Category Archives: Weather

National Hurricane Center’s Graphical Tropical Weather Outlook, as of 9/26/16

As of Monday, September 26, 2016, three areas of tropical disturbance (potential precursors of tropical cyclones) were present in the Atlantic basin (Atlantic Ocean, Caribbean Sea, and Gulf of Mexico).  The three areas are shown below in the National Hurricane Center’s (NHC) two-day graphical tropical weather outlook, as of 2 p.m. on 9/19/16, accessed at http://www.nhc.noaa.gov/.  Here are the NHC’s descriptions of the status of these disturbances (the numbers correspond to those on the photo below):

#1: showers and thunderstorms associated with a broad area of low pressure located about 950 miles east-southeast of the Windward Islands.  Environmental conditions remain conducive for development, and a tropical depression is likely to form during the next day or two while the system moves westward to west-northwestward at 15 to 20 mph.  Chance of formation of a tropical cyclone through 48 hours = 70 percent; formation chance through 5 days = 90 percent.

#2: shower activity in association with the remnants of Lisa (formerly a tropical storm), located about 700 miles southwest of the Azores.  This system is expected to merge with a cold front on Tuesday before regeneration into a tropical cyclone can occur.  Chance of formation of a tropical cyclone through 48 hours = 10 percent; formation chance through 5 days = 10 percent.

#3: widespread cloudiness and thunderstorms over the southwestern Gulf of Mexico, associated with a trough of low pressure that is drifting westward.  Upper-level winds are not expected to be conducive for significant development before this system moves inland over northeastern Mexico.  Chance of formation of a tropical cyclone through 48 hours = 10 percent; formation chance through 5 days = 10 percent.

tropical-outlook

A September 19, 2016, Rainbow at (Almost) the Start of Fall

Dear Virginia Water Central News Grouper Readers,

By Fridays, you’ve probably had just about enough news and information about water and all other subjects.  So here’s a non-verbal parting post for this week: a rather striking rainbow, photographed in Christiansburg, Va., Sept. 19, 2016, 7 p.m., a little over two days before fall 2016 arrived.

rainbow-sep19-2016-7pm-christiansburg-three

Virginia Precipitation and Stream Flow for the 7-day Period Ending September 20, 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 September 20, 2016 (information available as of September 21).  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/.

sep2016-gage-james-river-at-buchanan-sep19-2010

September 2016 Gaging Station of the Month: James River at Buchanan (Botetourt County), September 19, 2010.

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 September 20, 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-sep20precip-perc-sep20

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 September 20, 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-sep20
stream codes

National Hurricane Center’s Graphical Tropical Weather Outlook for 2 Days and 5 Days, as of 9/19/16

As of Monday, September 19, 2016, Tropical Storm Karl was in the Atlantic Ocean east of Puerto Rico and was predicted to track northwestward and affect Bermuda by Friday-Saturday, September 23-24.  Karl is the 11th named storm for 2016 in the Atlantic basin (Atlantic Ocean, Caribbean Sea, and Gulf of Mexico).  Shown below are the National Hurricane Center’s NHC) two-day and five-day graphical tropical weather outlooks, as of early afternoon EDT on 9/19/16, accessed at http://www.nhc.noaa.gov/.

tropical-outlook-2-day

tropical-outlook-5-day

Virginia Precipitation for the 7-day Period Ending September 14, 2016, Plus a Mid-Month Drought Assessment

Below are images showing precipitation in Virginia and other areas of the southeastern United States over the seven-day period ending September 14, 2016 (information available as of September 15).  (Please note: This weekly Water Center News Grouper post normally includes a map of stream flow over the previous seven days, but that map was not available from the U.S. Geological Survey on September 15.)  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 September 15.  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/.

sep2016-gage-james-river-at-buchanan-sep19-2010

September 2016 Gaging Station of the Month: James River at Buchanan (Botetourt County), September 19, 2010.

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 September 14, 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-sep14precip-perc-sep14

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.

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 September 12, 2016.  The report is available at the DMTF Web site, http://www.deq.virginia.gov/Programs/Water/WaterSupplyWaterQuantity/Drought.aspx.  The Task Force was scheduled to meet and report again on October 13, 2016.  Here’s an excerpt from the September 12 report:

“Rainfall amounts during August 2016 were well below normal across most of Virginia, causing the past month to rank as one of the driest on record at many observing stations.  Fortunately, relatively wet conditions and above-normal groundwater levels early in the summer mitigated the effect of low August rainfall in many areas.  Temperatures have recently been above normal across Virginia, with most locations reporting summer average temperatures among the highest recorded.  High August temperatures were a big contributor to these averages. This has led to higher than normal summer evapotranspiration rates, further increasing the drying conditions.  For the current water year (October 1, 2015–September 8, 2016), precipitation totals have been greater than normal for 11 of [Virginia’s] 13 drought-evaluation regions, with the remaining two regions (Northern Virginia and Northern Piedmont) nearly normal.”

The Task Force also produces a daily map rating drought-status indicators.  Shown below is the September 15, 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.

drought-va-sep15

 

National Hurricane Center’s Graphical Tropical Weather Outlook for 2 Days and 5 Days, as of 9/12/16

As of Monday, September 12, 2016, Tropical Storm Ian was in the Atlantic Ocean east of the Caribbean Sea’s Leeward Islands.  Ian was predicted to turn northeastward by Thursday, 9/15/16, and stay away from the U.S. East Coast.  Ian is the ninth named storm for 2016 in the Atlantic basin (Atlantic Ocean, Caribbean Sea, and Gulf of Mexico).  Shown below are the National Hurricane Center’s NHC) two-day and five-day graphical tropical weather outlooks, as of 2 p.m. on 9/12/16, accessed at http://www.nhc.noaa.gov/.

2-day-tropical-outlook
5-day-tropical-outlook

Virginia Precipitation and Stream Flow for the 7-day Period Ending September 6, 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 September 6, 2016 (information available as of September 7).  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/.

sep2016-gage-james-river-at-buchanan-sep19-2010 September 2016 Gaging Station of the Month: James River at Buchanan (Botetourt County), September 19, 2010.

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 September 6, 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-sep6precip-perc-sep6

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 September 6, 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-sep6stream codes