An active tropical wave combined with an upper-level low to create widespread shower and thunderstorm activity across the local area.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SJU wrote it up.
An active tropical wave combined with an upper-level low to create widespread shower and thunderstorm activity across the local area.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Juan, PR wrote its last area forecast discussion before the first event at Jun 23, 6:52 AM AST, 1 hour 38 minutes earlier.
Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
652 AM AST Sat Jun 23 2018
.UPDATE...Showers and thunderstorms continue to spread over Puerto
Rico and to a lesser extent the U.S. Virgin Islands. Have updated
grids to include isolated to scattered thunderstorms and a better
chance of rain during the morning. At this time still expect
thunderstorms with heavy rain over northwest Puerto Rico.
&&
.AVIATION...As below with additional MVFR/lcl IFR conds expected
in areas with heaviest rain.
&&
.MARINE...No changes.
&&
.PREV DISCUSSION... /issued 510 AM AST Sat Jun 23 2018/
SYNOPSIS...Moisture associated with a departing tropical wave
will continue to interact with an upper level trough northwest of
the area to result in cloudiness and periods of showers and
thunderstorms across the forecast area today. Weather conditions
are expected to improve early the upcoming work week.
SHORT TERM...Today through Monday...
Upper level trough interacting with low level moisture after
tropical wave passage resulted in thunderstorms and showers
developing over the Caribbean waters and the southern sections of
Puerto Rico. This activity is expected to continue to affect
sections of southern PR through the rest of the morning hours and
spread across the rest of the island through the day. Cloud cover
could delay afternoon convective development over the northwestern
quadrant of the island. Urban and small stream flooding is expected
with the heaviest showers as well as mudslides in areas of steep
terrain.
Moisture will quickly erode between Sunday through Monday. However
by Sunday afternoon, the available low level moisture will combine
with diurnal effects and result in showers with possible isolated
thunderstorms over western Puerto Rico. A surface high pressure just
northeast of the region will tighten the pressure gradient over the
islands and bring a trade wind surge. Saharan dust is expected to
return by Monday. Creating even drier conditions across the region.
LONG TERM...Tuesday through Sunday...
Although an upper level trough across the central Atlantic is
expected to amplify into the north central and northeast Caribbean
through the forecast cycle; moisture will remain below the normal
range which will be the limiting factor for shower and thunder
development the upcoming week. At lower levels, a tropical wave
passage is expected late in the week with bulk of moisture remaining
south of the area. A surface high pressure across the central
Atlantic will yield fresh easterly winds much of the forecast
period.
If the long term forecast holds, expect a fair weather pattern
across the local islands with locally induced afternoon showers
and thunderstorms across western areas of Puerto Rico each day.
Under easterly winds, temperatures should remain near normal
values.
AVIATION...SHRA/TSRA are expected across the Puerto Rico terminals
through at least 22z. Early in the period mainly across the southern
terminals, then by 17z across the northern and western terminals.
Tempo MVFR conditions are expected with this activity as well as
SCT/BKN layers from FL025-FL150 and mtn obscd along the interior.
Across the USVI terminals, SHRA could move briefly at times. Low
level winds will continue ESE at 10-20 kts.
MARINE...A departing tropical wave will continue to result in numerous
showers and isolated thunderstorms across the local waters today,
particularly the Caribbean waters. A high pressure system in the
central Atlantic will move into the west-central Atlantic, tightening
the local pressure gradient and increasing the winds. This will
create hazardous seas Sunday into early the next work week. Seas 6
to 8 feet with occasional seas up to 10 feet by Sunday night
across the Caribbean waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 86 77 89 78 / 80 30 30 20
STT 86 79 88 79 / 40 40 40 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Small Craft Advisory from 8 AM Sunday to 8 PM AST Monday for
Southeast.
VI...None.
AM...Small Craft Advisory from 2 AM Sunday to 8 PM AST Monday for
Anegada Passage Southward to 17N-Caribbean Waters of Puerto
Rico from 10 NM to 17N.
Small Craft Advisory from 8 AM Sunday to 8 PM AST Monday for
Coastal Waters of Southern Puerto Rico out 10 NM-Mona
Passage Southward to 17N.
&&
SHORT TERM...WS
LONG TERM....99Perspectivas sobre Condiciones Peligrosas del Tiempo Servicio Nacional de Meteorologia San Juan PR 455 AM AST sabado 23 de junio de 2018 AMZ710>745-PRZ001>013-240900- 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 lejanas a la costa del Atlantico y Caribe- 455 AM AST sabado 23 de junio de 2018 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 .Tronadas...Existe probabilidad de tronadas con lluvia fuerte y rafagas de vientos breves. .Inundaciones...Lluvias fuertes pudieran resultar en inundaciones urbanas. Aumentos subitos a lo largo de los rios y riachuelos son probables. Deslizamiento de lodo en terreno empinado es posible a traves del noroeste de Puerto Rico donde el suelo ya esta saturado. .Vientos...Se esperan vientos sostenidos en exceso de 20 mph a traves de las aguas locales. Viento mas alto localmente en los aguaceros y tronadas. .Olas...Se espera oleaje de hasta 6 pies a traves de las aguas del Caribe. Oleaje mas alto localmente en los aguaceros y tronadas. .Corrientes Marinas...Existe un riesgo moderado de corrientes marinas a lo largo del noroeste y suroeste de Puerto Rico asi como Vieques y Culebra. .Dias dos a siete...domingo a viernes Las condiciones ambientales permaneceran favorables para periodos de aguaceros y tronadas el domingo, por lo tanto, inundaciones aun son posibles. Un riesgo moderado de corrientes marinas continuara esta noche aumentando a alto el domingo. Se espera que las condiciones del tiempo mejoren temparno durante la semana laboral entrante. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores individuales reportar inundaciones y corrientes marinas al Servicio Nacional de Meteorologia en San Juan. AMZ715-725-VIZ001-002-240900- San Tomas, San John e Islas Adyacentes- Santa Cruz- Aguas cercanas del Atlantico y aguas costeras adyacentes del Caribe- 455 AM AST sabado 23 de junio de 2018 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 .Tronadas...Existe probabilidad de tronadas con lluvia fuerte y rafagas de vientos breves. .Inundaciones...Lluvias fuertes pudieran resultar en inundaciones urbanas y de cunetas. .Vientos...Se esperan vientos sostenidos en exceso de 20 mph a traves de las aguas locales. Viento mas alto localmente en los aguaceros y tronadas. .Olas...Se espera oleaje de hasta 6 pies a traves de las aguas del Caribe. Oleaje mas alto localmente en los aguaceros y tronadas. .Corrientes Marinas...Existe un riesgo moderado de corrientes marinas a lo largo de la costa sur de Santa Cruz. .Dias dos a siete...domingo a viernes Un riesgo moderado de corrientes marinas continuara esta noche aumentando a alto el domingo. Se espera que las condiciones del tiempo mejoren temparno durante la semana laboral entrante. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores individuales reportar corrientes marinas al Servicio Nacional de Meteorologia en San Juan.
The national radar mosaic for the moment the first event began.
2 flood, 1 flash flood, 1 heavy rain. Local standard time, as filed.
Road PR-184 closed due to Rio Grande de Patillas going out of its banks.
Road PR-31 reported impassable at Sector Pitina.
Mudslide reported at road PR-157 Km 21 at Barrio Damian Arriba.
Creek out of its banks flooding road PR-936, which was not allowing residents to get in or out of their homes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2018Every state in 2018This day in weather historyWarnings in Puerto Rico, June 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 766156, 766157, 766158, 766159.