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

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000 FXUS64 KMRX 151411 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1011 AM EDT Fri Mar 15 2024 ...New UPDATE... .UPDATE...
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Issued at 1006 AM EDT Fri Mar 15 2024 Currently the initial line of showers and thunderstorms is moving onto and east of the southern Appalachian Mountains. Satellite data is showing that most of the lightning activity associated with the line is south of the TN/NC state borders. This morning update was mainly to adjust hourly PoP/Wx forecast to come more in line with radar trends as the main line begins to leave the area. Have not completely eliminated storm chances the rest of the day as we could see redevelopment of much more isolated storms in the afternoon/evening ahead of the actual front... But have cut back on the precipitation chances across much of the valley.
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&& .SHORT TERM... (Today and tonight) Issued at 400 AM EDT Fri Mar 15 2024 Key Messages: 1. A line of showers and thunderstorms will move across the area this morning. Bringing strong gusty winds and locally heavy rainfall as the primary hazards. 2. More showers and some storms develop/move through this afternoon although more scattered and continue into the evening diminishing around midnight. Discussion: Early this morning convection that was over southern middle Tennessee and north Alabama quickly moved into southeast Tennessee and is spreading northeast up the Tennessee Valley toward Knoxville. A strong jet was moving through the Ohio Valley and a shortwave ahead of a frontal system moving into the Ohio Valley this morning had developed a line of showers and storms to the west from middle Tennessee into northern Mississippi. This will be the main weather maker today behind the initial convection. The storms were strongest in the past hour across the southern plateau. The storms to the west are expected to weaken as they approach eastern Tennessee later this morning. Behind the line showers and storms should become more scattered this afternoon as the more organized convection shifts south. More convection should develop later in the afternoon and evening ahead of the front. The instability looks to be limited later today but with precipitable water values high some heavy rainfall is possible through about mid afternoon mainly southern areas. Some stronger winds are possible this morning with the storms to as they move east and southeast today. Locally heavy rainfall could cause isolated flooding over the southern part of the Cumberland Plateau, southeast TN, and southwest NC...mainly this morning. By 06Z tonight the front should be east of the Appalachians and higher pressure will be building in from the west. Rain will end but with all the precipitation there will be patchy fog forming. Temperatures today will still be mild in the 60s to around 70. Tonight lows will still be in the mild 40s to lower 50s. && .LONG TERM... (Saturday through Thursday) Issued at 400 AM EDT Fri Mar 15 2024 Key Messages: 1. Mostly dry conditions Saturday through the end of the extended forecast period. 2. Hard Freeze growing likely for much of the area Tuesday morning. This would be accompanied by wind chills in the the teens for much of the area. Discussion: A cold front will be east of the forecast area at the start of extended forecast period. The upper level becomes westerly over Tennessee this weekend. A weak front will move down from the NW early Sunday. This front will be mostly dry but could produce a few showers in the south and southeast mountains of Tennessee and southwest North Carolina but amounts very light. Temperatures will be cooler in the 60s but still above normal by a few degrees. Monday a significant upper trough moves through the Ohio valley and southern Appalachians. Light precip is possible over southwest Virginia and it will be cold enough Monday night for a few snow showers. Elsewhere it will be dry and more significant will be the cold temperatures behind the trough and cold front Monday night into Tuesday morning. Lows Monday night should drop into the 20s area wide. Wind chills are expected to drop into the teens for parts of NE TN, SW VA, and the Cumberland Plateau. Wind chills in higher elevations of the East Tennessee mountains may fall below 10. The cold air will not last as higher pressure and the departing trough bring a gradual warming trend for the rest of the week. Next chance of rain will be Thursday as a southern system moves across the Gulf coast area. Rain chances will be about 30 percent later Thursday. && .AVIATION... (12Z TAFS) Issued at 740 AM EDT Fri Mar 15 2024 MVFR conditions at CHA with a line of showers and thunderstorms moving through during the next hour or so. TYS also has reduced visibility due to storms with the line. TEMPO for these storms will be for low visibilities. Storms should move out later but MVFR conditions continue. Possible storms at TRI this afternoon and Ceilings expected to be MVFR this morning. Later today more thunderstorms possible ahead of a cold front that will move through this evening. IFR conditions possible at CHA tonight and MVFR conditions persisting elsewhere as low clouds and fog remain after showers end during the day. && .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 70 53 71 48 / 100 40 0 0 Knoxville McGhee Tyson Airport, TN 69 51 67 46 / 90 40 0 0 Oak Ridge, TN 70 48 69 45 / 90 30 0 0 Tri Cities Airport, TN 67 47 64 43 / 90 40 10 0
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... LONG TERM....TD AVIATION...TD

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