Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, and drought, as of the end of June 2017. 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 June 2017 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. The values are in inches.
|Location||June 2017 Observed
|Monthly Normal||July 2016-
June 2017 Observed
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 June 30, 2017.
According to the U.S. Geological Survey WaterWatch for Virginia, average stream flows for the 28-day period through July 2, 2017, at 153 stream gages in Virginia and just beyond the state border were in the normal historical range at about 67% of gages, below normal at about 9%, above normal at about 22%, and much above normal at about 2%. Shown below is the color-coded, flow-percentile map for this period, accessed online at https://waterwatch.usgs.gov/index.php?m=pa28d&r=va&w=map on 7/3/17. 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 daily average streamflow conditions, compared to historical records for any given date. Below is the summary plot for 88 Virginia sites during the 45-day period ending June 30, 2017, accessed on July 3 at https://waterwatch.usgs.gov/index.php?id=pa01d&sid=w__plot&r=va.
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 June 27, 2017, categorized 0.9% of Virginia as “abnormally dry” (in Arlington and Fairfax counties).
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:
5/30/17 – drought-free;
4/25/17 – 46.4% abnormally dry or worse, 16.0% moderate drought;
3/28/17 – 61.0% abnormally dry or worse, 41.0% moderate drought or worse, 2.2% in severe drought;
6/28/16 – 3% abnormally dry.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent (as of 7/1/17) Drought Status Report on June 21, 2017. 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 Task Force is next scheduled to meet on July 13, 2017. Following is an excerpt from the June 21 report:
“Above normal precipitation during May and the first half of June eliminated dry surface conditions across Virginia. Stream flow gaging stations across the Commonwealth are reporting normal to above-normal flows. Most of the wells in the Virginia Climate Response network of groundwater level observation wells are also reporting normal to above-normal levels. However, levels in the network well representing the Northern Piedmont drought-evaluation region continue to be well below normal. The Virginia Department of Environmental Quality (DEQ) had issued a drought Watch for this region and for the Northern Virginia drought-evaluation region on March 22, 2017. The Task Force recommended the removal of the Drought Watch within the Northern Virginia region based on the improvement in all drought indicators in that area. The DMTF also agreed to recommend continuing the Drought Watch in the Northern Piedmont region, based upon continued low groundwater levels and consequent low base flows between storm events.”
The Drought Monitoring Task Force also produces a map rating drought-status indicators. Shown below is the map for June 27, 2017. 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 June 27, 2017, U.S. Drought Monitor categorized 23.2% of the United States (including all or parts of 34 states) as being abnormally dry or worse. The Drought Monitor categorized 2.7% of the country (including parts of 7 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 (categories D0-D4) and severe or worse (categories D2-D4) in the previous three months and one year ago were as follows:
5/30/17 – 20.7% abnormally dry or worse, 0.9% severe drought or worse;
4/25/17 – 23.6% abnormally dry or worse, 0.9% severe drought or worse;
3/28/17 – 34.9% abnormally dry or worse, 2.4% severe drought or worse;
6/28/16 – 40.8% abnormally dry or worse; 4.6% severe drought or worse.
Following are some more comments from the June 27 Drought Monitor on conditions in several parts of the country (bolding added).
“All substantial precipitation over the past week fell over the eastern half and southern portion of the United States. Tropical Storm Cindy played a large role. The storm made landfall near the Louisiana-Texas border on June 22, bringing heavy rains and subsequent flooding to parts of the South and the Ohio Valley.”
“The western areas of this region saw precipitations totals of 1 to 3 inches with less in the eastern areas, the exception being along the track of the remnants of Cindy. …The remnants of Cindy brought substantial rainfall to southeast Ohio…and northern West Virginia, enough to support the removal of all D0 in this area. No drought indicators show dryness at any of the shorter timescales here. …Abnormal dryness also extended south through Washington D.C. into Arlington and part of Fairfax Counties in Virginia. Generally, many mid-Atlantic pastures turned brown during the recent heat wave and remain brown in areas where Cindy didn’t provide much rain.”
“Moisture from Tropical Storm Cindy brought widespread heavy rains to alleviate lingering drought and dryness in several locations. The rain was enough to wash away all D1 and substantially shrink the remaining abnormally dry region in northwestern Alabama into northeastern Mississippi. …In Florida, the wet season, which is typically from June to November, began on time and with a lot of moisture. …Although there are some areas of lingering dryness in northern, central, and southern Georgia, only a small pocket of D1 remains, in southern White County in the northeast.”
“The 3-6 inches of rain in northwestern Louisiana effectively wiped out the dry region from Bienville to Caddo Parishes. Unfortunately, this past week’s rain was inadequate to ameliorate large deficits loom since the beginning of May in Oklahoma, with the prime rainy season (May through mid-June) disappointing for much of the state, especially central Oklahoma. …On-the-ground observations indicate that stock ponds are rapidly shrinking and grass is turning yellow. Local fire weather experts report that much of central Oklahoma began transitioning from live to dead fire fuel weeks ago….”
“…North Platte, Nebraska,…tied a June record on the 21st, reaching 107°F. …The most deterioration…occurred in the Dakotas, especially northwestern South Dakota and North Dakota, where the rapidly worsening conditions warranted expansion of moderate, severe, and extreme drought to many regions.”
“…States along the Pacific Coast are still seeing surpluses given the heavy rains and large snowpacks earlier this year. Thus no changes were made to most of the area, the exception being eastern Montana. Conditions [there]…have deteriorated quickly over the past few weeks and this flash drought will continue to be monitored closely in the midst of the growing season.”
“…[S]table conditions continue to keep things dry overall across the Islands. With less rainfall over the past 4 to 6 weeks, the Big Island is seeing the most impacts related to the dryness. Reports from the FSA indicate worsening conditions with ranchers having to destock pastures and haul water for their herds. Even on the normally wetter east side of the Big Island, field reports indicate drying vegetation and lowering stream levels.”
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 June 30, 2017.