Flash Flood — Lebanon, Pennsylvania

2025-06-30 · near Palmyra, Lebanon, Pennsylvania

Event narrative

Flash flooding was reported in Palmyra with water across a roadway.

Wider weather episode

A slow-moving warm front in an extremely moist (PWAT values exceeding 2.00, values closer to 2.25 across the Lower Susquehanna Valley) and unstable environment allowed for multiple clusters of thunderstorms to begin to form during the late morning hours and continue through the late evening hours of June 30, 2025. A shortwave trough stationed across the region allowed for enhanced lift, with relatively weak shear in place, bringing a severe threat in the form of wet downbursts and a flash flood threat given training thunderstorms with efficient rainfall rates in excess of two inches per hour across southern Pennsylvania. Isolated thunderstorm wind damage was observed across Tioga County, with tree damage observed in Lancaster County and a widespread area of trees and wires knocked down in Cumberland County due to a wet microburst. Multiple rounds of thunderstorms during the afternoon and evening hours across Lancaster County, where multiple days of heavy rainfall led to low flash flood guidance, prompted widespread flash flooding across the northern half of the county, with multiple water rescues reported in Mount Joy and Manheim. Multiple roadways were closed across northern Lancaster County and southern Lebanon County due to heavy rain, with isolated instances of flash flooding in Cumberland County. Flooding concerns in Lancaster County continued into the early morning hours of July 1, 2025 as the heaviest rain began to move out of the area.

View location on OpenStreetMap → (40.3072, -76.5920)

Source: NOAA Storm Events Database, event_id 1269042. Narrative written by the NWS forecast office that issued the report.