With fall 2013 well underway on October 3, here’s a look back at what happened with rainfall in the southeastern United States and stream flow in Virginia in summer 2013.
The following “Percent of Normal Precipitation” graph, from the National Oceanic and Atmospheric Administration’s (NOAA) Southeast Regional Climate Center, located at the University of North Carolina in Chapel Hill (http://www.sercc.com/climateinfo/precip_maps, accessed 10/3/13), shows how the previous 90-day precipitation amounts in the southeastern United States compared to historical normal values for those periods. These data are provisional. Note throughout much of Virginia the somewhat below-normal precipitation during this period (indicated by the tan and orange colors), with the obvious exception of far southwestern Virginia (green, indicating above-normal precipitation). These rainfall levels have helped lead about 30 percent of Virginia—most of the Coastal Plain and some parts of the eastern Piedmont—being rated as “abnormally dry” by the October 1, 2013, U.S. Drought Monitor (produced by the University of Nebraska-Lincoln, and available online at http://droughtmonitor.unl.edu/). Three months ago, in the July 2, 2013 Drought Monitor, Virginia was rated as drought-free.
Outside of Virginia, note that many areas received normal to above-normal precipitation (with the eastern half of North Carolina being a notable exception). This has the southeast region continue to be mostly drought free; the October 1 Drought Monitor categorized about nine percent of the region as abnormally dry, compared to approximately the same percentage on June 25, 2013.
For another color-coded map of precipitation in Virginia or any other state of your choosing, see the National Weather Service’s Advanced Hydrologic Prediction Service’s nationwide map of precipitation, with daily, monthly, and yearly archives; online at http://water.weather.gov/precip/.
The first graph below, from the U.S. Geological Survey’s (USGS) “WaterWatch—Current Water Resources Conditions” Web site (http://waterwatch.usgs.gov/new/index.php?id=pa01d&sid=w__plot&r=va), accessed 10/3/13), compares average daily stream flow to historical records for the period August 18—October 1, 2013. The second graph covers the period since January 2001. The data in the graphs come from 87 sites that have at least 30 years of records. Each graph uses a “stream flow index,” which measures how a site’s average stream flow over 24 hours compares to the historical average stream flow for that same site and date. The graphs shows a further average: the stream flow index averaged statewide over the 87 sites.
The Virginia Water Resources Research Center is grateful to the agencies mentioned above for their work to providing these valuable assessment products. For links to several other sources of streamflow, precipitation, groundwater, and other water-status information, please visit the Water Center’s “Water Status Information” Web page at http://vwrrc.vt.edu/waterstatus_new.html.
Please click the following for the Virginia Water Central News Grouper’s previous seasonal look-backs on precipitation and streamflow:
And please click the following for the News Grouper’s most recent monthly Virginia water status report (on precipitation, stream flow, groundwater, and drought), with links to access the previous 12 months’ reports: