Above-normal moisture due to a tropical wave, and a low pressure northeast of the |CWA resulted in the development of heavy rainfall and strong thunderstorms along the northern half of Puerto Rico. This activity led to urban and small stream flooding along the eastern and northern portions of Puerto Rico during the first couple of days of the month.
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.
Above-normal moisture due to a tropical wave, and a low pressure northeast of the |CWA resulted in the development of heavy rainfall and strong thunderstorms along the northern half of Puerto Rico. This activity led to urban and small stream flooding along the eastern and northern portions of Puerto Rico during the first couple of days of the month.
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 1, 10:14 AM AST, 6 hours 44 minutes earlier.
Area Forecast Discussion National Weather Service San Juan PR 1014 AM AST Tue Aug 1 2023 ...New UPDATE, AVIATION, MARINE... .UPDATE... Issued at 958 AM AST Tue Aug 1 2023 The U.S. Virgin Islands and Puerto Rico will experience above- normal moisture due to a tropical wave in the Caribbean Sea and a surface low-pressure in the Atlantic Ocean. This, combined with high air temperatures, will result in heat index values between 102-107 degrees Fahrenheit in urban and coastal areas (with isolated higher values). The north half of Puerto Rico may experience flooding rains due to thunderstorms caused by excessive heat, local effects, and sea breeze variations. Expect strong gusty winds, heavy rain, and frequent lightning during the most vigorous thunderstorms. && .AVIATION... (12Z TAFS) Issued at 958 AM AST Tue Aug 1 2023 SHRA/TSRA will form later today across the region, especially between 01/15-22z and may affect JSJ/JBQ. MVFR or even IFR conditions are possible at JSJ/JBQ, where TEMPOs are in place. SHRA/TSRA will develop after 01/15Z along and north/west of the Cordillera Central. Periods with reduced VIS and low ceilings, as well as mountain obscuration are expected until 01/22Z. Winds will be out from the ESE/SE at 10-15 kt, but locally higher due to sea breeze and near TSRA, winds will drop below 10 kt aft 01/23z. && .MARINE... Issued at 958 AM AST Tue Aug 1 2023 If you're planning to set sail, be aware that the sea will be between 1 and 4 feet, and there will be east-southeast winds at 5 to 15 knots. However, it's important to note that there could be dangerous marine conditions due to the possibility of thunderstorms forming today. Stay safe out there! && .SYNOPSIS... Issued at 435 AM AST Tue Aug 1 2023 Generally suppressive high pressure at upper levels will moderate shower and thunderstorm development in tropical waves set to pass through the area. Showers will be more numerous today, Thursday, Friday and Sunday with the passage of these waves. Saharan dust, although present, will not limit visibilities as much as in previous weeks. Lighter winds may bring more significant rain amounts to interior municipalities during the week owing to lack of movement of showers and thunderstorms that will develop each afternoon. && .SHORT TERM...Today through Thursday... The axis of a tropical wave is already west of the islands, but moisture lingers. Some cloudiness and showers were observed across the Caribbean waters, reaching eastern Puerto Rico, Vieques and St. Croix at times. The rainfall amounts were unimpressive, as the bulk of the wave split and missed the islands. A low pressure system well northeast of the region will keep the gradient weak, with winds out of the south-southeast today and a steering flow below 10 knots and even lighter for tomorrow and Thursday. Moisture is still above normal, and it should combine with strong diurnal heating and local effects to generate showers across the Cordillera Central. The showers will then be moving into northwestern and northern Puerto Rico, with some even reaching the San Juan metro area. On Wednesday, the steering flow will become light and variable. The afternoon showers will then develop along the Cordillera Central and also around the U.S. Virgin Islands, then spreading downstream into the coastal areas. Light winds also mean that the showers will not move too much, so rainfall accumulations in some areas could lead to urban and small stream flooding, water surges along rivers and streams and mudslides in areas of steep terrain. Moving into Thursday, a feeder band for the aforementioned low pressure (AL96) will reach the islands, bringing another round of showers and thunderstorms. Again, the amounts of the expected rainfall from this feature should not be too significant. The winds will gain a more easterly component, but still very light, so another round of afternoon convection is anticipated for the interior and west, with some showers spreading into the northern and southern coast of Puerto Rico. Additional activity may stream from the Virgin Islands as well. Temperatures will remain above the 30-year climatological mean, but if enough showers and clouds develop in the afternoon, it could bring a slight relief from the very high temperatures experienced lately. However, this will not be felt in all areas, and elevated heat indices will persist along the coastal and urban areas of every island of the forecast area. && .LONG TERM...Friday through Monday... On Friday, a tropical wave will follow close behind the feeder band mentioned above and will bring more showers and afternoon thunderstorms to Puerto Rico, but rain chances elsewhere will under perform. Winds will be southeasterly behind the wave and will maintain the above normal trend in temperatures--at least for the north coast of Puerto Rico. Another tropical wave will move through on Sunday with increasing precipitation amounts and better coverage, but again this should not lead to extreme conditions. At upper levels high pressure maintains its hold on the area. An inverted trough will move across the Lesser Antilles on Saturday and mostly south of the area on Sunday. A weak TUTT will approach the area from the northeast Monday and Monday night. While Saharan dust will not be absent, visibilities should remain above 10 miles. These conditions will produce an unremarkable typical summer scenario, but winds will increase somewhat during the period. && .AVIATION... (06Z TAFS) Issued at 435 AM AST Tue Aug 1 2023 SHRA will stream into the Caribbean waters, reaching the USVI terminals and eastern Puerto Rico at times. SHRA and TSRA are expected to develop after 01/17Z, for the Cordillera Central, spreading to the northwest, and possibly TJSJ. Periods with reduced VIS and low ceilings, as well as mountain obscuration are expected until 01/22Z. Winds at FL050 will be from the SE below 10 kts, becoming even lighter after 01/20Z. && .MARINE... Issued at 435 AM AST Tue Aug 1 2023 Generally tranquil seas will persist through the week. This and generally moderate or less winds will keep forecast rip current risk low through Friday night. The GFS is now delaying the entrance of 7 foot seas in the northeast Atlantic of the local area until Saturday night and Sunday. Small craft advisories may be necessary by early Sunday morning. A moderate risk of rip currents will return to the area beaches on Saturday with most beaches being affected on Sunday and Sunday night. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && CAM,RVT
Perspectivas sobre las Condiciones Peligrosas del Tiempo Nacional de Meteorologia en San Juan PR 420 AM AST martes 1 de agosto de 2023 AMZ711>745-PRZ001>013-020830- 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 del Caribe- 420 AM AST martes 1 de agosto de 2023 Esta perspectiva sobre las condiciones peligrosas del tiempo es para Puerto Rico. .DIA UNO...Hoy y esta noche .Rayos...Tronadas de aisladas son posibles a traves de sectores de las islas y las aguas. Este atento ante tronadas en su area y preparese para buscar refugio. .Lluvia Excesiva...Inundaciones en areas urbanas, carreteras y riachuelos en el interior, oeste y norte. Inundaciones repentinas posibles. .Calor Excesivo...Indices de calor de 102-107 grados en zonas urbanas y costeras. Agotamiento por calor probable con exposicion prolongada. .DIAS DOS A SIETE...miercoles a lunes Riesgo de calor elevado continuara por los proximos dias. Lluvia excesiva y rayos para cada dia, especialemente en el interior, norte y oeste en las tardes. Condiciones maritimas deterioradas durante el fin de seman. Riesgo moderado de corrientes marinas de viernes a domingo. .Comunicado sobre informacion reportada por observadores... No se requiere la activacion de los observadores. AMZ716-726-VIZ001-002-020830- San Tomas, San John y las Islas Adyacentes-Santa Cruz-Aguas cercanas a la Costa del Atlantico y aguas costeras adyacentes del Caribe- 420 AM AST martes 1 de agosto de 2023 Esta perspectiva sobre las condiciones peligrosas del tiempo es para las Islas Virgenes Estadounidenses. .DIA UNO...Hoy y esta noche .Rayos...Tronadas de aisladas son posibles a traves de las islas y aguas adyacentes. Este atento ante tronadas en su area y preparese para buscar refugio. .Calor Excesivo...Indices de calor de 102-107 grados en las zonas urbanas y costeras. Es probable que se experimente agotamiento por calor con una exposicion prolongada. .DIAS DOS A SIETE...miercoles a lunes Calor excesivo para cada dia en las islas. Riesgo moderado de corrientes marinas de viernes a domingo. .Comunicado sobre informacion reportada por observadores... No se requiere la activacion de los observadores.
Special Weather Statement
National Weather Service San Juan PR
436 PM AST Tue Aug 1 2023
PRZ001-002-004-012130-
San Juan and Vicinity PR-Northeast PR-Eastern Interior PR-
436 PM AST Tue Aug 1 2023
...A strong thunderstorm will impact portions of Trujillo Alto, San
Juan, Carolina, Loiza, Caguas, Guaynabo, Bayamon, Catano and Toa Baja
Municipalities through 530 PM AST...
At 435 PM AST, a strong thunderstorm was over San Juan, moving
northeast at 20 mph.
HAZARD...Frequent lightning.
SOURCE...Radar indicated.
IMPACT...Lightning is one of nature's leading killers. If you can
hear thunder, you are close enough to be struck by
lightning.
Locations impacted include...
San Juan, Trujillo Alto, Carolina, Guaynabo, Sabana Seca, Catano and
Levittown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
People outdoors should seek shelter immediately. Electrical
appliances should not be used unless in an emergency.
&&
LAT...LON 1845 6603 1846 6599 1844 6593 1830 6606
1843 6621 1847 6620 1847 6619 1845 6618
1845 6616 1847 6614 1845 6614 1843 6611
1843 6610 1845 6609 1847 6613
TIME...MOT...LOC 2035Z 221DEG 17KT 1843 6609
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...<30 MPH
RCThe San Juan radar (TJUA), 33 km away, was scanning. The volume nearest the first event began at 20:59 UTC.
1 flash flood, 1 thunderstorm wind, 1 flood. Local standard time, as filed.
Flooding was reported in Calle Matadero, close to NUMEAT. Two people were trapped in their vehicles.
Fallen tree at Calle C, in front of Escuela Moises Melendez in Hato Rey.
Rio Blanco was out of its banks and made PR-31 impassable, near exit #22. Two vehicles were trapped in the flood waters.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2023Every state in 2023This day in weather historyWarnings in Puerto Rico, August 2023
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: 1119956, 1119962, 1119965.