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

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514 FXUS64 KMRX 080536 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 136 AM EDT Tue Jul 8 2025 ...New SHORT TERM, LONG TERM, AVIATION... .SHORT TERM AND LONG TERM...
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(Today through Monday) Issued at 130 AM EDT Tue Jul 8 2025 Key Messages: 1. Today will be the warmest day this week. Expect heat indices in the mid 90s to low 100s. While ambient temperatures will trend cooler through the week, conditions will still be muggy. 2. Daily chances for showers and storms expected through the forecast period, with the best chances in the afternoon and evening hours. Discussion: Convection continues to dwindle across the region as instability wanes into the overnight hours. Overall, a mostly quiet night expected though cannot totally rule out isolated light rain. An upper trough axis will slowly progress through the Mississippi River Valley tomorrow. Combined with the potential for lingering outflow from this past afternoons convection, better coverage of shower and storms are expected. As always with diurnal convection, some stronger storms with locally gusty winds, heavy downpours, or even small hail could occur. PWAT values will be hovering between the 75th-90th percentile, thus, isolated flooding could occur on the condition of multiple strong cells impacting one location in quick succession. Expect Tuesday to be our warmest day with heat indices approaching the low 100s across portions of the southern and central valley. Coverage of diurnal convection will generally continue to increase Wednesday and into the late week as the aforementioned trough axis settles across the Tennessee Valley. While vort lobes rounding the base of a trough will lead to a slight uptick in synoptic forcing, the upper height falls and more persistent cloud cover will somewhat inhibit CAPE values. A few strong to severe storms possible during this mid to late week timeframe as well but no notable organized severe threat is expected. Daily chances of showers and storms also suggest some potential for isolated flooding, but overall confidence is low. This is largely due to uncertainties on coverage. Some guidance hints the trough axis shifts SE of the Appalachians, potentially limiting moisture advection in the the East TN valley. Height rises into the weekend and early next week will promote a slight warming trend with continued daily chances for showers and storms.
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&& .AVIATION...
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(06Z TAFS) Issued at 130 AM EDT Tue Jul 8 2025 We should see convection over the plateau and east TN mountains by 16-17z, and think this activity will at least be INVOF all terminals by 18z. While coverage will be higher than yesterday, I`m not confident enough to go with prevailing thunder. Will just carry PROB30 at all sites to account for TSRA. Otherwise, VFR conditions will prevail through the period along with light winds. Fog potential seems low, but if any site gets a lot of rain that could change.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 94 73 92 73 / 40 20 80 40 Knoxville McGhee Tyson Airport, TN 93 72 91 71 / 50 30 80 50 Oak Ridge, TN 92 71 90 71 / 50 30 80 50 Tri Cities Airport, TN 90 69 88 68 / 50 30 80 70
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...KRS LONG TERM....KRS AVIATION...CD