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 May 17, 2015. Also below is a map showing the status of several drought indicators in different Virginia regions, as of May 18. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.a
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 May 17, 2015. The maps were accessed 5/18/15 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).
For another precipitation-information source: 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 seven-day precipitation ending at 8 a.m. Eastern Daylight Time on May 18, 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 week ending May 17, 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 5/18/15). The map compares the previous week’s average stream flows—at 136 stream-gaging stations in Virginia and just beyond the state border—to the normal flow levels for that week over the historical record for each gaging station. The color codes/percentile classes used by USGS to compare flows to historical records are as shown in the chart following the map; the “bluer” the color, the higher the percentile and flow relative to normal for the site and time of year.
Mid-month Drought Status Update
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, produces a daily map rating drought-status indicators. Shown below is the May 15, 2015, map. The status-indicator abbreviations on that map are as follows: GW = groundwater levels, Prcp = precipitation deficits, Res = reservoir storage, and Flow = stream flow conditions. For each region of Virginia, the indicators are color coded for “normal,” “watch,” “warning,” or “emergency conditions.” Any given day’s current map and more information on drought status in Virginia are available the Task Force Web site, http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.