Summary (tl;dr)

"Flood watch" is trending due to widespread heavy rainfall and tropical storm activity across several regions, including Hawaii, parts of the United States, and Europe, driven by both immediate weather systems and the intensifying El Niño phenomenon. These conditions are increasing the risk of flash, urban, and river flooding.

Essential Background

A "flood watch" is issued by weather services when conditions are favorable for flooding to occur, meaning that while flooding is not yet happening, it is possible and residents should be prepared to take action. This differs from a "flood warning," which indicates that flooding is imminent or already underway. The current global weather patterns are significantly influenced by a strengthening El Niño, which is expected to intensify into a very strong event and continue through February 2027, leading to notable shifts in rainfall and temperature worldwide and increasing the risk of extreme weather, including floods.

The Full Story

"Flood watch" is trending as multiple regions globally are experiencing or anticipating heavy rainfall and potential flooding. In the United States, Hurricane Lowell recently brought over 23 inches of rain to Mount Waiʻaleʻale on Kauaʻi, leading to damaging winds, heavy rainfall, dangerous surf, and extensive flooding across the Hawaiian Islands, including Oʻahu and Niʻihau, causing road closures and power outages earlier in September 2026. Meanwhile, various parts of the continental U.S. are under "flash flood" alerts. The Southwest and West are grappling with active monsoon patterns, triggering rapid and dangerous flash flooding across the Great Basin and Four Corners region. Flash Flood Warnings have been issued in areas like Accomack County, Virginia. Additionally, heavy rainfall in Northern Georgia and Western North Carolina has resulted in flood watches and flash flooding reports, with some locales receiving 4 to 8 inches of rain. The Philadelphia metropolitan area, encompassing several counties in Pennsylvania and New Jersey, has already recorded a record number of flash flood warnings in 2026 due to persistent, heavy downpours, even without the influence of tropical storms. Further, the Ozarks region, spanning northern Arkansas and southern Missouri, is experiencing flash, urban, and moderate river flooding due to saturated soils and ongoing heavy rainfall. Internationally, northern Italy, Slovenia, and Croatia are also facing forecasts for widespread thunderstorms and heavy rainfall, posing a risk of rapid increases in watercourses and localized flash flooding, with severe storms already causing fatalities and evacuations.

Why It Matters

The widespread issuance of flood watches and warnings highlights an elevated risk of dangerous flooding events, which can lead to significant property damage, disruption of infrastructure, and pose serious threats to human life. Understanding these alerts is crucial for public safety, as most flood-related fatalities occur when people drive or walk through floodwaters. The compounding effect of active storm seasons and a strengthening El Niño suggests that these extreme weather patterns, and the associated flood risks, are likely to persist, making preparedness and awareness of evolving climate conditions increasingly vital for communities globally.

Geographic Location

• Kauaʻi, Hawaii, United States (heavy rainfall, flooding, road closures, power outages due to Hurricane Lowell)
• Niʻihau, Hawaii, United States (heavy rainfall, damaging winds due to Hurricane Lowell)
• Oʻahu, Hawaii, United States (heavy rainfall, flood waters, highway closure due to Hurricane Lowell)
• Maui County, Hawaii, United States (under Flood Watch)
• Big Island (Hawaiʻi), Hawaii, United States (under Flood Watch)
• Great Basin, United States (rapid and dangerous flash flooding due to monsoon patterns)
• Four Corners region, United States (rapid and dangerous flash flooding due to monsoon patterns)
• Accomack County, Virginia, United States (Flash Flood Warning issued)
• North Georgia, United States (under Flood Watch, heavy rainfall, flash flooding)
• Western North Carolina, United States (under Flash Flood Watch, heavy rainfall, flash flooding)
• Philadelphia, Philadelphia County, Pennsylvania, United States (record number of flash flood warnings)
• Bucks County, Pennsylvania, United States (record number of flash flood warnings)
• Chester County, Pennsylvania, United States (record number of flash flood warnings)
• Delaware County, Pennsylvania, United States (record number of flash flood warnings)
• Montgomery County, Pennsylvania, United States (record number of flash flood warnings)
• Burlington County, New Jersey, United States (record number of flash flood warnings)
• Camden County, New Jersey, United States (record number of flash flood warnings)
• Gloucester County, New Jersey, United States (record number of flash flood warnings)
• Northern Arkansas, United States (flash, urban, and river flooding in the Ozarks region)
• Southern Missouri, United States (flash, urban, and river flooding in the Ozarks region)
• Pima County, Arizona, United States (Flash Flood Warning issued)
• Northern Italy (widespread thunderstorms, heavy rainfall, risk of flash flooding, evacuations)
• Slovenia (widespread thunderstorms, heavy rainfall, risk of flash flooding, evacuations)
• Croatia (widespread thunderstorms, heavy rainfall, risk of flash flooding, evacuations)