Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of February 2015. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing the data and maps used in this post.
Here are National Weather Service (NWS) preliminary precipitation totals for February 2015 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.
|Location||Observed Precipitation(inches)||Above (+) or Below (-) Normal (inches)|
|Bluefield (Va.-W.Va. state line)||2.1||-0.7|
|Bristol (Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va.-Tenn.)||3.1||-0.4|
|Dulles Airport (Loudoun County)||1.8||-1.0|
|Wallops Island (Accomack County)||3.1||+0.3|
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 period from 1981 to 2010. 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/data-access/land-based-station-data/land-based-datasets/climate-normals.
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 February 28, 2015. Please note that the scale is different for the 90-day map.
According to the U.S. Geological Survey WaterWatch for Virginia, average stream flow values for February 2015 at 123 stream gages in Virginia and just beyond the state border were in the normal range at about 32 percent of gages and below normal at about 68 percent. (Please note: The USGS map for the average monthly flow in Virginia usually has readings from about 140 to 150 stations, but (according to the USGS) some stations during this period were affected by ice, so a monthly average could not be calculated. The empty circles on the map below indicate those stations.) 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:
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) for March 3, 2015, categorized about 31 percent of Virginia as being abnormally dry. That area included the upper James River basin, the upper Roanoke River basin, essentially all of the New River basin, and the upper Clinch/Holston basin).
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:
1/27/15 – 10 percent abnormally dry;
12/30/14 – 16 percent abnormally dry;
11/25/14 – 38 percent abnormally dry;
3/4/14 – drought-free.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on February 24, 2015. 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 March 1, 2015, map is shown below. The current map and more information on the ratings are available the Task Force Web site listed above.
Looking at drought conditions beyond Virginia: The March 3, 2015, U.S. Drought Monitor rated 49.4 percent of the United States (including all or parts of 41 states) as being abnormally dry or worse, and it rated 13.1 percent of the country (including all or parts of 12 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:
1/27/15 – 43.4 percent abnormally dry or worse; 14.1 percent severe drought or worse;
12/30/14 – 39.2 percent abnormally dry or worse; 14.1 percent severe drought or worse;
11/25/14 – 39.5 percent abnormally dry or worse; 14.0 percent severe drought or worse;
3/4/14 – 46.8 percent abnormally dry or worse; 18.0 percent severe drought or worse;
In the following states, over 50 percent of the state was categorized by the March 3 report as being in severe-or-worse drought:
California – 93% (with 67% in extreme or exceptional drought; California has had over 90 percent of its area categorized in severe-or-worse drought every week since February 11, 2014, and the Golden State had 100 percent in those categories from May 13—July 29, 2014);
Nevada – 64% (with 48% in extreme or exceptional drought).
Here’s a comment from the March 3 Drought Monitor on the kind of winter some New Englanders have experienced in 2014-15: “As of March 1 , the National Weather Service Forecast Office in Boston reported that several locations experienced their snowiest winter on record including Boston (99.4”) and Worcester, MA (101.4”)….”
For a look ahead, the National Weather Service/Climate Prediction Center’s “U.S. Seasonal Drought Outlook” for the next 90 days is available at http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.html. Shown below is the outlook map available on March 3, 2015.
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