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

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000 FXUS64 KMRX 301849 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 249 PM EDT SAT AUG 30 2014 .SHORT TERM...
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(TONIGHT THROUGH MONDAY)...GULF MOISTURE CONTINUES TO STREAM NORTHWARD FROM THE WESTERN GULF OF MEXICO THIS AFTERNOON. AIR MASS IS BECOMING SLIGHTLY TO MODERATELY UNSTABLE WITH SPOTTY CONVECTION POPPING OVER SE TN...AND MORE SO TO OUR SW OVER NE AL. I ADJUSTED THE SHORT TERM GRIDS FOR LATE AFTERNOON AND THIS EVENING IN LINE WITH THE SIMILAR HRRR AND RAP MODELS...WHICH SUPPORTS LIKELY POPS OVER WRN AREAS. THE SHORTWAVE TROUGH MOVES EAST ACROSS THE WRN GREAT LAKES AND OHIO VALLEY REGION OVERNIGHT...WHICH SHOULD KEEP HIGHER POPS IN ORDER AFTER MIDNIGHT ACROSS OUR NRN PLATEAU AND EXTREME WRN SW VA COUNTIES. FOR SUNDAY...STAYED WITH OUR LOW END OF LIKELY POPS...WHICH ARE HIGHER THAN 12Z MOS GUIDANCE...SINCE THE SRN END OF THE UPPER TROUGH WILL BE PASSING EAST ACROSS THE TN VALLEY AND SRN APPALACHIANS DURING PEAK HEATING. LOWERED POPS FROM THE WEST SUNDAY NIGHT WITH PASSAGE OF THE TROUGH AXIS. MONDAY ALSO SHAPING UP DRIER THAN PREVIOUS GRIDS...SO CUT POPS BACK TO 20 TO 30 PERCENT...AND PUSHED MAX TEMPS BACK UP TO THE SIMILAR UPR 80S TO LWR 90S FROM 12Z MOS. OTHERWISE...12Z NAM AND GFS MOS TEMPS WERE IN GENERAL AGREEMENT AND CLOSELY FOLLOWED. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)...NOT MUCH FOCUS FOR CONVECTION THROUGHOUT THE LONG TERM PERIOD OTHER THAN INTENSE SOLAR HEATING AND OROGRAPHIC LIFT ON THE MAJOR TERRAIN FEATURES. HOWEVER...THERE WILL BE SOME WEAK SHORT WAVE ENERGY MAKING ITS WAY ACROSS THE NORTHEASTERN QUARTER OF THE NATION LATER TUESDAY INTO WEDNESDAY AND THIS CONFIGURATION MAY COAX A WEAK COOL FRONT INTO THE SOUTHERN APPALACHIAN REGION WEDNESDAY THROUGH FRIDAY. THIS BOUNDARY MAY ALLOW FOR A SLIGHT INCREASE IN PROBABILITY OF PRECIPITATION MAINLY ON WEDNESDAY IF IT CAN MAKE IT FAR ENOUGH SOUTH. OTHERWISE GENERALLY KEPT POPS AROUND 20-25 PERCENT AS UPPER RIDGING HANGS AROUND THE SOUTHEASTERN U.S. TRENDED MAX TEMPS A LITTLE CLOSER TO SUGGESTED HIGHS FOR THE UPCOMING WEEK AS THE ANNUAL LATE SUMMER LAG IN HEATING DUE TO LONG WAVE RE-RADIATION FINALLY CATCHES UP TO US. STAYED PRETTY CLOSE TO MINS THROUGH THE PERIOD.
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&& .PRELIMINARY POINT TEMPS/POPS...
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CHATTANOOGA AIRPORT, TN 71 87 71 93 / 60 60 40 20 KNOXVILLE MCGHEE TYSON AIRPORT, TN 69 86 70 91 / 50 60 30 20 OAK RIDGE, TN 70 84 69 91 / 60 60 40 20 TRI CITIES AIRPORT, TN 66 87 65 87 / 50 60 40 20
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ TG

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