Tornado and Flood in Puerto Rico, May 1, 2022

Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
1200 PM AST Sun May 1 2022

.UPDATE... In the morning hours, cloudiness with a few passing
showers prevailed across most of the CWA. Then, by late morning
hours, heavy shower activity develop over the northeastern
sections of Puerto Rico, specially between Fajardo and Luquillo
municipalities. As the inverted trough exist the region,
rainfall activity still expected across Puerto Rico, mainly in the
daytime hours. This shower activity could result in ponding of
water in roadways and low-lying areas, as well some minor flooding
with the heaviest activity. After then, conditions are forecast
to slowly improve in the overnight hours and into tomorrow.

&&

.AVIATION...VFR for most of the TAF sites but periods of MVFR
conds will continue at times, especially over TJSJ and TJBQ with
-SHRA/Low CIG and VCTS from now through 01/23Z. SFC will continue
 around 8-10 kts from the E/ESE with seas breeze variation, then,
 by 02/06Z will prevail light/VRB will return at 02/06Z. For
 02/06Z wx conditions are forecast to improve and mainly VFR
 conditions will prevail.

&&

.MARINE...No changes to the inherited forecast. A fading
northerly swell and a moderate wind flow will continue to result
in some choppy conditions across the offshore Caribbean waters and
the Mona Passage with seas up to 6 feet. Elsewhere, seas will
remain up to 5 feet. There is a high risk of rip current across
all the north and northeast exposed beaches, as well Culebra and
the U.S. Virgin Islands.

&&

.PREV DISCUSSION... /issued 501 AM AST Sun May 1 2022/

SYNOPSIS...
The influence from the inverted trough weakens as conditions
improve throughout the day with most of the activity over the
eastern portion of the region and the Atlantic Offshore waters.
Typical weather will prevail for the beginning of the week until
Thursday afternoon when an upper level trough passes over the
region increasing the likelihood of thunderstorms and shower
activity. The northerly swell previously affecting local waters is
decaying yet a High Risk of Rip Currents remain as breezy
conditions increase overnight.

SHORT TERM...TODAY THROUGH TUESDAY...

Conditions will slowly improve throughout the day with mostly
stratiform rain across the local waters and the coastal sections
of the eastern third of Puerto Rico, Vieques, Culebra, St Thomas,
St John, and St Croix. The strongest activity should remain across
the surrounding waters. Isolated thunderstorms cannot be ruled
out across the Atlantic Offshore waters. Drier air slowly filters
from the southeast and gradually fills over the region, tapering
off rain activity throughout the day. However, afternoon
convection will develop one more time across the interior and
north of the Cordillera Central of Puerto Rico and the northern
Virgin Islands.

A more seasonal weather pattern with an easterly wind flow will
return Monday and Tuesday. This wind flow will push the lingering
moisture across the islands each day. The seasonal weather pattern
consists of the combinations of clouds and sunshine and a few
passing showers in the night and morning hours, followed by
afternoon convection across the interior and western portions.

LONG TERM...Wednesday through Monday...

As a high pressure system at the surface in the Western Atlantic
promotes northeast flow, variable patches of moisture move through
the region providing passing showers and afternoon development in
the western portions of Puerto Rico with contribution from
diurnal heating and local effects. Upper level flow is mostly
zonal until around Thursday afternoon when an upper level short
wave trough passes through the Eastern Caribbean. Mid-level
heights are expected to fall, reaching the the lowest values on
Friday. By this time, winds begin to veer to the southeast as the
surface high pressure system reaches a position northeast of the
Islands. GFS model guidance is showing a bump in precipitable
water on Friday which in combination with these dynamics may
provide afternoon thunderstorms. If enough diurnal heating
combines with diffluence aloft, there is the chance of vertical
development late in the day on Thursday and Friday that could
result in exceptional amounts of rain and potential thunderstorms.

With southeast winds persisting into the weekend, most of the
afternoon development will concentrate in the northwest with
windward showers occurring throughout the day. Saturday through
Monday appears to appear normal with slightly above average
moisture. As a deep surface low develops in the Western Atlantic
late on Sunday, a short lived perturbation may exist over the
region. Since the GFS is quite fickle this far out, this
occurrence remains speculative. Therefore after the upper level
trough moves out of the region Saturday morning, a typical weather
pattern is expected with light winds from the southeast.

AVIATION...VFR but periods of MVFR conds will continue at times
with -SHRA/Low CIG. Mtn top obscr over ctrl mountain range of PR
will continue and should return between 01/17-22z. BKN-OVC lyrs nr
FL025...FL040... FL120. SHRA/Isold-TSRA could return mainly north
of the Cordillera Central (near JSJ) and near St Thomas terminal
(IST) during the afternoon (btwn 01/18-22z). SFC will continue
calm to light/VRB thru 01/13z, then returning from the E/ESE at
10-15 kt with higher gusts and sea breeze variations.

MARINE..A decaying northerly swell continues to influences wave
heights up to 5 feet. As moderate winds from the east become fresh
by tonight, choppy conditions will prevail. Isolated
thunderstorms and scattered showers are expected over local waters
throughout the day. As breaking wave heights reach up to 8 feet
for much of the coastline along the Islands, a High Risk of Rip
Currents remains in effect for Puerto Rico and the U.S. Virgin
Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  82  74  86  74 /  60  40  50  40
STT  83  75  86  75 /  50  30  40  40

&&

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

VI...High Rip Current Risk through Monday afternoon for St Croix-
     St.Thomas...St. John...and Adjacent Islands.

AM...None.
&&

SHORT TERM...RAM
LONG TERM....LIS
PUBLIC DESK...ERG

Perspectivas sobre las Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia en San Juan PR
518 AM AST domingo 1 de mayo de 2022

AMZ710>745-PRZ001>013-020930-
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 del Caribe-
518 AM AST domingo 1 de mayo de 2022

.Dia Uno...Esta noche

.Tronadas...Existe un potencial de tronadas con lluvia fuerte y
rafagas en viento esta tarde a traves de sectores del norte de
Puerto Rico, Vieques y Culebra.

.Inundaciones...Lluvias fuertes pudieran resultar en inundaciones
urbanas y de riachuelos.

.Vientos... Vientos sostenidos en exceso de 20 MPH (17 nudos) se
esperan a traves del pasaje de la Mona.

.Oleaje...Se espera oleaje picado de hasta 6 pies a traves de las aguas del
Atlantico y el pasaje de la Mona.

.Corrientes Marinas...Existe un riesgo alto de corrientes
marinas para las playas del norte de Puerto Rico, Vieques y Culebra.

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

El riesgo de corrientes marinas se mantendra alto a traves de Puerto
Rico y Culebra hasta temprano la semana proxima.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Sin embargo, le
agradeceriamos reportar cualquier informacion sobre corrientes
marinas al Servicio Nacional de Meteorologia en San Juan.

AMZ715-725-VIZ001-002-020930-
San Tomas, San John e Islas Adyacentes-
Santa Cruz-Aguas cercanas del Atlantico y aguas costeras adyacentes
del Caribe-
518 AM AST domingo 1 de mayo de 2022

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

.Dia Uno...Esta noche

.Tronadas...Existe un potencial de tronadas con lluvia fuerte y
rafagas en viento esta tarde a traves de las aguas costeras de San
Thomas.

.Inundaciones...Acumulaciones de lluvia son posibles en carreteras y areas
de pobre drenaje.

.Oleaje...Se espera oleaje picado de hasta 6 pies a traves de
las aguas del Atlantico y el pasaje de la Mona.

.Corrientes Marinas...Existe un riesgo alto de corrientes marinas
para las playas del noroeste de San Tomas y este de Santa Cruz.

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

El riesgo de corrientes marinas se mantendra alto a traves de las
islas durante el inicio de la proxima semana.

.Comunicado sobre informacion reportada por observadores...

No se espera activacion amplia de observadores. Sin embargo, le
agradeceriamos reportar cualquier informacion sobre corrientes
marinas al Servicio Nacional de Meteorologia en San Juan.