Drought Information Statement for The Central Tennessee Valley July 12, 2024 Issued By: WFO Huntsville, AL Contact Information: sr-hun.webmaster@noaa.gov Widespread Moderate (D1) drought has developed in the area, with some areas of Severe (D2) Drought. Since the area is not in Extreme (D3) Drought, this product will be updated if conditions deteriorate substantially. Please see all currently available products at https://drought.gov/drought-information-statements Please visit https://www.weather.gov/hun/DroughtInformationStatement for previous statements Please visit https://www.drought.gov/dews/Southeast DROUGHT CONDITIONS HAVE DEVELOPED IN THE TENNESSEE VALLEY OVER THE LAST SEVERAL WEEKS. 1 U.S. Drought Monitor Latest U.S. Drought Monitor Map National Weather Service Huntsville, AL Image Caption: U.S. Drought Monitor valid 7 AM CDT, July 9, 2024. Drought intensity and Extent D4 (Exceptional Drought): None D3 (Extreme Drought): None D2 (Severe Drought): All of Lincoln County, TN, including western portions of Moore and Franklin Counties in TN. In northern AL, a relatively small area of NW Jackson County, about the northern half of Limestone and Madison Counties, and much of eastern Lauderdale County. Also, a very small area in southern Cullman County. D1 (Moderate Drought): All areas not in D2 Drought are in D1 Drought. D0 (Abnormally Dry): None Recent Change in Drought Intensity National Weather Service Huntsville, AL Four Week U.S. Drought Monitor Class Change Drought Worsened: Over the past four weeks, drought has increased three categories in the current area of D2 Drought, with a two category increase across the areas with D1 Drought. No Change: None Drought Improved: None Image Caption: U.S. Drought Monitor 4-week change map valid 7AM CDT July 9, 2024. Precipitation - Past 30 Days National Weather Service Huntsville, AL Left - 30-Day Precipitation Totals, Right - 30-Day Percent of Normal Precipitation. Data ending July 11, 2024 Main Takeaways Generally, rainfall has ranged around 1-2 inches for the past 30 days, with some areas receiving smaller amounts below one inch. Few, small areas have experienced heavier rainfall. These rainfall amounts are generally around 25-50% of normal for the past 30 day period. Temperature National Weather Service Huntsville, AL Temperatures have largely averaged around 1-3 degrees (F) above normal over the past 7 days, and 1-2 degrees above normal over the last 30 days. Note: the data period ends on July 7. Image Captions: Left - 7-Day Departure from Normal Temperature Right - 30-Day Departure from Normal Temperature Data Courtesy High Plains Regional Climate Center. Data period ending July 7, 2024 Summary of Impacts National Weather Service Huntsville, AL Hydrologic Impacts No hydrologic impacts of note currently, although streamflows and soil moisture have fallen significantly since early June due to the dry and hot conditions. See next slide for more hydrologic information including streamflows and lake levels. Agricultural Impacts USDA Crop and Progress Condition Reports have recently indicated that some crops have been negatively impacted due to the hot and mostly dry weather in recent weeks, in particular the corn crop. Also, livestock producers have indicated lack of sufficient grazing grasses due to the hot, dry weather, and that supplemental feeding has been required to maintain livestock conditions. Please see the 2024 Crop and Progress Condition Reports for Alabama and Tennessee from the USDA for more information. Fire Hazard Impacts No significant fire activity has been reported over the last 30 days. However, Keeth-Byram Drought Index (KBDI) values have increased significantly in recent weeks. KBDI values across the area now range from around 500 to over 600. Values of this magnitude indicate that lower duff and litter layers actively contribute to fire intensity and will burn actively. To see more information about recent fire activity and burn restrictions or permits visit: Alabama Forestry Commision, TN Wildland Fire Other Impacts None to report at this time. Mitigation Actions On June 18, 2024, The Alabama Dept. of Economic and Community Affairs - Office of Water Resources placed Drought Region 3 (which includes Cullman County) in a Drought Advisory. Water managers are urged to carefully monitor conditions and encourage the wise and efficient use of our water resources. Hydrologic Conditions National Weather Service Huntsville, AL Streamflows have fallen significantly over the last several weeks, with 14-day average streamflow values around the 10th to 24th percentile for many streams, and even lower in some cases. Big Wills Creek in Fort Payne was at the 4th percentile for this time of year. Other notable streamflow percentiles are as follows: Elk River (9th percentile), Big Nance Creek (11th percentile), Paint Rock River (17th percentile). Reservoir/ Lake Pool Elevation (ft) Current Elevation (ft) Percent Full Bear Creek 576 577 100% Little Bear Creek 620 619 <100% Cedar Creek 580 580 100% Tim’s Ford 887 888 100% Nickajack 633-635 634 Within Operating Range (WOR) Guntersville 594-595 595 WOR Wheeler 555-556 556 WOR Wilson 506-508 507 WOR Pickwick 413-414 414 WOR Lewis Smith 509 508 <100% Table caption: Reservoir conditions as of Jul 10, 2024 Figure Caption: USGS 14-day streamflow percentiles for Tennessee and Alabama, valid July 10, 2024 Lake Stages 14-Day Avg Streamflow Percentiles Agricultural Impacts National Weather Service Huntsville, AL Per the latest NASA SPoRT soil moisture data, 0-200 cm relative soil moisture values have decreased considerably, around 12-20% during the last 30 days. Relative soil moisture values in the deep 0-200 cm layer are currently around 20-40%, but are lower in more shallow layers (not shown). Image Captions: Left: NASA Short-term Prediction Research and Transition (SPoRT) Center 0-200 cm Soil Moisture Ranking Percentile based on a 33-year climatology (1981-2013), July 11, 2024 Right: NASA SPoRT 1-Month Difference in 0-200 cm Relative Soil Moisture, ending July 11, 2024 Agricultural Impacts National Weather Service Huntsville, AL The Lawn and Garden Moisture Index for northern Alabama and southern Middle Tennessee indicates much drier than normal soil conditions for the production of healthy lawns and gardens across much of the area. Values are largely around -1.0 to -1.5, indicating a 1.0 to 1.5 inch effective precipitation deficit for this time of year to maintain healthy lawns and gardens. However, recent rainfall on July 8-9 increased soil moisture values in a swath from NW Cullman and SW Morgan Counties eastward through portions of southern DeKalb County. Image Captions: The image to the right is the Lawn and Garden Moisture Index from the Office of the State Climatologist of Alabama. Negative values (warm colors) indicate soil moisture deficits, while positive values (shades of green) indicate moisture surplus. To learn more about the Lawn and Garden Index, please visit…https://www.nsstc.uah.edu/aosc/lawn_garden_se.html Fire Hazard Impacts Link to Wildfire Potential Outlooks from the National Interagency Coordination Center. National Weather Service Huntsville, AL Keetch Byram Drought Index (KBDI) values have increased to around 500-600. NWS offices may issue Red Flag Warnings when KBDI values climb above 300 in Alabama, although other weather criteria must be met. All of northern AL is in an Above Normal Significant Wildland Fire Potential for July, from the Predictive Services of the Southern Area Coordination Center. The Alabama Forestry Commission uses the KBDI as a system for relating current and recent weather conditions to potential or expected fire behavior. It is a numerical index calculated daily for each county. Each number is an estimate of the amount of rain, in hundredths of an inch, needed to bring the soil back to saturation. The index ranges from 0 to 800, with 0 representing a saturated soil and 800 a completely dry soil. Left Image Caption: Keetch-Byram Drought Index (KBDI) for the Continental U.S., estimated for July 10, 2024 Right Image Caption: Significant Wildland Fire Potential Outlook, July 2024 Seven Day Precipitation Forecast National Weather Service Huntsville, AL Forecast Precipitation (July 10-17): Around 0.10 inch of rainfall is expected for the weekly period ending July 17, although the latest forecast information suggests heavier rainfall may materialize on July 17th or 18th. Around 1.00 to 1.25 inch of precipitation is normal for this time of year for a weekly period. Image Caption: Weather Prediction Center 7-day precipitation forecast valid 7PM July 10 – 7PM July 17 (CDT) Monthly Outlooks The latest monthly and seasonal outlooks can be found on the CPC homepage National Weather Service Huntsville, AL Above Normal temperatures are favored (50-70% chance) for July. Equal Chances for Below, Near, or Above Normal precipitation exist across the area for July. Although, Below Normal precipitation is slightly favored just to our north, across most of Middle Tennessee, while Above Normal precipitation is favored just to our south. Seasonal Outlooks The latest monthly and seasonal outlooks can be found on the CPC homepage National Weather Service Huntsville, AL Main Takeaways Temperatures: Above Normal temperatures are favored (40-50% probability) across the area for the July to September three month period. Precipitation: Above Normal precipitation is slightly favored (33-40% chance) for July through September. Possible Impact The possibility for wetter than normal conditions may keep drought conditions from worsening during this period, although the prospects for above normal temperatures would help drive evaporative water losses from the environment.