Situational Awareness (Thursday, 2023-10-19)
The Potomac River at Point of Rocks is below 2,000 cfs, the CO-OP drought monitoring threshold, but is rising, with expected decreases ahead. According to the Middle Atlantic River Forecast Center predictions, there is no rain predicted in the next 24 hours. Over the next 3 days, the average basin rainfall may be around 0.2 inches.
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: 0.01 (inches)
Past 7-day cumulative area-weighted average basin precipitation: 0.77 (inches)
Daily flows:
Little Falls gage flow 2023-10-18: 1053 MGD (1630 cfs)
Little Falls gage flow 2023-10-19: 1183 MGD (est., based on recently available real-time data) (1830 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.
Point of Rocks flow 2023-10-18: 1209 MGD (1870 cfs)
Point of Rocks flow 2023-10-19: 1280 MGD (est., based on recently available real-time data) (1980 cfs)
Yesterday's Washington metropolitan area Potomac River withdrawals and discharges (2023-10-18):
Fairfax Water Corbalis withdrawal - Potomac: 89 MGD
WSSC Water Potomac withdrawal: 106 MGD
Washington Aqueduct withdrawal - Great Falls: 43 MGD
Washington Aqueduct withdrawal - Little Falls: 57 MGD
Loudoun Water withdrawal: 9 MGD
Loudoun Water Broad Run discharge: 7 MGD
Total Potomac withdrawal: 305 MGD
Total net Potomac withdrawal: 298 MGD
Loudoun Water Potomac River (PR) flow values for drought operations protocol (based on yesterday's flows):
QPR: 1870 cfs
QPR, obs: 1870 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.