A strong cold front driven by moderate jet stream winds interacted with a warm and humid airmass over northeast Pennsylvania during the mid afternoon. These features spawned scattered thunderstorms which tracked east and northeast through several counties.
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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 BGM wrote it up.
A strong cold front driven by moderate jet stream winds interacted with a warm and humid airmass over northeast Pennsylvania during the mid afternoon. These features spawned scattered thunderstorms which tracked east and northeast through several counties. A few storms became severe and provided brief bouts of damaging wind gusts and hail between 3:00 and 4:30 p.m where numerous trees and some powerlines were downed over the region. One tree found it's way onto an automobile in Bradford county and another toppled into a house in Susquehanna county.
The national radar mosaic for the moment the first event began.
4 thunderstorm wind. Local standard time, as filed.
Trees and powerlines knocked down from Troy to Wyalusing during this time with one tree landing on an automobile in the town of Milan at 3:45 pm.
Several trees and powerlines blown down. Three-quarter inch hail reported at 3:45 pm in Laceyville.
A tree was uprooted in Lehman.
Numerous trees uprooted from southwest to northeast across the county, with damage reported to a house in New Milford at 4:30 pm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 1999Every state in 1999This day in weather historyWarnings in Pennsylvania, May 1999
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: 5692568, 5692569, 5692570, 5692571.