


Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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200 FXUS64 KMRX 062325 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 725 PM EDT Fri Jun 6 2025 ...New AVIATION... .SHORT TERM... (This evening through Saturday) Issued at 351 PM EDT Fri Jun 6 2025 Key Messages: 1. Scattered to numerous showers and storms this afternoon and evening, some of which will be strong to severe. Damaging winds, heavy downpours, and hail will be the primary threats. 2. Additional showers and storms are possible Saturday afternoon into the overnight but much lower confidence exists for Saturday, especially regarding the potential for severe weather. Latest satellite trends depict some weakening of the Cu field across the East Tennessee valley as upper-level cirrus from widespread convection to our west advects aloft. As the activity across western & central KY/TN translates eastward with an associated shortwave late afternoon and into the evening, it will encounter an unstable airmass with MLCAPE near ~2000J/kg and effective bulk shear approaching 30 kts. This will maintain the strong to severe storm threat as mentioned the past few forecast packages, with primary hazard being damaging wind gusts. Anomalously high freezing levels and marginal lapse rates will limit the threat for large hail, though smaller hail could be common. Minimal low-level shear will hinder the tornado threat. The exception to this could be the southern Plateau and valley as the vort max progress through around midnight to 2am time frame. However the slightly better shear will be dueling with a developing surface inversion so confidence in a very low tornado threat is low. Nonetheless, a 2% chance was introduced by SPC per the latest afternoon update. We will see a lull in activity overnight though we will not remain totally dry. Latest HREF run suggest the development of low-level clouds is expected early Saturday morning to near mid-day. NAM cross sections also support that claim. This scenario would lead to notably lesser chance of a strong/severe threat Saturday afternoon and evening in which latest hi-res guidance diverges activity to our south with better instability and to our north where better upper- level divergence will be in place ahead of a surface front. Nam3km is the most bullish with CI ahead of the boundary during the overnight hours Saturday night but at that point instability will be waning. Overall the confidence in strong to severe weather Saturday is rather low. High PWAT content could lead to flash flooding concerns, especially in the event of repeated strong showers and storms over a single location both this afternoon and Saturday. && .LONG TERM... (Saturday night through next Friday) Issued at 351 PM EDT Fri Jun 6 2025 .LONG TERM...(Tuesday through Monday)... Key Messages: 1. Unsettled pattern with daily chances of showers and storms continue Sunday and into the first half of the week. Chances for severe weather are marginal at this point, with isolated flooding possible due to the repeated rounds of activity over multiple days. 2. Drier weather mid to late next week following a frontal passage Tuesday evening. Discussion: Overall the unsettled pattern with daily chances of showers and thunderstorms will continue Sunday into the first half of the week as troughing swings across the central and eastern CONUS. While it won`t be a total washout, bouts of energy rounding the base of the trough and diurnal heating will influence periods of showers and storms. Severe potential during Sunday through Tuesday seems marginal with limited instability per latest GFS soundings. Effective bulk shear will be greatest when the upper jet near 70- 80kts builds southward to the region and a cold front makes a passage. Chances for showers and storms will become much more limited Wednesday into the late week as surface high pressure builds in behind the front. Cannot rule out some diurnal activity across higher terrain with temperatures in the mid 80s and continued dewpoints in the upper 60s to near 70. && .AVIATION... (00Z TAFS) Issued at 723 PM EDT Fri Jun 6 2025 Periods of scattered showers and thunderstorms will continue throughout the next 24 hours with convection containing high rainfall rates and gusty winds. We expect to see a decrease in thunderstorm activity over the next couple hours with a tempo for thunderstorms around 04z to 07z across the region, with highest probabilities for impacts near TRI. Saturday morning is expected to have lower probabilities for showers and thunderstorms prior to an increase in coverage during the afternoon. However, uncertainty in convective coverage has precluded anything more than prob30 mention of thunderstorms on Saturday afternoon at this time. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 70 87 70 84 / 50 60 80 70 Knoxville McGhee Tyson Airport, TN 69 84 69 81 / 80 70 70 70 Oak Ridge, TN 68 84 68 81 / 80 60 70 60 Tri Cities Airport, TN 65 81 64 78 / 80 70 70 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...KRS LONG TERM....KRS AVIATION...JB