810 FXUS64 KMRX 062340 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 740 PM EDT Thu Apr 6 2023 ...New AVIATION... .SHORT TERM... (This evening through Friday) Issued at 320 PM EDT Thu Apr 6 2023 Key Messages: 1. Dry for most places through this evening. However, rain chances increase tonight and into Friday. Discussion: A slow moving front, that is currently hung up along the Cumberland Plateau this afternoon, continues to be a source of frustration in terms of rain chances in the forecast. Flow aloft is largely southwest and parallel with the front, which favors little to no movement through this evening. That doesn't change much until later tonight as upper troughing over the Great Lakes lifts northeast and allows high pressure over Missouri to slide east and push the front southeast. Until the front starts moving, rain chances are likely going to be isolated to scattered in nature. Updated PoPs reflect this, showing increasing rain chances later tonight as the front begins to move. Despite slow moving nature of the front, forcing and instability are lacking so do not believe there's much of a threat of any severe storms or flooding. For Friday, we should be on the cold side of the surface front so expect temperatures to be much colder. Flow aloft is still fairly southwest aloft, but an impulse lifting northeast from the Arklatex region should be cause for more widespread showers. This will likely be tied to the H85 front which remains further to the west this afternoon. && .LONG TERM... (Friday night through next Thursday) Issued at 320 PM EDT Thu Apr 6 2023 Key Messages: 1. Continuing rain chances through Saturday night, as a slow moving front likely stalls just to the southeast. 2. Dry conditions and a warming trend expected from Easter Sunday through the middle of next week. Discussion Frontal boundary will be stalled out across the southeastern US as we head into the weekend. Shortwave is expected to slowly move along the boundary Friday night into Saturday, giving one more round of precipitation before the boundary finally gets shoved off the coast. Best precipitation chances will be in southeast TN, southwest NC, and along the southern Appalachian Mountains. These locations are closer to the energy of the shortwave riding along the boundary, and the orographic lift could also enhance showers in the mountains and foothills of the Appalachians. Forecast soundings and deterministic models continue to show that these showers will likely be all rain with not enough instability to support thunderstorms over the weekend. Due to the training of the storms there is the possibility of isolated flooding in southeast TN and southwest NC if a particular location sees several rounds of rain Friday through Saturday. Chances of widespread flooding this far north of the boundary looks less likely, with storm total QPF amounts expected to remain below 2 inches in these areas, and decreasing totals as you head north. We'll be entering a dry period staring Sunday through much of the upcoming week as mid level ridging, and surface high pressure tries to set up. With the ridge and surface high in place, a slow warming trend will occur next week with daytime highs expected to increase each day and be back in the 70's by Tuesday. Interesting weather feature may develop next week as a trough moves into the southern planes states towards the Gulf. Some of the deterministic models try and turn it into a cut off low across the Gulf states getting stuck under the strong ridge and surface high to it's north. This Rex block pattern could set up for a couple of days next week before the low near the Gulf gets kicked out to the north/east with an approaching system coming out of the southwest US. This system could bring showers and thunderstorms to the Tennessee Valley late next week, but forecast confidence is somewhat low due to model variances and typically deterministic models struggle with slow moving or retrograding lows. && .AVIATION... (00Z TAFS) Issued at 740 PM EDT Thu Apr 6 2023 Still lower confidence of timing of incoming SHRA and its effect on ceilings and visibilities tonight. Looks like VFR conditions will hold for the rest of the evening then deteriorating conditions late tonight and Friday morning. Have gone with continued VFR conditions and no rain until late tonight. MVFR ceilings and SHRA moving in later tonight. Radar imagery shows little activity in east Tennessee and nearby early this evening compared to convection in the afternoon. Guidance shows new activity developing after 04-06Z along the TN/AL border and then spreading east northeast across east Tennessee before 12Z. showers should be over the TAF sites by about 10Z and reduce ceilings/visibilities to MVFR. Continued precipitation during the day will cause IFR conditions by mid to late afternoon. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 53 59 49 58 / 80 90 90 80 Knoxville McGhee Tyson Airport, TN 50 55 47 57 / 70 90 70 70 Oak Ridge, TN 48 55 47 57 / 70 90 60 60 Tri Cities Airport, TN 47 52 43 53 / 60 90 60 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...CD LONG TERM....ABM AVIATION...TD