074
FXUS64 KJAN 291555
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1055 AM CDT Wed May 29 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 1055 AM CDT Wed May 29 2024

The previously mentioned shortwave trough has been initiating
convective rainfall over the ArkLaTex region to our west, and a
more prominent area of convection over central LA associated with
greater moisture transport may help to enhance convergence over
southwest portions of the forecast area as we go into the early
afternoon. Given the quick increase in deep layer moisture and
fairly steep mid level lapse rates (e.g., 12z KLIX raob with 7.7
deg c/km) combined with peak heating and seasonably strong
mid/upper level flow for multicell storm development, have opted
to maintain the current marginal risk area west of I-55 to account
for a conditional severe risk. The area could be adjusted some
early this afternoon based on radar trends, but for now will
maintain some consistency in our messaging. Otherwise, showers
rooted above the boundary layer that developed earlier along the
I-20 corridor have dissipated some with stronger mixing and moved
off to the east. /EC/

&&

.DISCUSSION...
Issued at 343 AM CDT Wed May 29 2024

Today and tonight...A shortwave trough will move across the area
today and this will kick off isolated to scattered storms this
afternoon and evening. With lapse rates of around 6.0 to 6.5 c/km
and decent MU capes, a few of these storms could be strong to
possibly severe mainly for areas west of I-55. A marginal risk is
already being advertised for these areas. Hi-res models suggest
that scattered storms will continue to be possible tonight as
another short wave moves across the area. High temperatures today
will climb to around 90, while overnight lows will fall into the
mid/upper 60s./15/

Thursday through Wednesday...

Isolated to numerous showers and thunderstorms will continue through
the duration of the extended period. Early morning global guidance
show a 1024 mb sfc high shifting east across the Great Lakes Region.
With this sfc high propagating eastward, active westerlies over the
Southern Plains will begin to extend into our forecast area on
Thursday morning as the sfc boundary remains to our west/southwest.
Heading into Thursday afternoon, some strong storms will be possible
for areas west of the Mississippi River as a weak-level shortwave
interacts with sufficient instability and a surface boundary. Went
ahead and made a few adjustments to the forecast for Thursday by
increasing PoP chances across our CWA (45-60%). A stronger shortwave
will move through the area heading into Friday/Saturday bringing
increased chances for strong to isolated severe storms across the
area. A Marginal Risk (1 out of 5) has been introduced for much of
the forecast area. Forecast confidence regarding the exact timing of
this system is low at the moment, however we should start to have a
better understanding of the timing of this event as confidence start
to increase. We will continue to monitor trends and will provide
updates as we get closer to this event. Rain chances will continue
through Wednesday as temperatures and moisture increase, as low-
level flow increase across the southeast US bringing additional
chances for afternoon showers and storms across the forecast area.
/CR/

&&

.AVIATION...
(12Z TAFS)
Issued at 626 AM CDT Wed May 29 2024

All TAF sites are VFR this morning with the exception of KGLH
where fog has developed and is bringing IFR/LIFR visibilities.
Expect conditions to improve after 13-14Z and become VFR by 15Z.
All remaining sites should remain VFR through the period outside
of any thundestorm activity./15/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       90  67  85  67 /  20  40  50  30
Meridian      91  66  83  66 /  30  30  40  30
Vicksburg     91  69  85  67 /  30  40  50  40
Hattiesburg   93  69  89  68 /  30  20  30  30
Natchez       92  68  86  68 /  30  40  60  30
Greenville    89  69  81  68 /  20  60  50  40
Greenwood     90  67  80  67 /  10  50  50  30

&&

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

$$

EC/CR/15