repentinas aisladas son posibles.
.Calor Excesivo...Este nivel de calor afecta a la mayoría de los
individuos sensibles al calor, especialmente aquellos sin
enfriamiento efectivo y/o hidratación adecuada. Impactos posibles
en algunos sistemas de salud y en industrias sensibles al calor.
.Condiciones Marítimas...Las embarcaciones pequeñas deben ejercer
precaución a través de sectores de las aguas fuera de las 10 millas
nauticas del Atlántico.
.Corrientes Marinas...Corrientes marinas amenazantes a la vida son
posibles en la zona de olas rompientes, particularmente a través del
norte de Puerto Rico y Culebra.
.DÍAS DOS A SIETE...lunes a sábado
Contenido de humedad muy por encima de lo normal y las condiciones
inestables ayudarán al desarrollo de tormentas eléctricas en los
próximos días, manteniendo el riesgo de lluvia excesiva y rayos.
Mientras tanto, los vientos del sureste y un ambiente de alta
humedad producirán riesgos de peligro de calor excesivo. Un riesgo
moderado de corrientes marinas persistirá.
.COMUNICADO SOBRE INFORMACIÓN DE OBSERVADORES...
Se les exhorta a los observadores a reportar. Favor de reportar
cualquier información sobre inundaciones, vientos, olas y corrientes
marinas al Servicio Nacional de Meteorología en San Juan.
AMZ716-726-VIZ001-002-091000-
San Thomas San John e islas adyacentes-Santa Cruz-
Aguas cercanas a la costa del Atlántico y aguas costeras adyacentes
del Caribe-
448 AM AST domingo 8 de septiembre de 2024
Esta Perspectiva sobre las Condiciones Peligrosas del Tiempo es para
sectores de las Islas Vírgenes Americanas.
.DÍA UNO...Hoy y esta noche
.Rayos...Tormentas eléctricas aisladas son posibles. Esté atento a
las tormentas eléctricas en su área y esté preparado para buscar
refugio.
.Lluvia Excesiva...Inundaciones en áreas urbanas, carreteras,
riachuelos y lavados. Inundaciones repentinas aisladas posibles.
.Calor Excesivo...Este nivel de calor afecta a la mayoría de los
individuos sensibles al calor, especialmente aquellos sin
enfriamiento efectivo y/o hidratación adecuada. Impactos posibles
en algunos sistemas de salud y en industrias sensibles al calor.
.Condiciones Marítimas...Las embarcaciones pequeñas deben ejercer
precaución a través de sectores de las aguas fuera de las 10 millas
nauticas del Atlántico.
.DÍAS DOS A SIETE...lunes a sábado
Muy por encima del contenido de humedad y las condiciones inestables
apoyarán el desarrollo de tormentas eléctricas en los próximos días,
manteniendo el riesgo de lluvia excesiva y rayos. Mientras tanto,
los vientos del sureste y un ambiente de alta humedad producirán
riesgos de peligro de calor excesivo. Un riesgo moderado de
corrientes marinas regresará para Santa Cruz el lunes.
.COMUNICADO SOBRE INFORMACIÓN DE OBSERVADORES...
Se les exhorta a los observadores a reportar. Favor de reportar
cualquier información sobre inundaciones, vientos, olas y corrientes
marinas al Servicio Nacional de Meteorología en San Juan.