Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
1139 PM CDT Wednesday Jul 27 2016
updated for 06z aviation discussion.
Previous discussion... /issued 729 PM CDT Wednesday Jul 27 2016/
Unsettled weather will continue across the midsouth overnight as
a weak upper level low remains in place. Ample deep level moisture
will result in heavy rainfall rates...likely over 2 inches per
hour. Luckily the storms are expected to be progressive...and do
not appear likely to train over any particular region. Will
continue to monitor conditions for the need of a Flash Flood
Watch...but feel like most of the area can handle 2-3 inches of
rain without any widespread problems.
Previous discussion... /issued 621 PM CDT Wednesday Jul 27 2016/
Unsettled weather will be the main story across the mid-south for
the next several days. Weak tropical upper low continues moving
slowly north along the Arkansas/MS border. Daytime heating and upper low
combined to produce shra/tsra. Currently most numerous west of the
MS river, but another area getting organized near and south of our
Upper low to continue lifting out tonight, with a larger-scale
trough settling generally over the Ohio Valley area. Expect
rain showers/thunderstorms and rain to continue, with high precipitable water values favorable for
efficient/locally heavy rain. Will hold off on Flash Flood Watch
for now given expected localized nature of heavy rain, but will
highlight heavy rain threat in social media and messaging.
Upper trough to remain in place over the mid-south through Sunday.
Several small vort maxes to rotate through the upper trough. At this
time, best estimate of timing looks to be Thursday afternoon/eve,
Friday night, and Saturday night/early Sunday. Timing of such subtle
features is challenging at best, so will broad-brush chance /30-50/
pops and further evaluate as events get closer.
Upper ridge builds back over the area early next week. This will
bring warmer temps and a return to more scattered/diurnal pops.
06z taf period
Upper level low will keep lower cigs and visibility into the taf sites
along with showers and thunderstorms this period. Cigs at times
will fall to IFR overnight...then lift to MVFR/VFR with
morning/afternoon convection. The low will move out later in the
period with rain ending. Light southeast through south winds will
veer more westerly...increasing to 8-12 kts. Winds will diminish
some late allowing for a slow lowering of cigs and visibility.