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

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143 FXUS64 KMRX 292344 AAA AFDMRX Area Forecast Discussion...UPDATED National Weather Service Morristown TN 744 PM EDT Wed May 29 2024 ...New AVIATION... .SHORT TERM... (This evening through Thursday) Issued at 257 PM EDT Wed May 29 2024 Key Messages: 1. Dry weather with patchy fog possible tonight. Tomorrow is slightly cooler but overall pleasant and dry. Discussion: Satellite this afternoon depicts a lot of puffy cumulus clouds floating on by in the northwest flow. Winds are gusting to their usual 20 to 30 mph with the mixed atmosphere today, those will calm to light winds tonight. High resolution guidance has a couple spotty returns through this evening, and trends have been to be less vigorous than yesterday. Expect any light return to result in virga, given the dry lower atmosphere across the region. Tonight into tomorrow the dry weather pattern will continue. Winds aloft look to pivot to more northerly flow under the upper trough, which brings in a slightly cooler airmass in. Tomorrow morning patchy fog is possible in northern Tennessee into southwest Virginia, and HREF guidance keeps some low clouds around in the morning. This, coupled with the slightly cooler airmass, should result in slightly cooler afternoon highs tomorrow. && .LONG TERM... (Thursday night through next Wednesday) Issued at 257 PM EDT Wed May 29 2024 Key Messages: 1. Dry weather will continue through Friday night. 2. Chances for showers and thunderstorms start to creep back into the region starting Saturday afternoon. Rain chances to continue into the middle part of next week. Discussion: A narrow upper ridge just to our west to start will build in Thursday night into Friday. We will see dry weather continue through at least Friday night with near to below normal temperatures. Relative humidity values will be low Friday afternoon. By Saturday, the first in a series of upper level short waves is forecast to be approaching. This first wave is not expected to have much moisture to work with, so we have just some low PoPs in the forecast for Saturday afternoon across mainly southern and western portions of the area. While the models are in decent agreement on the timing of this first wave, beyond that there is poor agreement and consistency which is not surprising given the typical model difficulties in handling these types of features in the latter portions of the forecast period. The ensemble approach of the NBM shows chances for showers and storms for the remainder of the forecast from Saturday night through Wednesday. GEFS ensemble data shows modest median SBCAPE values overall although they do increase a bit for the latter periods (as does the spread), and mean deep layer shear is generally weak. While a few strong to severe storms may occur, right now the severe storm threat looks to be on the low side overall for the period. However, some of the models are hinting at a significant cold front approaching by Wednesday, which may provide a more favorable environment for stronger storms if this does occur. Temperatures will show an overall warming trend, with highs Sunday likely to be below normal but by late in the period temperatures are expected to be above normal across the area. && .AVIATION...
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(00Z TAFS) Issued at 741 PM EDT Wed May 29 2024 VFR conditions will prevail through the period. Winds will be light, less than 10kt, and out of the north. Some guidance indicates a chance at seeing some fog at KTRI, but will not include it at this time. Seems like a low chance of occurring given it hasn`t happened the last couple of nights, the temp and dewpoint spreads are larger versus 24 hours ago, and the fog is an outlier solution in the models.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 84 57 81 57 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 80 53 77 53 / 0 0 0 0 Oak Ridge, TN 80 53 77 53 / 0 0 0 0 Tri Cities Airport, TN 77 50 72 45 / 0 0 0 0
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...Wellington AVIATION...CD