PITTSBURGH, Pa. - A Flood Watch remains in effect through 8 a.m. Wednesday for parts of Western Pennsylvania and northern West Virginia as another round of rain threatens to produce river rises and additional flooding.
The National Weather Service Pittsburgh office continued the watch early Tuesday for an area that includes Allegheny, Washington, Greene, Westmoreland and Fayette counties in Pennsylvania, along with several counties in northern West Virginia.
The watch includes the Pittsburgh metropolitan area as well as communities including Washington, Waynesburg, Greensburg, Latrobe and Uniontown.
In West Virginia, the affected area includes portions of Brooke, Ohio, Marshall, Wetzel, Marion, Monongalia, Preston and Tucker counties, including Morgantown, Fairmont and Wheeling.
Flood threat continues into Wednesday
The latest Hazardous Weather Outlook from the National Weather Service says rounds of rain are expected through the middle of the week.
Forecasters said longer-duration periods of heavier rainfall could lead to river rises and areal flooding across portions of the region.
The Flood Watch is scheduled to remain in effect until 8 a.m. EDT Wednesday, Sept. 23.
A Flood Watch means conditions are favorable for flooding, but it does not mean flooding is occurring everywhere within the watch area.
Residents in flood-prone areas are encouraged to continue monitoring forecasts and be prepared to respond if warnings are issued.
Western Pennsylvania has already experienced repeated rounds of heavy rain and flooding in recent days, increasing concern as additional precipitation moves through the region.
The continuation of the watch means the flooding threat now extends into Wednesday morning rather than ending overnight Tuesday.
Pittsburgh and surrounding counties included
Allegheny County, including Pittsburgh, is among the areas covered by the watch.
Washington, Greene, Westmoreland and Fayette counties are also included, along with higher-elevation portions of Westmoreland and Fayette counties.
The watch extends west into portions of eastern Ohio and south into northern West Virginia.
The National Weather Service said weather spotters in the affected portion of the region are encouraged to report significant weather conditions according to established procedures.
River levels remain a concern
Forecasters are monitoring the potential for rainfall over an extended period to increase runoff into streams and rivers.
Unlike flash flooding caused by an intense burst of rain over a short period, areal flooding can develop as repeated rainfall saturates the ground and water accumulates across broader areas.
River rises can also continue after the heaviest rain has ended as runoff moves downstream.
The National Weather Service Pittsburgh office maintains real-time river observations and forecasts for waterways throughout the region.
Motorists should avoid flooded roads and should not attempt to drive through areas where water covers the roadway.
The National Weather Service advises residents to continue monitoring updated forecasts, watches and warnings as additional rain moves through Western Pennsylvania and northern West Virginia through midweek.