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

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483 FXUS64 KMRX 032012 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 312 PM EST Sat Dec 3 2016 .SHORT TERM (Tonight through Sunday)... Upper-storm system moving into the region this evening, bringing light isolated to scattered rain showers into the Southern Valley and Plateau after 00Z. After midnight, This activity will begin to overspread the entire region, with the best coverage and intensity occurring after sunrise on Sunday morning. The heaviest precipitation will occur across the far Southern Valley and Plateau. However, widespread totals of 0.25 to 1 inch or rainfall is possible through 00z on Monday. Complicating things overnight will be the height of the melting level (which will drop to around 3,000 ft). Thus, some very light snow could occur along the peaks of the East Tennessee and SW Virginia Mountains. Accumulations will be very light form a dusting to perhaps 1/2 an inch at most. The main concern will shift into the day on Sunday during the late morning through the late evening as a 40-50 kt 850 mb jet will shift along the high terrain of the North Carolina and East Tennessee Mountains. These upper-level winds and the strong SE (downslope) wind component will lead to sustained winds of 15 to 30 mph along the high terrain of the Smoky Mountains, along with gusts up to 50 mph. These winds could contribute to wildfire growth and spread in areas that are still burning in the park. This is true, even with light rain moving into those areas on Sunday as the downslope component of the winds will act to erode some of the precipitation shield along the mountains and their surrounding foothills. A wind advisory has been issued for these areas from 10 AM to 10 PM Sunday. .LONG TERM (Sunday Night through Saturday)...Scattered rain showers will continue over the area Sunday evening...with a few showers lingering over the area through the night as Sunday`s weather system slowly exits the region. The area will not see much of a break as another system moves in from the southwest. This next system will bring widespread rain into the area from southwest to northeast for Monday and Tuesday. Model consistency becomes quite poor for the rest of the extended. Should see a decrease in activity on Wednesday as the system continues to pull away from the region and the next system approaches the area. That next system will be a cold front that will move in around the Thursday time frame. The ECMWF is stronger with the frontal passage over the region with deeper moisture while the GFS has the main lobe of energy to our north with drier air in place across the MRX CWA. Will go with a compromise...bringing scattered showers across the area Wednesday night and Thursday. Much cooler air is expected to push in behind the front with lows on Thursday night expected to fall into the teens and 20s and highs Friday only reaching into the 30s. With this cooler air mass...any lingering showers will transition to light snow or flurries. All precip should exits the area for Friday night and Saturday for cool...dry conditions to begin the weekend. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 43 47 45 56 / 100 100 50 80 Knoxville McGhee Tyson Airport, TN 40 47 42 54 / 90 100 50 70 Oak Ridge, TN 39 47 42 54 / 90 90 50 60 Tri Cities Airport, TN 35 46 39 53 / 50 80 70 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...Wind Advisory from 10 AM to 10 PM EST Sunday for Cherokee-Clay. TN...Wind Advisory from 10 AM to 10 PM EST Sunday for Blount Smoky Mountains-Cocke Smoky Mountains-East Polk-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...None. && $$ AMP/MJB

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