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

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203 FXUS64 KMRX 151949 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 349 PM EDT Sat Jun 15 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM...
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(This evening through Sunday) Issued at 346 PM EDT Sat Jun 15 2024 Key Messages: 1. Nice this evening after it cools off after sunset. 2. Hot weather to continue on Sunday with a little more humidity. 3. Chances of showers and storms Sunday afternoon. Discussion: For tonight it should be quiet and relatively comfortable for being in the midst of a heat wave. For Sunday a return flow from the Gulf will allow humidities to rise again, although looking upstream the dewpoints aren`t overly rich back into central AL/MS where the air is supposed to be coming from. So, we have shaved back the initialized dewpoints by around 2 degrees for Sunday, but that still allows dewpoints to be around 70 degrees up the valley to at least Knoxville. Temperatures should rise into the 90s up through most of the valley as well. With higher moisture comes an increase in the chances for showers and storms for Sunday, but with much higher PoPs near the mountains. Also on Sunday the mid-level flow should be just about parallel to the mountains, so keeping the higher PoPs there as well. Expecting MLCAPES of about 1000-1500 J/kg, so gusty outflow winds, but mostly sub-severe.
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&& .LONG TERM...
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(Sunday night through next Saturday) Issued at 346 PM EDT Sat Jun 15 2024 Key Messages: 1. Isolated to scattered storms are expected Monday, especially along the higher terrain. 2. Hot weather to continue, pattern to turn dry Tuesday through the remainder of the week. Discussion: The dominant player from Monday onwards will be the position and strength of the upper level ridge. At the start of the long term period the center of the ridge axis will be east of us. With time it is scheduled to migrate northwards and bring a heat wave to the northeastern US before relaxing southwards late in the week again. Regardless of exact positioning, we will be running a few degrees above normal every single afternoon in the long term period. Beyond the temperatures, the only day with even slightly notable rain chances is Monday. A weak disturbance in the upper flow will be moving from south to north to our west along the Mississippi River. While most convection should remain out west where better moisture and dynamics will be present, the presence of weak upper flow may allow for a few scattered showers and thunderstorms to make an attempt against the influence of the upper ridge. General thunderstorm hazards would be expected with these storms. After Monday a lack of other synoptic players results in low to zero rain chances for the remainder of the period, with any resulting development likely to be isolated in nature. Finally, the GFS and Euro both depict an interesting subtropical disturbance late in the week approaching the SE US coastline, though low support from the ensembles will keep it as a curious model feature for now.
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&& .AVIATION... (18Z TAFS) Issued at 145 PM EDT Sat Jun 15 2024 Dry day today with a light surface wind flow. Just scattered cumulus clouds at TAF sites. Skies should be clearing tonight, then scattered cumulus building again late Sunday morning; holding off any mention of afternoon convection--better chances after 18z on Sunday anyway. Did not put any fog to repeat at KTRI. && .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 73 95 74 94 / 0 30 20 20 Knoxville McGhee Tyson Airport, TN 68 92 72 92 / 0 20 20 30 Oak Ridge, TN 68 93 71 92 / 0 20 20 30 Tri Cities Airport, TN 66 89 69 89 / 0 20 20 40
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...GM LONG TERM....Wellington AVIATION...