The combination of a deep-layered trough and sufficient low-level moisture combined with strong daytime heating and sea breeze convergence to generate heavy showers and thunderstorms across portions of the area. The heaviest rainfall activity occurred along the San Juan metro area as well as across portions of interior and western Puerto Rico.
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.
The combination of a deep-layered trough and sufficient low-level moisture combined with strong daytime heating and sea breeze convergence to generate heavy showers and thunderstorms across portions of the area. The heaviest rainfall activity occurred along the San Juan metro area as well as across portions of interior and western Puerto Rico.
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 Aug 17, 1:58 PM AST, 1 hour 2 minutes earlier.
Area Forecast Discussion National Weather Service San Juan PR 158 PM AST Sat Aug 17 2019 .SYNOPSIS... An induced surface trough is producing showers and thunderstorms across the local islands. This activity will spread across the western interior and western sections of Puerto Rico through this evening. A tropical wave will bring showers and thunderstorms Sunday through Tuesday. && .SHORT TERM...Tonight through Monday... An upper-level trough is inducing a surface trough across the islands today. This trough will continue to produce periods of showers and thunderstorms through this evening. Urban and small stream flooding, frequent lightning and brief gusty winds are possible with this activity. Activity should diminish overnight, as a relative drier air mass ahead of a tropical wave moves from the east across the archipelago of the U.S. Virgin Islands and Puerto Rico. However, the proximity of an upper-level trough will keep alive the potential for shower and thunderstorm formation across the local waters and the windward sections overnight and Sunday morning. The leading edge of a tropical wave is expected to increase the potential for shower and thunderstorm formation by Sunday afternoon. The available moisture combined with local effects and the diurnal heating will aid in another round of heavy showers and thunderstorms over the west sections of the islands and between the USVI and eastern PR waters. At this time, a wet and unstable weather pattern is likely through the short term period. It is important to mention that GOES-16 detected a Dry air mass with Saharan dust surrounding the aforementioned tropical wave, which could weakens this feature. Total rainfall accumulations should range between 2 and 4 inches with locally higher amounts. .LONG TERM...Tuesday through Saturday... High pressure at upper levels will have nosed in from the east northeast over the local area by Tuesday. Although lower pressure will be southeast high pressure will hold to the north through the end of the period and be the dominant influence over the weather. Behind the tropical wave that moved through late Sunday and Monday a band of moisture will flow over the area in east southeast flow until a 700 mb ridge passes on Tuesday afternoon (20/18Z). Then flow will switch to east northeast at 700 mb and bring some of the moisture back over the area. This will allow good convection over Puerto Rico during the afternoon and evening. This flow will also be weakly reflected in the surface flow so as to keep temperatures on the north coast more moderate and generally no higher than the lower 90s a few miles inland. Conditions on Wednesday and Thursday become more stable and moisture will fall below 2 inches of precipitable water on Tuesday night with only minor peaks on Wednesday night and Thursday evening to bring enhancement to shower activity. Thunderstorms should be limited, if any, to the afternoon in western Puerto Rico Wednesday. Although moisture will continue low Wednesday through Friday, some disturbances will trigger scattered showers Thursday afternoon and Friday night into Saturday. && .AVIATION... Mainly VFR conditions expected across TIST/TISX/TNCM/TKPK/TJPS. TEMPO MVFR to brief IFR conditions are possible across TJMZ/TJBQ, with brief MVFR conditions possible across TJSJ. It'll be breezy during thunderstorm activity as well. In general, winds will be out of the east at 10 to 20 knots. && .MARINE... A surface high pressure centered across the north central Atlantic and a surface trough moving across the regional waters will help to maintain moderate to fresh east to northeast winds across the local waters. Seas will continue between 4 and 6 feet across open waters and below 4 feet across protected areas. Thunderstorm formation will continue across the coastal western waters of Puerto Rico and the Mona Passage through this evening, as well as across the surrounding waters of the U.S. Virgin Islands and eastern PR. Brief gusty winds and torrential rainfall are expected with this activity. Small craft advisories are not expected through much of the forecast cycle. Brief gusty winds, torrential rains and frequent lightning will accompany thunderstorms generated by a passing tropical wave Sunday night through Tuesday night. && .PRELIMINARY POINT TEMPS/POPS... SJU 79 89 78 86 / 20 40 60 70 STT 80 88 78 88 / 40 50 70 60 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && SHORT TERM...ERG LONG TERM....CAM AVIATION...ERG
Perspectivas sobre Condiciones Peligrosas del Tiempo Servicio Nacional de Meteorologia San Juan PR 524 AM AST sabado 17 de agosto de 2019 AMZ710>745-PRZ001>013-180930- 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- 524 AM AST sabado 17 de agosto de 2019 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 la probabilidad de tronadas con lluvias fuertes y vientos en rafagas breves esta tarde a traves de sectores del el area metropolitana de san Juan, el interior y el oeste de Puerto Rico. Estas tronadas podrian producir fuertes vientos. .Inundaciones... Lluvia fuerte podria resultar en acumulacion de lluvia en las carreteras y en riachuelos. .Vientos...Vientos sostenidos en exceso de 20 mph (17 nudos) son posibles a traves de la mayoria de las aguas del Caribe y Atlantico de Puerto Rico. .Corrientes marinas...Existe un riesgo moderado de corrientes marinas a lo largo de la costa norte central de Puerto Rico. .Calor...Vientos del sureste resultaran en indices de calor por encima de lo nrmal a lo largo de las areas bajas de la isla. .Dia dos a siete...domingo a viernes Se esperan aguaceros y tronadas a traves del interior y oeste de Puerto Rico el domingo en la tarde. Esto podria resultar en inundaciones urbanas y de riachuelos. Aguaceros mas amplios y tronadas se esperan para el lunes con el paso de una onda tropical, con posibilidad de inundaciones urbanas y de riachuelos a traves de mas areas. Un riesgo moderado de corrientes marinas continuara a traves de algunas de las playas locales durante los proximos dias. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores individuales a reportar vietos fuertes, granizos, inundaciones, trombas marinas y corrientes marinas al Servicio Nacional de Meteorologia en San Juan. AMZ715-725-VIZ001-002-180930- San Tomas, San John y Islas Adyacentes-Santa Cruz- Aguas cercanas del Atlantico y aguas costeras adyacente del Caribe- 524 AM AST sabado 17 de agosto de 2019 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 .Corrientes marinas...Existe un riesgo moderado de corrientes marinas para las playas de la costa este de Santa Cruz. .Calor...Vientos del sureste resultaran en indices de calor por encima de lo nrmal a lo largo de las areas bajas de la isla. .Dia dos a siete...domingo a viernes Se espera que una onda tropical brinde actividad de aguaceros y tronadas entre el domingo en la tarde y hasta lunes a traves de las Islas Virgenes Americanas. Inundaciones urbanas son posibles con esta actividad. Un riesgo moderado de corrientes marinas continuara para algunas playas del este y sur Santa Cruz durante los proximos dias. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores individuales a reportar vietos fuertes, granizos, inundaciones, trombas marinas y corrientes marinas al Servicio Nacional de Meteorologia en San Juan.
Special Weather Statement
National Weather Service San Juan PR
1245 PM AST Sat Aug 17 2019
PRZ005>007-009-171730-
North Central-Central Interior-Western Interior-Ponce and Vicinity-
1245 PM AST Sat Aug 17 2019
...A STRONG THUNDERSTORM IS AFFECTING THE MUNICIPALITIES OF CENTRAL
PUERTO RICO...
At 1243 PM AST, a strong thunderstorm was located near Jayuya with
possible winds in excess of 30 mph. Conditions are favorable for
additional thunderstorm development through the afternoon.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 1834 6639 1809 6643 1809 6651 1817 6653
1818 6660 1813 6676 1836 6676 1842 6649
TIME...MOT...LOC 1643Z 000DEG 0KT 1822 6654
ERGComunicado Especial de las Condiciones del Tiempo Servicio Nacional de Meteorologia San Juan PR 1245 PM AST domingo 17 de agosto de 2019 PRZ005>007-009-171730- Norte central- Central Interior- Oeste Interior- Ponce y Vecindad- 1245 PM AST domingo 17 de agosto de 2019 ...UNA TRONADA FUERTE ESTA AFECTANDO MUNICIPIOS DEL CENTRO DE PUERTO RICO... A las 1243 PM AST, una tronada fuerte estaba localizada cerca de Jayuya con posbles vientos en exceso de 30 mph. Las condiciones son favorables para el desarrollo de tronadas adicionales esta tarde. Lluvia torrencial esta ocurriendo con esta tronada y pudiera causar inundaciones localizadas. No conduza su vehiculo a traves de carreteras inundadas. Rayos frecuentes de nube a tierra estan ocurriendo con esta tronada. Impactos de rayos pudieran ocurrir hasta a 10 millas de la tronada. Busque refucio dentro de un edificio o vehiculo. ERG/LIS
Special Weather Statement
National Weather Service San Juan PR
112 PM AST Sat Aug 17 2019
PRZ005-007>011-171800-
Northwest-North Central-Mayaguez and Vicinity-Western
Interior-Southwest-Ponce and Vicinity-
112 PM AST Sat Aug 17 2019
...A STRONG THUNDERSTORM WILL AFFECT THE MUNICIPALITIES OF THE
INTERIOR AND WESTERN PUERTO RICO...
At 110 PM AST, a strong thunderstorm was located across western
Puerto Rico with winds in excess of 30 mph possible.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 1834 6672 1808 6672 1808 6716 1818 6717
1820 6715 1822 6716 1822 6717 1835 6718
TIME...MOT...LOC 1710Z 240DEG 0KT 1819 6694
ERGComunicado Especial de las Condiciones del Tiempo Servicio Nacional de Meteorologia San Juan PR 112 PM AST domingo 17 de agosto de 2019 PRZ005-007>011-171800- Noroeste- Norte Central- Mayaguez y Vecindad- Oeste interior- Suroeste- Ponce y vecindad- 112 PM AST domingo 17 de agosto de 2019 ...UNA TRONADA FUERTE ESTA AFECTANDO MUNICIPIOS DEL INTERIOR Y OESTE DE PUERTO RICO... A las 110 PM AST, una tronada fuerte estaba localizada cerca de Jayuya con posbles vientos en exceso de 30 mph. Lluvia torrencial esta ocurriendo con esta tronada y pudiera causar inundaciones localizadas. No conduza su vehiculo a traves de carreteras inundadas. Rayos frecuentes de nube a tierra estan ocurriendo con esta tronada. Impactos de rayos pudieran ocurrir hasta a 10 millas de la tronada. Busque refucio dentro de un edificio o vehiculo. ERG/LIS
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Road 65 de Infanteria in front of Cuartel de Antillas was closed due to flooding.
Avenida Baldorioty with Luisa Street was closed due to flooding.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2019Every state in 2019This day in weather historyWarnings in Puerto Rico, August 2019
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: 849626, 849627.