Karen will not only impact those along the upper Gulf Coast, but also up the spine of the Appalachians and to the Northeast.
The AccuWeather.com Hurricane Center expects Karen to make its first landfall in southeastern Louisiana early Sunday morning.
Karen will be either a minimal tropical storm or depression at that time, but will weaken to a tropical rainstorm before the close of the weekend.
Around that same time, Karen will merge with a cold front and begin its journey up the spine of the Appalachians and to the Northeast--accompanied by heavy rain.
This cold front will first continue triggering some drenching and gusty thunderstorms across the Midwest this weekend.
Sunday night, a band of heavy rain will stretch from eastern Michigan to the eastern Tennessee Valley and southward to the Florida Panhandle.
The rain will then shift northeastward Monday through Tuesday across the Appalachians, mid-Atlantic and New England.
Monday is when the rain will soak Charlotte, N.C., Pittsburgh and Harrisburg, Pa., and Buffalo and Syracuse, N.Y.
The rain will then spread to Albany, N.Y., Burlington, Vt., and the I-95 cities of Richmond, Va., Washington, D.C., Philadelphia, New York City and Boston Monday night through Tuesday.
Rain totals will generally range from 1 to 2 inches, with locally higher amounts, from the spine of the Appalachians to the Northeast.
More adverse than ruining outdoor plans, enough of that rain could fall in a short enough time to trigger flash flooding in low-lying and poor drainage areas. These downpours could also slow down motorists and lead to flight delays.
Fallen leaves could worsen the situation by clogging storm drains and making roads slippery, while some of the heaviest downpours will be accompanied by a burst of strong winds.
Prolonged gusty winds will whip the coastline from the Carolinas to New England Monday through Tuesday ahead of the rain. Rough surf will result and pose dangers to swimmers and small craft.
There is good news to the upcoming soaking. The rain will be beneficial to those places that are currently in the midst of a dry spell.