458
FXUS64 KMEG 181130
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
630 AM CDT Tue Aug 18 2026

...New AVIATION...

.KEY MESSAGES...
Issued at 630 AM CDT Tue Aug 18 2026

- A Heat Advisory remains in effect through Tuesday for portions
  of eastern Arkansas and north Mississippi.

- Heat is expected to persist through Wednesday over portions of
  the Mid-South with little if any relief expected until a cold
  front moves through the area later this week.

&&

.DISCUSSION...
(Tonight through next Monday)
Issued at 1126 PM CDT Mon Aug 17 2026

00Z upper air analysis centers an 597 dm ridge axis over portions
of the southwest U.S. and the Southern Plains. Meanwhile, the
Lower Mississippi Valley is now within northwest flow aloft.
Latest surface analysis shows a weak quasi-stationary boundary
bisecting the Lower Mississippi Valley from Middle Tennessee back
through north Mississippi and southern Arkansas. Warm and humid
air remains in place across the Mid-South this evening with
temperatures and dewpoints in the 70s.

Rainfall from late afternoon convection over north Mississippi
has produced conditions favorable for the development of patchy
fog overnight. The weak front is expected to settle near the
southwestern edge of the forecast area into Tuesday. Short-term
CAMs indicate a low potential (<20% chance) for isolated showers
and thunderstorms overnight into Tuesday morning west of the
Mississippi River in association with a weak shortwave over
western Arkansas. Very hot temperatures in the middle 90s to
approaching 100 degrees are expected again across the area mostly
along and south of a line from Jonesboro to Tupelo, including the
Memphis metro area. However, slightly drier air will keep heat
index values below advisory criteria to an extent across the area
with the exception of portions of north Mississippi bordering
central Mississippi and east Arkansas south of I-40. A Heat
Advisory remains in effect across this aforementioned area with
the addition of Chickasaw and Monroe counties in Mississippi
through 8 PM Tuesday. Latest short-term trends suggest any
convective development may remain just to the south and west of
the area on Tuesday during peak heating.

The aforementioned surface boundary is expected to return back
north as a warm front Tuesday night into Wednesday with higher
dewpoint air returning across the area. This more humid air
combined with temperatures near or exceeding 100 degrees may
necessitate the issuance of a Heat Advisory across much of the
Mid-South on Wednesday with heat index values approaching
109 degrees.

By Wednesday, a series of mid-level shortwaves embedded within
northwest flow aloft will drop into the Lower Mississippi Valley
into Thursday. A large variance in solutions exists during this
period with the NAM suggesting weakening convection dropping into
the Mid-South during the day Wednesday and dissipating with GFS
and ECMWF solutions hinting at convection developing towards
Wednesday evening. Overall shear at this time appears to be weak
across the region with more favorable shear occurring north of
the area. This will continue to be monitored as additional data
arrives into Tuesday.

Thankfully, deterministic and ensemble solutions remain in good
agreement with a mid-level trough settling across the eastern U.S
later this week into the upcoming weekend. This will bring
slightly cooler and drier air to the area through at least the
weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 630 AM CDT Tue Aug 18 2026

VFR expected at MEM/JBR/MKL through the period. TUP could see
MVFR visibilities from mist through the first couple hours of the
TAF, but will also otherwise be VFR through the period. An area
of rain showers over east-central Arkansas will continue east
through the beginning of the TAF period, eventually making its
way to MEM. However, coverage is expected to dwindle by that time
with only enough coverage to warrant VCSH. Winds will start out
northeasterly, backing to a more northerly direction throughout
the day, then begin to veer southerly through the end of the TAF
period after 00z Wednesday.

&&

.FIRE WEATHER...
Issued at 1126 PM CDT Mon Aug 17 2026

Fire danger is expected to remain low through the period due to
light 20 ft winds, although minimum relative humidity values may
drop below 40% in some areas on Wednesday. Fog potential remains
low due to dry soils with the exception of north Mississippi
Tuesday morning due to recent localized rainfall.

&&


.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 8 PM CDT this evening for ARZ049-058.

MO...None.
MS...Heat Advisory until 8 PM CDT this evening for MSZ007-010>012-
     020>024.

TN...None.
&&

$$

PUBLIC FORECAST...CJC
AVIATION...JAB