Scientific Forecaster Discussion
fxus64 kmeg 220122
Area forecast discussion
National Weather Service Memphis Tennessee
822 PM CDT Thu Sep 21 2017
Extended pops through midnight based on radar trends and added
patchy fog after midnight for much of northeast MS and west Tennessee.
Otherwise, the forecast looks in good shape. No significant
Previous discussion... /issued 620 PM CDT Thu Sep 21 2017/
Skies are mostly sunny across the region this afternoon with
temperatures in the upper 80's to lower 90's. A few showers and
thunderstorms are approaching the Tennessee River from the east
in association with an elongated trough of low pressure extending
from Tropical Storm Jose. Outflow from these storms may trigger
additional scattered convective development this evening,
primarily in eastern sections of our area.
Summer-like conditions continue with temperatures peaking in the
lower 90's each day through Sunday with overnight temperatures
dropping to near 70. But while high pressure remains in control
at the surface, conditions aloft will be a bit more interesting as
we head into the weekend. The previously aforementioned elongated
trough associated with Jose will become cut off from the main
flow as Hurricane Maria begins to overtake what's left of Jose's
circulation. As a result, a cut off upper-level low will
retrograde toward the midsouth by Sunday morning, bringing with it
a slightly more unstable atmosphere and higher chances for
precipitation across the midsouth on Sunday and Monday,
particularly in the afternoon hours when diurnal heating is
maximized. By Tuesday this feature should be scooped up and driven
out of the southeast US entirely as Hurricane Maria heads out to
Meanwhile a much more significant synoptic feature in the form of
a deep longwave trough, more typical of fall, will be forming to
our west. This feature is expected to deepen by midweek and become
positively tilted before finally crashing through the eastern US.
This will bring welcomed lowered temperatures and humidity by late
week, as well as higher chances for precipitation across the area.
VFR...with a period of IFR/MVFR visibility from morning light fog. Calm
or light and variable winds will become easterly at 4-5kts late.