502 FXUS64 KMRX 292323 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 723 PM EDT Sat Oct 29 2022 ...New AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 239 PM EDT Sat Oct 29 2022 Key Messages: 1. Dry tonight with increasing clouds. 2. Scattered rain showers on Sunday with light precip amounts. Discussion: We remain dry tonight with increasing clouds as the stacked, closed low approaches from the west with southwesterly flow aloft. As the upper level low shifts eastward tonight and Sunday, upper diffluence increases across the region and low-level southerly flow increases in response to the upper divergence. As moisture increases from the south, widespread rain showers will become likely with an overcast sky. Highest PoPs are expected across southeast Tennessee, the Cumberland Plateau, and the central valley with lowest PoPs across the western foothills of the Appalachians due to southeasterly downslope flow. This will also lead to the highest max temperatures on Sunday being across the lower elevations just west of the Appalachian chain. Overall rain totals appear minimal with 0.25 to 0.5 inches of rain most likely with the highest amounts across the southern Cumberland Plateau. Downslope winds will limit overall rainfall across the lower elevations west of the Appalachians and across northeast Tennessee.&& .LONG TERM... (Sunday night through next Saturday) Issued at 239 PM EDT Sat Oct 29 2022 Key Messages: 1. Rain showers Sunday night through Monday night. 2. Low chance for additional showers Wednesday. 3. Ridging rebuilds starting Thursday and continues through Saturday with continued above normal temperatures. Discussion: As the next system moves in late Sunday a surface low will be over St Louis with warm air advection producing rain across the Tennessee and Ohio Valleys. There is limited instability so thunder should be minimal but showers could produce 0.25 to 0.75 inches Sunday night into Monday. Surface high pressure over North Carolina will only very slowly shift eastward Monday. Upper trough slowly advances east into the Tennessee Valley Monday as surface low moves northeast toward southern Michigan. A trailing shortwave Monday night will keep a chance of a few more showers across northern sections through early Tuesday. High pressure builds in Tuesday with some brief clearing. Models continuing to show another weak system developing over the Gulf coast Tuesday and Tuesday night just south of the base of the upper trough over the lower Mississippi Valley. This system will get caught up in the upper level southwest flow and weaken Wednesday. A weak upper low may form overhead as the system moves northeast across the forecast area. Will continue to forecast a few light showers with cloudy skies Wednesday. From Thursday through Saturday a ridge aloft builds over the southeast and into the Tennessee Valley. Surface high pressure will build over the southeast states too. Expect sunny skies and warm temperatures for the last three days. Highs will be about 10 degrees above normal. && .LONG TERM... (Sunday night through next Saturday) Issued at 239 PM EDT Sat Oct 29 2022 Key Messages: 1. Rain showers Sunday night through Monday night. 2. Low chance for additional showers Wednesday. 3. Ridging rebuilds starting Thursday and continues through Saturday with continued above normal temperatures. Discussion: As the next system moves in late Sunday a surface low will be over St Louis with warm air advection producing rain across the Tennessee and Ohio Valleys. There is limited instability so thunder should be minimal but showers could produce 0.25 to 0.75 inches Sunday night into Monday. Surface high pressure over North Carolina will only very slowly shift eastward Monday. Upper trough slowly advances east into the Tennessee Valley Monday as surface low moves northeast toward southern Michigan. A trailing shortwave Monday night will keep a chance of a few more showers across northern sections through early Tuesday. High pressure builds in Tuesday with some brief clearing. Models continuing to show another weak system developing over the Gulf coast Tuesday and Tuesday night just south of the base of the upper trough over the lower Mississippi Valley. This system will get caught up in the upper level southwest flow and weaken Wednesday. A weak upper low may form overhead as the system moves northeast across the forecast area. Will continue to forecast a few light showers with cloudy skies Wednesday. From Thursday through Saturday a ridge aloft builds over the southeast and into the Tennessee Valley. Surface high pressure will build over the southeast states too. Expect sunny skies and warm temperatures for the last three days. Highs will be about 10 degrees above normal. && .AVIATION... (00Z TAFS) Issued at 654 PM EDT Sat Oct 29 2022 Clouds and precip chances will continue to slowly increase across the area through the period ahead of an incoming upper level system. CHA will go MVFR later tonight as ceilings lower and should remain MVFR through the end of the period. Downsloping winds at TYS and TRI should keep both terminals VFR through the period but a prob30 is in at TYS tomorrow afternoon for MVFR. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 56 65 56 70 / 30 70 60 30 Knoxville McGhee Tyson Airport, TN 51 70 55 69 / 10 60 70 50 Oak Ridge, TN 50 67 54 68 / 10 70 70 40 Tri Cities Airport, TN 47 69 50 67 / 0 30 70 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...JB LONG TERM....TD AVIATION...SR