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

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000 FXUS64 KMRX 091949 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 249 PM EST Fri Dec 9 2016 .SHORT TERM...(Tonight and Saturday)...An area of surface high pressure will drift across the area during the period. It will be the coldest night of the season so far in valley areas tonight with winds becoming light under a mainly clear sky. Tomorrow will feature plenty of sunshine with just some increase in high clouds especially late in the day, but it will still be rather cool. Will make only minor adjustments to MAV temps. .LONG TERM...(Saturday Night through Friday)...At the beginning of this period, we will be under and upper level zonal pattern, with not significant troughs of ridges over the US. At the surface, cold high pressure has settled over the area. On Sunday, as the surface high slides to the east, a return flow from the south begins, and out west a surface low and associated cold front begin to gather organization in the Plains and Miss Valley. Ahead of the front, an upper shortwave will be moving toward us Sunday night with chances of rain increasing. Also Sunday night, fast 850 mb winds will be moving into the area, but the pattern is not lined up for the full mountain wave effect, as the 850 mb winds look to be lined up along the TN/NC ridgeline, rather than across the ridgeline, and the surface low drifts farther north...into the Great Lakes, rather than the favored mid Miss Valley for a classic mountain wave event. Still looks like an opportunity for a possible wind advisory for the mountains for late Sunday and into Sunday night. Looks like that cold front will pass through on Monday, then high pressure builds in again. Then the much talked about arctic blast will hit with the initial frontal passage roughly around Tuesday night or Wednesday, but that cold push is somewhat up in the air as models still show great differences in timing, but there is good agreement that Thursday and Friday will be cold. Not crazy about the post-frontal POPs that the blend has come up with; have cut the POPs generally about 10% overall in the Wed-Fri timeframe, thinking that the timing of these systems--some member having a slower solution with lingering POPs in the warmer air, while other solutions are colder and drier, with the averaging getting some more abundant moisture than will really be in the cold air. Anyway, at this point, any wintry precip in the latter half of the week should be light. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 22 45 28 51 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 19 41 25 50 / 0 0 0 10 Oak Ridge, TN 19 42 25 49 / 0 0 0 10 Tri Cities Airport, TN 16 39 21 46 / 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ LW/GM

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