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

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470 FXUS64 KMRX 130717 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 317 AM EDT Thu Jun 13 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM...
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(Today and tonight) Issued at 221 AM EDT Thu Jun 13 2024 Key Messages: 1. Low probability of showers/thunderstorm across the far east Tennessee Mountains and southwest North Carolina this afternoon. 2. Increasingly hot conditions developing. Discussion: A weak shear axis will move slowly east of the southern Appalachians this morning taking the high and mid-level clouds with it. HREF shows widely scattered/scattered convection across the far east Tennessee mountains and southwest North Carolina. Due to continued relatively dry airmass, stable layer/inversion between 850-700mb, and low MLCAPE values of 250-500 at best, plan on limiting convection to low probability. Temperatures will continue the trend of warmer highs/lows for today and tonight. For tonight, besides a few light showers in the mountains early, dry conditions.
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&& .LONG TERM...
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(Friday through Wednesday) Issued at 221 AM EDT Thu Jun 13 2024 Key Messages: 1. Temperatures rising through the weekend, peaking on Sunday but remaining above normal through the first half of next week. 2. Isolated to scattered showers and thunderstorms are possible each afternoon, mainly over the higher terrain. Discussion: A cold front will be pushing into our area from the north at the start of the forecast period. It will likely be a dry fropa, since the midlevel flow remains NW-N ahead of the front. Friday will have some slight chance PoPs in northern sections and the mountains. High pressure over the Great Lakes will feed some lower dewpoints into the area, but temperatures will remain above normal, with highs in the upper 80s to mid 90s Friday and Saturday. The heat and humidity ramp up on Sunday as the large mid/upper level high pressure ridge over the southern Plains shifts east to MS/AL/GA, and the surface high shifts off the Mid-Atlantic coast. With highs well into the 90s across the TN Valley, and dewpoints in the upper 60s to lower 70s, the heat index may exceed 100 in the central and southern Valley. Organized convection is unlikely under the ridge, but there may be enough low level moisture and afternoon instability to spark a few showers and thunderstorms in the higher terrain areas through the first half of next week. Monday appears to have the best chance as we get a more southerly low level flow up the Valley and higher 850 mb theta-e values. Still, this is only a low chance to slight chance as the 500 mb ridge remains directly over the southern Appalachians. Previous model runs that had shown a Gulf moisture plume spreading into the region in the Monday-Tuesday time frame have now shifted that moisture farther west. So any precip chances next week will be mainly diurnally-driven and favor the terrain areas. With the mainly dry conditions, high temps will be bumped up a little over NBM for Monday hrough Wednesday - highs in the 90s will continue.
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&& .AVIATION... (06Z TAFS) Issued at 130 AM EDT Thu Jun 13 2024 VFR conditions throughout the forecast at all TAF sites with surface ridging producing light winds. && .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 92 70 95 71 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 89 67 91 69 / 10 0 10 0 Oak Ridge, TN 90 66 91 68 / 0 0 10 0 Tri Cities Airport, TN 86 63 88 65 / 10 0 20 10
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DH LONG TERM....DGS AVIATION...DH