Potomac River flows continue to slowly decline. A modest amount of rain – ranging from 0.1 to 0.5 inches – is expected in the basin over the next 3 days according to Middle Atlantic River Forecast Center forecasts.
Recent basin-wide average precipitation (above Little Falls):
(based on CO-OP's Low Flow Forecast System analysis of Middle Atlantic River Forecast Center (MARFC) gridded multisensor precipitation estimates)
Yesterday's area-weighted average basin precipitation: 0 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.27 (inches)
Daily flows:
Little Falls gage flow 2023-08-21: 659 MGD (1020 cfs)
Little Falls gage flow 2023-08-22: 611 MGD (est., based on recently available real-time data) (945 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-08-21: 879 MGD (1360 cfs)
Point of Rocks flow 2023-08-22: 834 MGD (est., based on recently available real-time data) (1290 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2023-08-21):
Fairfax Water Corbalis withdrawal (Potomac): 145 MGD
WSSC Water Potomac withdrawal: 139 MGD
Washington Aqueduct withdrawal: 143 MGD
Loudoun Water withdrawal: 5 MGD
Loudoun Water Broad Run discharge: 5 MGD
Total Potomac withdrawal: 432 MGD
Total net Potomac withdrawal: 427 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1360 cfs
QPR, obs: 1360 cfs
QPR, WS: 0 cfs
Note to Loudoun Water: See NWS ensemble flow forecasts (HEFS, GEFS, NAEFS) for Point of Rocks flow for the next 7 days – see https://www.weather.gov/erh/mmefs_marfc?id=PORM2&model=NAEFS.