Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Nashville Tennessee
525 am CST Sat Feb 6 2016
for 12z aviation discussion.
Shortwave upstream will gain some strength as the axis works across
the middle state by afternoon. Other than some added middle level
cloudiness...no precipitation is expected. Tonight...skies will
clear as strong negative vorticity advection prevails. On Sunday...some upper level energy
will be intensifying over the upper Midwest. An associated cold
front will extend southward toward the middle MS valley. This cold
front will work across the area Sunday nt. By then...low level
moisture return will be in place and there does appear to be some
low level forcing with the frontal passage. Furthermore...an upper trough
will deepen considerably with numerous impulses upstream. Will
therefore include a chance of rain showers for Sunday night. As we
move toward sunrise Monday...freezing levels will drop down to
below 700 feet above ground level for much of the area. Thus...will include a
general changeover from rain to a rain/snow mix and then to all
snow by Monday afternoon. The upper trough is rather broad so the
impulses will be on the weak side. But...we could see a half inch
or so of snow accumulate across the plateau and far northern counties
during the day on Monday.
As for the short term temperatures...will see a slow warming trend just
prior to the frontal passage on Sunday nt. Highs will reach 50 for many areas
today and then well into the 50s for Sunday. Lows will be in the
lower 30s tonight and Sunday night. On Monday...will undercut the
guidance as all the models support clouds with light precipitation and
falling 850 mb temperatures to around -8c to -10c by Monday afternoon. Wind
speeds on Monday will add to the chill but not looking too terribly
high...and will go with a west wind of 10 to 15 miles per hour or so. High
temperatures on Monday will hold in the 30s...windchills of 25 to 30 so
not too horrible.
A deep longwave trough will be in place over the eastern states
midweek. Temperatures across middle Tennessee will be 10-15 degrees below
normal...with highs in the 30s Tuesday and Wednesday...and lows in
the teens. There will be enough lingering low level moisture with
cyclonic flow to keep some snow showers going into
Tuesday...especially for the plateau. Any accumulations lasting into
Tuesday would be very light and mainly over the higher elevations.
Late week will bring mainly dry weather with gradually moderating
12z taf discussion.
VFR with light winds.