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

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000 FXUS64 KMRX 161105 AAA AFDMRX Area Forecast Discussion...UPDATED National Weather Service Morristown TN 705 AM EDT Sat Mar 16 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 258 AM EDT Sat Mar 16 2024 A cold front has cleared the area, leaving a N-NW flow pattern. The upslope flow has kept some lingering showers going in the mountains, but these should end in the next few hours as dry air continues to build in at 850 mb. Low level moisture has collected against the mountains, which should gradually erode this morning with daytime boundary layer mixing. By the afternoon, most of the area will have mostly sunny skies. A 850 mb thermal boundary will be moving into the area today, with weak cold advection slightly offsetting the solar heating. Highs will be mainly in the mid to upper 60s. A high pressure ridge will be over the area tonight, with another cold front approaching from the north. Increasing clouds with a midlevel shortwave trough can be expected tonight, with lows mainly in the 40s. && .LONG TERM... (Sunday through Friday) Issued at 258 AM EDT Sat Mar 16 2024 Key Messages: 1. Much cooler airmass arriving Monday. Frost early Monday. Tuesday morning a more Widespread frost and hard freeze expected. 2. High pressure and drier air Monday until Thursday, with rain chances increasing Thursday night and Friday with next approaching system. Discussion: Sunday morning will be mostly dry behind a fast moving cold front that crossed the state overnight. This will reinforce the longwave trough over the Ohio Valley and Southern Appalachians Sunday and Sunday night. The front will pick up a little moisture as it exits the area Sunday. Just a few showers expected over the southern plateau, southern valley and into the southeast Tennessee and southwest North Carolina mountains. High pressure builds in across the area Monday and Tuesday behind this front but the front will usher in a much colder airmass. The air will be very dry and temperatures will be much below normal, mostly 40s. Widespread frost is possible Monday morning. Then much colder with widespread frost and a hard freeze early Tuesday morning could affect early growing plants and flowers. Another factor with this front will be strong Northwest winds 15 to 25 mph with gusts in the 30s to over 40 mph in some areas which may require a wind advisory late Monday into Monday night. Wind Chill temperatures will drop into the teens to single digits higher elevations. The cold spell will be short lived as the surface high modifies as it shifts east. Tuesday temperatures will be at least 5 degrees warmer than Monday as southwest winds develop. Wednesday flow turns more westerly but still warming another 10 degrees with highs in the 60s. Thursday into Friday A weak front approaches from the north. A more southerly flow will keep temperatures mild Thursday and with increasing moisture Friday some light showers become more numerous Friday. Lower pressure will approach from the west Friday with a southern system moving across the gulf coastal states Friday. Winds will increase from the southeast and temperatures will be several degrees lower with the clouds and showers. The track and timing of the front to the north and southern system is still uncertain so rain chances may change as time gets closer. && .AVIATION...
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(12Z TAFS) Issued at 704 AM EDT Sat Mar 16 2024 MVFR cigs across the TN Valley will be trending upward through the morning hours. Exactly how quickly that happens is uncertain, but all sites are expected to be VFR in the 15-18Z time frame. The rest of the day will have scattered to few clouds, then clouds increase again at VFR levels tonight as a front approaches the area.
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&& .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 70 50 64 37 / 0 10 20 0 Knoxville McGhee Tyson Airport, TN 68 47 63 34 / 0 0 10 0 Oak Ridge, TN 68 47 64 34 / 0 0 10 0 Tri Cities Airport, TN 67 44 61 32 / 0 0 10 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DGS LONG TERM....TD AVIATION...DGS

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