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090
FXUS64 KMEG 040231
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
931 PM CDT Wed Jul 3 2024

...New UPDATE...

.UPDATE...
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Issued at 930 PM CDT Wed Jul 3 2024

00Z upper air analysis continues to depict an upper-level ridge
located over the Lower Mississippi Valley and Southeast United
States. 850 mb analysis shows a plume of low level moisture across
the Lower Mississippi Valley, and extending as far north as
central Illinois. Regional WSR-88D radar trends show a cluster of
showers and thunderstorms over southern Missouri associated with a
weak mid-level shortwave trough moving through eastern Kansas.
Latest mesoanalysis yields about 40 kts of effective shear and
mixed-layer CAPE values in excess of 2000 J/kg across this area.
Ample instability is present across the remainder of the Mid-South
and very weak shear. Earlier convection dissipated with the loss
of daytime heating.

Latest short-term model trends indicate the potential for
additional showers and thunderstorms overnight will be limited at
best and mainly near the MO/AR border. Will make some adjustments
downward mainly to rain chances overnight. Otherwise, the
remainder of the forecast is in decent shape overall. Another day
of excessive heat is expected across the Mid-South on Thursday as
temperatures rise into the middle to upper 90s with dewpoints
approaching the upper 70s to around 80 degrees. (90th percentile)

CJC
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&&

.SYNOPSIS...
Issued at 306 PM CDT Wed Jul 3 2024

Hot and humid conditions will persist through Thursday. A few strong
to severe storms are possible this evening and again tomorrow
evening. A brief period of drier and cooler conditions will return
Friday before rain chances ramp up again on Sunday.

&&

.DISCUSSION...
(This evening through next Tuesday)
Issued at 306 PM CDT Wed Jul 3 2024

Hot and humid conditions encompass the Mid-South as of 2 PM with
temperatures in the 90s and dewpoints in the mid to upper 70s. A few
stray showers and thunderstorms are depicted on KNQA at this hour
due to the surge of moisture ahead of an approaching shortwave. This
shower activity is most likely not all reaching the surface, due to
a 596 dam ridge. This area of high pressure will dominate the area
through tomorrow. An Excessive Heat Warning will continue through
the overnight hours until tomorrow (Independence Day) at 9 PM. Areas
that don`t quite meet Excessive Heat requirements (110 degrees or
greater) will transition to a Heat Advisory into the overnight
hours until tomorrow at 9 PM.

The aforementioned ridge will act as a blocking mechanism for an
approaching frontal boundary. If this boundary is strong enough, a
few strong to severe thunderstorms may develop later this
afternoon into evening hours. Confidence remains fairly low in
severe storm development as shear is on the low end, just barely
reaching 25 kts. There is plentiful CAPE and the CIN from this
morning has dissipated. However, the lack of shear and mid- level
lapse rates near 5 C/km indicate convection would remain surface
based and would quickly fizzle out once daytime heating ends.
Nonetheless, if a strong to severe storm does develop it would
most likely be in extreme northeast Arkansas, the Missouri
Bootheel, and extreme northwest Tennessee.

A repeat of today is expected tomorrow for the holiday with hot and
humid conditions and a chance for a strong to severe storm or two. A
bowing segment aims to surge across the region late tomorrow night,
but again will be dependent on shear. Both rounds of potentially
severe weather will be capable of producing damaging winds and
heavy rainfall. PWs do remain at or above 2" which is supportive
of a heavy rainfall threat.

A cold front will sweep across the region Friday evening keeping
rain chances around through Saturday afternoon. Residing behind the
front, is a brief period of cooler conditions with highs in the
upper 80s and lower 90s beginning on Saturday. Zonal flow will
keep conditions dry briefly. Sunday brings the return of rain
chances as the possible remnants of Hurricane Beryl interact with
a trough. There is a high level of uncertainty with the
interaction, so we will continue to monitor for now.

DNM

&&

.AVIATION...
(00Z TAFS)
Issued at 659 PM CDT Wed Jul 3 2024

Mostly VFR conditions will prevail across the TAF sites through
the period. Light winds will be generally from the southwest.
Chose to include VCSH for TUP until sunset due to some lingering
convection to the southeast. Recent CAMs are hinting at convection
beginning tomorrow afternoon around 21Z for MEM and TUP, so
included thunder in the TAF. However, there was lower confidence
for coverage and timing for MKL and JBR, so thunder was excluded.
A cold front will approach JBR after this TAF cycle, so precip
will increase in coverage.

ACH

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
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AR...Excessive Heat Warning until 9 PM CDT Thursday for ARZ009-018-
     026>028-035-036-048-049-058.

MO...Excessive Heat Warning until 9 PM CDT Thursday for MOZ113-115.

MS...Excessive Heat Warning until 9 PM CDT Thursday for MSZ001-007-
     008-010>012-020>024.

     Heat Advisory until 9 PM CDT Thursday for MSZ002>006-009-013>017.

TN...Excessive Heat Warning until 9 PM CDT Thursday for TNZ001>004-
     019>022-048>055-088>092.
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&&

$$

PUBLIC FORECAST...DNM
AVIATION...ACH