FXUS64 KMRX 050508 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 108 AM EDT Sun May 5 2024 ...New AVIATION... .UPDATE... Issued at 1015 PM EDT Sat May 4 2024 A weakening thunderstorm complex is progressing across the Tennessee valley, Athens and Monroe County Airports recently reported gusts to 20 mph in these storms. Earlier heavier rain from this cluster had produced some minor flooding in Bledsoe County, but with the cluster weakening post sunset and moving steadily onwards, not expecting to see any more issues overnight. Elsewhere a few small cells have popped up once more in the Chattanooga metro, but should amount to nothing apart from short downpours. The forecast is otherwise well on track. Nighttime microphysics and regional observations depict clear or mostly clear skies to our west. Even with a low chance of another popup shower overnight, temperatures are at or near area dewpoints, therefore fog seems increasingly likely overnight into the early morning. && .SHORT TERM... (This evening through Sunday) Issued at 241 PM EDT Sat May 4 2024 Key Messages: Drying trend tonight, then less coverage of showers and storms on Sunday than is occurring today. Discussion: The short wave trough that is over the region will exit tonight, followed by rising heights/short wave ridging on Sunday. Scattered to numerous showers and thunderstorms this afternoon will gradually diminish overnight, but some at least isolated weaker convection will be possible through much of the night. On Sunday the overall environment will consist of minimal shear and modest instability, with MLCAPEs likely to top out between 500 and 1000 J/kg most locations. Given the weak subsidence over our area as the short wave ridging builds in, expect less convective coverage with mostly isolated to scattered showers and storms especially in the afternoon. && .LONG TERM... (Sunday night through next Saturday) Issued at 241 PM EDT Sat May 4 2024 Key Messages: Shower and thunderstorm chances are possible almost every day for the next week. With the strongest and most organized storms likely to occur Wednesday/Thursday. Discussion: By Sunday night yet another shortwave will be moving into the southern Appalachian region, but will lose some of it's power as it flattens out and runs into the more stable atmosphere. This will however be enough to spark off even more showers and thunderstorms, with the greatest coverage and intensity of storms expected during the daytime on Monday as the vortmax moves right over head. Luckily with the almost continuous cloudy conditions we should struggle to destabilize on Monday which will hopefully lead to weaker thunderstorms. However if some sun is able to make it through to the surface we could see pockets of stronger storms. On Tuesday the shortwave should be out of our area, but the rain chances don't completely go away as LLJ begins to increase in strength and move eastward through the Tennessee/Ohio Valleys. Storms that are able to form on Tuesday will have an atmosphere more conducive to organized convection, but again the CAPE looks to remain limited with cloudy conditions. Wednesday and Thursday look to have an interesting set up as the LLJ continues to strengthen and a low moves through the Great Lakes region bringing with it a frontal boundary to the southeast, which will aid in synoptic level forcing across the southern Appalachian region. Wednesday into Thursday still looks to be the day with the best chances to see strong to severe convection with this synoptic set up, and we cannot rule out an MCS moving through somewhere in our area. With that being said we are still 4-5 days out from this event with LOTS of convection and turnover in the atmosphere between now and late next week, so still expect models to change the location and timing of the front/low/jet into next week. Also of note will be the increasing chances to see flooding with all this shower and thunderstorm activity. There will likely be large differences in rainfall totals from county to county by this time next week due to the convective nature of the storms, but we could see several counties get widespread 2-3 inches of rain before Friday. Cannot pinpoint exactly where the heaviest rain will be over the next week, but expect we could see several flood advisories or warnings issued before next weekend. && .AVIATION... (06Z TAFS) Issued at 105 AM EDT Sun May 5 2024 Sct showers and thunderstorms are moving eastward across the region early this morning associated with a subtle upper level feature. This convection is currently impacting CHA and may impact TYS and TRI over the next few hours. Drier weather is expected by 10z across the region with shortwave ridging limiting convective coverage. Winds will be generally light with a diurnal trend in convective probabilities as low chances of showers and thunderstorms increase on Sunday afternoon. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 85 66 82 65 / 30 50 80 30 Knoxville McGhee Tyson Airport, TN 82 63 79 63 / 40 30 90 40 Oak Ridge, TN 83 63 79 63 / 40 30 90 30 Tri Cities Airport, TN 79 60 77 60 / 50 30 90 30 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...Wellington AVIATION...JB