Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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305 FXUS64 KMRX 131134 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 634 AM EST Wed Nov 13 2024 ...New AVIATION... .SHORT TERM... (Today through Tuesday) Issued at 221 AM EST Wed Nov 13 2024 Key Message: Rain will move through the area starting tonight and continuing through much of Thursday. Discussion: Currently a quiet overnight period as we sit under mid level ridging ahead of an incoming system that will affect the region the next couple of days. A low pressure system is moving through the plains states on its way towards the Great Lakes Region during the middle part of the work week. This system will also bring help sweep through a front in the Ohio/Tennessee Valleys as it interacts with an enhanced plume of moisture moving out of the Gulf of Mexico and into the eastern Tennessee Valley. Expect the precipitation to move onto the Cumberland Plateau this evening, right near sunset ahead of the front. Depending on the timing of the the precipitation and how fast the front moves through, we could see a brief period of isolated thunder during the hottest part of the late afternoon on/near the Plateau. Still looks as though the vast majority of people will not see any thunder, but cannot completely rule out a few rumbles this afternoon/evening. As the sun sets the precipitation will continue to spread eastward overnight bringing rainfall to most locations in the Southern Appalachians. Rain should continue through sunrise for most places, and eventually come to an end as the front moves through during the daytime on Thursday. Expect the precipitation to end over the Appalachian Mountains right around sunset on Thursday, with most places seeing approximately 12-18 hours worth of light to moderate rain when everything is said and done. We could see some wrap around precipitation late Thursday across northeast TN and southwest VA, but the QPF amounts associated with this portion of the system are expected to be very light. QPF amounts continue to tick slightly upward as high resolution models are getting a hold of the system. Expect storm total rainfall amounts to be between 0.50" and 1.50" with the highest amounts likely west of I-75 and lower amounts east of I-75. Flooding appears unlikely as this rain is expected to fall over the course of approximately 12-24 hours and we`re still fairly dry in our region. However, with the possibility of an isolated thunderstorm this afternoon/evening a brief heavy downpour west of I-75 leading to flooding of poor drainage areas cannot be completely ruled out, even though it appears unlikely. && .LONG TERM... (Thursday Night through Tuesday) Issued at 221 AM EST Wed Nov 13 2024 Key Messages: 1. Dry weather is expected this weekend through Monday. 2. The next system approaches midweek as a deep trough moves into the Eastern U.S. Discussion: In the upper levels, a ridge will slowly build in by Friday evening. This ridge will hold through the weekend. Mid next week, a deep trough will move into the Eastern U.S. At the surface, high pressure will be in place through Monday. A frontal passage will be possible mid next week. Saturday, Sunday and Monday will be dry with a warming trend as ridging and high pressure dominate the region. Temps will be slightly above normal with highs in the 60s. By next Tuesday or Wednesday, a cold front followed by a deep trough will be possible. Rain ahead of the cold front is likely Tuesday and/or Wednesday. The deep trough may bring some snow to the higher elevations late next week but it is still very far out. && .AVIATION... (12Z TAFS) Issued at 632 AM EST Wed Nov 13 2024 Main weather story will be the incoming rain later this afternoon/evening. Expect widespread rain to drop ceilings/visibilities into the MVFR/IFR categories for much of the overnight hours. Ceilings and visibilities should rebound just beyond this TAF cycle. Cannot completely rule out a rogue lightning strike this afternoon at KCHA right as the rain begins, but chances are too low to mention in the TAFs. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 66 50 61 49 / 40 90 60 0 Knoxville McGhee Tyson Airport, TN 69 49 61 47 / 10 100 90 10 Oak Ridge, TN 68 48 59 47 / 20 100 90 10 Tri Cities Airport, TN 63 44 56 46 / 0 90 100 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... LONG TERM....McD AVIATION...