Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
988 FXUS64 KMRX 300002 AAA AFDMRX Area Forecast Discussion...UPDATED National Weather Service Morristown TN 802 PM EDT Sun Jun 29 2025 ...New AVIATION... .SHORT TERM... (This evening through Monday) Issued at 131 PM EDT Sun Jun 29 2025 Key Messages: 1. Scattered showers and thunderstorms this afternoon will diminish this evening, then increase again on Monday. 2. A few of the stronger storms may produce strong gusty winds, and isolated flash flooding will be a concern in areas that see repeated or prolonged heavy rains. Discussion: Isolated to scattered showers and thunderstorms this afternoon will diminish this evening, then will increase again on Monday with diurnal heating. PW values this afternoon of 1.7 to 2 inches will be around a tenth of an inch higher Monday, with locally heavy rain rates and the potential for isolated flash flooding issues. Enough convective energy is expected this afternoon and again Monday afternoon for a few stronger storms with the potential for strong gusty winds, although the threat of severe storms will be low overall given the lack of shear and modest DCAPE values. High temperatures will generally be around seasonal normals. && .LONG TERM... (Monday night through next Sunday) Issued at 131 PM EDT Sun Jun 29 2025 Key Messages: 1. Numerous showers and thunderstorms Tuesday. High PW values will lead to the potential for some heavy rain rates and flash flooding. 2. Drier conditions beginning Wednesday. 3. Near normal high temperatures Wednesday, but then a gradual warming trend with highs around 3 to 5 degrees above normal Friday into the weekend. Discussion: A shortwave trough and cold front will be approaching Tuesday and will push across our area late Tuesday and/or Tuesday night. Ahead of this, we will likely see MLCAPE values in the 1500 to 2500 J/kg range Tuesday although shear will tick a bit higher it will still be limited (EBWD values of 10 to 20 kts are likely). We will see numerous showers and thunderstorms, and a few storms will likely become strong to marginally severe with damaging winds the primary severe threat. Heavy rain rates will also be a primary concern as PW values increase to between 1.9 and 2.2 inches which will result in flash flooding chances across the region. Some areas could see some 3 to 4+ inch per hour rain rates in the heaviest downpours. Most model guidance shows the front being southeast of our area by early Wednesday. Subsidence and drier air will build in from the northwest on Wednesday and Thursday with mostly dry conditions expected area-wide. By Friday upper level ridging will build in from the west along with mostly dry and warmer conditions that will continue into the weekend. High temperatures are expected to be around 3 to 5 degrees above normal Friday through Sunday. There will be an increase in chances for isolated to scattered diurnal convection by Sunday as the ridge begins to weaken its grip. && .AVIATION... (00Z TAFS) Issued at 749 PM EDT Sun Jun 29 2025 Scattered convection will continue for another few hours before dissipating. Outside of KTYS, not expecting any terminals to be affected until convection starts back up tomorrow. Coverage of SHRA/TSRA looks to be greater tomorrow, and likely to start earlier in the day, with terminals being impacted as early as 18z instead of 20-21z like the last couple of days. Otherwise, there is a possibility of low clouds or fog again tonight in the TN valley. It is a low confidence forecast whether terminals are affected, so I left it out. But I wouldn`t be surprised if some MVFR VSBY or CIGS are seen, especially again at KTRI. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 90 72 90 73 / 50 30 70 40 Knoxville McGhee Tyson Airport, TN 90 71 90 72 / 50 30 60 50 Oak Ridge, TN 90 70 88 71 / 50 30 70 50 Tri Cities Airport, TN 88 68 88 69 / 50 30 60 60 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... AVIATION...CD