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563
FXUS64 KMEG 260213
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
913 PM CDT Tue Jun 25 2024

...New UPDATE...

.UPDATE...
-- Changed Discussion --
Issued at 855 PM CDT Tue Jun 25 2024

Conditions remain unpleasantly hot across the Mid-South at this
hour. Although, all heat products have been allowed to expire,
heat indices remain in the upper 90s to 100 F across much of the
region. The focus now shifts to convection over southern Kentucky
and southeast MO. A slow-moving outflow boundary, as seen from
KPAH, is moving SW around 15 knots towards the TN/MO/KY border. A
few showers have formed behind the boundary without much
consequence. Nonetheless, did increase PoPs to slight to account
for the potential shower activity.

To the west, and over SE Missouri, a cluster of storms has formed
on the edge of an organizing MCS. This MCS is reasonably resolved
by the CAMs and is progged to move south into NE AR and the MO
Bootheel shortly after midnight. There is some uncertainty as to
how strong the storms may be when they enter the CWA. Regardless,
SPC did go ahead and add a small Marginal Risk to the top row of
counties in west TN and northeast AR. Storm mode will be outflow
dominant, so gusty winds are certainly possible.

A more organized threat looks to arrive by mid-morning tomorrow,
as yet another MCS propagates south into the region by early
afternoon. Uncertainty remains higher than expected with this
system, as the first system could act to stabilize the atmosphere
ahead of the second push. Nonetheless, storm mode will continue to
be cold pool dominant with the potential for damaging winds and
small hail. Some of the latest Hi-res model soundings suggest the
threat may be a bit higher than a Marginal. Will continue to
monitor and collaborate with SPC this evening.

Increased PoPs slightly through midnight and smoothed them out
through the overnight hours. The rest of the forecast is on track.

AC3
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&&

.SYNOPSIS...
Issued at 204 PM CDT Tue Jun 25 2024

A cold front will push through the region on Wednesday with chances
of showers and thunderstorms followed by mild temperatures and dry
weather on Thursday. The heat will rebuild Friday into the weekend
as upper ridging re-strengthen across the region.

&&

.DISCUSSION...
(This evening through next Monday)
Issued at 204 PM CDT Tue Jun 25 2024

Very hot and humid air has pushed into the region on the backside of
the surface high over the Southeast U.S. Temps well into the 90s
combined with dewpoints in the mid to upper 70s across the Delta are
creating heat index values around 110 degrees. Conditions are only
slightly more reasonable toward the TN River where dewpoints are a
little lower. Stifling conditions will continue into the early
evening and Excessive Heat Warnings and Heat Advisories remain in
effect. A few pop up showers or thunderstorms are possible through
early evening though coverage will be sparse.

Any evening convection will quickly dissipate with the loss of
heating. A warm and humid night is on tap with lows in the 75 to 80
degree range. A cold front pushing south through the Mid-MS
Valley combined with a decent mid level shortwave is expected to
generate an MCS over MO overnight. The 12z CAMs timing is quite
variable with some solutions showing convection reaching NE AR
before 12z while the slower models are a little later. The MCS
will push south across the area during the morning hours while
probably going through a weakening phase. The latest hi-res model
data points to perhaps the strongest push from the MCS occurring
west of the Mid-South toward central AR where the 0-6km bulk
shear is a little stronger. As the MCS pushes south into north MS
expect redevelopment during the afternoon along any outflows or
boundaries that push out from the morning convection. Expect a few
severe storms either from the MCS or afternoon redevelopment with
damaging winds being the main threat. PWs will be anomalously
high with values reaching around 2 inches so very heavy downpours
are possible.

The MCS complicates the temp forecast. The MCS will probably move
across much of the area by peak heating so that will limit the
extent of the high heat. A few areas across north MS may reach a
heat index of 105 degrees before convection moves through but given
the uncertainty will let later shifts issue any heat headlines for
Wednesday.

Precip chances will taper off Wednesday night as upper level ridging
builds in for Thursday. Thursday will be a mild day with light
northerly flow behind the cold front. Southerly flow redevelops by
the end of the week as surface high pressure moves off the SE
Atlantic Coast. Meanwhile, broad upper level ridging will stretch
across the region. This will result in a quick return to hot and
humid conditions with heat headlines probably needed by the end of
the week into the weekend. Pops start to increase by Sunday as a
front tries to sag into the region. That is a long way out though
so confidence is quite low attm.

&&

.AVIATION...
(00Z TAFS)
Issued at 639 PM CDT Tue Jun 25 2024

Vicinity showers will remain possible through midnight at MEM.
VFR conditions look to continue through around noon tomorrow. As
TSRA moves in along a cold front, ceilings are expected to briefly
lower to MVFR tomorrow afternoon. CAMs are once again not having
a great handle on coverage of TSRA tomorrow afternoon, thus,
leading to a PROB30 across all TAF sites. Showers and
thunderstorms are expected to exit all terminals by 02Z tomorrow
behind the cold front as begin shifting northwest.

AEH

&&

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

$$

PUBLIC FORECAST...SJM
AVIATION...AEH