The advisory is in effect until 11 p.m. Sunday, Sept. 4.
Excessive rainfall is expected to result in minor flooding in low-lying and poor drainage areas.
NWS says up to two inches of rain have already fallen in the advisory area, and an additional inch of rainfall is expected.
Click here to view flood safety tips.
NWS wants to remind those in the advisory area to be cautious when traveling and to "turn around, don't drown."