Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
675 FXUS64 KMRX 300522 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 122 AM EDT Thu Jul 30 2026 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 124 AM EDT Thu Jul 30 2026 - Dry weather with more moderate temps and humidity through Friday. - Showers and thunderstorms return for this weekend into next week. - A low chance for a few strong to severe storms this weekend, but details still uncertain. && .DISCUSSION... Issued at 124 AM EDT Thu Jul 30 2026 Surface high pressure to our north and northwest will continue to extend into our area through Friday as it slides slowly east. The post frontal airmass over our area will provide a mild and sunny day Thursday, with temperatures generally a bit below normal and a noticeable absence of the humid stickiness that was around earlier in the week. Friday will be mostly sunny and dry as well, with high temperatures closer to seasonal normals. For the weekend, southerly flow brings an increase in moisture as an upper level shortwave energy and trough drop from out of the northern/central Great Plains into our area. The increase in moisture combined with the incoming trough/low pressure and a frontal boundary will lead to chances for showers and storms returning to the area Saturday into Sunday. The details are still not clear, but while the LREF ensemble data currently suggests the joint probability of at least 500 J/kg of CAPE and 25 kts of bulk shear are very low (around 10%), there is certainly potential in this pattern for a period favorable for some strong to severe storms since at least marginal shear will likely be present, with the most likely time frame for any severe threat being Saturday into Saturday night. However, whether or not this threat materializes will depend on details, including the timing of best forcing and available CAPE, that are still unknown. Localized flooding will also be possible in any locations that see repeated or prolonged periods of heavy rain during the weekend. This will bear close watching as we get closer. There are model differences for the early part of next week with some models showing the upper trough cutting off somewhere over our region and gradually weakening. If it does, then chances for showers and storms will remain elevated into next week as this upper low continues to slowly spins across the region with no where to go before it eventually dissipates. && .AVIATION... (06Z TAFS) Issued at 124 AM EDT Thu Jul 30 2026 Low confidence in fog forming at KTRI for a few hours before sunrise with the lower dew points. Outside of brief fog at KTRI expect VFR conditions for the next 24 hours. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 88 66 91 70 / 0 0 0 30 Knoxville McGhee Tyson Airport, TN 84 63 88 68 / 0 0 0 10 Oak Ridge, TN 84 62 87 67 / 0 0 0 10 Tri Cities Airport, TN 80 57 83 64 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...99 AVIATION...99