The National Weather Service (NWS) in San Juan issued flood advisories for several Puerto Rico municipalities on the afternoon of September 7. Vega Alta, Morovis, and Corozal were under flood advisories until 3:30 PM due to 1–2 inches of rain, with the NWS advising residents to avoid crossing flooded areas and stay away from high ground before flooding begins.
Vega Baja was under a flash flood warning until 4:15 PM after 1–3 inches of rain, with the NWS flagging rising levels on the Cibuco, Indio, and Unibón rivers. San Juan, Carolina, Canóvanas, Loíza, and Río Grande were under flood advisories until 3:30 PM after 1–1.5 inches of rain, with the NWS warning of minor flooding in roads, urban areas, and low-lying, poorly drained zones.
Fajardo and Luquillo were under advisories until 4:15 PM after 1–2 inches of rain. At 1:01 PM, the NWS issued an advisory valid until 4:00 PM for Hatillo, Isabela, Lares, Moca, Quebradillas, and San Sebastián, citing Doppler radar readings of heavy rain from thunderstorms, up to one inch already recorded, with an additional 1–2 inches expected, warning of minor flooding in urban areas and small streams.