Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, and drought, as of the end of July 2016. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing the data and maps used in this post. Icons for precipitation, stream flow, and drought are by George Wills of Blacksburg, Va. (https://www.etsy.com/people/BlacksburgArt). For previous monthly water status reports, please see this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Water+Status.
Here are National Weather Service (NWS) preliminary (still needing verification) precipitation totals for July 2016 at 11 Virginia or near-Virginia locations, along with the “normal” (three-decade average) for this month of the year at each location. Also shown are the precipitation totals at each location for the previous 12 months and the annual precipitation normals for each location. All values are in inches.
|Monthly Normal||August 2015-July 2016 Precipitation
1 – The Bluefield location is the Mercer County, W. Va., airport, near the Va.-W.Va. state line.
2- The Bristol location Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va./Tenn.
3 – The Charlottesville location is the (Charlottesville-Albemarle Airport.
4 – Wallops Island is in Accomack County.
5 – Washington-Dulles Airport is in Loudoun County.
Precipitation sources: Climate pages of the following National Weather Service Forecast Offices:
Blacksburg, Va. (http://www.nws.noaa.gov/climate/index.php?wfo=rnk);
Morristown, Tenn. (http://www.weather.gov/climate/index.php?wfo=mrx;
Baltimore-Washington (http://www.nws.noaa.gov/climate/index.php?wfo=lwx); and
Wakefield, Va. (http://www.nws.noaa.gov/climate/index.php?wfo=akq).
The normal values used by the National Weather Service (NWS) in these provisional reports are based on the period from 1981 to 2010. The National Climatic Data Center released these normal values in July 2011. For information on the normal values, see the National Climatic Data Center Web page at http://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/climate-normals.
For graphs of precipitation, visit the Southeast Regional Climate Center (Chapel Hill, N.C) at http://www.sercc.com/climateinfo/precip_maps, where you can find maps of total precipitation and percent of normal precipitation for the past 7, 30, 60, or 90 days; or the NWS’ Advanced Hydrologic Prediction Service at http://water.weather.gov/precip/ for a map of precipitation nationwide or by state, with capability to show county boundaries, and archives available for specific days, months, or years. Shown below are the Southeast Regional Climate Center’s preliminary maps of the percent-of-normal precipitation for the previous 30 days, 60 days, and 90 days, through July 31, 2016.
According to the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/index.php?m=mv01d&r=va&w=map), monthly average stream flow values for July 2016 at 151 stream gages in Virginia and just beyond the state border were in the normal range at about 66% of gages, above normal at about 30%, much above normal at about 4%, and below normal at the James River/Kanawha Canal near Richmond. The color-coded, flow-percentile map for this period is shown below. The color codes/percentile classes used by USGS to compared flows to historical records for the month are shown in the chart below the map.
An overall look at Virginia streamflow conditions is provided in the USGS WaterWatch summary plot of average streamflow conditions. Below is the summary plot for 88 Virginia sites during the 45-day period ending July 30, 2016, accessed at http://waterwatch.usgs.gov/index.php?id=pa07d&sid=w__plot&r=va on August 1, 2016.
Information on current groundwater levels in Virginia monitoring wells is available from the U.S. Geological Survey’s National Water Information System, online at http://waterdata.usgs.gov/va/nwis/current/?type=gw; and from the USGS Climate Response Network, online at http://groundwaterwatch.usgs.gov/net/ogwnetwork.asp?ncd=crn (at that page, you can find a national map showing the status of groundwater monitoring wells compared to historical values).
DROUGHT IN VIRGINIA
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) for July 26, 2016, showed about 6% of Virginia as “abnormally dry,” covering all or part of about nine northern and northwestern counties along with part of Scott County in far southwestern Virginia.
Drought Monitor categories are as follows:
D0 = abnormally dry;
D1 = moderate drought;
D2 = severe drought;
D3 = extreme drought;
D4 = exceptional drought.
The Drought Monitor notes that it “focuses on broad-scale conditions [and] local conditions may vary.”
For comparison, here are Virginia ratings from previous Drought Monitors from about one month, two months, three months, and one year ago:
6/28/16 – about 3% abnormally dry;
5/31/16 – about 2% abnormally dry;
4/26/16 – about 95% abnormally dry or worse; about 4% in moderate drought;
7/28/15 – drought-free.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on July 19, 2016. A link to the report, along with other current drought-status information, is available online at http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx. The Task Force’s reports typically include 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. The next report is scheduled for August 11, 2016.
The Drought Monitoring Task Force also produces a daily map rating drought-status indicators. Shown below is daily map for August 1, 2016. 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 listed above.
The July 26, 2016, U.S. Drought Monitor rated 46.1% of the United States (including all or parts of 49 states, plus Puerto Rico) as being abnormally dry or worse. The Drought Monitor rated 6.0% of the country (including all or parts of 20 states), as being in severe drought or worse (categories D2, D3, and D4). The highest percentage in the severe-or-worse categories reported by the Drought Monitor since it began in 2000 was 38.5% of the country for the week of August 7, 2012.
The nationwide percentages for abnormally dry or worse (D0-D4) and severe or worse (D2-D4) in the previous three months and one year ago were as follows:
6/28/16 – 40.8% abnormally dry or worse; 4.6% severe drought or worse;
5/31/16 – 29.4% abnormally dry or worse; 3.6% severe drought or worse;
4/26/16 – 37.0% abnormally dry or worse; 5.0% severe drought or worse;
7/28/15 – 48.4% abnormally dry or worse; 15.0% severe drought or worse.
In California, 59.0% of the state was categorized by the July 26 report as being in severe-or-worse drought. This severe-or-worse percentage—which has been the Drought Monitor rating for California since the week of 5/31/16—is the lowest reported by the Drought Monitor for the Golden State since 53.5% for the week of June 11, 2013. California’s current drought began in late 2011 to early 2012.
Following are some comments from the July 26, 2016, Drought Monitor on extreme high temperatures seen in several parts of the country in July.
“…Daily-record highs for July 23 reached 99°F in Williamsport, PA, and 97°F in Bridgeport, CT. On July 24-25, Pennsylvania locations such as Reading (96 and 97°F) and Allentown (95°F both days) posted consecutive daily-record highs. All of the major airports in the Washington, D.C., area hit 100°F (and noted daily-record highs) on July 25, marking the first triple-digit heat in all three locations since July 2012. For several Mid-Atlantic locations, including Newark, NJ (99°F), and Philadelphia, PA (97°F), highs on July 25 broke daily records originally set in 1999….Impacts of the Northeastern drought were obvious in the agricultural sector, with the U.S. Department of Agriculture (USDA) rating topsoil moisture at least half short to very short on July 24 in Rhode Island (97%), Connecticut (85%), Massachusetts (80%), New Hampshire (70%), Pennsylvania (63%), and New York (54%)….”
“… In recent days, triple-digit daily-record highs were reported in Southeastern locations such as Columbia, South Carolina (102°F on July 26), and Athens, Georgia (101°F on July 25). By July 24, USDA indicated that topsoil moisture ranged from 40 to 74% very short to short in eight states stretching from Texas to South Carolina. …In addition to agricultural effects, Southeastern drought impacts were apparent in low streamflows and beginning to show in some lake levels. For example, Georgia’s Lake Lanier was 4.40 feet below full pool on July 27, 2016, and 4.07 feet below the level observed 2 years ago, on July 27, 2014.”
“…On July 25, Midland, Texas, set a July record with its 19th day of triple-digit heat. Previously, Midland had recorded 18 days with high of 100°F or greater in July 1964. Midland also set a July record with 9 days of 105-degree heat—all from July 3-14—eclipsing its July 1995 standard of 6 days….”
“…In South Dakota, triple-digit, daily-record highs for July 20 soared to 108°F in Dupree and 107°F in Timber Lake. On July 24, South Dakota led the nation with 15% of its spring wheat rated in very poor to poor condition, followed by North Dakota at 10%….”
“…By July 25, daily-record heat returned to portions of the interior Northwest, where Yakima, Washington, posted a high of 102°F. …Farther south, heat also returned to southern California, where record-setting highs for July 23 rose to 110°F in Riverside and 108°F in Campo. …On July 19, Salt Lake City, Utah, noted its first-ever minimum temperature above the 80-degree mark—the low was 81°F—with records dating to 1874.”
90-DAY DROUGHT OUTLOOK
For a look ahead, the National Weather Service/Climate Prediction Center’s “U.S. Seasonal Drought Outlook” is available at http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php. Shown below is the outlook map available on August 1, 2016.