Monitoring Reports

Potomac River flow has remained relatively steady over the past week. According to National Weather Service forecasts, we can expect about 2 inches of rain during the next three days, mainly on Friday, as the remnants of tropical storm Nicole pass over 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)

There was no precipitation in the Potomac basin yesterday and none is forecast for the next three days. However, it looks like relief is on the way - there is a good chance of heavy rain late this week from subtropical storm Nicole.

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)

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.

Light rain is forecast in the Potomac basin over the next three days, with accumulations of up to 0.25 inches predicted for some areas. Longer range forecasts indicate heavier rain – with accumulations of about an inch - 6 and 7 days in the future. 

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)

River flow at Point of Rocks continues to track close to CO-OP’s daily monitoring threshold of 2000 cfs and is expected to for the next couple of days. The basin received no precipitation yesterday. Precipitation forecast totals are between 0.01 and 0.1 inches for the next three days.

River flow at Point of Rocks is expected to remain close to CO-OP’s daily monitoring threshold, 2000 cfs, for the next several days. The basin received negligible precipitation yesterday. Precipitation totals between 0.0 and 0.1 inches are forecast for the next three days.

River flow at Point of Rocks is expected to remain close to CO-OP’s daily monitoring threshold, 2000 cfs, for the next several days. The basin received negligible precipitation yesterday. Precipitation totals between 0.01 and 0.1 inches are forecast for the next three days.

River flow at Point of Rocks is expected to remain close to CO-OP’s daily monitoring threshold, 2000 cfs, for the next several days. The basin received negligible precipitation yesterday and no rain is forecast during the next three days.

Most parts of the Potomac basin above Little Falls received 1/10 to ½ inch of rain yesterday. River flows are already responding. However, the forecast is for dry conditions over the next 7 days, so we expect this slight increase in flows to be short-lived.

Daily flows:
Little Falls gage flow 2022-10-31: 1196 MGD (1850 cfs)
Little Falls gage flow 2022-11-01: 1209 MGD (est., based on recently available real-time data) (1870 cfs)

Over the past day, 0 to 0.1 inches of precipitation occurred in the Potomac basin above Little Falls; the majority occurred in the North Branch. According to the MARFC’s 72-hour forecast, total rainfall in the basin will range from 0.01 to 0.5 inches over the next three days, with more rain occurring in the southeastern portions (including the DC area) than in the northwestern parts.