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

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247 FXUS64 KMRX 151721 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 121 PM EDT Tue Jul 15 2025 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 1243 AM EDT Tue Jul 15 2025 Key Messages: 1. Scattered storms are expected this afternoon into the evening with localized flooding and a few stronger storms possible. 2. Hot and humid conditions will continue with highs rising into the 90s for most places. Discussion: Currently early this morning, weak flow is in place aloft with 500mb ridging of over 5,910m centered over the eastern U.S. Bermuda High pressure is also in place over the Atlantic. This will provide a continuation of the typical summer pattern with hot and humid conditions and diurnal convection expected again. The better moisture is expected to remain to our northwest and to our south and east with a weak tropical system likely to develop east of Florida and track westward. The convective environment will comparable to yesterday with virtually 0 shear and MLCAPE in excess of 1,500 J/kg. While they differ, the CAMs collectively show better coverage of convection than yesterday with the most likely timing to be 3 PM until 9 or 10 PM. As in recent days, localized flooding and a few strong storms remain possible. Activity will diminish overnight with mild temperatures and patchy fog for places that see rainfall. && .LONG TERM... (Wednesday through Monday) Issued at 1243 AM EDT Tue Jul 15 2025 Key Messages: 1. Daily storms are expected through the period with better coverage possible than early in the week. 2. Hot and humid conditions will persist with highs in the 90s and heat index values around 100 degrees for many places. Wednesday through Friday At the start of the period, strong ridging will be in place with Bermuda High pressure prevailing to our east. The weak tropical system referenced in the short term period is expected to be tracking along the northern Gulf. This will continue the summer pattern with weak flow aloft and similar thermodynamics as in the short term period. Hot and humid conditions and diurnal convection can be expected. A frontal boundary will also come into view over the northern Plains on Wednesday with southward progression into Thursday. The aforementioned tropical disturbance is also expected to move over Louisiana before gradually dissipating as it progresses northward. This will provide better moisture in our area for the end of the week, compared to recent days. The front is likely to weaken as it settles near the Ohio River Valley, which, combined with increased moisture, will make the case for better convective coverage. As in recent days, localized flooding and isolated strong storms will remain possible. Saturday through Monday Heading into the weekend, a similar pattern will remain in place with 500mb heights reaching or exceeding 5,940m across much of the eastern U.S. Hot and humid conditions will prevail with abundant moisture keeping daily chances for showers and storms. The threat for localized flooding and isolated strong storms will remain each day. The overall flooding threat will be specific to which places see repeated convection, but efficient rainfall rates will be realized, given the environment. && .AVIATION...
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(18Z TAFS) Issued at 117 PM EDT Tue Jul 15 2025 Afternoon and evening convection is possible at each TAF site. TRI/TYS have the greatest chance of storms as the upper ridge is strongest across the southern valley. Another concern is the potential of fog/low-cloud development. Since TRI has the greatest potential of storms included the potential of low-clouds there. Otherwise VFR conditions.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 75 95 75 94 / 20 50 30 60 Knoxville McGhee Tyson Airport, TN 73 93 74 93 / 30 50 40 60 Oak Ridge, TN 72 93 74 92 / 20 50 30 60 Tri Cities Airport, TN 69 90 70 89 / 50 60 40 70
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DH LONG TERM....DH AVIATION...DH