Below are images showing precipitation in Virginia and other areas of the southeastern United States, and stream flow in Virginia, over the seven-day period ending July 28, 2015. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images. For monthly reviews of precipitation, stream flow, and drought, please see the News Grouper posts available at this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Monthly+Water+Status. For more information on current and historical surface-water and groundwater conditions in Virginia, please see the U.S. Geological Survey (USGS) Virginia Science Center’s Web site, http://va.water.usgs.gov/.
The following maps show southeastern U.S. precipitation amounts (top map) and the percent of normal precipitation for the given location at this time of year (bottom map) over the seven-day period ending July 28, 2015. The maps were accessed 7/29/15 from the National Oceanic and Atmospheric Administration’s (NOAA) Southeast Regional Climate Center, located at the University of North Carolina in Chapel Hill; online at http://www.sercc.com/climateinfo/precip_maps. As of that date, these data were provisional (needing to be verified for accuracy and subject to possible revision).
Another source of precipitation data is the National Weather Service’s Advanced Hydrologic Prediction Service, http://water.weather.gov/precip/, provides maps showing precipitation nationwide or by state for specific days, months, or years. The site also has the capability to show county boundaries. Shown below are maps of precipitation and percent of normal precipitation for the 7-day precipitation ending at 8 a.m. Eastern Daylight Time on July 29, 2015. (Please note that UTC, the time shown on the map below, is five hours ahead of Eastern Standard Time and four hours ahead of Eastern Daylight Time.)
Average Virginia stream flow over the seven-day period ending July 28, 2015, is indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/classic.php?m=pa07d&r=va&w=mv01d%2Cmap, accessed 7/29/15). For about 140 stream-gaging stations in Virginia and just beyond the state border, the map’s color-coded dots compare the previous week’s average stream flows to the normal flow levels for that week over the historical record for each gaging station. The “bluer” the color of the dots, the higher the percentile and flow relative to normal for the site and time of year; the “wetter” the dots, the lower the percentile and flow relative to normal. The color codes/percentile classes used by USGS are as shown in the chart following the map.