Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, flooding, and drought, as of the end of January 2021. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing the data and maps used in this post. Icons for precipitation, stream flow, groundwater, and drought are by George Wills of Blacksburg, Va. (https://www.etsy.com/people/BlacksburgArt). For previous monthly water status reports, please see this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Water+Status.
Here are National Weather Service (NWS) preliminary (still needing verification) precipitation totals for January 2021 at 12 Virginia or near-Virginia locations, along with the “normal” (three-decade average) for this month of the year at each location. Also shown are the precipitation totals at each location for the previous 12 months and the annual precipitation normals for each location. The values are in inches.
|Location||January 2021 Observed||Monthly Normal||Feb. 2020- Jan. 2021 Observed||Annual Normal|
|Reagan National Airport4||1.93||2.81||56.48||39.74|
1 – The Bluefield location is the Mercer County, W. Va., airport, near the Va.-W.Va. state line.
2- The Bristol location is the Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va./Tenn.
3 – The Charlottesville location is the Charlottesville-Albemarle Airport.
4 – Reagan National Airport is in Arlington County.
5 – Wallops Island is in Accomack County.
6 – Washington-Dulles Airport is in Loudoun County.
Precipitation sources: Climate pages of the following National Weather Service Forecast Offices:
Blacksburg, Va. (https://w2.weather.gov/climate/index.php?wfo=rnk);
Morristown, Tenn. (https://w2.weather.gov/climate/index.php?wfo=mrx);
Baltimore-Washington (https://w2.weather.gov/climate/index.php?wfo=lwx); and
Wakefield, Va. (https://w2.weather.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 (now the National Centers for Environmental Information) released these normal values in July 2011. For information on the normal values, see the “Climate Normals” page at http://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/climate-normals.
For graphs of precipitation, visit the High Plains Regional Climate Center at https://hprcc.unl.edu/maps.php?map=ACISClimateMaps), where you can find maps of total precipitation and percent of normal precipitation for the past 7, 30, 60, or 90 days for all U.S. regions; 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 preliminary maps from the High Plains Center of the percent-of-normal precipitation for the southeastern United States for the previous 30 days, 60 days, and 90 days, and for Virginia for the previous 30 days, all through January 31, 2020. Please note that the scale is different for the 60-day regional map.
Shown below is a color-coded percentile map of monthly average stream flow values for January 2021 at stream gages in Virginia and just beyond the state border, compared to the historical range for each gage. The map is from the U.S. Geological Survey (USGS) WaterWatch for Virginia, accessed online at https://waterwatch.usgs.gov/index.php?m=mv01d&r=va&w=map. The chart below the map shows the color codes/percentile classes used by USGS to compare flows to historical records for the month.
An overall look at Virginia streamflow conditions is provided in the USGS WaterWatch summary plot of daily average streamflow conditions, compared to historical records for any given date. Below is the summary plot for 89 Virginia sites during the 45-day period ending January 30, 2020, accessed on February 1, 2021, at https://waterwatch.usgs.gov/index.php?id=pa01d&sid=w__plot&r=va.
NATIONWIDE FLOODING OVERVIEW
Following is the National Weather Service’s Advanced Hydrologic Prediction Service’s (AHPS) map of stream and river levels relative to flood stage (color-coded) for the continental United States, as of 3:21 p.m. EST on February 1, 2021. The current map is available online at http://water.weather.gov/ahps/forecasts.php; at that site, one can select Virginia or any other state of interest.
Information on current groundwater levels in Virginia monitoring wells is available from the U.S. Geological Survey’s National Water Information System, online at http://waterdata.usgs.gov/va/nwis/current/?type=gw.
DROUGHT IN VIRGINIA
The weekly U.S. Drought Monitor report from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) for January 26, 2021, categorized 0.02% of Virginia as abnormally dry. This was the Drought Monitor’s first indication of any level of drought in Virginia since the report for August 11, 2020.
Drought Monitor categories are as follows:
D0 = abnormally dry;
D1 = moderate drought;
D2 = severe drought;
D3 = extreme drought;
D4 = exceptional drought.
The Drought Monitor notes that it “focuses on broad-scale conditions [and] local conditions may vary.”
For comparison, here are Virginia ratings from previous Drought Monitors from about one month, two months, three months, and one year ago:
12/29/20 – drought-free;
11/24/20 – drought-free;
10/27/20 – drought-free;
1/28/20 – 1.81% abnormally dry.
The January 26, 2021, U.S. Drought Monitor categorized about 54.7% of the United States (including parts of 43 states plus Puerto Rico) as being abnormally dry or worse. (The highest percentage in the abnormally or worse categories—that is, in all categories—reported by the Drought Monitor since it began in 2000 was 72.38 % of the country for the week of July 17, 2012.) The Drought Monitor categorized about 27.1% of the country (including parts of 22 states) as being in severe drought or worse (categories D2, D3, and D4). (The highest percentage in the severe-or-worse categories reported by the Drought Monitor since it began in 2000 was 38.48% of the country for the week of August 7, 2012.)
The nationwide percentages for abnormally dry or worse (categories D0-D4) and severe or worse (categories D2-D4) in the previous three months and one year ago were as follows:
12/29/20 – 57.0% abnormally dry or worse; 28.6% severe drought or worse;
11/24/20 – 58.2% abnormally dry or worse; 26.8% severe drought or worse;
10/27/20 – 56.0% abnormally dry or worse; 25.0% severe drought or worse;
1/28/20 – 23.9% abnormally dry or worse, 2.0% severe drought or worse.
The following states had 50% or more of their land area categorized by the January 26, 2021, Drought Monitor as being in severe-or-worse drought:
Arizona = 97%;
California = 76%;
Colorado = 91%;
Nevada = 93%;
New Mexico = 100% (99.6%);
North Dakota = 58%;
Oregon = 60%;
Utah = 98%;
Wyoming = 68%.
90-DAY DROUGHT OUTLOOK
For a look ahead, the National Weather Service/Climate Prediction Center’s “U.S. Seasonal Drought Outlook” is available at http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php. Shown below is the outlook map available on February 1, 2021.