Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of September 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 September 2014 at 11 Virginia or near-Virginia locations, with the amount above (+) or below (-) normal for this month of the year historically. All values are in inches, rounded to the nearest 0.1 inch from NWS values.
|Above (+) or Below (-) Normal (inches)|
|Bluefield (Va.-W.Va. state line)||2.4||-0.7|
|Bristol (Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va.-Tenn.)||1.4||-1.6|
|Dulles Airport (Loudoun County)||0.9||-3.0|
|Wallops Island (Accomack County)||4.7||+0.8|
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 normal values, 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 the percent-of-normal precipitation for the previous 30 days, 60 days, and 90 days, through September 30, 2014.
Next, in stream flow: According to the U.S. Geological Survey WaterWatch for Virginia, average stream flow values for the September 2014 at about 146 stream gages in Virginia and just beyond the state border were in the normal range at about 66 percent of gages; below normal at about 19 percent; much below normal at about 3 percent; above normal at about 7 percent; and much above normal at about 5 percent. 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 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, the drought watch:
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) on September 30, 2014, categorized about 48 percent of Virginia as being abnormally dry. The area covered was essentially all of the northern half of the state, excluding the Eastern Shore and the northernmost tier of counties. Also included as abnormally dry were the areas around Danville, Galax, and Martinsville along the southern state border.
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:
9/2/14 – 11 percent abnormally dry;
7/29/14 – 27 percent abnormally dry;
7/1/14 – 10 percent abnormally dry; 2 percent in moderate drought;
10/1/13 – 30 percent abnormally dry.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on August 18, 2014. 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 Drought Monitoring Task Force also produces a daily map rating groundwater levels (GW), precipitation deficits (Prcp), reservoir storage (Res), and stream flow (Flow) conditions across the Commonwealth. In each area, a color code indicates “normal,” “watch,” “warning,” or “emergency conditions.” The October 1, 2014, map is shown below. The current map and more information on the ratings are available the Task Force Web site listed above.
Looking beyond Virginia: The September 30 U.S. Drought Monitor rated 40.1 percent of the United States (including all or parts of 47 states) as being abnormally dry or worse, and it rated 15.6 percent of the country (including all or parts of 15 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:
9/2/14 – 39.2 percent abnormally dry or worse; 17.5 percent severe drought or worse;
7/29/14 – 39.8 percent abnormally dry or worse; 19.0 percent severe drought or worse;
7/1/14 – 37.2 percent abnormally dry or worse; 20.9 percent severe drought or worse;
10/1/13 – 55.8 percent abnormally dry or worse; 17.3 percent severe drought or worse.
In the following four states, over 50 percent of the state was categorized by the September 30 report as being in severe-or-worse drought:
California – 95% (with 82% in extreme or exceptional drought; California was rated as having 100 percent severe-or-worse drought from May 13—July 29, 2014).
Nevada – 70% (with 48% in extreme or exceptional drought);
Oklahoma – 58% (with 21% in extreme or exceptional drought);
Oregon – 56% (with 35% in extreme drought).
Finally, here’s an interesting comment from the September 30, 2014, Drought Monitor on lingering drought effects in Oklahoma:
“[During the previous week], conditions deteriorated in Oklahoma, where 65% of the topsoil and 74% of the subsoil were short or very short of moisture…. The fact that more (greater percentage) subsoil was dry to very dry compared to topsoil indicated that the region never fully recovered from the drought of 2011-2012.”
For previous News Grouper monthly water status reports during the past 12 months, please click these links: