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

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FXUS64 KMRX 250540 AAA

National Weather Service Morristown TN
140 AM EDT Fri Sep 25 2020




The forecast remains in pretty good shape tonight. Area radar
imagery shows light to moderate rainfall across much of the
forecast area this evening. Some cooling cloud tops on IR and
lightning were observed moments ago and could lead to some heavier
showers. For the remainder of the night...expect the upper level
dynamics to begin to shift north which will likely take the
heavier precip north with it. Additional heavy rainfall is
certainly possible given the 30-40 knot low-level jet pumping
high theta-e air northward and convergence as suggested by area
VWP`s. The plan is to keep the FA.A going for a couple more hours
since moderate rain is expected to continue over the next couple
of hours. Additional rainfall amounts of 0.25 to 0.5 inches are
possible across southeast Tennessee. Any convective activity could
produce heavier rainfall rates.




Quite variable conditions late tonight as broad surface low
pressure over northern Alabama from the remnants of tropical
system Beta moves slowly northeast. Ceilings and visibilities have
varied widely this evening and are now mostly VFR but occasionally
MVFR with heavier rainfall periods. Expect conditions to deteriorate
in the next few hours and become MVFR and at times IFR ceilings
and or visibility as rain continues. Steady rain will end later
tonight at CHA but MVFR conditions continue through the morning
and afternoon improving late afternoon or evening. At TYS and TRI
rain continues overnight and through the morning. Lower ceilings
will persist through the period with IFR ceilings possible with
heavier rainfall through the morning. Some improvement in the
afternoon Friday. Winds will be light northeast overnight and then
light and variable at CHA during the day Friday. At TYS and TRI
winds will stay northeast to east into the afternoon Friday.




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