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

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000 FXUS64 KMRX 251922 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 322 PM EDT Sat Mar 25 2017 .SHORT TERM...
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(Tonight and Tomorrow)...Overall, unsettled short term period as a low pressure system moves in and brings showers and a few thunderstorms across the area. System is rather slow moving and it will take awhile before we see any precip. To begin the period have narrow zone of likely pops in place across the far southwest corner of the CWA, chance pops across Plateau and Southern Valley and slight chance extending up into the Central and Northern Valley. The general progression of pops overnight will be to have increasing pops from southwest to northeast, thus keeping Northeast TN and Southwest VA driest the longest. For most locations, mainly expecting rain but soundings do show a few hundred joules of CAPE overnight so will include slight chance for a Tstorm, expect for NETN and SWVA where airmass is more stable. Lows tonight will once again be very mild, with lows around 15 degrees above normal. A stronger 850mb jet core moves in after 00z and will bring near wind advisory criteria to the highest peaks of the Smokies. Sustained winds of 20 to 25 mph with gusts near 40 mph will be possible above 5000 feet. Elevations below 5000 feet will see breezy and gusty conditions as well, with sustained winds of 15 to 20 mph and gusts near 30 mph. These breezy and gusty winds will continue into tomorrow. No advisory planned at this time. Initial wave of showers begins to decrease in coverage and intensity tomorrow morning after sunrise and that trend continues through late morning and early afternoon. Later tomorrow afternoon, the forecast is a little more tricky. With cold front still back to our west, and partial clearing expected, it appears that shower and thunderstorm redevelopment is possible just back to our west with activity moving into our area by mid to late afternoon. If we can get redevelopment some of the storms could become strong with an isolated severe not out of the question. Tomorrow afternoon NAM soundings show 500 to 1000 J/KG of MLCAPE across the area with steep lapse rates along with 30 to 40 kts of 0-6km shear and near 30kts at 0-3km. Will continue to watch model runs to see how they handle afternoon redevelopment. Current SPC outlook has our area under a marginal risk tomorrow. Highs tomorrow will be in the upper 60s to low 70s. .LONG TERM...(Sunday night through Saturday)...Will stay in an active weather pattern through the extended forecast period as a series of systems move through the area. To start the period, a cold front will slowly be exiting the forecast area, bringing reduced thunderstorm chances for Sunday night. The next system is right on its heels, with a shortwave over the central plains moving east into the area by Monday evening into Tuesday. This will bring another round of showers and thunderstorms to the region. Shortwave pushes east by Tuesday evening and upper level ridging builds, bringing the only stretch of dry weather for Wednesday into Thursday. Another system strengthening over the south-central US will push east for the end of the workweek, but this is where model solutions begin to diverge with the ECMWF progressing the system slightly faster than the GFS and tracking it further north. Regardless, rain chances increase once again for Thursday into Friday with more showers and thunderstorms possible as this system impacts the forecast area.
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Chattanooga Airport, TN 58 72 57 75 / 90 70 40 40 Knoxville McGhee Tyson Airport, TN 57 70 56 75 / 80 80 50 40 Oak Ridge, TN 56 71 55 75 / 90 80 40 40 Tri Cities Airport, TN 53 68 51 73 / 30 80 60 40
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ SR/EMH is the U.S. government's official web portal to all federal, state and local government web resources and services.