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

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000 FXUS64 KMRX 300721 AFDMRX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 321 AM EDT TUE JUN 30 2015 .SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... AN ACTIVE WEATHER PATTERN WILL KEEP HIGH CHANCE TO LIKELY POPS ACROSS THE AREA THROUGH THE SHORT TERM. ONGOING CONVECTION THIS MORNING WILL LIKELY LEAVE NUMEROUS BOUNDARIES THAT WILL BE THE MESOSCALE TRIGGERS FOR ADDTIONAL AFTERNOON CONVECTION. SYNOPTIC LIFT IS ENAHNCED THIS AFTERNOON BY A JET STREAK LOCATED OVER WV AND FALLING HEIGHTS AS THE UPPER TROUGH APPROACHES. THE NAM SHOWS GOOD INSTABILITY AS WELL WITH MLCAPE VALUES OF 1500-2000 J/KG...SUPPORTING SOME STRONG TO SEVERE STORMS WITH WIND/HAIL THREATS. IT IS DIFFICULT TO PINPOINT ONE PART OF THE AREA THAT IS FAVORED FOR STORMS TODAY AND TONIGHT...SO WILL BLANKET LIKELY POPS EVERYWHERE THIS AFTERNOON AND EVENING. BEHIND THE UPPER TROUGH AXIS...WE WILL HAVE A NW FLOW THAT WILL BRING UPSTREAM DISTURBANCES INTO THE AREA. THE NAM AND GFS BOTH SHOW UPSTREAM CONVECTION AND ASSOCIATED MCV MOVING TO THE THE AREA...BUT WITH DIFFERING TIMING AND VERY DIFFERENT QPF AMOUNTS. THE NAM IS THE FASTER OF THE TWO AND WITH MUCH MORE QPF...AND WILL LEAN THE FORECAST IN THIS DIRECTION. WILL HAVE LIKELY POPS STARTING WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT AS THE 850 MB LOW TRACKS FROM WESTERN KY TO VA. STRONG TO SEVERE STORMS WILL BE POSSIBLE THROUGH THIS PERIOD...BUT HEAVY RAINFALL MAY BE A BIGGER CONCERN WITH UNIDIRECTIONAL FLOW FROM 850-500 MB CAUSING TRAINING CELLS AND PW VALUES AROUND 1.75 INCHES. WILL MENTION LOCALLY HEAVY RAINFALL FOR NOW...AND A FLOOD WATCH MAY BE NEEDED WITH LATER FORECASTS. TOTAL AREA-WIDE QPF THROUGH THE SHORT TERM PERIOD WILL BE 2-3 INCHES...WITH LOCALLY HIGHER AMOUNTS. .LONG TERM (FRIDAY THROUGH MONDAY NIGHT)... SOME UNCERTAINTY AS USUAL FOR THE LONGER TERM PERIOD OF THE FORECAST WITH MODELS ATTEMPTING TO PREDICT CONVECTIVE EPISODES. THE PERIOD STILL LOOKS A BIT ON THE ACTIVE SIDE...MAINLY EARLY IN THE PERIOD...WITH THE LONG WAVE TROUGH HOLDING ITS POSITION BUT WEAKENING TO SOME DEGREE OVER THE WEEKEND. FRIDAY MAY CONTINUE TO BE MORE ACTIVE IN TERMS OF MORE WIDESPREAD CONVECTION WITH MODELS INDICATING SOME SHORT WAVE LIFT IN A STILL MOIST AND UNSTABLE MID SOUTH ATMOSPHERE. DEVELOPMENT OF SHOWERS AND THUNDERSTORMS MAY BECOME A LITTLE MORE DIURNAL IN NATURE ON INDEPENDENCE DAY WITH A GRADUAL DECREASE IN PROBABILITY OF PRECIP INTO MONDAY. IT IS BEST TO ALSO GRADUALLY CRANK UP THE HEAT BACK TO WHAT IS MORE TYPICAL FOR EARLY JULY IN THE SOUTHERN APPALACHIANS IN THIS SCENARIO OF INCREASING INSOLATION AND DECREASING POPS. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 85 69 84 70 / 60 60 60 70 KNOXVILLE MCGHEE TYSON AIRPORT, TN 83 67 81 68 / 60 60 60 70 OAK RIDGE, TN 83 66 80 67 / 60 60 60 70 TRI CITIES AIRPORT, TN 81 64 79 64 / 60 60 60 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ 24/99

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