NWS: Moderate Drought conditions have returned to north Alabama, southern Tennessee

After an extended period of little to no rainfall this winter, abnormally dry conditions have developed through much of the state of Alabama, and the National Weather Service in Huntsville says that Moderate Drought (D1) conditions have developed in the northeastern sector of the state.

Below is additional information regarding the current drought situation.

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Drought Information Statement
National Weather Service Huntsville AL
144 PM CST Thu Jan 25 2018

…Moderate Drought (D1) conditions have returned to the region…

Synopsis…
According to the Drought Monitor valid Tuesday, January 23rd, 2018,
Moderate Drought (D1) has developed across portions of northern
Alabama and southern middle Tennessee. This includes nearly all of
Jackson and DeKalb Counties, southern portions of Cullman County,
extreme southeastern and northern portions of Marshall County, most
of the northern two-thirds of Madison County, portions of western and
central Limestone County, far southeastern portions of Lincoln
County, and about the southern two-thirds of Franklin County (TN).
Elsewhere, all other locations in the Huntsville County Warning and
Forecast Area are under an Abnormally Dry (D0) designation.

Summaries of Impacts will be included below to show the general
degradation in conditions, especially for soil moisture and
streamflow, that has taken place in recent weeks and months.

Note: Precipitation and other conditions (streamflows, soil
moisture, etc.) that determine drought designations each week for
the U.S. Drought Monitor are based on data that end at 6 AM CST each
Tuesday. So, any precipitation that occurs after the 6 AM cutoff is
not factored into drought designations for that week, but will of
course be factored into designations for the following weekly
issuance. Also, it’s important to note that the designation of
drought categories is a multi-faceted process that includes numerous
data from a variety of physical systems on different space and time
scales, which include precipitation, soil moisture, streamflows,
groundwater, and various drought indices, just to name a few.

Summary of Impacts…
State and local declarations: The Alabama Department of Economic and
Community Affairs (ADECA) Office of Water Resources has no current
drought declarations in effect. For further information about the
ADECA Drought Designations and Planning, see the link near the bottom
of the page.

The Keetch-Byram Drought Index (KBDI) available from the U.S. Forest
Service Wildland Fire Assessment System shows values over 400 mainly
centered over DeKalb County in northeastern Alabama. Values over 400
are more typical for late summer or early fall and indicate that
lower litter and duff layers actively contribute to fire intensity
and will burn actively.

Climate Summary…
Over the last 30 days, temperatures have wavered back and forth from
below to above normal, but below normal temperatures have certainly
dominated in the region since late December. In fact, average
temperatures have been around five to six degrees below normal for
the period. The intrusion of cold Arctic air masses into the region
has brought not only cold air, but very dry air with low dew point
temperatures, leading to further evaporation of water from soils and
surface water sources.

Precipitation has averaged well below normal during the past 30 days
across the region, with deficits up to four to five inches in the
moderate drought designated areas. On longer time scales out to 90
days (reaching back to late October) precipitation deficits are
around eight inches or more in the moderate drought areas.

Precipitation/Temperature Outlook…
Temperatures are expected to average above normal through the
weekend, with a change to below normal temperatures briefly for
Monday and Tuesday, and then a return to near to above normal for
Wednesday and Thursday. Chances for precipitation return to the
region for Saturday and Sunday, but forecast precipitation amounts
are relatively low, generally under one half inch. Chances for
precipitation return later in the forecast period, on Thursday.
Precipitation amounts could be heavier with this next system.

The 8-14 Day Outlook from the Climate Prediction Center (CPC) valid
for February 1st to 7th slightly favors above normal temperatures,
while the precipitation outlook strongly favors above normal
precipitation during the period.

The Monthly Outlook for February from the CPC slightly favors above
normal temperatures for the month, with equal chances for below, near
or above normal precipitation. The outlook indicates that above
normal precipitation is favored farther to our north over the Ohio
Valley region, with below normal precipitation favored along and near
the Gulf Coast region to our south, which is typical during La Nina
conditions.

The latest Seasonal Outlook from the CPC for the February through
April period indicates a slight shift toward higher probabilities for
above normal precipitation in the region.

Hydrologic Summary and Outlook…
7-day streamflow averages across the area have experienced
significant degradation in recent weeks. Most streamflow percentiles
are currently around the 10th to 20th percentiles for this time of
year across the area. Among the lowest streamflow percentiles
currently are: Big Wills Creek near Fort Payne (6%), Elk River at
Prospect TN (7%), Paint Rock River near Woodville (10%) and Big
Nance Creek at Courtland (10%).

Lake and river levels along the Tennessee River are largely
unaffected by the early stage of drought occurring in the region and
are generally near normal operating levels for this time of year.
Lake and river levels of Bear Creek and Cedar Creek in western
portions of Franklin County are also near normal for this time of
year. Water levels at Smith Lake in Cullman County are a little below
the guide curve for this time of year.

According to the CPC, the latest Daily Soil Moisture rankings
indicate relatively low soil moisture values for this time of year. As
of January 24th, soil moisture ranking was in the 20th to 30th
percentiles for parts of northeastern Alabama, with smaller deficits
elsewhere. Other soil moisture analyses from the North American Land
Data Assimilation System (NLDAS) and NASA SPoRT Land Information
System indicate relatively dry two meter depth soil conditions in
Moderate Drought areas, with ranking percentiles generally around the
10th to 20th percentile for this time of year.

The U.S. Geological Survey (USGS) groundwater well site in Cullman
County shows that groundwater levels fell below the daily median
value in mid-December and have since remained below normal. Water
levels at the USGS site in Lawrence County have averaged near to
slightly below normal for most of the last month.

The outlook for the next week is for slightly degraded conditions as
overall rainfall totals for this time of year are expected to be
below normal.

Next issuance date…
Since only Moderate Drought (D1) conditions are present in the area
as of late January, the next drought statement issuance is not
planned until late February. However, a statement will be issued
sooner if conditions and drought designations change significantly.

&&

Related Web Sites…(use lower case)

U.S. Drought Monitor webpage: http://droughtmonitor.unl.edu

Climate Prediction Center: http://www.cpc.ncep.noaa.gov

For information about Alabama Drought Declarations, visit:
http://www.adeca.alabama.gov/divisions/owr/pages/default.aspx

For information from the Alabama Forestry Commission, visit:
http://forestry.alabama.gov

Wildfire information from the Alabama Forestry Commission:
http://forestry.alabama.gov/fire_totals.aspx?bv=1&s=4

Radar estimated precipitation amounts can be obtained here:
http://water.weather.gov/precip

Streamflows are obtained from the USGS here:
http://waterwatch.usgs.gov/index.php

Lake levels for the Tennessee River can be obtained here:
http://www.tva.com/Environment/Lake-Levels

Soil moisture levels from the NLDAS can be found here:
http://www.emc.ncep.noaa.gov/mmb/nldas/drought

USGS groundwater well site information for Alabama:
http://waterdata.usgs.gov/al/nwis/current/
?type=gw&group_key=county_cd

Acknowledgements…

Some data used in this statement were provided by the U.S.
Geological Survey, the U.S. Forest Service, the Tennessee Valley
Authority, and the States of Alabama and Tennessee.

Questions or Comments…

For questions or comments on the drought, please contact:
National Weather Service Huntsville
320A Sparkman Drive
Huntsville, AL 35805
Phone: 256-890-8503
sr-hun.webmaster@noaa.gov