NWS Issues Flash Flood Watch for Florida, Pacific Northwest

Lead: The National Weather Service issued a flash flood watch Wednesday for the southern Florida Peninsula and parts of the Pacific Northwest as heavy thunderstorms driven by a slow-moving front and an upper-level low threaten excessive rainfall.

Nut Graf: Forecasters warn that 1-3 inches of rain, with localized amounts up to 4 inches, could inundate urban and burn-scar areas, prompting rapid runoff and potential flash flooding through Thursday morning.

Florida Peninsula Threat

A stationary front draped across northern Florida will slowly shift southward, colliding with Gulf moisture and spawning clusters of heavy showers and thunderstorms Wednesday afternoon. Meteorologists note 2000-3000 J/kg of instability and precipitable water values above 1.75 inches will fuel rainfall rates capable of overwhelming soils already near saturation, especially in urban corridors of Miami-Dade and Broward counties.

Pacific Northwest Concerns

In Oregon and northwest California, a deep upper-level trough and cutoff low will stall thunderstorms over burn scars from recent wildfires. Flash flood guidance values in affected mountain zones are low, raising the risk of sudden creek and canyon inundations late Wednesday into early Thursday.

Timing and Impacts

• Effective: 12 UTC September 10 through 12 UTC September 11
• Expected Rainfall: 1-3 inches widespread; localized 4+ inches
• Primary Hazards: Rapid runoff in urban, coastal-plain, and burn-scar terrains; flooded roadways; stranded vehicles

Motorists should avoid low-lying underpasses and water-covered roads, while residents in flash-prone zones are urged to monitor local alerts and prepare for possible evacuations. Emergency managers and first-responders remain on heightened alert as multiple rounds of storms track through both regions.