091
FXUS64 KJAN 081156
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
656 AM CDT Wed May 8 2024

...New AVIATION...

.DISCUSSION...
Issued at 501 AM CDT Wed May 8 2024

Today through tonight: After a hot day in which temperatures are
expected to reach ~90 F over much of the forecast area, we should
see the threat for severe weather increase late tonight.

Subsidence associated with anticyclonic flow aloft will maintain
a capping inversion over the forecast area today, and this will
help keep thunderstorm chances to a minimum through this evening
in spite of the hot and humid surface conditions. While isolated
discrete storms could manage to develop during peak heating near
the Highway 82 corridor, where ML CAPE will likely exceed 3000
j/kg, the threat for any organized storms will remain well north
of the area until the cold front and associated convective system
begin to shift southward late tonight.

The combination of very unstable air and moderately strong deep
layer shear will help to maintain a potential MCS as it shifts
south, but the persistent ridge over the forecast area will tend
to deflect greater forcing and slow the system progression down
while veering the lower level flow. So will maintain the
slight/marginal risks over northwest portions of the area and
continue to emphasize damaging straight line/hail potential over
tornado threats. The overall severe weather threat should be
diminished as we approach daybreak Thursday morning. /EC/

Thursday through Thursday Night: A more significant severe weather
threat may evolve late afternoon into the overnight. Most models
indicate shortwave energy digging southward from the upper
midwest will help to flatten the ridge and allow the cold front
to shift closer to the I-20 corridor by late in the day. During
the day, steep lapse rates and strong heating will make for a very
unstable airmass with ML CAPE approaching 4000 j/kg, but the lack
of forcing combined with a capping inversion will keep the
potential for deep convection relatively low.

The potential for strong to severe storms will begin to pick up
during the evening (starting a little after 5pm) as greater ascent
in the mid levels interacts with the stalled frontal boundary.
This is when forecast confidence diminishes due to increased
spread in the guidance concerning the convective evolution. While
storms will likely develop well to the west over eastern TX
initially, determining how they organize and where they go from
there is a challenge. It appears the most probable scenario will
follow that of the consistent GFS, which indicates the potential
for an intense linear convective moving west to east across our
forecast area with damaging wind gusts up to 70 mph and hail up to
golf ball size being the primary concerns with these storms.

The ceiling is relatively high concerning the potential severity
of the late Thursday/Thu night convective system given the extreme
thermodynamic parameters combined with strong deep layer shear,
but in terms of probability, there is a good bit of spread still
among the guidance in the placement/timing, and will maintain a
slight risk in the outlook for now. As the event gets closer in
time and guidance hopefully come into more agreement, then an
increase in risk level will be likely for portions of the forecast
area, especially for locations along/south of the I-20 corridor.
In addition to the severe potential, there may be some potential
for multiple storms to move across the area and produce locally
heavy rainfall at times which could lead to minor runoff issues in
poor drainage areas. We will continue to monitor trends
associated with this system and will provide updates as they
become available.

Friday through Tuesday: Any thunderstorm chances will come to an end
Friday as the frontal boundary surges further south out of our
forecast area. Heading into the weekend, a 1020mb sfc high will
develop in the ArkLaTex region before slowly pushing east towards
our CWA. This will allow for quiet weather to settle across the
south with cooler-than-normal temperatures expected. Rain chances
will return to the area on Monday and Monday as future guidance
hints at another low pressure pressure system developing across the
Central Plains. /CR/EC/

&&

.AVIATION...
(12Z TAFS)
Issued at 650 AM CDT Wed May 8 2024

Persistent southerly flow will continue to drive the cycle of late
night/morning stratus development during this forecast period.
Expect MVFR category ceilings for the most part early this
morning. As has been the case, mixing will lead to improvement
during the mid/late morning and VFR conditions along with gusty
southerly surface wind should prevail during the afternoon and
evening, then expect MVFR category stratus to redevelop by late
this evening. Any significant TSRA chances should hold off until
late tonight at northern sites. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       90  72  88  65 /  10  30  40  60
Meridian      91  71  89  64 /  10  30  50  60
Vicksburg     90  72  89  65 /  10  30  20  60
Hattiesburg   92  73  91  68 /  10  20  30  60
Natchez       90  72  91  64 /  10  20  20  60
Greenville    89  72  87  64 /  10  60  30  40
Greenwood     89  71  87  63 /  20  70  40  40

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

EC/CR/EC