DROUGHT INFORMATION STATEMENT NATIONAL WEATHER SERVICE MORRISTOWN TN 1100 AM EDT FRI MAY 2 2008
...DROUGHT IMPROVES IN EAST TENNESSEE, EXTREME SOUTHWEST VIRGINIA, AND CHEROKEE AND CLAY COUNTIES IN NORTH CAROLINA. PLEASE NOTE FORMAT CHANGE FOR THIS ANNOUNCEMENT...
SYNOPSIS...
THIS STATEMENT IS ALSO ISSUED UNDER AWIPS HEADER MEMPNSMRX, AND WMO HEADER NOUS44 KMRX.
ALL GEOGRAPHIC DESCRIPTIONS ARE APPROXIMATE.
D2 (SEVERE) DROUGHT CONDITIONS EXIST IN SOUTHEAST TENNESSEE GENERALLY SOUTH OF A LINE FROM TELLICO PLAINS TO ROCKWOOD, AND OVER THE SOUTHERN CUMBERLAND PLATEAU. THIS INCLUDES THE CHATTANOOGA METRO AREA. SUCH CONDITIONS ALSO EXIST IN CHEROKEE AND CLAY COUNTIES, IN NORTH CAROLINA.
D1 (MODERATE) DROUGHT EXISTS GENERALLY SOUTH OF A LINE FROM DEER LODGE TO KNOXVILLE (INCLUDING THE KNOXVILLE METRO AREA) TO DANDRIDGE TO KINGSPORT, IN EAST TENNESSEE. THIS INCLUDES THE GREAT SMOKY MOUNTAINS, AND MOST OF THE TRI-CITIES METRO AREA. IN VIRGINIA, THEY EXIST OVER THE SOUTHERN HALF OF WASHINGTON COUNTY. IT ALSO INCLUDES THE CITY OF BRISTOL.
D0 (ABNORMALLY DRY) CONDITIONS EXIST IN EAST TENNESSEE NORTH OF A LINE FROM DEER LODGE TO KNOXVILLE (EXCLUDING THE KNOXVILLE METRO AREA) TO DANDRIDGE TO KINGSPORT, AND IN VIRGINIA IN LEE, SCOTT, WISE, RUSSELL, AND THE NORTHERN THIRD OF WASHINGTON COUNTIES.
A SMALL SLIVER OF SCOTT COUNTY, TN ALONG THE KENTUCKY BORDER IS IN A NEAR NORMAL STATE OF WETNESS.
SUMMARY OF IMPACTS...
NO WIDESPREAD LOCAL OR STATE WATER SUPPLY, FIRE, NAVIGATION, OR RECREATIONAL IMPACTS ARE KNOWN. SOME SMALL SPRINGS AND WELLS ARE STILL LOWER THAN NORMAL AROUND THE REGION, WHICH AFFECT LOCAL OR INDIVIDUAL WATER SUPPLIES. FOR INFORMATION ON LOCAL WATER RESTRICTIONS, PLEASE CALL YOUR LOCAL WATER BOARD. NO WIDESPREAD FIRE RESTRICTIONS ARE KNOWN TO EXIST, HOWEVER CONTACT LOCAL AUTHORITIES FOR FURTHER INFORMATION OR PERMITS.
CLIMATE SUMMARY...
RAINFALL AT INDIVIDUAL POINTS IS NOT ALWAYS AN ACCURATE REFLECTION OF AN AREA'S PRECIPITATION. RAINFALL OVER LARGE AREAS IS A MORE REALISTIC REPRESENTATION A REGION'S RAIN SITUATION. BELOW ARE THE DATA FOR THE MAIN NATIONAL WEATHER SERVICE OBSERVATION POINTS FOR THE PERIOD STARTING JANUARY 1, 2007. THE DATA GO THROUGH MIDNIGHT THURSDAY, MAY 1, 2008:
SITE RAIN NORM DEFICIT %NORM CHATTANOOGA 56.00 75.32 -19.32 74 KNOXVILLE 49.90 66.10 -16.20 75 OAK RIDGE 54.23 74.87 -20.64 75 TRI-CITIES 36.19 55.51 -19.32 65 NWS MORRISTOWN 44.59 62.00 -17.41 72
RAIN TOTAL OVER LARGE AREAS SUCH AS RESERVOIR DRAINAGE BASINS IS A MUCH BETTER INDICATOR OF AN AREA'S "RAIN HEALTH" THAN SIMPLE POINT TOTALS. BELOW ARE THE DATA FOR THE TVA BASINS IN THE UPPER TENNESSEE RIVER DRAINAGE FOR THE PERIOD STARTING JANUARY 1, 2007. THE DATA GO THROUGH 6 AM THURSDAY, MAY 1, 2008:
BASIN RAIN NORM DEFICIT %NORM SOUTH HOLSTON 44.69 58.53 -13.84 76 WATAUGA 45.54 61.92 -16.38 74 BOONE 41.96 60.12 -18.16 70 CHEROKEE 43.32 59.01 -15.69 73 DOUGLAS 45.56 62.74 -17.18 73 FONTANA 58.81 80.17 -21.36 73 NORRIS 45.65 61.76 -16.11 74 MELTON HILL 50.54 66.82 -16.28 76 CHATUGE 49.86 80.32 -30.46 62 NOTTELY 56.68 74.57 -17.89 76 HIWASSEE 52.28 78.05 -25.77 67 FT. LOUDOUN/TELLICO 45.16 65.87 -20.71 69 WATTS BAR 51.80 69.58 -17.78 74 CHICKAMAUGA 44.23 72.98 -28.75 61 NICKAJACK 43.43 73.96 -30.53 59 GUNTERSVILLE 41.83 75.18 -33.35 56
TEMPERATURES IN THE REGION WERE NEAR NORMAL DURING THE MONTH OF APRIL. TWO COLD SNAPS IN THE MIDDLE AND END OF THE MONTH BROUGHT MUCH ABOVE NORMAL TEMPERATURES DOWN TO EARTH.
CHATTANOOGA ENDED THE MONTH ABOUT 1.6 DEGREES ABOVE NORMAL. KNOXVILLE WAS 1.7 DEGREES ABOVE
NORMAL FOR THE MONTH. OAK RIDGE WAS NEARLY BALMY WITH 2.5 DEGREES ABOVE NORMAL FOR THE MONTH.
TRI-CITIES AIRPORT WAS 1.6 DEGREES ABOVE NORMAL. AGAIN, A COLD SNAP AT MONTH’S END BROUGHT THE
AVERAGE DOWN FROM VERY MUCH WARMER THAN NORMAL FOR MOST OF THE MONTH.
WARMER THAN AVERAGE TEMPERATURES MEAN MORE EVAPORATION FROM TOP SOILS AND DRIER SOIL CONDITIONS. HOWEVER, THIS CAN BE BALANCED OUT BY RAIN FALLING AT KEY TIMES AND OVER LONGER PERIODS. THE FACT THAT TWO MAJOR COLD SPELLS OCCURRED DURING THE MONTH MEANS THAT MUCH LESS EVAPORATION THAN NORMAL OCCURRED DURING THOSE TIMES. OVERALL, A FAIRLY AVERAGE MONTH FOR TEMPERATURES.
PRECIPITATION/TEMPERATURE OUTLOOK...
THROUGH ABOUT MAY 11, GENERAL CONDITIONS ARE EXPECTED TO BE ABOUT NORMAL FOR TEMPERATURE, WITH ABOVE AVERAGE RAINFALL FOR THE REGION AS A WHOLE. INDIVIDUAL LOCATIONS MAY VARY.
THE SECOND WEEK OF MAY IS EXPECTED TO BE COOLER AND WETTER THAN NORMAL.
THE PERIOD OF MAY THROUGH JULY IS EXPECTED TO ABOUT NORMAL FOR BOTH TEMPERATURE AND RAINFALL.
THE RAMIFICATIONS OF THIS OUTLOOK ARE THAT LOWER THAN NORMAL EVAPOTRANSPIRATION COULD OCCUR. LESS EVAPOTRANSPIRATION MEANS THAT TOP SOILS COULD REMAIN SLIGHTLY WETTER THAN NORMAL, AND STREAM FLOWS WOULD BENEFIT, TOO. FOR RESERVOIR LEVELS TO RISE SIGNIFICANTLY, MUCH HIGHER THAN AVERAGE RAIN MUST OCCUR. THIS IS NOT ANTICIPATED AT THIS TIME, THOUGH SOME IMPROVEMENT IS EXPECTED.
HYDROLOGIC SUMMARY AND OUTLOOK...
DURING THE LAST WEEK OF APRIL, STREAMS COMING OUT OF THE MOUNTAINS INTO EAST TENNESSEE AND IN EXTREME SOUTHWEST VIRGINIA HAD BENEFITED GREATLY FROM RECENT HEAVY RAINS. EXTREME SOUTHWEST NORTH CAROLINA STREAMS DID NOT BENEFIT AS MUCH. STREAMFLOWS THAT WEEK WERE ABOVE THE 75TH PERCENTILE IN EAST TENNESSEE AND EXTREME SOUTHWEST VIRGINIA, AND ABOVE NORMAL IN CHEROKEE AND CLAY COUNTIES. FLOODING WAS NOT A PROBLEM BUT THEY HAD NOT BEEN THAT HIGH FOR MONTHS.
THIS HAS CHANGED AND FLOWS ARE NOW DROPPING BACK TO NORMAL AND EVEN LOWER LEVELS. THIS INDICATES THAT GROUND WATER TABLES ARE STILL BELOW NORMAL. RAINFALL HITTING THE GROUND DURING A DROUGHT ENTERS THE WATER TABLE INSTEAD OF RUNNING OFF INTO CHANNELS. HENCE, RESERVOIRS FILL MORE SLOWLY THAN THEY OTHERWISE WOULD. WHILE TOP SOILS ARE WETTER THAN THEY HAVE BEEN IN WEEKS, GROUND WATER IS STILL LOW.
THE OUTLOOK FOR LARGE TRIBUTARIES OF THE TENNESSEE RIVER THROUGH EARLY SUMMER IS FOR A LESS THAN NORMAL CHANCE OF FLOODING. THIS WILL DEPEND LARGELY ON THE AMOUNT OF RAIN OVER THE LONG TERM AND THE NUMBER OF HEAVY RAIN EVENTS IN THE PERIOD. BUT IT WILL ALSO DEPEND ON THE HYDROGRAPHY OF THE INDIVIDUAL STREAM. THINGS LIKE LOCAL GEOGRAPHY, WHETHER SINKHOLES ACCOUNT FOR MUCH UNDERGROUND STORAGE, LOCAL LAND USE, FLORA, AND SO FORTH, WILL ALSO MAKE A DIFFERENCE.
FOR SMALL STREAMS AND URBAN AREAS, THIS WILL DEPEND ENTIRELY ON THE AMOUNT OF RAIN RECEIVED IN A SHORT TIME, AND CHARACTERISTICS OF THE SPOT IN WHICH IT FALLS, SUCH AS PAVEMENT OR CONCRETE, TOPOGRAPHY, ETC.
NEXT ISSUANCE DATE...
THE NEXT DROUGHT INFORMATION STATEMENT WILL BE ISSUED ON OR BEFORE MAY 23, 2008, DEPENDING ON THE SITUATION. IF NO LARGE SCALE CHANGES OCCUR IN THE DROUGHT SITUATION, IT WILL BE LATER THAN SOONER. WE WILL MONITOR THE SITUATION AND KEEP YOU ABREAST.
RELATED WEB SITES...
FOR ONE-STOP SHOPPING ON THE DROUGHT IN THE REGION GO TO HTTP://WWW.SRH.NOAA.GOV/MRX/HYDRO/DROUGHT07/MAIN.PHP
OR YOU CAN GO TO WWW.WEATHER.GOV THEN CLICK ON THE EAST TENNESSEE REGION, AND THEN CLICK ON THE DROUGHT INFORMATION LINK AT THE BOTTOM OF THE MORRISTOWN, TENNESSEE HOME PAGE.
YOU MAY ALSO VISIT WWW.TVA.GOV FOR MORE INFORMATION ON LAKES LEVELS, STREAMFLOWS AND RAINFALL IN THE TENNESSEE VALLEY AUTHORITY SYSTEM.
STREAMFLOW DATA CAN ALSO BE OBTAINED FROM THE UNITED STATES GEOLOGICAL SURVEY AT HTTP://WATERDATA.USGS.GOV/NWIS/RT AND THEN CLICKING ON YOUR STATE OF INTEREST.
ADDITIONAL LONG TERM STREAMFLOW FORECASTS CAN BE OBTAINED AT THE NWS MORRISTOWN "ADVANCED HYDROLOGIC PREDICTION SERVICES" WEBSITE AT HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=MRX
FOR SPECIFIC DATA, DROUGHT INDICES, AND THE NATIONAL DROUGHT PICTURE WITH CLICKABLE ZOOMING, GO TO HTTP://WWW.DROUGHT.UNL.EDU/DM/
ACKNOWLEDGMENTS...
APPRECIATION FOR THE DATA IN THIS DOCUMENT GO TO THE TENNESSEE VALLEY AUTHORITY (TVA), UNITED STATES GEOLOGICAL SURVEY (USGS), THE STATES OF TENNESSEE AND NORTH CAROLINA, THE COMMONWEALTH OF VIRGINIA, THE U.S. ARMY CORPS OF ENGINEERS (USACE), THE NATIONAL PARK SERVICE (NPS), THE NATIONAL FOREST SERVICE (NFS), THE UNIVERSITY OF NEBRASKA AT LINCOLN FOR HOSTING THE DROUGHT MONITOR WEBSITE, AND NUMEROUS COUNTY AND CITY OFFICIALS. ALSO, THANKS GO TO VARIOUS MEDIA OUTLETS INCLUDING TELEVISION AND RADIO STATIONS AND NEWSPAPERS, FOR ASKING THE QUESTIONS THE DRIVE THE GATHERING OF DATA AND IMPACT INFORMATION.
QUESTIONS OR COMMENTS...
FOR MORE INFORMATION OR FOR MEDIA INTERVIEWS PLEASE CONTACT:
BRIAN BOYD SENIOR SERVICE HYDROLOGIST NATIONAL WEATHER SERVICE 5974 COMMERCE BLVD. MORRISTOWN, TN 37814 423-586-1964 (MEDIA ONLY; FOR IMMEDIATE RESPONSE) 423-586-2296 (ALL OTHER CALLS; MAY GET VOICE MAIL) 423-586-6429 (FOR IMMEDIATE RESPONSE, NON-MEDIA CALLS, IF 2296 IS NOT AVAILABLE) EMAIL: BRIAN.BOYD@NOAA.GOV WEBSITE: WWW.SRH.NOAA.GOV/MRX
NOTE: IN THE EVENT THE ABOVE PERSON IS NOT AVAILABLE, OTHER STAFF MEMBERS WILL BE ABLE TO HELP YOU.