Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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000 FXUS64 KMRX 270716 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 316 AM EDT SUN JUL 27 2014 .SHORT TERM (TODAY AND TONIGHT)...CURRENT SURFACE ANALYSIS SHOWS A WARM FRONT OVER THE OHIO RIVER VALLEY AND CENTRAL APPALACHIANS...WITH A VERY WARM AND MOIST AIR MASS OVER THE FORECAST AREA. A COLD FRONT OVER THE MID WEST THIS MORNING WILL MOVE SOUTHEASTWARD TODAY...AS AN UNSEASONABLY STRONG UPPER-LEVEL TROUGH AMPLIFIES OVER THE EASTERN HALF OF THE NATION. THIS UPPER TROUGH IS PROGGED TO CREATE A MODERATELY TO POTENTIALLY HIGHLY UNSTABLE AIR MASS AND STRONG WIND FIELD OVER THE FORECAST AREA THIS AFTERNOON AND EVENING. LAPSE RATES APPEAR TO BECOME FAIRLY STEEP THROUGHOUT THE TROPOSPHERE OVER THE FORECAST AREA THIS AFTERNOON AND EVENING...WITH DECENT 0-3 KM HELICITY VALUES (AROUND 300 M2/S2) AND LOW LCL HEIGHTS CONDUCIVE FOR TORNADO DEVELOPMENT. OVERALL...IT APPEARS THAT THERE WILL BE THE POSSIBILITY FOR WIDESPREAD DAMAGING WINDS...VERY LARGE HAIL...LOCALLY HEAVY RAINFALL...AND ISOLATED TORNADOES THIS AFTERNOON AND EVENING. AS FOR TEMPS...GFS AND NAM GUIDANCE NUMBERS REVEAL SOME DISCREPANCIES WITH MAXES FOR TODAY... BUT ARE IN GOOD AGREEMENT WITH MINS FOR TONIGHT. WILL GENERALLY TREND TOWARDS THE COOLER NAM MAXES FOR TODAY...SINCE AN EXTENSIVE AREA OF HIGH CLOUDS AND SCATTERED CONVECTION ARE EXPECTED. .LONG TERM (MONDAY THROUGH FRIDAY)...IN WAKE OF A STRONG COLD FRONT THAT IS PROGGED TO MOVE THROUGH THE REGION SUNDAY NIGHT...ANY REMNANT STORM/SHOWER ACTIVITY FROM THE EARLIER SQUALL LINE/MCS WILL QUICKLY DISSIPATE AND SHIFT OFF THE EAST AS SOME PARTIAL CLEARING BEGINS TO OCCUR WITH DRIER AND COOLER AIR FILTERING INTO THE AREA. THIS WILL SET UP THE FORECAST PATTERN FOR THE REMAINDER OF THE WEEK AS A STALLED UPPER-LEVEL TROUGH WILL REMAIN IN PLACE OVER THE EASTERN CONUS THROUGH THE END OF THE WORK WEEK. THIS WILL PROMOTE ABNORMALLY LOW TEMPERATURES OF UP TO 10 TO PERHAPS 15 DEGREES LOWER THAN NORMAL /WITH THE MERCURY PEAKING IN THE UPPER 70S TO LOWER 80S FOR MOST OF THE WEEK/. THOUGH THIS COOL/DRY NORTHWESTERLY FLOW SHOULD LIMIT PRECIPITATION CHANCES SIGNIFICANTLY...SOME ISOLATED SHOWERS AND STORMS WILL BE POSSIBLE ALONG THE HIGHER TERRAIN OF THE EAST TENNESSEE AND SOUTHWEST VIRGINIA MOUNTAINS EACH DAY. LATER IN THE WEEK...ANOTHER BROAD LONGWAVE TROUGH WILL SWING OUT OF THE GREAT LAKES AROUND THE BASE OF THE PARENT CLOSED LOW...PUSHING ANOTHER FRONT TOWARD THE REGION WHICH WILL GIVE THE AREA ANOTHER SOT OF UNSEASONABLY COLDER AIR. THIS UPPER-TROUGH WILL ALSO RESULT IN SOME ADDITIONAL MORE ORGANIZED CONVECTION LATER ON IN THE WEEK AS ANOTHER PUSHES TOWARD THE REGION. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 93 72 85 62 / 20 50 20 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 91 71 82 60 / 30 60 20 10 OAK RIDGE, TN 91 71 82 60 / 40 60 10 10 TRI CITIES AIRPORT, TN 88 66 79 58 / 50 60 20 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DMG/AMP

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