According to MARFC and CO-OP's Low Flow Forecast System, precipitation totals between 0 and 0.28 inches occurred yesterday. The next 72-hour forecast predicts a precipitation total of up to 0.1 inches for basin locations above the USGS gage at Point of Rocks. Longer-range forecasts (5- and 7-days) indicate heavier rain with accumulations of about an inch in the North Branch area of the basin.
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: 0.08 (inches)
Past 3-day cumulative area-weighted average basin precipitation: 0.08 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.28 (inches)
Daily flows:
Little Falls gage flow 2022-11-06: 1215 MGD (1880 cfs)
Little Falls gage flow 2022-11-07: 1176 MGD (est., based on recently available real-time data) (1820 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2022-11-06: 1222 MGD (1890 cfs)
Point of Rocks flow 2022-11-07: 1222 MGD (est., based on recently available real-time data) (1890 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2022-11-06):
Fairfax Water Corbalis withdrawal (Potomac): 71 MGD
WSSC Water Potomac withdrawal: 120 MGD
Washington Aqueduct withdrawal: 121 MGD
Loudoun Water withdrawal: 15 MGD
Loudoun Water Broad Run discharge: 6 MGD
Total Potomac withdrawal: 326 MGD
Total net Potomac withdrawal: 320 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1890 cfs
QPR, obs: 1890 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.