Category Archives: Weather

Virginia Precipitation and Stream Flow for the 7-day Period Ending August 26, 2014

Below are images showing precipitation in the southeastern United States and stream flow in Virginia over the seven-day period ending August 26, 2014. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.

Precipitation

The following maps—accessed 8/27/14 from the National Oceanic and Atmospheric Administration’s (NOAA) Southeast Regional Climate Center, located at the University of North Carolina in Chapel Hill; online at http://www.sercc.com/climateinfo/precip_maps — show southeastern U.S. precipitation amounts over the past seven days (top map), and the percent of normal precipitation for the given location at this time of year (bottom map).  As of 8/27/14, these data remained provisional (needing to be verified for accuracy and subject to possible revision).

Precip Aug26

7dPNormSERCC

For another precipitation-information source: The National Weather Service’s Advanced Hydrologic Prediction Service, http://water.weather.gov/precip/, provides maps showing precipitation nationwide or by state for specific days, months, or years. The site also has the capability to show county boundaries.

Stream Flow

Average Virginia stream flow over week ending August 26, 2014, is indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/classic.php?m=pa07d&r=va&w=mv01d%2Cmap, accessed 8/27/14). The map compares the previous week’s average stream flows at about 140 stream-gaging stations (in Virginia and just beyond the state border) to the normal flow levels for that week over the historical record for each gaging station. The color codes/percentile classes used by USGS to compared flows to historical records for the month are as follows:

KEEP ON DESK _ Stream Flow Chart

Streams Aug 26

 

Virginia Precipitation and Stream Flow for the 7-day Period Ending August 20, 2014

Below are images showing precipitation in the southeastern United States and stream flow in Virginia over the seven-day period ending August 20, 2014. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.

Precipitation

The following maps—accessed 8/21/14 from the National Oceanic and Atmospheric Administration’s (NOAA) Southeast Regional Climate Center, located at the University of North Carolina in Chapel Hill; online at http://www.sercc.com/climateinfo/precip_maps — show southeastern U.S. precipitation amounts over the past seven days (top map), and the percent of normal precipitation for the given location at this time of year (bottom map).  As of 8/13/14, these data remained provisional (needing to be verified for accuracy and subject to possible revision).

Precip Aug 20

 

Precip perc Aug20

 

For another precipitation-information source: The National Weather Service’s Advanced Hydrologic Prediction Service, http://water.weather.gov/precip/, provides maps showing precipitation nationwide or by state for specific days, months, or years. The site also has the capability to show county boundaries.

Stream Flow

Average Virginia stream flow over week ending August 20, 2014, is indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/classic.php?m=pa07d&r=va&w=mv01d%2Cmap, accessed 8/21/14). The map compares the previous week’s average stream flows at about 140 stream-gaging stations (in Virginia and just beyond the state border) to the normal flow levels for that week over the historical record for each gaging station. The color codes/percentile classes used by USGS to compared flows to historical records for the month are as follows:
KEEP ON DESK _ Stream Flow Chart

Streams Aug 20

 

Drought Report for Virginia and Elsewhere as of mid-August 2014

The August 12, 2014, U.S. Drought Monitor from the University of Nebraska-Lincoln (available at http://droughtmonitor.unl.edu/) rated about 12 percent of Virginia as “abnormally dry.”

The Drought Monitor notes that it “focuses on broad-scale conditions, and local conditions may vary.” The Drought Monitor’s categories, from mildest to most severe, are as follows:
D0 = Abnormally Dry;
D1 = Moderate Drought;
D2 = Severe Drought;
D3 = Extreme Drought;
D4 = Exceptional Drought.

Virginia’s abnormally dry areas on August 12 included parts of the far southwest, the Alleghany Highlands, and Southside.  The current Virginia drought map and a link to archived maps are available at http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?VA.

The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on July 11, 2014. The report typically includes 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. Task Force reports and other current drought-status information are available online at http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.

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 August 14, 2014, map is shown below. The current map and more information on the ratings are available the Task Force Web site listed above.

Va Drought Aug 14

Elsewhere in the United States, the August 14 Drought Monitor categorized about 40 percent of the country (in 43 states) as at least abnormally dry (combined categories D0-D4), and about 18 percent (in 14 states) in at least severe drought (combined categories D2-D4). Four states—listed below—had at least 50 percent of their area rated severe drought or worse (Categories D2-D4).
Arizona = 70%
California = 100%
Nevada = 87%
Oregon = 56%

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 July 17—October 31, 2014, outlook map, the latest one available as of 8/14/14.

Drought outlook

For previous Virginia Water Central News Grouper mid-month drought reports, please click the following links.

Mid-July 2014
[No reports for December 2013—June 2014]
Mid-November 2013
Mid-October 2013
Mid-September 2013
Mid-August 2013
Mid-July 2013

Virginia Precipitation and Stream Flow for the 7-day Period Ending August 12, 2014

Below are images showing precipitation in the southeastern United States and stream flow in Virginia over the seven-day period ending August 12, 2014. The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.

Precipitation

The following maps—accessed 8/13/14 from the National Oceanic and Atmospheric Administration’s (NOAA) Southeast Regional Climate Center, located at the University of North Carolina in Chapel Hill; online at http://www.sercc.com/climateinfo/precip_maps — show southeastern U.S. precipitation amounts over the past seven days (top map), and the percent of normal precipitation for the given location at this time of year (bottom map).  As of 8/13/14, these data remained provisional (needing to be verified for accuracy and subject to possible revision).
Precip Aug 13Precip per Aug 12

For another precipitation-information source: The National Weather Service’s Advanced Hydrologic Prediction Service, http://water.weather.gov/precip/, provides maps showing precipitation nationwide or by state for specific days, months, or years. The site also has the capability to show county boundaries.

Stream Flow

Average Virginia stream flow over week ending August 12, 2014, is indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia (online at http://waterwatch.usgs.gov/classic.php?m=pa07d&r=va&w=mv01d%2Cmap, accessed 8/13/14). The map compares the previous week’s average stream flows at about 140 stream-gaging stations (in Virginia and just beyond the state border) to the normal flow levels for that week over the historical record for each gaging station. 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.

Stream Flow ChartStreams Aug 12

On Virginia Water Radio for 8-11-14: “Natural Disaster,” by John McCutcheon, for the Approaching Busiest Part (Historically) of the Atlantic Tropical Storm Season

This week, Virginia Water Radio features music about a human cyclone to remind us that mid-August to late October is usually the busiest part of the Atlantic tropical cyclone season.  Click here to have a listen (2 min./57 sec.)

NOAA (National Oceanic and Atmospheric Administration) graph showing the predicted number of Atlantic tropical storms in 100 years, based on historical records; accessed online at http://www.nhc.noaa.gov/climo/, 8-11-14.

Virginia Water Radio, online at http://www.virginiawaterradio.org, is the Virginia Water Resources Research Center’s weekly podcast using sounds and music to focus on issues, events, people, and creatures connected to Virginia’s waters.

Virginia Water Status Report as of the End of July 2014, Plus a Look at Drought Nationally

Here is the Virginia Water Central News Grouper’s monthly water-status report, as of the end of July 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 July 2014 at 11 Virginia or near-Virginia locations, with the amount above (+) or below (-) normal for this month of the year historically in parentheses.  All values are in inches, rounded to the nearest 0.1 inch from NWS values.

Location Observed Precipitation(inches) Above (+) or Below (-) Normal (inches)
Blacksburg 1.9 -2.3
Bluefield (Va.-W.Va. state line) 3.0 -1.2
Bristol (Tri-Cities Airport in Tenn., about 20 miles from Bristol, Va.-Tenn.) 5.3 +0.6
Charlottesville 3.1 -1.3
Danville 3.7 -0.9
Dulles Airport (Loudoun County) 2.1 -1.6
Lynchburg 5.8 +1.4
Norfolk 7.9 +2.7
Richmond 2.6 -1.9
Roanoke 3.4 -0.6
Wallops Island (Accomack County) 3.4 -0.7

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 precipitation and percent-of-normal precipitation for the 30-day period of July 2 to July 31, 2014.

Precip July

 Precip Perc July

 

 

Next, in stream flow: According to the U.S. Geological Survey WaterWatch for Virginia, average stream flow values for the 28-day period ending July 31, 2014, at 146 stream gages in Virginia and just beyond the state border (that is, the monthly average of stream flow readings taken at each gage) were as folows:
normal range at about 68 percent of gages;
below normal at about 21 percent;
much below normal at about 3 percent;
above normal at about 7 percent;
and much above normal at about 1 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.

Stream Flow Chart

 

 

 

 

Streams July

 

Finally, our drought watch:
The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) on July 29, 2014, categorized about 27 percent of Virginia as being abnormally dry.  The areas included were the Alleghany Highlands; all of southwestern Virginia, from Roanoke west, excluding the four westernmost coalfield counties; the Danville/Martinsville area; the upper Chowan River basin, from Dinwiddie County to the North Carolina border; and northern Accomack 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 from about one month, two months, three months, and one year ago:
7/1/14 – 10 percent abnormally dry; 2 percent in moderate drought;
6/3/14 – 9 percent abnormally dry;
4/29/14 – 0.1 percent abnormally dry;
7/30/13 – drought-free.

The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on July 11, 2014.  That report is online (as PDF) at http://www.deq.virginia.gov/Portals/0/DEQ/Water/WaterResources/VirginiaDroughtStatus/CurrentDroughtTaskForceReport.pdf; 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 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 July 30, 2014, map is shown below.  The current map and more information on the ratings are available the Task Force Web site listed above.

Drought VA map Jul 30
Looking beyond Virginia: The July 29, 2014, U.S. Drought Monitor rated 39.8 percent of the United States (including all or parts of 42 states) as being abnormally dry or worse, and it rated 19.0 percent of the country (including all or parts of 14 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:
7/1/14 – 37.2 percent abnormally dry or worse; 20.9 percent severe drought or worse;
6/3/14 – 43.6 percent abnormally dry or worse; 22.8 percent severe drought or worse;
4/29/14 – 41.3 percent abnormally dry or worse; 22.4 percent severe drought or worse;
7/30/13 – 56.6 percent abnormally dry or worse; 27.4 percent severe drought or worse.

In 6 states, over 50 percent of the state was categorized by the July 29 report as being in severe-or-worse drought:
Arizona – 68% (with 17% in extreme drought);
California – 100% (with 82% in extreme or exceptional drought; this level of extreme/exceptional drought is the highest percentage in California since at least January 2000, the start of the Drought Monitor’s records shown online);
Nevada – 87% (with 55% in extreme or exceptional drought);
New Mexico – 54% (with 18% in extreme drought);
Oklahoma – 60% (with 23% in extreme or exceptional drought);
Oregon – 56% (with 20% in extreme drought).

Here are some excerpts from the July 29, 2014, Drought Monitor:

On the southeast, including Virginia: “Despite periods of very cool weather, dryness has begun to take a toll on Southeastern pastures. On July 27, USDA [U.S. Department of Agriculture] reported 45% of the pastures were rated in very poor to poor condition in South Carolina, along with 23% in Virginia and 20% in Kentucky. By the morning of July 30, in the midst of the latest cool spell, daily-record low temperatures were established in Southeastern locations such as Blacksburg, Virginia (49°F); Jackson, Kentucky (52°F); Muscle Shoals, Alabama (55°F); and Meridian, Mississippi (56°F).”

On the southwest, particularly the Colorado River basin in Arizona and Nevada: “Lake Mead—above Hoover Dam—which serves multiple states, recently fell to its lowest level since being filled during the 1930s.”

On California: “For California’s 154 intrastate reservoirs, storage at the end of June stood at 60% of the historical average. Although this is not a record for this time of year—the standard remains 41% of average on June 30, 1977—storage has fallen to 17.3 million acre-feet. As a result, California is short more than one year’s worth of reservoir water, or 11.6 million acre-feet, for this time of year. The historical average warm-season drawdown of California’s 154 reservoirs totals 8.2 million acre-feet, but usage during the first 2 years of the drought, in 2012 and 2013, averaged 11.5 million acre-feet.”

For previous News Grouper monthly water status reports during the past 12 months, please click these links:
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013

July 2014 Atlantic Tropical Storm Summary from the National Hurricane Center Issued August 1, 2014; Tropical Storm Bertha Approaching Caribbean Sea That Same Day

Two tropical cyclones—Hurricane Arthur and a tropical depression—formed in July 2014 in the North Atlantic Basin, Gulf of Mexico, or Caribbean Sea, according to the National Weather Service/National Hurricane Center’s (NHC) monthly tropical weather summary for the North Atlantic, Caribbean Sea, and Gulf of Mexico, issued by the NHC at 8 a.m. EDT on August 1, 2014.  The August 1, 2014, report and other monthly summaries, along with maps, public advisories, and links to satellite photos, and other information during the Atlantic tropical storm season (June 1-November 30) are available online at http://www.nhc.noaa.gov/index.shtml.

Here is an excerpt from the August 1 report: “Based on a 30-year (1981-2010) climatology, one named storm forms in the basin in July, with a hurricane occurring about once every other year. In terms of accumulated cyclone energy, which measures the combined strength and duration of tropical storms and hurricanes, activity in the [Atlantic] basin so far in 2014 has been near normal.”

Also from the August 1 report, here is the NHC’s list of all tropical storms this year through July, with their dates of occurrence and maximum wind speeds:
(abbreviations: H = hurricane; MH = major hurricane; TD = tropical depression; TS = tropical storm):

H Arthur – Jul. 1-5 – 100 mph
TD Two – Jul. 21-23 – 35 mph

When completed, reports on individual 2014 storms (including tracks) will be available online at http://www.nhc.noaa.gov/2014atlan.shtml.

Right on the heels of the NHC’s report for July, as of August 1 the season’s second named storm, Tropical Storm Bertha, was just east of the Caribbean Sea and was predicted to enter the Caribbean by August 2 and approach Puerto Rico that day.

Below is an August 1 satellite photo of TS Bertha.

TS Bertha

Tropical Storm Bertha (lower right of photo) just east of the Caribbean Sea, 8/1/14, 1:45 p.m. EDT.  Photo taken from the National Oceanic and Atmospheric Administration (NOAA) Web site at http://www.goes.noaa.gov/browsh.html, on 8/1/14, 2:45 p.m. EDT.