Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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000 FXUS64 KMRX 140241 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 1041 PM EDT Wed Mar 13 2024 ...New UPDATE... .UPDATE...
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Issued at 1031 PM EDT Wed Mar 13 2024 No drastic changes needed to the immediate forecast period. Blended forecast with most recent observations and overnight lows with recent model data. Still expecting a mostly clear night, although temperatures will be a bit mild compared to last night, with moisture on the incline. KS
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&& .SHORT TERM... (This evening through Thursday) Issued at 315 PM EDT Wed Mar 13 2024 Key Message: Afternoon relative humidities low this afternoon with above normal temperatures today and tomorrow. Discussion: Currently mostly clear skies with high pressure over the region and a few passing mid to high level clouds traversing across the region. Temperatures this afternoon are once again warming up very quickly with the dry air in place, about 5 degrees warmer than what we experienced yesterday and about 10 degrees warmer than seasonal normals. Quiet weather will continue overnight and into tomorrow, with the main difference being an even warmer day ahead of the upcoming system. Temperatures tomorrow are expected to climb to near 80 degrees across parts of the eastern Tennessee Valley... And temperatures look like they will be within about 5 degrees of the record highs for March 14th. Daily Record High Maximum Temperatures Date Chattanooga Knoxville Tri-Cities Oak Ridge 03-13 83(1967) 81(1967) 78(1990) 83(1967) 03-14 83(2012) 85(1990) 82(1990) 84(1990) && .LONG TERM... (Thursday night through next Wednesday) Issued at 315 PM EDT Wed Mar 13 2024 Key Messages: 1. Chances for thunderstorms increasing Friday. Isolated flooding may become a concern if an area sees repeated moderate to heavy convectively enhanced rainfall. A strong thunderstorm is possible south of Interstate 40. 2. Hard freeze growing increasingly likely (60-70%) for much of the area Tuesday morning. Discussion: Synoptic pattern over the continental US still appears to be the same this afternoon for the next week`s weather. An upper trough over the Rockies will cut off into a Rex block set up, with the upper low underneath the upper ridge. This eventually allows for an upper trough to dig in over the eastern US, bringing a harsh but brief end to our warm weather. The start of the period (Friday morning) is growing increasingly interesting. CAMs this morning came in aggressive, depicting a mesoscale convective system (MCS) moving across western and middle Tennessee Thursday night arriving sometime Friday morning. The 12z GFS has moved closer to be in agreement, depicting a likely band of thunderstorms entering east Tennessee Friday morning. Time of day is definitely a drawback for severe potential. With all early spring events, especially early morning, the biggest question is how much CAPE will be available for storms, with some guidance (like the HRRR) depicting potentially up to 1000 J of MUCAPE available, allowing for storms to persist closer (or into) East Tennessee. Though SPC did not place us under any risk for Day 2, this does not preclude the possibility of strong to severe thunderstorms for the southern valley Friday morning. The other main risk to watch is for any potential flooding on Friday, and with CAMs being aggressive with thunderstorm development and maintenance, heavy convective downpours given the moist atmosphere could produce isolated flooding. One hour flash flood guidance across the southern valley is roughly two inches, which provides a decent buffer, even against convection. Lesser so up across northeastern Tennessee, which is where the orientation of showers and thunderstorms will also play a role. Rain will be moving out Friday evening and Friday night, followed by a weak cold front. Weekend still looks to be mostly dry, maybe a light shower possible Sunday afternoon as a shortwave moves by and weak isentropic lifting may encourage shower development, though odds overall are low. Heading into next week, a deep upper trough will dig into the Eastern US, sending sharp cold southwards behind a strong cold front. Subfreezing temperatures look likely Tuesday morning, with 60-70% of a hard freeze for good swaths of the region. With the recent warmth thus far in March, this will hurt. The good news is the trough is progressive and the cold short lived. For the most part, the first half of next week looks to be dry, with not much moisture at present for any snow showers in the mountains early Tuesday. && .AVIATION... (00Z TAFS) Issued at 729 PM EDT Wed Mar 13 2024 Surface high pressure, thus dry conditions, will continue through the end of the latest TAF issuance. Some mid to high level FEW- SCT at times between clear skies. Winds calm and variable overnight will increase to around 10KT out of the southwest tomorrow afternoon. && .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 48 79 60 70 / 0 0 30 100 Knoxville McGhee Tyson Airport, TN 45 79 58 68 / 0 0 30 100 Oak Ridge, TN 45 78 58 68 / 0 0 40 100 Tri Cities Airport, TN 41 75 52 67 / 0 0 20 90
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... LONG TERM....Wellington AVIATION...KS

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