Monitoring Reports

There was no rain in most of the Potomac basin over the past 24 hours, but according to Middle Atlantic River Forecast Center (MARFC) estimates, 0.25 to 0.50 inches of rain fell in a few isolated locations in the western part of the basin yesterday. Forecasts call for the dry conditions to continue, but the MARFC predicts precipitation accumulations of over 0.10 inches in the far western portion of the basin over the next 3 days.

REVISION Recent basin-wide average precipitation (above Little Falls):

According to the Middle Atlantic River Forecast Center, little precipitation fell in the basin over the past 24 hours, and little is expected for the next three days.

According to Middle Atlantic River Forecast Center estimates, little or no rain fell in the Potomac basin over the past 24 hours. According to forecasts, 0.01 to 0.75 inches of rain is expected for the next 7 days (very little of this rain is expected for the next 5 days).

According to Middle Atlantic River Forecast Center estimates, little or no rain fell in the Potomac basin over the past 72 hours. According to forecasts, no significant rain is expected for the next 7 days.

Yesterday brought no relief from the dry conditions in the Potomac basin. The National Weather Service forecasts negligible accumulations of precipitation over the next 7 days.

Daily Flows:
Little Falls gage flow 2019-09-25: 1060 MGD (1640 cfs)
Little Falls gage flow 2019-09-26: 1034 MGD (est., based on recently available real time data) (1600 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

Dry conditions persist, with negligible precipitation in the Potomac basin over the past several days. The National Weather Service's forecast calls for little rain over the next 7 days.

Daily Flows:
Little Falls gage flow 2019-09-24: 1053 MGD (1630 cfs)
Little Falls gage flow 2019-09-25: 1034 MGD (est., based on recently available real time data) (1600 cfs)
Note: Gage flow at Little Falls is measured after water supply withdrawals.

The Potomac remains dry with 2.8 inches below normal basin average precipitation over the past 30 days. The Middle Atlantic River Forecast Center's 24 and 72 hour precipitation forecast shows 0 to 0.1 inch of precipitation over isolated parts of the basin. The 7-day total precipitation forecast shows 0 to 0.1 inch of precipitation over most of the basin.

Potomac River flow at Point of Rocks has dropped below the low-flow threshold of 2,000 cfs. Today CO-OP is initiating daily monitoring and reporting of Potomac flows and withdrawals. Today's report appears below.

Conditions have been dry throughout the basin over the past couple of months. National Weather Service precipitation estimates indicate that the basin received no appreciable rain over the past 7 days, and forecasts call for little rain over the next seven days.

The National Weather Service (NWS) 24 hour observed precipitation shows that there was between 0.10 and 3.00 inches of precipitation in the Potomac basin above Little Falls. The NWS 3-day and 5-day forecasts both predict 0.00 to 0.25 inches of rain in this same area.

According to the Middle Atlantic River Forecast Center (MARFC), portions of the basin received no rain or trace amounts over the last 24 hours, and the northwestern edge of the basin received up to 2 inches. Over the next day, MARFC predicts 1 to 1 3/4 inches in the drainage area above Little Falls dam. Although flow at the US Geological Survey gage at Point of Rocks is currently above 2,000 cfs, our trigger for daily monitoring, we will continue daily monitoring efforts until we see that flows have significantly improved for several days.