Drought Information Statement for The Central Tennessee Valley Aug 23, 2024 Issued By: WFO Huntsville, AL Contact Information: sr-hun.webmaster@noaa.gov Moderate Drought Expands Again, with Severe Drought Returning for Some Locations. This information will be updated when drought conditions or impacts change significantly. 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 EXPAND ONCE AGAIN ACROSS PARTS OF THE AREA. 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, August 20, 2024. Drought intensity and Extent D4 (Exceptional Drought): None D3 (Extreme Drought): None D2 (Severe Drought): A relatively small area in portions of southern/eastern Lauderdale, NE Colbert, and NW Lawrence Counties (includes the Quad Cities area) D1 (Moderate Drought): Much of NW Alabama, small portions of NE Alabama and southern Middle Tennessee. D0 (Abnormally Dry): Mainly portions of Franklin, Cullman, Morgan, Madison, all of Moore and most of Franklin County (TN). Huntsville Recent Change in Drought Intensity National Weather Service Huntsville, AL Two-Week U.S. Drought Monitor Class Change Drought Worsened: Generally northwest and north central areas, including areas from around Cullman to the Bankhead Nat’l Forest, Moulton, the Quad Cities, and Waterloo No Change: Much of the area remained status-quo Drought Improved: A small area of southeastern Franklin County (TN) and north-central Jackson County Image Caption: U.S. Drought Monitor 2-week change map valid 7AM CDT August 20, 2024. Precipitation - Past 30 Days National Weather Service Huntsville, AL Left - 30-Day Precipitation Totals, Right - 30-Day Percent of Normal Precipitation. Data ending Aug 23, 2024 Main Takeaways Generally, rainfall has ranged around 1.5 to 3 inches for the past 30 days, but most of this rainfall fell in late July into early August for western and central locations. Rainfall in the driest portions of the area in northwestern and north central AL range generally from the 25th to 50th percentiles. Summary of Impacts National Weather Service Huntsville, AL Hydrologic Impacts No hydrologic impacts of note currently, although streamflows and soil moisture fell significantly from early June into early/mid July due to the mostly dry and hot conditions. Rainfall in July especially reduced soil moisture deficits, but deficits have begun climbing again recently due to the dry weather, especially in northwestern and north central portions of the area. See next slide for more hydrologic information including streamflows and lake levels. Agricultural Impacts USDA Crop and Progress Condition Reports during June and July indicated that crops had been negatively impacted due to the hot and generally dry weather from early June to early July, with corn, soybeans, cotton, hay and pastures all being affected. However, it’s been noted that the most significant damage has occurred specifically to the corn crop. Also, livestock producers had indicated lack of sufficient grazing grasses due to the hot, dry weather, and that supplemental feeding was required to maintain livestock conditions. Very recent reports over the last two weeks have indicated wilting with some row crops and stress to soybeans. 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, although more than 35 acres burned have been reported in northern Alabama over the last week by the Alabama Forestry Commission. Keetch-Byram Drought Index (KBDI) values have increased to around 500-600 recently. Mitigation Actions On July 17, 2024, The Alabama Dept. of Economic and Community Affairs - Office of Water Resources placed Drought Regions 1 and 3 (which encompasses all of the Huntsville, AL NWS County Warning and Forecast Area) in a Drought Watch. 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 14-Day average streamflows are generally near the 25th percentile for this time of year, but recent significant decreases in streamflow have been observed on smaller timescales. Reservoir/ Lake Pool Elevation (ft) Current Elevation (ft) Percent Full Bear Creek 576 578 >100% Little Bear Creek 620 619 <100% Cedar Creek 580 580 100% Tim’s Ford 888 888 100% 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 505 505 100% Table caption: Reservoir conditions as of Aug 23, 2024 Figure Caption: USGS 14-day streamflow percentiles for Tennessee and Alabama, valid Aug 22, 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 significantly in most areas over the last 30 days, with decreases of around 8-12 percent. 0-200 cm climatological percentiles are largely around the 10th to 30th percentile in the driest areas of north central and northwest Alabama. Image Captions: Left: NASA SPoRT 1-Month Difference in 0-200 cm Relative Soil Moisture, ending Aug 23, 2024 Right: NASA Short-term Prediction Research and Transition (SPoRT) Center 0-200 cm Soil Moisture Ranking Percentile based on a 33-year climatology (1981-2013), Aug 23, 2024 Agricultural Impacts National Weather Service Huntsville, AL The Lawn and Garden Moisture Index for northern Alabama and southern Middle Tennessee has shown mostly decreases in recent weeks. Values are largely around negative 1-2, indicating at least one to two inch rainfall deficits in most areas for the maintenance of healthy lawns and gardens. . 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. 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 fallen in the last couple of weeks especially, with values around 500-600 in the east and 600-700 in western areas. NWS offices may issue Red Flag Warnings when KBDI values climb above 300 in Alabama, although other weather criteria must be met. 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 Aug 22, 2024 Right Image Caption: Significant Wildland Fire Potential Outlook, August 2024 Seven Day Precipitation Forecast National Weather Service Huntsville, AL Forecast Precipitation (Aug 23-31): Rainfall amounts over the next week are expected to be below normal, with amounts generally below 0.10”. Around 1.00 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 Aug 23 – 7PM Aug 31 (CDT) Rapid Onset Drought Outlook Links to the latest Climate Prediction Center 8 to 14 day Temperature Outlook and Precipitation Outlook. National Weather Service Huntsville, AL Rapid Onset Drought Risk has increased across much of the area, with the exception of portions of northeast Alabama and southern Middle Tennessee. This means that drought deterioration of two more more categories are possible over the next month. Monthly Outlooks - Sep 2024 The latest monthly and seasonal outlooks can be found on the CPC homepage National Weather Service Huntsville, AL Above Normal temperatures are favored (40-50% chance) for September for about the northern half of the area, with higher chances (50-60%) for the southern half. For September, there area Equal Chances for Below, Near, or Above Normal Precipitation. Seasonal Outlooks - Sep to Nov 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 moderately favored (40-50% probability) for the September to November period. Precipitation: Equal Chances for Below, Near, or Above Normal Precipitation for the September to November period. 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. Drought Outlook The latest monthly and seasonal drought outlooks can be found on the CPC homepage National Weather Service Huntsville, AL As of the latest Monthly Drought Outlook last updated on July 31, 2024, drought conditions are expected to persist across the northwest half of the area, with improved conditions expected for the southeast half of the area. Links to the latest: Climate Prediction Center Monthly Drought Outlook Climate Prediction Center Seasonal Drought Outlook