Potomac River at Harpers Ferry Forecast Change
Begins May 3rd, 2016

On Tuesday, May 3rd, 2016, the National Weather Service will improve the level of forecast services being provided on the Potomac 
River at Harpers Ferry, West Virginia. This forecast point currently serves all of the Potomac River in Jefferson County, West
Virginia, and a portion of the Potomac River in eastern Washington County, Maryland; generally the area from Dam Number Four
downstream to Harpers Ferry. 

Currently, the National Weather Service only provides a forecast at Harpers Ferry if the river is expected to reach high water
levels -- that is, it is forecast to be near or above flood stage. When that forecast is provided, it is only a specific peak or
crest value with no indication of when flood stage will be exceeded, or how long the flood is expected to last.

On May 3rd, when these changes take effect, a full 72-hour forecast will be provided every day and updated as needed, 
whether flooding is expected or not. This will be similar to the forecast services provided on most of the remainder of 
the Potomac, including downstream at Point of Rocks.

Flood watch and warning services will remain unchanged -- they will still be issued when the river is forecast to exceed
the defined flood stage of 18 feet. However, after May 3rd, those watches and warnings will contain more detailed and
specific information on the timing of potential or expected flooding.

It is also important to note that due to the location of the gauging equipment on the shoreline, at lower flows observed
data from this location is not available. This usually happens for several months each year. Despite this limitation, 
forecasts will still be provided, giving recreational users along the Potomac a more precise idea of what water levels
are likely to be.

Forecasts for Harpers Ferry, starting May 3rd, can be found at this link:
https://water.weather.gov/ahps2/hydrograph.php?wfo=lwx&gage=hfew2