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 December 16, 2014. Also below is a map showing the status of drought indicators in Virginia as of December 17, 2014. 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: http://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 December 16, 2014. The maps were accessed on 12/17/14 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 12/17/14, these data are 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. As an example, shown below is the map of one-day precipitation ending at 7 a.m. EST on December 17, 2014. (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 December 16, 2014, 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 12/17/14). The map compares the previous week’s average stream flows at about 140 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 compared flows to historical records for the month are as follows (higher the percentile and the “bluer” the color, the higher the flow):
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on December 16, 2014. The report typically includes information from some or all of the following agencies: University of Virginia Climatology Office, U.S. Geological Survey (USGS), and the Virginia departments of Agriculture and Consumer Services, Health, and Environmental Quality. Task Force reports and other current drought-status information are available online at http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.
Here is the first paragraph of the December 16 report, summarizing statewide conditions: “The dry conditions across parts of central and eastern Virginia that have persisted for several months were moderated by precipitation events during late November and early December. Consequently, streamflows at some gaging stations in these regions are now within normal ranges. Below normal streamflows still persist in parts of eastern Virginia, however. Below normal groundwater levels also persist in several climate-response observation wells in these areas. A significant continuation of dry conditions through the winter months will negatively affect the normal ground water recharge pattern.”
The Drought Monitoring Task Force also produces a daily map rating groundwater levels (GW), precipitation deficits (Prcp), reservoir storage (Res), and stream flow (Flow) conditions across the Commonwealth. In each area, a color code indicates “normal,” “watch,” “warning,” or “emergency conditions.” Shown below is the December 8, 2014, map (the most recent one available on 12/17/14). A given day’s current map and more information on the ratings are available the Task Force Web site listed above.