Here is Virginia Water Central’s monthly water-status report, as of the end of July 2012.
First, here are National Weather Service preliminary precipitation totals for July 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: 3.9 inches (0.4 inches below normal)
Bristol (at Tri-Cities Airport in Tenn., about 20 miles from Bristol): 12.7 inches (8 inches above normal and a new monthly record for July; the former record was 9.7 inches in July 1949).
Charlottesville: 4.3 inches (0.02 inches above normal)
Danville: 2.6 inches (2 inches below normal)
Dulles Airport (in Loudoun County): 2.4 inches (1.2 inches below normal)
Lynchburg: 2.7 inches (1.6 inches below normal)
Norfolk: 4.8 inches (0.3 inches below normal)
Richmond: 5.3 inches (0.8 inches above normal)
Roanoke: 3.1 inches (0.9 inches below normal)
Wallops Island (in Accomack County): 3.5 inches (0.6 inches below 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 (as of 8/7/12).
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 July 2012 were in the normal range at about 47 percent of stream gages in Virginia and just beyond the state border; above normal at about 5 percent of gages; below normal at about 32 percent of gages; and much below normal at about 16 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 July 31, 2012, showed “abnormally dry” or worse conditions in about 76 percent of Virginia (everywhere except an area around Danville/Martinsville, the southwestern coalfield counties, the far southeastern corner, and the western part of the Shenandoah Valley. “Moderate drought” conditions covered about 18 percent of the Commonwealth, including the Eastern Shore, the Northern Neck, an area of northern Virginia from Fairfax County to Page County, 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 0.6 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:
7/3/12: 91 percent abnormally dry or worse; 6 percent in moderate drought;
5/1/12: 61 percent abnormally dry or worse; 10 percent in moderate drought;
7/26/11: 37 percent abnormally dry or worse; 2 percent in moderate drought.
Meanwhile, looking beyond Virginia at the continuing historic drought in the Midwest and elsewhere, the July 31 Drought Monitor rated 38.1 percent of the entire United States as being in severe drought or worse. This is the highest such percentage since the Drought Monitor started in 2000, and compared to 28.7 percent of the country rated in severe drought a month ago (July 3, 2012). Twenty-four states has some area rated in severe drought or worse, and in 17 states, over 50 percent was so rated. In Colorado, Iowa, Kansas, Missouri, and Nebraska, 100 percent were rated in severe drought or worse, and significant areas of those states were in the extreme and exceptional drought categories as well (for example, 93 percent of Missouri was in extreme or exceptional drought).
The July 31 Drought Monitor included this stark comment about the 2012 drought: “In addition to the large geographic footprint of this year’s drought, the quick onset and rapid ramping up of intensity, coupled with extreme temperatures and subsequent impacts, has really left an imprint on those affected and has set this drought apart from anything we have seen at this scale over the past several decades.”