Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, and drought, as of the end of October 2015. 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, 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: Please see this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Water+Status.
Here are National Weather Service (NWS) preliminary (still needing verification) precipitation totals for October 2015 at 11 Virginia or near-Virginia locations, along with the normal 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 normal annual precipitation for each location. All values are in inches.
|Normal for Month
||Nov. 2014-Oct. 2015 Precipitation
|Normal Annual Precipitation
1 – The Bluefield location is the Mercer County, W. Va., airport, near the Va.-W.Va. state line.
2- The Bristol location Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va./Tenn.
3 – The Charlottesville location is the (Charlottesville-Albemarle Airport.
4 – Wallops Island is in Accomack County.
5 – Washington-Dulles Airport is in Loudoun County.
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 preliminary maps of the percent-of-normal precipitation for the previous 30 days, 60 days, and 90 days, through November 1, 2015. Please note that the scale is different for the 30-day map.
According to the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/index.php?m=mv01d&r=va&w=map), monthly average stream flow values for October 2015 at 151 stream gages in Virginia and just beyond the state border were in the normal range at about 25% of gages, below normal at about 1%, above normal at about 48%, and much above normal at about 26%. 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 shown in the chart below the map.
An overall look at Virginia streamflow conditions is provided in the USGS WaterWatch summary plot of average streamflow conditions. Below is the summary plot for 87 Virginia sites during the 45-day period ending November 2, 2015, accessed at http://waterwatch.usgs.gov/index.php?id=pa07d&sid=w__plot&r=va on 11/4/15.
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; and from the USGS Climate Response Network, online at http://groundwaterwatch.usgs.gov/net/ogwnetwork.asp?ncd=crn (at that page, you can find a national map showing the status of groundwater monitoring wells compared to historical values).
DROUGHT IN VIRGINIA
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) for October 27, 2015, showed Virginia as essentially drought-free, with only 0.01 percent of the state rated as abnormally dry. The Drought Monitor notes that it “focuses on broad-scale conditions [and] local conditions may vary.” 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:
9/29/15 – 39% abnormally dry;
8/25/15 – 7% abnormally dry;
7/28/15 – drought-free;
10/28/14 – 23% abnormally dry.
The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on October 13, 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 next report is scheduled for November 2015. 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 drought-status indicators. Shown below is daily map for November 2, 2015. The status-indicator abbreviations on that map are as follows: GW = groundwater levels, Prcp = precipitation deficits, Res – reservoir storage, and Flow = stream flow conditions. For each region of Virginia, the indicators are color coded for “normal,” “watch,” “warning,” or “emergency conditions.” Any given day’s current map and more information on drought status in Virginia are available the Task Force Web site listed above.
The October 27, 2015, U.S. Drought Monitor rated 48.7% of the United States (including all or parts of 47 states, plus Puerto Rico) as being abnormally dry or worse. It rated 14.4% of the country (including all or parts of 13 states, plus Puerto Rico), as being in severe drought or worse (categories D2, D3, and D4; the highest percentage in these categories reported by the Drought Monitor since it began in 2000 was 38.5% of the country during the week of August 7, 2012).
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:
9/29/15 – 53.0% abnormally dry or worse; 16.8% severe drought or worse;
8/25/15 – 49.2% abnormally dry or worse; 15.1% severe drought or worse;
7/28/15 – 44.2% abnormally dry or worse; 14.4% severe drought or worse;
10/28/14 – 36.4% abnormally dry or worse; 15.1% severe drought or worse.
In the following states, over 50% of the state was categorized by the 10/27/15 report as being in severe-or-worse drought.
California – 92% (with 71% in extreme or exceptional drought). California has had over 80% of its area categorized in severe-or-worse drought every week since June 25, 2013, and the Golden State had 100% in those categories from May 13—July 29, 2014. California’s current drought began in late 2011 to early 2012.
Louisiana – 68% (with 53% in extreme or exceptional drought).
Nevada – 73% (with 35% in extreme or exceptional drought). Nevada has had over 50% of its area in severe-or-worse drought since the week of March 27, 2012.
Oregon – 100% (with 67% in extreme drought). Oregon has had 100% of its area categorized in severe-or-worse drought every week since July 28, 2015.
Washington – 91% (with 68% in extreme drought).
Following are some comments from the 10/27/15 Drought Monitor on some notable conditions or events in various parts of the country, particularly on the effects of Hurricane Patricia in Texas and other southern states.
On Hurricane Patricia
“Patricia is the strongest hurricane on record. On the morning of October 23, several hours prior to crossing the southwestern coast of Mexico, Patricia’s sustained winds peaked at 200 mph and the central barometric pressure plummeted to 25.96 inches, or 879 millibars. When Patricia made landfall later that day near Cuixmala, Mexico, winds were estimated at 165 mph and the central pressure was 27.17 inches, or 920 millibars.”
Mid-South, Mississippi Delta, and Texas
“A historic rainfall event unfolded from Texas to the Mississippi Delta, greatly easing or completely eradicating short-term drought that had been intensifying during the last 2 to 4 months. The storm system responsible for the drought relief (and flooding) was infused with moisture from record-setting eastern Pacific Hurricane Patricia, which made landfall in southwestern Mexico on October 23. Even before tapping into Patricia’s moisture, the parent storm unleashed heavy rain on northwestern Texas. Daily-record amounts for October 21 included 2.38 inches in Borger and 1.38 inches in Dalhart. …Waco experienced its wettest 24-hour period on record, with 9.67 inches of rain falling on October 23-24. Previously, Waco’s wettest 24-hour period had occurred on December 20, 1997, when 7.98 inches fell. … Farther east, Shreveport, La., received 6.01 inches from October 23-26. Storm-total rainfall exceeded 20 inches at a few locations in northeastern Texas, including Corsicana. From October 23-25, Corsicana was inundated by 21.05 inches of rain, most (16.35 inches) of which fell on the 23rd. Antecedent dryness prevented large-scale flooding, but downpours resulted in flash flooding and river rises. …
“In southwestern Mississippi, October 24-27 rainfall totaled 8.27 inches in Natchez and 7.71 inches in Vicksburg. Before the storm hit, Natchez had not received a drop of rain since September 21 and had not experienced a 1-inch rainfall since July 5. In southern Louisiana, October 24-26 totals reached 10.85 inches in Baton Rouge and 8.88 inches in New Orleans. Prior to the 24th, neither location had received measurable rainfall in October. The bulk of southern Louisiana’s rain fell on October 25, when totals reached 8.60 inches in Baton Rouge and 8.67 inches in New Orleans.”
“On October 25, California led the nation in topsoil and subsoil moisture rated very short to short (both 90%). Oregon ranked second in both categories (77% very short or short for topsoil moisture and 87% very short or short for subsoil moisture), and led the U.S. with 66% of its rangeland and pastures rated in very poor to poor condition.”
“…[H]eavy, late-October rain in parts of Puerto Rico helped to provide some drought relief. …Slight improvements in the drought depiction were also noted in other parts of eastern Puerto Rico, except along the southern coast, where water rationing is ongoing and aquifer levels have not yet responded.”
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 November 2, 2015.