090
FXUS64 KMEG 201708
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1208 PM CDT Thu Aug 20 2026

...New DISCUSSION, AVIATION, FIRE WEATHER...

.KEY MESSAGES...
Issued at 1208 PM CDT Thu Aug 20 2026

- Isolated to scattered strong to severe thunderstorms could occur
  this afternoon and evening along and south of I-40. Damaging
  wind gusts are the primary threat.

- A Heat Advisory remains in effect until 8 PM CDT today for
  eastern Arkansas and north Mississippi, with heat index values
  peaking between 105 and 109 degrees.

- Friday is the final day of oppressive heat and humidity for the
  Delta region, with a transition to drier and cooler conditions
  expected this weekend.

&&

.DISCUSSION...
(This evening through next Wednesday)
Issued at 1208 PM CDT Thu Aug 20 2026

A few showers and thunderstorms are ongoing across West Tennessee
as of 11 AM. These are being initiated as a frontal boundary
remains nearly stationary along the I-40 corridor. This front
will begin to sink south in the coming hours. This will provide
lift to generate isolated to scattered thunderstorm development
in the wake of the front. Temperatures across north Mississippi
are projected to climb into the mid to upper 90s which will allow
SBCAPE to surge between 2500-3000 J/kg. Effective shear is
anticipated to remain below 30 kts which will support a
single/multi-cell mode. Deterministic soundings do favor the
inverted v, increasing confidence in a damaging wind/wet
microburst threat. Due to surface temperatures, the hail threat
will most likely be sub-severe but the potential for quarter
sized hail cannot be ruled out. The RRFS is the most aggressive
in storms this afternoon and favors 3 PM to 11 PM as an
initiation window. Aside from severe weather, there is a heat
advisory in effect through 8 PM for portions of eastern Arkansas
and north Mississippi.

It will take additional time for the continental polar air mass
to sink all the way south, thus one more heat advisory has been
issued for the Delta region for Friday heat index values peaking
around 109. Elsewhere, the cooler and drier air will filter in
and take hold through the weekend. An upper level disturbance,
embedded in northwest flow aloft, may bring a few showers across
the area on Saturday afternoon. The Canadian and NAM models are
very aggressive with the coverage, which likely inflates NBM
PoPs. NBM soundings show a rather dry air column, and QPF values
are less than a quarter of an inch. Would expect these two models
to fall more in line with the Euro and be a better fit for the
current QPF forecast.

For the long term, the GFS and Euro have fallen in line and keep
an upper level ridge centered over the central US. This will keep
the Mid-South under northwest flow and bring increased rain
chances through the work week. Increased rain chances however
does normally favor a cooler temperature regime. The LREF and its
ensemble members currently have nil probabilities of severe
weather ingredients through this pattern. Despite the increased
rain chances, probabilities of accumulating 1" or more of
rainfall from the LREF ensemble members is low (10-30%). One
ensemble member, (GEPS) is highlighting a 40-50%  chance of
accumulating 1" or more over the Missouri Bootheel by next
Thursday. While the pattern change brings cooler temperatures,
confidence in significant drought relief remains low given the
lack of substantial QPF signal.

DNM

&&

.AVIATION...
(18Z TAFS)
Issued at 1208 PM CDT Thu Aug 20 2026

VFR conditions are expected to prevail at JBR, MEM, and MKL
through tomorrow. Convection should be confined to north
Mississippi this afternoon along and south of a stalled cold
front. As a result, all mentions of convection were omitted from
the 18Z update for these locations. A PROB30 group for
thunderstorms has been included for TUP.

&&

.FIRE WEATHER...
Issued at 1208 PM CDT Thu Aug 20 2026

A low fire weather risk will hold across the region over the next
three days. While summer heat remains strong across the Mid-
South, adequate moisture levels and exceptionally light surface
winds will prevent critical fire weather conditions from
developing. Rainfall from this morning will result in the
development of patchy to locally dense fog late tonight for areas
east of the Mississippi river.

&&


.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 8 PM CDT this evening for ARZ048-049-058.

     Heat Advisory from 11 AM to 8 PM CDT Friday for ARZ049-058.

MO...None.
MS...Heat Advisory until 8 PM CDT this evening for MSZ007-008-010>017-
     020>024.

     Heat Advisory from 11 AM to 8 PM CDT Friday for MSZ007-010-011-
     020.

TN...None.
&&

$$

PUBLIC FORECAST...DNM
AVIATION...JDS