The watch goes into effect at 4 p.m. and will remain in effect through the evening
The NWS says thunderstorms will increase in late afternoon and early evening and their is the potential for rainfall rates of 1-2 inches per hour in some areas.
From the NWS:
LOCALLY EXCESSIVE RAINFALL COULD CAUSE RAPID FLOODING OF SMALL STREAMS AS WELL AS LOW-LYING AND URBAN AREAS.
A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.
YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION SHOULD FLASH FLOOD WARNINGS BE ISSUED.