* WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Portions of central, northeast, and northern Maryland, including the following areas, in central Maryland, Anne Arundel and Central and Southeast Howard. In northeast Maryland, Cecil. In northern Maryland, Northern Baltimore, Northwest Harford, Southeast Harford and Southern Baltimore. * WHEN...Through late tonight. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - Strong to severe thunderstorms are likely to push across the area this afternoon and evening with a humid air mass in place. Very heavy rainfall rates are possible in these storms. These rates could approach 1 to 2 inches per hour, with higher instantaneous rates possible. The most vulnerable locations would be urbanized areas along I-95 as well as areas which have experienced heavy rainfall in recent days. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.