171
FXUS64 KMEG 240935
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
435 AM CDT Mon Jun 24 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
Issued at 430 AM CDT Mon Jun 24 2024

Hot temperatures in the 90s combined with lingering humidity will
result in afternoon heat index values rising to around 105 degrees
across portions of the Mid-South, especially along and west of the
Mississippi River into Tuesday. A cold front will bring an
increased chance for showers and thunderstorms across the area on
Wednesday followed by slightly cooler and drier air. A building
upper level ridge will bring a return of very hot and humid
conditions, and isolated to scattered shower and thunderstorms
into next weekend.

&&

.DISCUSSION...
(Today through Sunday)
Issued at 430 AM CDT Mon Jun 24 2024

GOES-16 Water Vapor satellite trends show a mid-level shortwave
trough moving through portions of the Great Lakes region and Ohio
Valley. Meanwhile, latest surface analysis places a weak cold
front stretching from New England into the Lower Mississippi
Valley. KGWX WSR-88D radar trends indicate an isolated rain
shower over Union county. Otherwise, the remainder of the Mid-
South remains rain-free. Temperatures as of 4 AM CDT range from
near 70 degrees along the Tennessee River, and mid 70s to around
80 degrees elsewhere.

The aforementioned back door cold front is expected to wash out
over the Mid-South today. Dewpoints north of the boundary are
expected to drop back into the middle to upper 60s by this
afternoon with areas generally along and west of the Mississippi
River not dropping as much. 925 mb temperatures rising to 27C
should translate to afternoon highs in the middle to upper 90s.
These very hot temperatures combined with lingering low level
moisture should result in afternoon heat index values around 105
degrees especially along and west/southwest of the Memphis metro
area. Surface dewpoints are expected to rebound on Tuesday as 925
mb temperatures approach 28C with afternoon highs approaching 100
degrees in a few spots. As a result, the existing Heat Advisory
was extended until 8 PM Tuesday, and issued a new Heat Advisory
covering the remaining counties along the Mississippi River.
Additional expansion of the heat headlines will be considered for
Tuesday if conditions warrant.

Short-term models indicate mid-level heights will weaken Tuesday
night into Wednesday as the upper-level high retrogrades to the
southwest U.S. Shower and thunderstorm chances will increase late
Tuesday night into Wednesday as a mid-level trough and associated
cold front drop into the Lower Mississippi and Tennessee Valleys.
A potential exists for a Mesoscale Convective System to develop
upstream and attempt to drop into the Mid-South on Wednesday. At
the same time, the best upper-level forcing is expected to move
east into the Ohio Valley. LREF Grand Ensemble output indicates
the potential for surface-based CAPE values up to 2500 J/kg, with
overall shear remaining around 20 kts. As a result, current
thinking is that any upstream convection would be in a weakening
phase given the minimal shear across the area. A potential would
exist for redevelopment during peak heating along residual
outflow boundaries. Damaging winds will be main threat if any
thunderstorms can become severe.

Slightly cooler and drier air will filter in for late week with
rain chances remaining minimal at best. The upper-level ridge is
expected to build east into next weekend resulting in a return of
increasing heat and humidity and the potential for isolated to
scattered showers and thunderstorms mainly during peak heating.

CJC

&&

.AVIATION...
(06Z TAFS)
Issued at 1143 PM CDT Sun Jun 23 2024

A few lingering SHRAs will continue over the next hour or so
before dissipating, but should not affect any TAF sites. A couple
of wind shifts will occur through the period behind a backdoor
quasi-stationary front.

AC3

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory from 11 AM this morning to 8 PM CDT Tuesday for
     ARZ009-018-026-027-035-036-048-049-058.

     Heat Advisory from 11 AM to 8 PM CDT Tuesday for ARZ028.

MO...Heat Advisory from 11 AM to 8 PM CDT Tuesday for MOZ113-115.

MS...Heat Advisory from 11 AM this morning to 8 PM CDT Tuesday for
     MSZ001-007-008-010>013-020>024.

TN...Heat Advisory from 11 AM this morning to 8 PM CDT Tuesday for
     TNZ088.

     Heat Advisory from 11 AM to 8 PM CDT Tuesday for TNZ001-002-019-
     048-049.

&&

$$

PUBLIC FORECAST...CJC
AVIATION...AC3