Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
FXUS64 KMRX 251956
Area Forecast Discussion
National Weather Service Morristown TN
256 PM EST Sat Feb 25 2017
.SHORT TERM (Tonight and Tomorrow)...
Cold front is now east of the area with colder drier airmass
working its way eastward into the area. Gusty winds this afternoon
will gradually subside as we head into this evening. Couple that
with clearing skies area wide overnight, and we could expect some
very efficient radiational cooling to help drop the overnight lows
down into the middle to upper 20s, or about 5 degrees below late
Zonal flow aloft through the period will allow for a rapid
eastward progression of surface high currently centered over
central Oklahoma this afternoon. Overnight, this high shifts east,
becoming centered across the area by Sunday afternoon. With it,
we will see plenty of sunshine, with seasonal afternoon high
temperatures in the upper 40s over SW VA to the mid to upper 50s
over SE TN.
.LONG TERM (Tomorrow Night through Saturday)...
The upper pattern becomes amplified again during the period as a
long wave trough builds slowly east out of the Western U.S. As the
southerly flow strengthens Monday into Tuesday, a warm front will
be pressing north across the forecast area. Isentropic lifting
with this boundary along with some weak short wavelength energy
should lead to the development of scattered showers during the
first couple days of the work week. As previously advertised, the
best chance of widespread showers will be Wednesday into Wednesday
night as another strong cold front sweeps through the eastern
states. Of course, in this period of changing seasons with warm
and moist low level air rising into very cold air aloft,
thunderstorms will be part of the equation again on Wednesday.
Will need to watch this again as these storms could become rather
strong. The rain tapers off on Thursday and temperatures may be
cold enough in the higher terrain for a few snow showers on the
tail end of the departing system. Models are not all on the same
page for Friday but generally show a trailing short wave dropping
southeast out of the lakes. The chance for precipitation will be
limited geographically and probabilistically at this point. So,
just added a slight or low chance pop for showers along with some
snow showers across Southwest Virginia and Northeast Tennessee due
to some cold air advection building in with the upper feature.
Was able to keep Saturday dry as the upper flow trends back toward
a zonal configuration with some higher pressure.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 30 57 40 56 / 0 10 10 70
Knoxville McGhee Tyson Airport, TN 28 53 36 58 / 0 10 0 50
Oak Ridge, TN 28 53 35 58 / 0 10 10 40
Tri Cities Airport, TN 24 49 31 58 / 0 10 0 20