Virginia Water Status Report as of the End of September 2012, Plus a Quick Look at Nationwide Drought

Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of September, 2012.

First, here are National Weather Service preliminary precipitation totals for September 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: 3.6 inches (0.5 inches above normal)
Bristol (at Tri-Cities Airport in Tenn., about 20 miles from Bristol): 6.0 inches (3.0 inches above normal)
Charlottesville: 2.3 inches (2.2 inches below normal)
Danville: 3.9 inches (0.1 inches below normal)
Dulles Airport (in Loudoun County): 2.7 inches (1.2 inches below normal)
Lynchburg: 2.4 inches (1.5 inches below normal)
Norfolk: 1.3 inches (3.5 inches below normal)
Richmond: 4.1 inches (0.1 inches below normal)
Roanoke: 3.6 inches (0.3 inches below normal)
Wallops Island (in Accomack County): 5.8 inches (1.8 inches above normal

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.  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) 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.  Shown below is the Southeast Regional Climate Center’s 30-day percent-of-normal precipitation map for September 4-October 3, 2012.

Second, in stream flow: According to the U.S. Geological Survey WaterWatch for Virginia, average streamflows over the month of September 2012 were in the normal range at about 62 percent of stream gages in Virginia and just beyond the state border; above normal at about 23 percent; much above normal at about 2 percent; below normal at about 9 percent; and much below normal at about 4 percent.  The percentile classes used by USGS to categorize flows are as follows:
Below 10^th percentile = much below normal
10^th to 24^th percentile = below normal
25^th to 75^th percentile = normal
76^th to 90^th percentile = above normal
Above 90^th percentile = much above normal

And third, our drought watch: The weekly The National Drought Monitor map from the University of Nebraska-Lincoln on October 2, 2012, showed “abnormally dry” or worse conditions in about 43 percent of Virginia (essentially the Piedmont and upper Coastal Plain, plus the Eastern Shore).  “Moderate drought” conditions covered about 11 percent of the Commonwealth (the lower Potomac basin, the Northern Neck, and an area in central Virginia approximately from Prince Edward County to Hanover County).

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:
9/4/12: 53 percent abnormally dry or worse; 14 percent moderate drought; 0.5 percent severe drought (northern half of Accomack County).

7/3/12: 91 percent abnormally dry or worse; 6 percent moderate drought;

10/4/11: 4 percent abnormally dry (following after Hurricane Irene in August 2011 and Tropical Storm Lee in September 2011).

Meanwhile, looking beyond Virginia at the continuing historic drought in middle of the United States, the October 2 Drought Monitor rated 33.5 percent of the entire United States as being in severe drought or worse (categories D2, D3, and D4).  This compares to 35.5 percent in these categories a month ago (9/4/12) and 38.5 percent on 8/7/12, which was 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 13 states, over 50 percent was so rated.  In Iowa, Kansas, Nebraska, and Oklahoma, 100 percent was rated in severe drought or worse (98 percent in Colorado).  Significant areas of those and other states were in the extreme and exceptional drought categories (D3 and D4); for example, Nebraska, 98 percent; Kansas, 93 percent; Oklahoma, 80 percent; Iowa, 75 percent; Wyoming, 58 percent; Colorado, 55 percent; and South Dakota, 51 percent.

Click these links for previous News Grouper monthly status reports during the current year:
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012

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