Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of April 2014. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing the data and maps used in this post.
First, in precipitation: Here are National Weather Service (NWS) preliminary precipitation totals for April 2014 at 11 Virginia or near-Virginia locations, with the amount above (+) or below (-) normal for this month of the year historically in parentheses. All values are in inches, rounded to the nearest 0.1 inch from NWS values.
Blacksburg = 4.1 (+0.6)
Bluefield (Va.-W.Va. state line) = 2.8 (-0.6)
Bristol (Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va.-Tenn.) = 2.5 (-0.9)
Charlottesville = 5.8 (+2.5)
Danville = 5.8 (+2.3)
Dulles Airport (Loudoun County) = 7.4 (record high for April) (+3.9)
Lynchburg = 5.6 (+2.3)
Norfolk= 4.9 (+1.5)
Richmond = 4.1 (+0.8)
Roanoke = 4.2 (+0.8)
Wallops Island (Accomack County) = 4.0 (+0.9)
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 1981-2010 period. The National Climatic Data Center released these normal values in July 2011. For information on the normals, see the National Climatic Data Center Web page at http://www.ncdc.noaa.gov/oa/climate/normals/usnormals.html.
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 provisional (still needing verification) maps of precipitation and percent-of-normal precipitation for the 30-day period of April 1 to April 30, 2014.
Next, in stream flow: According to the U.S. Geological Survey WaterWatch for Virginia, average streamflow values for April 2014 at 148 stream gages in Virginia and just beyond the state border (that is, the monthly average of streamflow readings taken at each gage) were in the normal range at about 64 percent of gages; below normal at about 6 percent; above normal at about 22 percent; and much above normal at about 8 percent. The color-coded, flow-percentile map for April 2014 is shown below. The color codes/percentile classes used by USGS to compared flows to historical records for the month are as follows:
Red and maroon dots: Below 10th percentile = much below normal to record low;
Yellow dots: 10th to 24th percentile = below normal;
Green dots: 25th to 75th percentile = normal;
Light blue dots: 76th to 90th percentile = above normal;
Dark blue and black dots: Above 90th percentile = much above normal to record high.
Finally, our drought watch:
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) on April 29, 2014, categorized about 0.1 percent of Virginia (in northern Fredercik County) Virginia as being abnormally dry. Virginia had been rated as drought-free since the Drought Monitor report for January 14, 2014; prior to that report, Virginia had been rated as having some percentage of the state’s area categorized as abnormally dry since the Drought Monitor report of October 29, 2013.
The Drought Monitor notes that it “focuses on broad-scale conditions [and] local conditions may vary.” The Drought Monitor categories are as follows:
D0 = abnormally dry;
D1 = moderate drought;
D2 = severe drought;
D3 = extreme drought;
D4 = exceptional drought.
For comparison, here are Virginia ratings from previous Drought Monitors from about one month, two months, three months, and one year ago:
4/1/14 – drought-free;
3/4/14 – drought-free;
1/28/14 – drought-free;
4/30/13 – drought-free.
Looking beyond Virginia: The April 29 Drought Monitor rated 41.3 percent of the United States (including all or parts of 34 states) as being abnormally dry or worse, and it rated 22.4 percent of the country (including all or parts of 14 states), as being in severe drought or worse (categories D2, D3, and D4). (On August 7, 2012, 38.5 percent of the country was in the three worst categories; that was the highest percentage in these categories reported by the Drought Monitor since it began in 2000.)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:
4/1/14 – 44.7 percent abnormally dry or worse; 20.0 percent severe drought or worse;
3/4/14 – 46.8 percent abnormally dry or worse; 18.0 percent severe drought or worse;
1/28/14 – 49.1 percent abnormally dry or worse; 17.4 percent severe drought or worse;
4/30/13 – 54.8 percent abnormally dry or worse; 27.4 percent severe drought or worse.
In eight states, over 50 percent of the state was categorized by the April 29 report as being in severe-or-worse drought (this is up from six such states in the April 1 report):
Arizona – 61% (with 8% in extreme drought);
California – 96% (with 77% in extreme or exceptional drought; these are the worst numbers in California since the start of the current drought in 2012);
Kansas – 72% (with 25% in extreme drought);
Nevada – 85% (with 39% in extreme or exceptional drought);
New Mexico – 86% (with 33% in extreme or exceptional drought);
Oklahoma – 55% (with 39% in extreme or exceptional drought).
Oregon – 52% (with 9% in extreme drought);
Texas – 53% (with 38 in extreme or exceptional drought).
For previous News Grouper monthly water status reports during the past 12 months, please click these links: