Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, and drought, as of the end of March 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 March 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. All values are in inches.
|Location||March 2017 Observed
|Monthly Normal||April 2016-
March 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 April 2, 2017. Please note that the scale is different for the 30-day map.
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 March 2017 at 156 stream gages in Virginia and just beyond the state border were in the normal historical range at about 11% of gages, below normal at about 27%, and much below normal at about 62%. 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 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 April 1, 2017, accessed on April 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 March 28, 2017, showed about 61.0% of Virginia as “abnormally dry”; about 41.0% in “moderate drought” (the middle one-third of the state, from Loudoun County to the central North Carolina border, plus the Martinsville region); and about 2.2% in “severe drought” (parts of about seven northern Va. 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:
2/28/17 – 80.5% abnormally dry or worse, 17.1% moderate drought or worse, 2.9% in severe drought;
1/31/17 – 30.0% abnormally dry or worse, 0.5% moderate drought;
1/3/17 – 70.9% abnormally dry or worse, 15.4% moderate drought;
3/29/16 – drought-free.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent (as of 3/1/17) Drought Status Report on March 20, 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 in April 13, 2017. Following is a short excerpt from the March 20 report:
“Drier-than-normal conditions continued to extend over much of the state due to below-normal precipitation during the winter season. Portions of Northern Virginia, especially those areas within the Northern Virginia and Northern Piedmont drought-evaluation regions, continue to experience the driest conditions. The DMTF agreed to recommend to the Virginia Drought Coordinator that a Drought Watch Condition should be declared for the Northern Virginia and Northern Piedmont drought-evaluation regions. Recognizing that dry conditions are also continuing within adjoining drought-evaluation regions, plus the Roanoke River drought-evaluation region, the DMTF also agreed to distribute a message to water users in those areas to raise awareness of the long-term water supply impact of the dry winter and early spring conditions.
“…For the current water year (October 1, 2016–March 9, 2017) precipitation totals have so far been below 85% of normal for nine of Virginia’s thirteen drought-evaluation regions. The Northern Virginia and Northern Piedmont regions have received just 56% and 52% of normal precipitation, respectively. The Shenandoah and Roanoke regions have received 68% and 70% of normal precipitation, respectively….
“The Virginia Department of Agriculture and Consumer Services (VDACS) reported that growers and producers in most areas of Virginia report dry conditions. Most crop land is currently dormant; however, some small grain and cover crops have suffered due to the recent dry conditions. During this time of year, producers do not rely on their pastures to feed livestock, which is typically fed stored hay during much of the winter. However, some producers have expressed concern that the current dry conditions will impact pasture growth and result in deficiencies in the spring.
“The Virginia Department of Game and Inland Fisheries (VDGIF) reported that there have been concerns from their staff, as well as from the angler community, regarding low water levels. The DGIF’s Montebello fish hatchery has had difficulty with cold conditions and low water levels this winter. The Virginia Department of Forestry (VDOF) reported that the dry conditions in Virginia led to an early and active spring wildfire season. The VDOF has responded to 260 wildfires which have burned almost 1100 acres in the Commonwealth since the first of the year. Although activity is trending above average in terms of fire numbers, the VDOF believes that we have been fortunate that our overall acres burned have been less that what is normally expected.
“U.S. Army Corps of Engineers (USACE) staff from the Wilmington District office reported that, while they have concerns about low inflows to the Philpott and J. H. Kerr reservoirs in the Roanoke River basin, water levels are expected to remain in the normal range for now. The guide curve for water levels at J. H. Kerr is now rising in order to hold water for the striped bass spawning season that begins April 1. Without an increase in inflow over the next few weeks, levels at that reservoir may not keep up with the guide curve.”
The Drought Monitoring Task Force also produces a map rating drought-status indicators. Shown below is the map for March 30, 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 March 28, 2017, U.S. Drought Monitor rated about 34.9% of the United States (including all or parts of 42 states) as being abnormally dry or worse; [OMIT THIS TIME this is the lowest nationwide percentage of abnormally dry-or-worse conditions since the week of August 3, 2010]. The Drought Monitor rated 2.39% of the country (including parts of 22 states), as being in severe drought or worse (categories D2, D3, and D4); this is the lowest nationwide percentage of severe-or-worse drought since 2.34% for the week of October 5, 2010. (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:
2/28/17 – 34.0% abnormally dry or worse, 3.1% severe drought or worse;
1/31/17 – 28.3% abnormally dry or worse, 3.2% severe drought or worse;
1/3/17 – 40.3% abnormally dry or worse, 7.2% severe drought or worse;
3/29/16 – 35.3% abnormally dry or worse, 5.2% severe drought or worse.
No state had 50% or more rated by the March 28 Drought Monitor in severe-or-worse drought. The highest percentage of those categories was in Connecticut, at 42%.
In California, just over 1% of the state was rated on 3/28/17 as being in severe-or-worse drought. This severe-or-worse rating, in effect since the week of March 14, 2017, was the lowest for the Golden State since the week of February 14, 2012. Most of California is out of the drought that began in late 2011 to early 2012 and continued into early 2017.
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 April 3, 2017.