NWS San Juan, PR wrote its last area forecast discussion before the first event at Mar 31, 11:55 AM AST, 2 hours 5 minutes earlier.
Area forecast discussion, Mar 31, 11:55 AM AST, 2 hours 5 minutes before
Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
1155 AM AST Fri Mar 31 2023
...New UPDATE, AVIATION...
.UPDATE...
Issued at 1139 AM AST Fri Mar 31 2023
Only very minor changes to the forecast package as dry air has
enveloped the area as expected. Dew points across the area have
generally fallen into the mid 60s. Temperatures may be a little
cooler than expected as 1000-850 mb thicknesses are now forecast
to be a little smaller. According to the latest morning sounding
from San Juan, Puerto Rico at 31/12Z the top of the moist layer is
below 7 Kft, and with 1.11 inches of precipitable water there is
little moisture above this, although the relative humidity at 34.4
Kft was 43 percent.
For marine interests, the outer buoy is again showing 3 foot swell
at 14 seconds, but energy at 7 seconds is little higher now. The
marine forecast is on track.
&&
.SYNOPSIS...Breezy and mostly dry and stable conditions will
likely prevail through tomorrow across the local islands as a
drier air mass filters into the region. An upper level trough will
move across the region during the next couple of days but it will
have minimal impacts as mid-level ridging continues. Today's
hazards include elevated to critical fire weather conditions as
well as deteriorating marine and coastal conditions.
&&
.SHORT TERM...Today through Sunday...
Surface high pressure over the western North Atlantic will dominate
the local weather conditions in the short term. This feature will
reinforce the trade winds across the northeast Caribbean region
through at least the weekend while providing a generally fair
weather pattern today and Saturday. At upper levels, a short-wave
trough will move eastward over Puerto Rico during the next 24-48
hours, but its impact on the local weather conditions will be
minimal as the 700 mb high pressure will keep a foothold on the
region.
In terms of moisture, precipitable water values will remain below
normal through Saturday, reaching a minimum of 0.7 inches this
afternoon. Moisture will return to normal levels on Sunday when
fragments of low-level moisture move near or over Puerto Rico and
the U.S. Virgin Islands.
In summary, Breezy and generally dry and stable conditions will
likely prevail through Saturday across the local islands. On Sunday,
scattered showers embedded in the fresh to strong trade winds will
bring variable conditions. However, the fast movement of those
showers will limit the rainfall accumulation over the U.S. Virgin
Islands and Puerto Rico.
&&
.LONG TERM...Monday through Friday...
No significant changes to the long term forecast. The workweek will
start with intervals of patches of moisture and dry air filtering
into the region, promoting passing shower activity across windward
sectors of the islands. Model guidance continues to vary on the
timing of the moisture patches but shows an overall increase by mid
week and by the end of the workweek, with precipitable water (PWAT)
values at to slightly above normal values. At surface level, a high
pressure system will be over the central Atlantic to start the
workweek and another high pressure will move into the western
Atlantic to end the forecast period. Winds start off next week being
generally easterly, before becoming more northeasterly by midweek
and more southeasterly by the end of the week. In the upper levels,
the long term period is forecast to start with an upper level trough
moving east the region. To start next week, moisture will be limited
to the lower levels with mid level ridging persisting, but current
model guidance indicates that available moisture will reach the mid
to upper levels by Wednesday and Thursday. This is due to an upper-
level trough, that current model guidance is suggesting, affecting
the region through the second part of the workweek. To start the
workweek shower activity will mostly depend on patches of shallow
moisture, reaching near normal PWAT values, embedded in the trade
wind flow and reaching windward sectors mainly during the evening
and morning hours. Limited afternoon convection, due to diurnal and
local effects, is possible mainly over sectors of western Puerto
Rico. As moisture and instability will possibly increase by midweek,
promoting stronger shower activity.
&&
.AVIATION...VFR conditions expected to prevail. Scattered cumulus
dominate the cloud field with ENE flow of 10-20 kt and some hir
gusts. SHRA, if any, will develop between TJMZ and TJPS. No
operational impacts are anticipated through the forecast period.
VCSH possible at TJSJ tonight. ENE Winds around 15- 20 kt
increasing to around 20 kt during the weekend. Occasional wind
gusts around 25-30 at times then. Maximum winds latest sounding
WSW 60-70 kts btwn FL 350-410 with a rapid ramp up to the lower
edge with height.
&&
.MARINE...Moderate to locally fresh trade winds across the
regional waters are resulting in choppy conditions. A small
northeasterly swell will continue to affect the local Atlantic
waters and passages. Small craft should exercise over most local
waters due to seas up to 6 ft and/or increasing winds. Due to
increasing winds, marine conditions will deteriorate by tonight
and into the weekend. Small Craft Advisories will be in effect
starting this evening across most of the local waters. For today
and tonight, a high risk of rip currents will be in effect for the
north oriented of Puerto Rico, as well as for beaches of Culebra
and the northern USVI. Tonight the high risk of rip currents
extends to the eastern beaches of St. Croix and to the beaches of
Aguada and Rincon.
&&
.FIRE WEATHER...Dry air and breezy conditions will promote
elevated to critical fire weather conditions during the late
morning and into the late afternoon. Therefore, a Red Flag
Warning was issued for the southern coastal plains of Puerto Rico.
Additionally, a Fire Danger Statement was issued for the southern
hills, west coast, northern hills, and central mountain range of
Puerto Rico. For more information, please refer to the Red Flag
Warning (RFWSJU), Fire Danger Statement (RFDSJU) and Fire Weather
Planning Forecast (FWFSJU) products.
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001-002-
005-008-012.
Red Flag Warning until 5 PM AST this afternoon for PRZ014-027.
High Rip Current Risk from 6 PM AST this evening through late
Sunday night for PRZ010.
VI...High Rip Current Risk through late Sunday night for VIZ001.
High Rip Current Risk from 6 PM AST this evening through late
Sunday night for VIZ002.
AM...Small Craft Advisory from 8 PM this evening to 8 AM AST Monday
for AMZ711-723-741.
Small Craft Advisory from 8 AM Saturday to 8 AM AST Monday for
AMZ712.
Small Craft Advisory from 2 AM Saturday to 8 AM AST Monday for
AMZ716.
Small Craft Advisory from 8 PM this evening to 8 AM AST Sunday
for AMZ733.
&&
SHORT TERM/AVIATION...WS
MARINE/UPPER AIR....LISHazardous weather outlook, Mar 31, 5:40 AM AST, 8 hours 20 minutes before
Perspectivas sobre las Condiciones Peligrosas del Tiempo
Servicio Nacional de Meteorologia en San Juan PR
517 AM AST viernes 31 de marzo de 2023
AMZ711>745-PRZ001>013-010930-
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 cercanas y lejanas a la
costa del Atlantico y del Caribe-
517 AM AST viernes 31 de marzo de 2023
Esta perspectiva sobre las condiciones peligrosas del tiempo es para
Puerto Rico.
.DIA UNO...Hoy y esta noche
.Viento...Condiciones ventosas se esperan especialmente en la costa
norte y sur de Puerto Rico, Culebra y Vieques. Artículos no
asegurados podrian salir volando debido al viento fuerte.
.Condiciones Maritimas...Vientos fuertes y oleaje generado por
viento de 4-7 pies esta afectando la mayoria de las aguas locales.
Condiciones peligrosas para embarcaciones pequenas.
.Corrientes marinas... Es probable que hayan corrientes marinas que
pongan en peligro la vida en las playas a lo largo de las costas del
noroeste, norte y noreste de Puerto Rico, Culebra y Vieques.
.Fuego...Combustibles secos, baja humedad relativa y condiciones
ventosas promovera condiciones criticas para incendios en toda la
zona costera del sur. Para obtener mas informacion, consulte el
producto de Bandera Roja (RFWSJU). Ademas, existe un peligro de
incendios elevado, para la mayoria de Puerto Rico hasta esta tarde
debido a que la humedad relativa estara muy baja esta tarde.
.DIAS DOS A SIETE...sabado a jueves
Las condiciones ventosas y el mar peligroso continuaran al menos
hasta principios de la proxima semana. El riesgo moderado a alto de
corrientes marinas persistira durante los próximos dias. Un area de
mayor humedad debe moverse sobre la región el domingo, aumentando el
riesgo de encharcamiento de agua en caminos y areas bajas.
.Comunicado sobre informacion reportada por observadores...
Se requiere la activacion de observadores. Favor compartir cualquier
informacion sobre inundaciones, viento, oleaje y corrientes marinas
para el Servicio Nacional de Meteorologia.
AMZ716-726-VIZ001-002-010930
-San Tomas, San John e Islas Adyacentes-Santa Cruz-Las aguas cercanas
a la costa del Atlantico y las aguas costeras adyacentes del Caribe-
517 AM AST viernes 31 de marzo de 2023
Esta perspectiva sobre las condiciones peligrosas del tiempo es para
las Islas Virgenes Estadounidenses.
.DIA UNO...Hoy y esta noche
Viento...Condiciones ventosas se esperan hoy. Artículos no
asegurados podrian salir volando debido al viento fuerte.
.Condiciones Maritimas...Vientos fuertes y oleaje generado por
viento de 4-7 pies esta afectando la mayoria de las aguas locales.
Condiciones peligrosas para embarcaciones pequenas.
.Corrientes marinas...Es probable que hayan corrientes marinas que
pongan en peligro la vida en las playas a lo largo de las costas
norte y este de las Islas Virgenes Americanas.
.DIAS DOS A SIETE...sabado a jueves
Las condiciones ventosas y el mar peligroso continuaran al menos
hasta principios de la proxima semana. El riesgo moderado a alto de
corrientes marinas persistira durante los próximos dias. Un area de
mayor humedad debe moverse sobre la región el domingo, aumentando el
riesgo de encharcamiento de agua en caminos y areas bajas.
.Comunicado sobre informacion reportada por observadores...
Se requiere la activacion de observadores. Favor compartir cualquier
informacion sobre inundaciones, viento, oleaje y corrientes marinas
para el Servicio Nacional de Meteorologia.