Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of August 2012.
First, here are National Weather Service preliminary precipitation totals for August 2012 at 10 Virginia locations (with the amount above or below normal for the month historically in parentheses; rounded to nearest 1/10 inch):
Blacksburg: 2.9 inches (0.7 inches below normal)
Bristol (at Tri-Cities Airport in Tenn., about 20 miles from Bristol): 2.0 inches (1.5 inches below normal)
Charlottesville: 4.9 inches (1.3 inches above normal)
Danville: 1.5 inches (2.5 inches below normal)
Dulles Airport (in Loudoun County): 3.0 inches (0.5 inches below normal)
Lynchburg: 2.7 inches (0.6 inches below normal)
Norfolk: 6.1 inches (0.6 inches above normal)
Richmond: 3.5 inches (1.2 inches below normal)
Roanoke: 3.9 inches (0.4 inches above normal)
Wallops Island (in Accomack County): 6.0 inches (1.8 inches above normal)
The normal values used by the National Weather Service (NWS) in these provisional reports are based on normal values from 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.
(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).
For graphs of precipitation, visit the Southeast Regional Climate Center (Chapel Hill, N.C) 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 daily map of precipitation nationwide or by state, with capability to show county boundaries, and archives available for specific days, months, or years.
Second, in stream flow: According to the U.S. Geological Survey WaterWatch for Virginia, average streamflows over the month of August 2012 were in the normal range at about 66 percent of stream gages in Virginia and just beyond the state border; above normal at about 8 percent of gages; below normal at about 17 percent of gages; and much below normal at about 9 percent of gages. The percentile classes used by USGS to categorize flows are as follows:
Below 10th percentile = much below normal|
10th to 24th percentile = below normal
25th to 75th percentile = normal
76th to 90th percentile = above normal
Above 90th percentile = much above normal
And third, our drought watch: The weekly The National Drought Monitor map from the University of Nebraska-Lincoln on September 4, 2012, showed “abnormally dry” or worse conditions in about 53 percent of Virginia, including most of the state east of the Blue Ridge, except for the southeastern corner). “Moderate drought” conditions covered about 14 percent of the Commonwealth, the lower Potomac basin and an area in central Virginia from Dinwiddie County to Buckingham County. “Severe drought” conditions were found in the northern half of Accomack County (about 0.5 percent of the state).
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 one month, three months, and one year ago:
8/7/12: 70 percent abnormally dry or worse; 18 percent moderate or severe drought; 0.6 percent severe drought;
6/5/12: 9 percent abnormally dry;
8/30/11: 37 percent abnormally dry or worse; 17 percent moderate drought (just after Hurricane Irene in August 2011 and just prior to Tropical Storm Lee in September 2011).
Meanwhile, looking beyond Virginia at the continuing historic drought in middle of the United States, the September 4 Drought Monitor rated 35.5 percent of the entire United States as being in severe drought or worse (categories D2, D3, and D4). This compares to 38.5 percent rated in severe drought or worse a month ago (8/7/12), the highest percentage in these categories since the Drought Monitor began in 2000. Twenty-two states had some area rated in severe drought or worse, and in 15 states, over 50 percent was so rated. As at the end of July 2012, in Colorado, Iowa, Kansas, and Nebraska, 100 percent was rated in severe drought or worse (as well as 98 percent in Missouri), and significant areas of those states were in the extreme and exceptional drought categories as well (for example, 98 percent of Nebraska was in extreme or exceptional drought, with 71 percent of the state in exceptional drought).