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

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000 FXUS64 KMRX 141807 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 207 PM EDT Thu Mar 14 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM...
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(This evening through Friday) Issued at 204 PM EDT Thu Mar 14 2024 Key Messages: 1. Very warm temperatures the rest of this afternoon. 2. A line of showers and thunderstorms will move across the area tomorrow morning. Bringing strong gusty winds and locally heavy rainfall as the primary hazards. Discussion: Currently mostly clear skies today along with very warm temperatures as lower dew points, high pressure, and lots of sun combine to drive up temperatures today. Most locations have crossed above the 70 degree mark today, but still look like they`ll remain several degrees below the record highs for today. The weather pattern will change dramatically overnight and into tomorrow as a strong jet moves through the Ohio Valley, strengthening low level convergence... This jet will be accompanied by an incoming frontal boundary to help focus shower and thunderstorm activity overnight into Friday morning. High resolution models are still in good agreement on the location of the strongest storms, but still some timing differences on when the main line will move into the eastern Tennessee Valley. As of now still expect the strongest storms to move through the eastern Tennessee Valley between 6am and noon EDT, with a few lingering storms possible along the mountains after that. Forecast soundings and CAMs are still showing a few hundred J/Kg of CAPE with the incoming storms, but with the current timing, most of the instability is elevated, hopefully limiting the tornadic threat. With the very warm atmosphere precipitable water values continue to remain very high, nearing 1.5 inches, which is well above the 90th percentile for this time of year. So the primary threats with the incoming storms on Friday will be damaging straight line winds and locally heavy downpours leading to isolated flooding... With areas along the Cumberland Plateau, southeast TN, and southwest NC being at the highest risk. The biggest change has been to exit the precipitation a bit faster than previously forecasted as most guidance is showing a quicker exit of the system. Temperatures will be cooler, but still warmer than normal tomorrow behind the departing storms as cloudy weather lingers the rest of the day.
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&& .LONG TERM...
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(Friday night through next Thursday) Issued at 204 PM EDT Thu Mar 14 2024 Key Messages: 1. Showers/storms quickly diminish Friday night, with mostly dry conditions expected the remainder of the extended forecast period. 2. Hard Freeze growing increasingly likely for much of the area Tuesday morning. This would be accompanied by wind chills in the the teens for portions of SW Virginia, the Cumberland Plateau, NE Tennessee Valley, and the E TN mountains. Discussion: A cold front will be moving through the forecast area by the start of the long term period, with showers quickly coming to an end Friday night. Upper flow will be largely westerly over Kentucky and Tennessee on Saturday and Sunday, with another weak front moving through early Sunday. This front looks to be moisture-starved, so will continue to advertise dry conditions both days. That said, some models do show some scattered showers south of I-40 on Sunday afternoon. This seems to be the outlier though. Temps will cool down, especially Sunday behind the next front, but they`ll continue to run several degrees above normal. On Monday, a sharp upper trough swings through the Ohio valley and southern Appalachians. Could see some light precip in the far northeast but expect most places to remain dry. The more important aspect of this will be the cold air moving in behind the trough for Monday night. Temperatures Monday night likely drop into the 20s area wide. Additionally, light northwesterly winds will result in windchill values in the teens for portions of NE TN, SW VA, and the Cumberland Plateau. Wind chills in higher elevations of the East Tennessee mountains may fall into the single digits. The cold blast will be short-lived however. Height rises will lead to a gradual warming trend through the remainder of the work week. Could see rain chances return by the Thu/Fri timeframe next week as a southern stream trough moves through the central Gulf states. NBM PoPs come back up to the 20-30 percent range by Thu night, which seems reasonable for now.
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&& .AVIATION... (18Z TAFS) Issued at 1259 PM EDT Thu Mar 14 2024 Mostly clear skies with occasional wind gusts expected the rest of the daytime hours today. Late tonight and into tomorrow morning a line of showers and thunderstorms will quickly blast through the region. Have put in PROB30 during the most likely time period of heaviest showers/storms, but will hold off on the details until later TAF issuances. Expect lower ceilings to remain in place tomorrow after the initial round of storms. && .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 60 71 55 71 / 50 80 60 0 Knoxville McGhee Tyson Airport, TN 59 69 51 67 / 50 70 30 0 Oak Ridge, TN 59 68 50 69 / 60 70 30 0 Tri Cities Airport, TN 53 67 47 64 / 40 80 50 10
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... LONG TERM....CD AVIATION...

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