Rip Current in Puerto Rico, January 24, 2020

Area Forecast Discussion
National Weather Service San Juan PR
1027 AM AST Fri Jan 24 2020

.UPDATE..Doppler radar is detecting showers across portions of
northeastern PR. This shower activity will begin to diminish in
the late morning hours. This will bring moments of sunshine that
will support locally induced afternoon convection over the
region. However, there is a high uncertainty in the precipitation
forecast as light steering flow will prevail during the forecast
period. However, GFS suggest shower activity will mainly develop
over portions of interior, northcentral and eastern PR during the
afternoon hours. Then, showers will focus over the southwestern
quadrant during the evening hours.

&&

.AVIATION... Mainly VFR cnds at TAF sites will prevail drg
fcst prd. TEMPO MVFR CIGs are psbl at TSJU due to low visibility
by -SHRA/SHRA in the afternoon hours. VCSH is expected for the
USVI terminals til 24/23z. Mostly VRB sfc winds will privail drg
fcst prd, mainly for in TKPK.

&&

.MARINE...Northerly swell will continue generating hazardous
marine conditions across the Atlantic through Sunday. San Juan
41043 buoy is currently observing seas up to 8 feet and 41053 buoy
is reporting seas up to 6 feet. No major change were made to the
forecast.

&&

.PREV DISCUSSION... /issued 459 AM AST Fri Jan 24 2020/

SYNOPSIS...

More rainfall is expected today and for the next few days as a
cold front stalls over the region. The thunderstorm threat remains
low, but once again persistent showers could lead to urban and
small stream flooding. More showers are expected to continue
through much of the next week. Another swell will be impacting us
beginning this morning, and lasting through the weekend. Calmer
seas will prevail thereafter for the rest of the workweek.

SHORT TERM...Today through Sunday...

The cold front was just southeast of Saint Croix at 5 AM AST this
morning. Showers persist along the local coastal Atlantic waters and
are generally moving east northeast to east southeast owing to the
shallow depth of the cold air behind the front. Showers are also
moving southeast over the Caribbean southwest of Saint Croix. Modest
moisture will persist just behind the front and the best resolution
models show winds from the south in southern Puerto Rico and from
the north in northern Puerto Rico. This should generate considerable
shower activity in the interior of Puerto Rico by midday or early
afternoon. Forecast soundings show capping is expected just above 10
kft that will limit activity and prevent thunderstorms, but some
showers could produce locally heavy rain and urban and small stream
flooding.  The front is now moving only very slowly and may not
completely exit the forecast area today. An upper level ridge will
move through this evening and a jet will continue over the area
through the rest of the weekend.

The GFS is not as bullish on low level omega in the 24/00Z run as it
was 12 hours ago, but expect that showers activity over interior and
northeast Puerto Rico will be healthy and some shower activity will
continue over and around the U.S. Virgin Islands. Showers will not
be as heavy as yesterday. The moisture around the frontal boundary
will continue over Puerto Rico and the U.S. Virgin Islands on
Saturday and low level winds will be quite light and likely less
than 10 knots. According to the GFS, winds at 850 mb do not really
shift from southwest to northwest until late Saturday. Owing to the
confused nature of the pattern around the area, with the decaying
front and the col between the front and the shearline in the
vicinity, the GFS is not consistent with the amount of moisture that
will be available Saturday or Sunday, but has moisture increasing
Saturday into Saturday night that should allow showers to be likely--
at least in the interior, both Saturday and Sunday.

LONG TERM......Monday through Saturday...

Our pesky front will continue to impact us as we begin the workweek.
Though the main low pressure system associated with the front
will be well off to the east, leftover moisture along with
additional moisture being drawn up from the south will keep us
wet. Upper level atmospheric conditions still look uninspiring in
forecast models, so only a minimal thunderstorm threat is
expected. However, given the moist conditions expected over the
weekend and associated saturated soils, additional rainfall on
Monday could lead to urban and small stream flooding. Less of a
flooding threat is expected for Tuesday, though there will still
be some lingering moisture to produce scattered showers. During
this period of the first part of the week, it should be mentioned
that the southern coast where the earthquakes have occurred will
be particularly susceptible to rainfall under these conditions.

For the rest of the week, another cold front moving in from the
west will bring more rainfall across the region. At this point,
Wednesday and Thursday will only see scattered showers. However,
as the front nears on Friday and Saturday, shower activity could
become more numerous according to long range models. Again, upper
level conditions still do not look favorable for thunderstorms,
though an isolated thunderstorm cannot be ruled out.

AVIATION...

VFR conditions will prevail at TAF sites thru 25/02Z
except for brief MVFR CIGs and psbly VSBYs in SHRA due to cold front
in the vcnty. Aft 24/16Z mtn obscurations in  clds and SHRA. Sfc
winds northerly in nrn PR/USVI, southerly in srn PR and TISX. Winds
shift to northerly in TNCM aft 24/15Z, VRB in TKPK. Max winds west
65-80 kt btwn FL340-470 strongest near FL400.

MARINE...

Another swell is moving in this morning, induced by an area of low
pressure to our north-northwest. This swell does not look as intense
as the last swell, and will not last as long. However, dangerous
marine conditions will continue through Sunday, after which calmer
seas will prevail. Active weather will continue into next week, with
scattered to numerous showers across the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  85  74  83  74 /  70  70  60  60
STT  84  73  83  72 /  50  50  70  70

&&

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

     Small Craft Advisory from 8 PM this evening to 2 AM AST Sunday
     for Southwest.

VI...High Rip Current Risk through Sunday afternoon for
     St.Thomas...St. John...and Adjacent Islands.

AM...Small Craft Advisory until 2 PM AST Sunday for Atlantic Waters
     of Puerto Rico and USVI from 10 NM to 19.5N-Coastal Waters
     of Northern Puerto Rico out 10 NM.

     Small Craft Advisory from 8 PM this evening to 2 AM AST Sunday
     for Anegada Passage Southward to 17N-Coastal Waters OF
     Southwestern Puerto Rico out 10 NM-Coastal Waters of
     Southern USVI Vieques and Eastern Puerto Rico out 10 NM.

     Small Craft Advisory from 2 PM this afternoon to 2 AM AST Sunday
     for Coastal Waters of Northern USVI and Culebra out 10 NM.

     Small Craft Advisory from 2 PM this afternoon to 2 PM AST Sunday
     for Coastal Waters OF Northwestern Puerto Rico out 10 NM-
     Mona Passage Southward to 17N.

&&

SHORT TERM...FRG
LONG TERM....DS
PUBLIC DESK...ICP

Perspectivas sobre Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia San Juan PR
453 AM AST viernes 24 de enero de 2020

AMZ710>745-PRZ001>013-250900-
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-
453 AM AST viernes 24 de enero de 2020

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 inundaciones
urbanas y de riachuelos en areas localizadas y acumulacion de agua
en carreteras.

.Olas...Se espera que oleaje picado/vigoroso de hasta 8 pies invada
las aguas locales del Atlantico y pasajes del Caribe hoy y esta
noche.

.Corrientes marinas...Existe riesgo alto de corrientes marinas para
la costa norte de Puerto Rico y Culebra.

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

Se espera que la probabilidad del oleaje peligroso culmine el lunes.
Las corrientes marinas pudieran continuar hasta el miercoles a lo
largo de la costa norte de Puerto Rico.

.Comunicado sobre informacion reportada por observadores...

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

AMZ715-725-VIZ001-002-250900-
San Tomas, San John y Islas Adyacentes-
Santa Cruz-Aguas cercanas del Atlantico y aguas costeras adyacentes
del Caribe-
453 AM AST viernes 24 de enero de 2020

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 espera que oleaje picado/vigoroso de hasta 8 pies invada
las aguas locales del Atlantico y pasajes del Caribe hoy y esta
noche.

.Corrientes marinas...Existe un riesgo alto de corrientes marinas
para las playas del noroeste de San Tomas.

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

Se espera que la probabilidad de oleaje peligroso y el riesgo alto
de corrientes marinas para las playas del noroeste culmine el lunes.

.Comunicado sobre informacion reportada por observadores...

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