Scientific Forecaster Discussion
fxus64 kmeg 240442
Area forecast discussion
National Weather Service Memphis Tennessee
1142 PM CDT Sat Sep 23 2017
Updated for the 06z aviation discussion.
Previous discussion... /issued 711 PM CDT Sat Sep 23 2017/
updated to diminish cloud cover.
satellite trends show convection quickly waning with the loss of
heating...leaving only a few clouds across the southern and
eastern counties. The remaining midsouth was observing clear
skies. Therefore dropped the overnight cloud cover wording to
clear or mostly clear. The only weather concern will be patchy
fog developing in the east after midnight.
Previous discussion... /issued 315 PM CDT Sat Sep 23 2017/
Another warm day across the midsouth with a broad area of high
pressure in control of the weather across the eastern half of the
contiguous US. This will remain the case for several more days as
the upper level pattern slowly breaks down and eventually leads to
big changes by the second half of next week.
Temperatures are in the upper 80s to lower 90s across the region
with a daytime cumulus field fully developed but very little rain
to speak of. There are a few isolated showers across northern
Mississippi that may increase slightly in coverage this evening
before fading overnight. A weak upper level low centered over
coastal Alabama and the Florida Panhandle will retrograde slightly west
over the next couple of days. This will lead to decreasing ridging
aloft, allowing a slightly more unstable atmosphere capable of at
least slight chances for showers and thunderstorms tomorrow
afternoon and Monday afternoon respectively. Unfortunately this
may be our best shot at measurable precipitation in the forecast
By Tuesday the aforementioned upper level low will be pulled back
to the east, drawn in by the circulation of Hurricane Maria. This
feature will determine how far west Maria is able to progress
before finally being scooped up into the Atlantic and delivered
its death sentence by the polar jet stream. Interests in the
Carolinas should pay close attention to the track of Maria over
the next several days. Here in the midsouth, the departure of the
upper level low means a return to upper level ridging which
should keep conditions dry on Tuesday and Wednesday.
Wednesday night into Thursday will finally bring a surface cold
front that will begin a cooling trend more typical of this time of
year. The initial front itself will be quite weak with little
surface convergence and upper level dynamic support. This will
result in a dry frontal passage on Thursday with falling humidity
and lower daytime highs ranging from the upper 70s in the north to
the mid 80s in the south. Beyond Thursday the cooling trend looks
to continue with a Continental polar airmass slowly being
advected into the region. A reinforcing cold front looks to move
through the area on Saturday, likely bringing the coolest
temperatures just in time for the weekend. Daytime highs can be
expected to reach the mid 70s while lows could dip closer to 50,
which hasn't been experienced in Memphis since may.
VFR conditions will persist through much of the period. The
exception will again be vsby reductions in fog at kmkl and ktup
early Sunday morning.
A few isolated thunderstorms this evening in the vicinity of ktup
will gradually diminish this evening. Isolated showers and
thunderstorms should again develop areawide by late morning
through Sunday afternoon. Convection will again diminish by early
Winds should again remain light through the forecast period.