956
FXUS64 KMEG 311746
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1246 PM CDT Fri May 31 2024

...New AVIATION...

.UPDATE...
Issued at 1128 AM CDT Fri May 31 2024

Skies are mostly cloudy along and west of the Mississippi River,
although there have been some instances of sunshine as clouds have
thinned a bit in the past hour. The main area of showers has
begun to weaken over the region and mostly dry conditions are
expected for the next couple of hours across the Mid-South.
Dewpoint temperatures have climbed into the 60s areawide with a
few locations near 70F in our southwestern counties.

Hi-res models seem to have a pretty good handle of the evolution
of showers and thunderstorms throughout the rest of the day and
into tonight. As such, decreased PoPs through this afternoon and
increased them late afternoon into this evening. The main threat
still appears to be instances of flash flooding as a slow-moving
upper low pushes into the region from the west. Areas along and
west of the Mississippi River could see 2-4 inches with isolated
higher amounts and 1-3 inches further eastward. Instances of flash
flooding are possible, especially if multiple waves of heavy
rainfall occur. There is some concern that the LLJ will kick up
tonight and could enhance rainfall rates and the flooding threat.

A Slight Risk of Excessive Rainfall remains in effect for nearly
the entire forecast area through tomorrow morning. The rest of the
forecast is on track with temperatures climbing into the mid to
upper 70s this afternoon.

AC3

&&

.SYNOPSIS...
Issued at 432 AM CDT Fri May 31 2024

Humid conditions will return to the Midsouth today and persist
through early next week. The increased atmospheric moisture will
support showers and thunderstorms each day. Rain chances will be
greatest tonight and Saturday, aided by an upper level low pressure
system lifting out of the southern plains. A few severe thunderstorms
will be possible this afternoon, primarily to the south and west
of a line from Jonesboro to Memphis to Oxford. Damaging winds and
localized flash flooding will be the primary severe weather
threats, with large hail a secondary threat.

&&

.DISCUSSION...
(Today through Thursday)
Issued at 432 AM CDT Fri May 31 2024

Tropical maritime air will return to the Midsouth today, in
advance of an upper level trough lifting out of the southern
Great Plains. Showers were already evident on KNQA radar at
discussion time, extending from central AR into north MS. Lightning
has been confined to central AR, but should expand eastward into
the Midsouth with midlevel height falls and a transition to
surface-based convection. 700-500mb lapse rates will range from
5.5-6.0 C/km, rather modest by last week`s standards. Surface-
based CAPE near 1200 J/kg will coincide with 0-6km bulk shear of
20-30KT to support a Slight Risk of severe storms over east
central AR and northwest MS during peak heating. The severe
threat should wane through the evening, given modest deep layer
shear and a stabilizing boundary layer. A 40KT low level jet will
nonetheless sustain convection through the overnight. A pre-dawn
flare up in thunderstorm coverage and intensity may occur ahead of
the midlevel trough axis passage. Midlevel lapses rates will
increase slightly to around 6 C/km during this period.

Saturday`s thunderstorm coverage and intensity appears more
nebulous in the wake of the midlevel trough. Storm coverage will
likely peak with daytime heating, though an MCV or two from
upstream convection over the plains may enter the mix.

Weak zonal flow / low amplitude ridging will prevail over the
Midsouth on Sunday. The southern Great Plains remain primed for
thunderstorms, given diffluent flow overspreading a weakly-
capped low level instability and moisture axis. Any convectively-
generated waves would likely propagate east through the Midsouth.
With surface dewpoints in the lower 70s, PWAT of 1.5-2.0 inches,
and daytime heating, it won`t take much to organize deep
convection over the Midsouth during the early part of next week.

Medium range global models remain consistent in depicting deep
upper low formation over the northern Great Lakes by the middle
of next week, with highly meridional (for early June) flow over
the eastern half the CONUS. For the Midsouth, northwest flow aloft
will facilitate a cold frontal passage on Wednesday. This front
will likely serve as focus for thunderstorms. A less humid
midcontinental airmass will likely follow, as we head into the
latter part of next week.

PWB

&&

.AVIATION...
(18Z TAFS)
Issued at 1245 PM CDT Fri May 31 2024

A boundary continues to lift north with associated -SHRA
along its movement. Around 22Z, VCTS looks to begin along this
same boundary as increased cloud cover moves across the airspace.
Around sunset, ceilings are expected to begin lowering to MVFR/IFR
conditions, spreading west to east with the movement of
convection. Confidence is on the lower end as far as -TSRA
prevailing across each terminal. Highest confidence in -TSRA
exists over TUP as the line of convection looks to bow out over
northern Mississippi. Fog also looks to develop across each
terminal around sunset as ample moisture will be associated with
convective movement.

AEH

&&

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

$$

PUBLIC FORECAST...PWB
AVIATION...AEH