Southaven, Mississippi 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

510
FXUS64 KMEG 180532
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1232 AM CDT Sun May 18 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 1225 AM CDT Sun May 18 2025

- Thunderstorms will return late tonight. There is a Slight Risk
  for severe thunderstorms over southwestern portions of the
  Midsouth with a Marginal Risk across NE Arkansas, SW TN, and
  north Mississippi. The primary risks will be damaging winds and
  large hail.

- An unsettled weather pattern will continue through Tuesday with
  chances for showers and thunderstorm each day. A few
  thunderstorms could be strong to severe each day and night.

- Cooler and less humid conditions will follow for Wednesday
  through Friday behind a cold front.

&&

.UPDATE...
Issued at 1005 PM CDT Sat May 17 2025

Another potential stormy night for parts of the Midsouth.
Instability will be much lower than last night, but when coupled
with 40kt of deep layer bulk shear, the environment will be
sufficient to support marginal damaging winds and severe hail for
a few hours.

Midevening surface analysis showed a diffuse stationary front from
near Aberdeen MS westward through southern AR. Further west, the
front curved to the northwest, into northeast OK. South of the
front, extreme MLCAPE to 5000 J/kg was noted over southeast OK. GOES
IR imagery showed multiple supercells, some with deviant crossing
trajectories over northeast TX and southeast OK. KLZK radar VWP
product shows relatively strong low level warm advection, with a
35kt low level jet. KNQA VWP low level jet was weaker, at around
15kt.

As we head into the early overnight, expect the warm front to
mix north over AR and north MS. The diffuse warm frontal position
will likely coincide with the main storm corridor, just south of
I-40. 00Z HRRR appears to have correctly identified the southeast
OK storms as the more dominant cluster, moving this convection
into east central AR/northwest MS after midnight. 02Z MLCAPE over
these areas prevailed at 1000-1500 J/kg, per SPC mesoanalysis.
This is more than adequate for marginal severe storms but down
considerably from the 4000+ J/kg of MLCAPE in this region 24 hours
ago and down considerably from the current analyzed MLCAPE over
the Arklatex.

While the 00Z HRRR depicts a marginal severe event for a few
hours over the MS delta, the model depicts a potentially more
impactful bowing MCS entering northwest MS toward 7 AM. This
appears to be sourced from storms that have developed over central
OK at midevening. The HRRR tracks these storms east-southeast
along the midlevel thickness gradient, as midlevel height rises
occur to the west, over AR. This scenario appears to be supported
by the 18Z GFS, and to a lesser extent, the 00Z NAM.

Recent variations in the HRRR guidance aside, current forecast
PoPs remain on track. No changes to the grids are planned at this
time.

PWB

&&

.DISCUSSION...
(This evening through next Friday)
Issued at 230 PM CDT Sat May 17 2025

A gorgeous late spring day across the Mid-South at this hour.
Temperatures are in the low to mid 80s under blue skies. The
latest surface analysis places a cold front from Lake Huron south
through Lake Eerie and southwest back through the Ohio River
Valley to just south of I-40. Behind the front, drier air is
working its way into the region. This break from the humidity will
be short-lived as winds turn back around to the southeast this
evening and keep dewpoints in the low to mid 60s. Aloft, mainly
zonal flow is prevalent across the Lower Mississippi Valley with a
trough over west Texas.

Dry and benign weather will take a backseat to active weather tonight
through the middle of next week. A shortwave, currently located
over north central Texas, will translate east into the Lower
Mississippi Valley through Sunday morning. A MCS is forecast to
develop this evening near the ArkLaTex and push east into
southwestern portions of the Mid-South overnight. Ahead of this
feature, a tight MLCAPE gradient will develop over NW MS and
extreme SE AR ranging from 800 to 2500 J/kg over just 50 miles or
so. HRRR model guidance suggests that at least a marginal wind and
hail threat will occur from approximately 11PM through 4AM. The
HREF supports both the timing and intensity of this activity.
Uncertainty remains as to how far north the showers and
thunderstorms will occur. Nonetheless, a Slight Risk (2/5) exists
across the SE portions of the Mid-South for large hail and
damaging winds with a Marginal Risk (1/5) extending NE across NE
AR, SW TN, and the rest of N MS.

Timing of showers and thunderstorms will be nebulous at best over
the next couple of days, as multiple weak perturbations translate
through weak southwest flow aloft. HREF guidance suggests a
mostly dry Sunday afternoon, however, NBM guidance seems to be
heavily weighted towards the HRRR, generating 60-70 PoPs across
the majority of the region. Decided to decrease PoPs considerably
for tomorrow afternoon, warranting a 30-40 PoP at best, due to
uncertainty redevelopment in the afternoon hours.

A more organized threat of showers and thunderstorms will develop
late Sunday night into Monday morning as a shortwave helps lift a
warm front back north through the region. An unstable warm sector
will be in place on both Monday and Tuesday, as dewpoints swell
into the lower 70s. A couple of weak waves will rotate into the
region Monday morning, afternoon, and evening. The strength of
storms will depend largely on the instability available and
strength of each successive wave. A Marginal Risk (1/5) for winds
and hail is currently in effect for both days and nights, which is
hard to argue against. Nonetheless, it will be more a nowcast each
day and night, due to the small scale waves impacting the region.

A more organized threat will occur on Tuesday, as a large trough
digs across the Central Plains. This trough is progged to deepen
and take on a negative tilt as it moves into the Lower Mississippi
Valley on Tuesday. 20 to 30 meter height falls will overspread a
moderately unstable airmass Tuesday afternoon. Preliminary
soundings show large looping hodographs, 2500 J/kg MLCAPE, and
steep lapse rates. Chances for a busted forecast is much less
than yesterday`s as the cold front accelerates quickly through the
region and there is good low and mid level lift. The parameter
space appears plenty healthy enough to support an Slight Risk
(2/5) to Enhanced Risk (3/5) of severe thunderstorms for a large
portion of the Mid-South. All modes of severe weather are on the
table as shear and instability will be in the medium to high
range. The evolution of this system will need to be watched over
the coming days as the threat could increase.

Drier and cooler weather will persist Wednesday through late next
week as surface high pressure builds in behind a cold front.

AC3

&&

.AVIATION...
(06Z TAFS)
Issued at 1225 AM CDT Sun May 18 2025

A decaying MCS approaching from the ArkLaTex region warrants a few
TEMPOs overnight for SHRA and/or TSRA. This is moving along a
stalled frontal boundary draped across the southern airspace.
Will note that there is almost uncharacteristic short term model
discrepancy with this convective activity; there are a few CAMs
that have initialized the ongoing rain shield with embedded
thunderstorms well but from there, all bets are off. Latest HRRR
suggests a drastic weakening trend over the next few hours, while
a few other CAMs simulate a more stout MCS bowing out closer to
sunrise. Given this uncertainty, there is precip mentioned all the
TAF sites overnight but not all of them have the same level of
confidence. If anything, looks like TUP may be the one most likely
to see activity hold together early Sunday morning.

Ceilings are expected to remain at or above 4 kft through the
period so no concerns there. Winds will generally sway between
easterly and southerly around 5-10 kts as that surface boundary
meanders about the area.

CAD

&&

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

$$

PUBLIC FORECAST...AC3
AVIATION...CAD