976
FXUS64 KMEG 180758
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
258 AM CDT Wed Jun 18 2025

...New DISCUSSION, FIRE WEATHER...

.KEY MESSAGES...
Updated at 122 AM CDT Wed Jun 18 2025

- A cold front will move through the region this afternoon,
  bringing a line of strong to severe storms. A Slight Risk of
  severe weather is in effect for areas along and north of I-40
  through the overnight period.

- Strong to severe storms may redevelop around sunrise tomorrow,
  though confidence is much lower in this second round.

- Hot and humid conditions will develop late week, with heat
  indices above 100 degrees by Saturday.

&&

.DISCUSSION...
(Today through Tuesday)
Issued at 122 AM CDT Wed Jun 18 2025

All is mostly calm across the Mid-South at this hour, save for a
few straggling showers still working their way out of the area.
We`ll have a brief break this morning in between systems before
more active weather moves in this afternoon. A very well organized
MCS currently racing across eastern OK is on the leading edge of a
surface low that will eventually dig a longwave trough down
through the Ozarks this afternoon. The associated cold front is
our weather-maker for this evening. A line of showers and
thunderstorms will reorganize ahead of this front in the mid to
late afternoon hours and continue holding together fairly well
throughout the FROPA overnight. Will note that the timing has
significantly shifted earlier with the last few CAM runs... With
yesterday morning`s forecast, it looked like the convection
wouldn`t be at our doorstep until 00Z Thursday (7PM tonight) at
the latest, but now it`s looking like the front`s arrival may have
sped up to as early as 18Z (1PM) today. If the earlier timing
solution is correct, peak heating in the afternoon may help storms
pack more of a punch with the added resultant instability.

Regardless of the timing, the primary threat for this line of
thunderstorms is damaging winds. Especially on the northern end of
the risk area near the MO and KY state lines, bulk shear is on
the order of 30 kts this afternoon and evening, which provides
more than enough organizational support for bowing segments and
strong downbursts on the leading edge of the line. With any
isolated cells ahead of the main line or even broken segments
within the line itself, midlevel lapse rates just over 6 degC/km
will support marginally severe hail up to about an inch in
diameter. The low level kinematics in play are much weaker,
though, which explains why the tornado threat is comparatively
much weaker. 00Z HREF puts the mean 0-1 km SRH right at 100 m2/s2
during the frontal passage this afternoon and evening for areas
north of I-40. In a moderately sheared environment like this one,
that SRH is not necessarily raising any alarm bells, but it`s not
something to balk at either. The tornado potential will largely
depend on the convective mode: if this remains a well organized
QLCS, the tornado potential will be quite low, but if we get more
supercellular storms and broken segments, the threat will
increase.

Despite the earlier arrival time, the front will be rather slow
moving overnight. This is the reason for the introduction of a
D2/Thursday marginal risk over north Mississippi. Even after the
first wave of convection clears the area just after midnight
Thursday, the front itself will still be lingering from the
ArkLaTex up through eastern Kentucky. By the time the reinforcing
airmass arrives and pushes the front out once and for all, more
convection will fire up along the boundary by daybreak on Thursday
morning. These storms will have a much less favorable environment
to work with, namely strong CIN and very weak shear, but the
forcing is quite robust and may help storms break out of the
capped environment. There will be a very small window of time
early Thursday morning where convection in the southeastern part
of our CWA can take advantage of the eroding cap before losing all
its kinematic support entirely.

After the front finally moves out on Thursday morning, the trends
quickly shift to lower PoPs and warmer temperatures. A 595 dam
midlevel ridge will park itself over the Mid-South by Friday and
stay there through the weekend. This heat dome will warrant the
first heat headlines of the year at some point in the near future.
It may be as early as Friday afternoon in the MS Delta, but heat
indices will certainly climb above 105F by Saturday and Sunday,
which is our criteria for a Heat Advisory. By Monday, the upper
level pattern will deamplify just enough to allow diurnally driven
convection to return. 30-40% chance PoPs are in the forecast
Monday through Wednesday of next week, mostly in the form of
isolated summertime convection. It`ll still be very hot and humid
well into the work week, so any showers and thunderstorms that
develop will be a nice cooldown from the heat and humidity.

CAD

&&

.AVIATION...
(06Z TAFS)
Issued at 1123 PM CDT Tue Jun 17 2025

TAFs expected to be mostly VFR with the chance for showers and
thunderstorms. All terminals are currently VFR with these
conditions expected to persist through tonight with an isolated nearby
shower. A chance exists for a line of showers tomorrow with a
remnant outflow boundary with MVFR CIGs and some reduced
visibility. More thunderstorms are anticipated during the
afternoon at all terminals that will last into the evening hours
along with gusty southerly winds up to around 20 knots.

&&

.FIRE WEATHER...
Issued at 122 AM CDT Wed Jun 18 2025

South winds and high humidity will prevail again this afternoon.
A cold front will move through this evening, bringing widespread
showers and thunderstorms overnight into tomorrow morning. Hot and
humid conditions will move in Friday through the weekend with
temperatures rising into the lower to mid 90s.

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$

PUBLIC FORECAST...CAD
AVIATION...JAB