263
FXUS64 KMEG 050436
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1136 PM CDT Thu Jul 4 2024

...New AVIATION...

.UPDATE...
Issued at 905 PM CDT Thu Jul 4 2024

00Z upper air analysis still shows an upper-level ridge present
across the Lower Mississippi Valley and Southeast U.S. with a
slight weakness in the ridge over northwest Arkansas. Coverage of
showers and thunderstorms have decreased substantially over the
Mid-South with the loss of daytime heating. The only remaining
showers and thunderstorms are located near Grand Junction, TN.
Surface dewpoints still remain high but temperatures have dropped
enough to cancel the Excessive Heat Warning early.

Short-term models including convective allowing solutions have
struggled to resolve convective trends in this weakly sheared
environment. The HRRR seems to have a better handle than the other
model solutions with the potential for additional showers and
thunderstorms overnight if the upstream activity holds together.
Confidence in strong to severe thunderstorm potential for the
remainder of the night remains low at best as any additional
convective activity will likely be elevated. Will make some
changes to rain chances for the remainder of the night.

Updated grids will be available shortly.

CJC

&&

.SYNOPSIS...
Issued at 248 PM CDT Thu Jul 4 2024

Hot and humid conditions will prevail for Independence Day. A few
strong to severe storms are possible this afternoon and evening.
A brief period of mostly dry and cooler conditions will return
tomorrow before rain chances ramp up again on Sunday.

&&

.DISCUSSION...
(This evening through next Wednesday)
Issued at 248 PM CDT Thu Jul 4 2024

Hot and humid conditions encompass the Mid-South as of 2 PM with
heat indices ranging from 105-113 degrees. A few stray showers and
thunderstorms are depicted on KNQA at this hour due to the surge of
moisture ahead of an approaching shortwave. At this time, these
storms currently are only threatening heavy rain and frequent
lightning. An Excessive Heat Warning for the entire area will
continue through 9 PM.

A stalled frontal boundary is currently stretched from the Great
Lakes to central Missouri. This boundary is pulling moisture ahead
of itself and allowing scattered storms to develop in its wake. As
this boundary slowly starts moving, a bowing segment will dive SSE
across Arkansas and West Tennessee late tonight into tomorrow
morning. The bowing segment appears to hit a localized vorticity
maxima as it should exit the region by late tomorrow morning.

Confidence remains low in severe storm development as shear is on
the lower end nearing 30 kts. The lack of shear and mid-level lapse
rates near 5 C/km indicate convection would remain surface based (as
there is plentiful SBCAPE) and will likely 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 cold front will sweep across the region tomorrow evening keeping
rain chances around through Saturday morning. Friday may still be a
bit humid in some portions of the Mid-South, particularly north
Mississippi, until the drier air can prevail. A Heat Advisory may be
needed, but given the potential for convection and cloud cover,
holding off on issuance for now. 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...
(06Z TAFS)
Issued at 1128 PM CDT Thu Jul 4 2024

Scattered thunderstorms are expected to move across much of the
Mid-South overnight and into Friday morning ahead of a cold front.
Current radar trends suggest thunderstorms may not be as
widespread as 00Z HRRR shows. Decided to use PROB30 instead of
TEMPO for all four TAF sites. Along with the thunderstorms, some
MVFR ceilings are possible. Behind cold front, VFR conditions will
return. Light south winds are expected overnight before shifting
to the west as thunderstorms approach. Behind cold front,
northwest winds at 5 to 10 knots are expected with light and
variable winds Friday evening.

&&

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

$$

PUBLIC FORECAST...DNM
AVIATION...ARS