Category Archives: Weather

On Virginia Water Radio for 5-23-16: Name That Atlantic Tropical Storm – 2016 Edition

Virginia Water Radio’s latest episode, for the week of May 23, 2016, is “After Hurricane Alex’s Unusual January Appearance, Atlantic Tropical Storm Season 2016 Officially Begins June 1.”  The 3 min./44 sec. episode, available online at http://www.virginiawaterradio.org/2016/05/episode-317-5-23-16-after-hurricane.html, is Water Radio’s annual preview of the upcoming Atlantic tropical storm season, featuring the names planned for this year’s storms.

Hurricane Alex

The first 2016 Atlantic tropical storm, a very early arrival: Hurricane Alex over the Azore Islands (in the North Atlantic Ocean, west of Portugal) at 9:20 a.m. EST on January 15, 2016.  Photo taken from the National Aeronautics and Space Administration (NASA) Web site, http://www.nasa.gov/feature/goddard/2016/alex-atlantic-ocean, 5/20/16.   Photo credits: Jeff Schmaltz, NASA, and the National Oceanic and Atmospheric Administration (NOAA).

Virginia Water Radio’s is a weekly broadcast/podcast produced by the Virginia Water Resources Research Center.  The home page is http://www.virginiawaterradio.org.  Have a listen or two!

National Hurricane Preparedness Week, May 15-21, 2016

The Atlantic tropical storm season runs officially from June 1 to November 30.  But nature doesn’t always follow the official rules, as shown by the occurrence of this year’s first Atlantic tropical storm—Hurricane Alex—in the mid-Atlantic in January 2016.  (For more on Alex, see the National Hurricane Center’s 2016 Atlantic tropical storm archive, online at http://www.nhc.noaa.gov/archive/2016/ALEX.shtml.)

Alex may have caught you by surprise, but mid-May is a good time to get ready for the bulk of the coming Atlantic tropical storm season.  National Oceanic and Atmospheric Administration (NOAA) has designated May 15-21, 2016, as National Hurricane Preparedness Week.  The agency has identified seven areas of preparedness, one for each day of the week: Determine your risk; Develop and evacuation plan; Secure an insurance check-up; Assemble disaster supplies; Strengthen your home; Identify your trusted sources of information for a hurricane event; and Complete your written hurricane plan.  Information on these areas and lots of other information resources are available online at http://www.nws.noaa.gov/com/weatherreadynation/hurricane_preparedness.html.

Virginia Precipitation and Stream Flow for the 7-day Period Ending May 17, 2016, Plus a Mid-Month Drought Assessment

Below are images showing precipitation in Virginia and other areas of the southeastern United States, and stream flow in Virginia, over the seven-day period ending May 17, 2016 (information available as of May 18).  Also below is the Virginia Drought Monitoring Task Force’s daily map showing the status of several drought indicators in different Virginia regions, as of May 17.  The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.  For the current month’s other weekly reports on stream flow and precipitation, please see the News Grouper posts available at this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Virginia+Precipitation.

For monthly reviews of precipitation, stream flow, and drought, please see the posts available at this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Monthly+Water+Status.

For more information on current and historical surface-water and groundwater conditions in Virginia, please see the U.S. Geological Survey (USGS) Virginia Science Center’s Web site, http://va.water.usgs.gov/.

USED GRMay2016 - Johns Creek at New Castle Craig Co 5-30-12May 2016 Gaging Station of the Month: On Johns Creek (James River basin) at New Castle, Va. (Craig County), May 30, 2012.

Precipitation

The following two color-coded maps show southeastern U.S. precipitation amounts (top map) and the percent of normal precipitation compared to normal for this period of the year (bottom map) over the seven-day period ending May 17, 2016.  The maps were accessed 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.  As of that date, these data were provisional (needing to be verified for accuracy and subject to possible revision).

precip May 17precipperc May 17

Another source of precipitation data is 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, and other map layers available include river flood forecasts and current flood/severe weather warnings.  Please note that UTC, the time shown on the maps at the site, is five hours ahead of Eastern Standard Time and four hours ahead of Eastern Daylight Time.

Stream Flow

Seven-day-average Virginia stream flows at different gaging stations as of May 17, 2016, are indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia, accessed online at http://waterwatch.usgs.gov/index.php?m=pa07d&r=va&w=map.  The map’s color-coded dots compare the previous week’s average stream flows to the normal flow levels for that week over the historical record for each gaging station.  The color codes/percentile classes used by USGS are as shown in the chart following the map.

Streams May 17KEEP on deskto - Stream flow code graph

Mid-month Drought Status Update

The Virginia Drought Monitoring Task Force (DMTF), a collaboration of state and federal agencies, issued its latest Virginia drought-status report on May 16, 2016.  The report is available at the DMTF Web site, http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.  The Task Force is scheduled to meet next on July 14, 2016.  Following is an excerpt from the May 16 report:

“Following an extended period of below normal precipitation across Virginia during March and the first half of April, rainfall during late April and early May 2016 has been well above normal.  Average precipitation totals for the current water year (October 1, 2015 –May 11, 2016) are greater than normal for 11 of the 13 drought-evaluation regions, with the remaining two regions (Big Sandy and Northern Piedmont) nearly normal.  The most recent U.S. Drought Monitor web page for Virginia (as of May 12, 2016) shows abnormally dry conditions (D0) across approximately 16% of the Commonwealth.  The abnormally dry regions are mainly within the southwestern portion of the state (primarily the Big Sandy drought evaluation region).”

The Task Force also produces a daily map rating drought-status indicators.  Shown below is the May 17, 2016, map.  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, http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.

VA Drought may 17

Virginia Precipitation and Stream Flow for the 7-day Period Ending May 10, 2016

Below are images showing precipitation in Virginia and other areas of the southeastern United States, and stream flow in Virginia, over the seven-day period ending May 10, 2016 (information available as of May 11).  The Virginia Water Resources Research Center thanks the agencies mentioned below for providing precipitation and stream-flow information and images.

For the current month’s other weekly reports on stream flow and precipitation, please see the News Grouper posts available at this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Virginia+Precipitation.  For monthly reviews of precipitation, stream flow, and drought, please see the posts available at this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Monthly+Water+Status.

For more information on current and historical surface-water and groundwater conditions in Virginia, please see the U.S. Geological Survey (USGS) Virginia Science Center’s Web site, http://va.water.usgs.gov/.

USED GRMay2016 - Johns Creek at New Castle Craig Co 5-30-12May 2016 Gaging Station of the Month:
Johns Creek (James River basin) at New Castle, Va. (Craig County), May 30, 2012.

Precipitation

The following two color-coded maps show southeastern U.S. precipitation amounts (top map) and the percent of normal precipitation compared to normal for this period of the year (bottom map) over the seven-day period ending May 10, 2016.  The maps were accessed 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.  As of that date, these data were provisional (needing to be verified for accuracy and subject to possible revision).

PrecipMay 10PrecippercMay 10

Another source of precipitation data is 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, and other map layers available include river flood forecasts and current flood/severe weather warnings.  Please note that UTC, the time shown on the maps at the site, is five hours ahead of Eastern Standard Time and four hours ahead of Eastern Daylight Time.

Stream Flow

Seven-day-average Virginia stream flows at different gaging stations as of May 10, 2016, are indicated in the map below, from the U.S. Geological Survey WaterWatch for Virginia, accessed online at http://waterwatch.usgs.gov/index.php?m=pa07d&r=va&w=map.  The map’s color-coded dots compare the previous week’s average stream flows to the normal flow levels for that week over the historical record for each gaging station.  The color codes/percentile classes used by USGS are as shown in the chart following the map.

streams May 10 KEEP on deskto - Stream flow code graph

Weather Systems, Predictions, and Events in Kevin Myatt’s Weather Journal

Any time of year’s a good time to discuss the weather, and Kevin Myatt’s “Weather Journal” blog and column for The Roanoke Times discusses the underlying causes of weather systems, predictions and results of those systems, variations in precipitation among years, and many other aspects of weather (focusing primarily on effects on southwestern Virginia).

The Weather Journal is available online at http://www.roanoke.com/weather/columns_and_blogs/blogs/weather_journal/.

Virginia Water Status Report as of the End of April 2016, Plus a Look at Drought Nationally

Here is the Virginia Water Central News Grouper’s monthly water-status report on precipitation, stream flow, and drought, as of the end of April 2016.  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: https://vawatercentralnewsgrouper.wordpress.com/?s=Water+Status.

Precipitation Icon by George Wills
Here are National Weather Service (NWS) preliminary (still needing verification) precipitation totals for April 2016 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.

Location April 2016

Precipitation

 

Normal for Month May 2015-Apr. 2016 Precipitation

 

Normal Annual Precipitation
Blacksburg 1.75 3.48 47.17 40.89

 

Bluefield1

 

2.22 3.34 36.53 39.63
Bristol2

 

3.59 3.33 42.29 41.01
Charlottesville3

 

3.37 3.36 46.90 42.71
Danville

 

2.80 3.46 55.26 44.41
Lynchburg

 

2.12 3.31 46.35 41.57
Norfolk

 

2.78 3.41 53.26 46.53
Richmond

 

2.17 3.27 43.68 43.60
Roanoke

 

1.13 3.37 52.94 41.25
Wallops Island4

 

1.68 3.07 41.66 40.84
Washington-Dulles Airport5 1.88 3.47 39.57 41.54

Location notes
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 May 1, 2016.

Precip30precip60precip90 Stream flow icon by George WillsAccording 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 April 2016 at 153 stream gages in Virginia and just beyond the state border were in the normal range at 28% of gages, below normal at 41%, and much below normal at 31%.  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.

Streams April

KEEP on deskto - Stream flow code graph

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 88 Virginia sites during the 45-day period ending April 30, 2016, accessed at http://waterwatch.usgs.gov/index.php?id=pa07d&sid=w__plot&r=va on May 2, 2016.

Stream plot

Water status icons groundwater by George Wills

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 Watch icon by George Wills
DROUGHT IN VIRGINIA

The weekly National Drought Monitor map from the University of Nebraska-Lincoln (http://droughtmonitor.unl.edu/) for April 26, 2016, showed 95% of Virginia as abnormally dry or worse, and 4% of the Commonwealth in moderate drought.  This was Virginia’s highest percentage of D0 or worse since the Drought Monitor report for March 1, 2011, and the first occurrence of moderate drought since the report for July 15, 2014.

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:
3/29/16 – drought-free;
3/1/16 – drought-free;
1/26/16 – drought-free;
4/28/15 – drought-free.

The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on March 15, 2016.  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 next report is scheduled for May 12, 2016.

The Drought Monitoring Task Force also produces a daily map rating drought-status indicators.  Shown below is daily map for May 2, 2016.  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.

Drought VA DROUGHT ELSEWHERE

The April 26, 2016, U.S. Drought Monitor rated 37.0% of the United States (including all or parts of 42 states, plus Puerto Rico) as being abnormally dry or worse.  The Drought Monitor rated 5.0% of the country (including all or parts of 8 states, plus Puerto Rico), 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 38.5% 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:
3/29/16 – 35.3% abnormally dry or worse; 4.9% severe drought or worse;
3/1/16 – 28.6% abnormally dry or worse; 6.5% severe drought or worse;
1/26/16 – 25.3% abnormally dry or worse; 7.1% severe drought or worse;
4/28/15 – 48.5% abnormally dry or worse; 16.7% severe drought or worse.

In California, 74% of the state was categorized by the 4/26/16 report as being in severe-or-worse drought.  While still high and serious, this severe-or-worse percentage for California is the lowest is about two years.  California’s current drought began in late 2011 to early 2012.

Following are some comments from the 4/26/16 Drought Monitor on dry conditions in early 2016 in the Ohio Valley, Central Appalachians, and East, including Virginia:
“According to a Southeast Regional Climate Center analysis, for the 90-day period January 26-April 26, Walhalla, South Carolina had the third driest January 26-April 26 period in the last 106 years; Clarkesville, Georgia, ranked fourth driest; Bent Creek, North Carolina, second driest; Jefferson City, Tennessee, third driest; Charlotte, North Carolina, eighth driest out of 75 years; Bluefield, West Virginia, second driest; and Frostburg, Maryland, second driest. The dryness has intensified over the last eight weeks, with many stations experiencing the driest March 1-April 26 on record from Tennessee and North Carolina to West Virginia and Maryland.”

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 May 2, 2016.

US Drought Outlook

 

Abnormally Dry Conditions Across Almost All of Virginia, Plus Moderate Drought in Parts of the Commonwealth, Shown in April 26, 2016, U.S. Drought Monitor Map; First Areas of Moderate Drought Since Drought Monitor of Jul. 15, 2014

The April 26, 2016, U.S. Drought Monitor rated about over 95 percent of Virginia (everywhere except the southeastern corner) as being “abnormally dry.”  The Drought Monitor categorized about four percent of the Commonwealth (on the  northwestern and southwestern borders) as being in “moderate drought”; this was the first Drought Monitor designation of moderate drought in Virginia since the week of July 15, 2014.

The Drought Monitor is issued weekly by the University of Nebraska-Lincoln; it’s available online at http://droughtmonitor.unl.edu/.  The authors note that the assessment “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.

The current Virginia drought map and a link to archived maps are available at http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?VA.  The archive of weekly category ratings for Virginia is available at http://droughtmonitor.unl.edu/MapsAndData/DataTables.aspx.

For more on drought status in Virginia: The Virginia Drought Monitoring Task Force, a collaboration of state and federal agencies, issued its most recent Drought Status Report on March 15, 2016, and the group is scheduled to meet again on May 12, 2016.  The status reports and other information are available online at http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.  Information is typically provided by 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 April 28, 2016.  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.

imagemap_status.1

For monthly water-status reports for Virginia, including updates on drought, please see this Water Central News Grouper link: https://vawatercentralnewsgrouper.wordpress.com/?s=Virginia+Water+Status.