Flood Potential Outlook
Issued by NWS Knoxville/Tri Cities, TN

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Hydrologic Outlook
National Weather Service Morristown TN
901 AM EST Thu Mar 1 2018 /801 AM CST Thu Mar 1 2018/

...The 2018 Spring Flood Potential Outlook for East Tennessee...
Southwest Virginia...and Extreme Southwest North Carolina...

...Flood Risk Is Above Average For The Forecast Area...

Introduction...

This is the 2018 Spring Flood Potential Outlook issued by the
National Weather Service in Morristown, Tennessee for east
Tennessee, southwest Virginia, and extreme southwestern North
Carolina. This issuance outlines current river and soil moisture
conditions and highlights potential situations that would induce
flooding or exacerbate drought.

In summary, the 2018 Spring Flood Potential is ABOVE AVERAGE.

The following sections describe past and current conditions and
future expectations.


Snow pack...

Snow pack is nearly absent thanks to a warm February.


Precipitation...

Over the past 30 days, thanks to a wet February, precipitation has
generally ranged from near normal across the eastern mountains,
southeast Tennessee, and southwest North Carolina, to over 200%
of normal across the northern Cumberland Plateau and much of
southwestern Virginia.

Over the past 60 days, precipitation ranged generally from 65 to 85
percent of normal across the eastern mountains as well as the
southern tier of counties from southeast Tennessee to southwest
North Carolina, to 125 to 150 percent of normal across the northern
Cumberland Plateau and much of southwestern Virginia.

Beyond 60 days, December precipitation was generally below normal
across most of the area.


Temperatures...

December temperatures averaged only 1 degree below normal. January
was a little cooler, running 3 to 4 degrees below normal. February
brought a few days of record warmth, and the month as a whole
averaged 8 to 10 degrees above normal.


Drought...

While abnormally dry conditions continue to be displayed by the
Drought Monitor this week in the counties surrounding Chattanooga,
heavy rainfall this week will likely bring about the end of those
lingering climatologically dry conditions.


Soil Moisture...

February rains have brought soil moisture conditions back to near
seasonal normals. Rainfall this week will temporarily bring surface
soils to saturation.


Streamflows...

Streamflows were near to much above normal thanks to plentiful
rainfall during February and in recent days. The locations listed
below are not expected to flood during the current rain event.
However, a few rivers in extreme southeastern Tennessee are expected
to experience minor flooding today.

Streamflows as a percent of daily normal are given for river points
in, or immediately upstream from, our hydrologic service area:

River...                        Location...    2/28/18
N Fork Holston River           Saltville VA      89%
Clinch River                   Cleveland VA     145%
Clinch River                    Tazewell TN     176%
Powell River                      Arthur TN     255%
Emory River                      Oakdale TN     249%
Pigeon River                       Hepco NC      91%
French Broad River             Asheville NC     106%


Tennessee River Basin Reservoir Levels...

Due to recent heavy rain and flood events, the percent of available
flood control storage for reservoirs in the Tennessee Basin above
Chattanooga is down to 84 percent.


Meteorological Outlook...

The Week Two Outlook for days 8 to 14 shows an expectation of below
normal temperatures...and near normal precipitation.

The Climate Outlook for the month of March shows no discernible
trends on the temperature forecast, meaning there are equal chances
for below...near...or above normal temperatures. But there is a
slightly elevated expectation for above normal precipitation.

The longer term Climate Outlook for the 3 month period of March
through May indicates slightly elevated expectations for above
normal temperatures and above normal precipitation.


The 2018 Spring Flood Outlook...

Based on all of the above considerations...an ABOVE AVERAGE flood
potential is expected for the East Tennessee, Southwest Virginia,
and extreme Southwest North Carolina basins.


Acknowledgments...

This outlook was created with input from the Lower Mississippi River
Forecast Center, the United States Geological Survey, the Tennessee
Valley Authority, state and county officials, and various cooperative
weather spotters. For more information, see the following websites:

www.weather.gov/morristown
www.srh.noaa.gov/lmrfc
waterdata.usgs.gov/nwis
www.tva.gov
www.tennessee.gov/environment
www.deq.virginia.gov
www.ncwater.org
drought.unl.edu
www.nohrsc.noaa.gov
www.cpc.ncep.noaa.gov


You may also contact...

For general weather information of forecasts, call 423-586-3771.

For information related to this outlook, contact...

Glenn Carrin, Service Hydrologist, at 423-586-3771
George Mathews, Meteorologist in Charge
 at 423-586-1964 Media only, please

or write Glenn.Carrin@noaa.gov and George.Mathews@noaa.gov

$$

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