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

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000 FXUS64 KMRX 010730 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 330 AM EDT MON SEP 1 2014 .SHORT TERM (TODAY AND TONIGHT)...CURRENT SURFACE ANALYSIS SHOWS A WARM AND VERY MOIST AIR MASS OVER THE FORECAST AREA...WITH DEWPOINTS NEAR 70 OVER MOST OF THE FORECAST AREA. MODELS ARE IN GOOD AGREEMENT THAT THE COVERAGE OF CONVECTION OVER THE FORECAST AREA WILL BE LESS TODAY THAN IN PREVIOUS DAYS...DUE TO A LACK OF CONVECTIVE TRIGGERING MECHANISMS. HOWEVER...WITH A MARGINALLY TO POTENTIALLY MODERATELY UNSTABLE AIR MASS DEVELOPING THIS AFTERNOON AND EVENING...WILL PLAN TO MENTION ISOLATED CONVECTION EVERYWHERE. MODEL SOUNDINGS EVEN REVEAL AN INVERTED-V PROFILE THIS AFTERNOON IN THE LOWER LEVELS WHERE DRY AIR MAY HELP TO ENCOURAGE STRONG DOWNDRAFTS WITH ANY CONVECTION. AS FOR TEMPS...GFS AND NAM GUIDANCE NUMBERS ARE IN GENERAL AGREEMENT FOR TODAY AND TONIGHT...BUT WILL COMPROMISE WHERE SOME SLIGHT DIFFERENCES ARE NOTED. .LONG TERM (TUESDAY THROUGH SUNDAY)...A WEAK COLD FRONT WILL DROP SOUTH OUT OF THE OHIO VALLEY ON TUESDAY...WHICH WILL PUSH SOME CONVECTION TOWARD THE REGION DURING THE LATE AFTERNOON/EVENING... AND INTO THE OVERNIGHT HOURS. THE FRONT ITSELF HOWEVER SHOULD STALL AND WASH OUT TO THE NORTH OF THE AREA ALONG THE NORTHERN PERIPHERY OF A BROAD/FLATTENED SUBTROPICAL RIDGE OF HIGH PRESSURE. THIS RIDGE WILL BEGIN TO AMPLIFY SLIGHTLY OVER THE AREA WEDNESDAY AND THURSDAY...PROMOTING CONTINUED HOT AND HUMID CONDITIONS. WITH THE ABUNDANT GULF MOISTURE UNDERNEATH THIS RIDGE...GOOD CHANCES FOR SCATTERED DIURNALLY DRIVEN CONVECTION WILL EXIST EACH DAY THROUGH THE REMAINDER OF THE WORK WEEK AND EVEN INTO THE WEEKEND. A 30 TO 40 POP SEEMED WARRANTED MOST DAYS...WITH HIGHS IN THE UPPER 80S TO LOWER 90S DEPENDING ON STORM/CLOUD COVERAGE. THE RIDGE WILL SLOWLY RETROGRADE WEST HEADING TOWARD THE WEEKEND...WHICH WOULD PLACE THE REGION IN NORTHWEST FLOW ALOFT AND PERHAPS ENHANCE PRECIPITATION CHANCES AT THE TAIL END OF THE PERIOD. HOWEVER...CONFIDENCE IS LOW ATTM REGARDING WHICH DAY WOULD BE MORE FAVORED FOR COVERAGE...SO HAVE MAINTAINED SCATTERED/CHANCE POPS EACH DAY THROUGH THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 91 72 92 70 / 20 20 30 30 KNOXVILLE MCGHEE TYSON AIRPORT, TN 91 70 90 69 / 20 20 30 30 OAK RIDGE, TN 91 71 90 68 / 20 20 40 30 TRI CITIES AIRPORT, TN 89 66 89 63 / 20 20 50 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DMG/AMP

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