ESS124
Prof.
Jin-Yi Yu
Flooding from Frontal
Overrunning
•During the cold season, east-west oriented warm fronts often develop across the southeastern US.
•Sometimes these fronts stall, or moves so slowly that they are essentially
stationary.
•When such a front present, warm, moist air originating over the Gulf of Mexico flows northward over the cool air-mass north of
the front.
•This process, called frontal overrunning, produces clouds and rains north of the
frontal boundary.
•Heavy rain and
thunderstorms can develop north of the surface frontal position.
•If the front is present over a region for several days, the rain accumulated can lead to
local flash
flooding or even widespread flooding.