537
FXUS64 KJAN 240342
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1042 PM CDT Thu May 23 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 1042 PM CDT Thu May 23 2024

Rest of tonight...

A mostly quiet evening should remain mostly intact through the
next few hours, but some reinvigoration of convection into the
overnight in a deeply sheared & unstable aloft could support some
severe potential. Shortwave ridge axis continues to build
eastward across the Gulf Coast region, with broad southwesterly
ascent ahead of additional shortwave energy propagating eastward
from TX / Red River Valley across the ArkLaTex into MS River
Valley into the overnight. Guidance has been a little too bullish
on the aftn convection with evening regional radars indicating
little in the way of confidence of development the next several
hours. Earlier runs of convective allowing models (CAMs),
including the HRRR & FV3, indicated some potential redevelopment
along the northwest ArkLaMiss Delta. In this zone, isentropic
ascent, some 30-40kt flow in the 310K Theta E layer, should work
on deeply unstable environment for some convergence/potential
shower & isolated storm redevelopment after 1-2AM. There has been
some run-to-run variability concerns but enough signals to at
least continue to advertise some severe potential but into the
overnight. Recent runs of the Warn on Forecast (WoFs) domains have
been a touch too far west, but on the eastern fringes there is
some development indicate in south-central AR to north-central LA
that could move into our area after 2AM. Main concerns with any
storms would be damaging wind & large hail of quarter to golf
ball size, but tornado threat looks lower so removed that from the
graphic. Flash flooding concerns remains low but westerly flow
could lead to some training potential. Left flood HWO graphic as
is. PoPs are a challenge & lowered them across the board southeast
of the Natchez Trace to more isolated to more scattered to the
northwest. Fcst & HWO severe graphic updates are out. /DC/

&&

.DISCUSSION...
Issued at 251 PM CDT Thu May 23 2024

Today through Saturday Night:

As of mid afternoon today, our forecast area is under the temporary
influence of a shortwave ridge in the wake of this morning`s
shortwave trough passage. For the time being, this has resulted in
weaker deep-layer wind shear and likely some subsidence aloft.
Farther to the west however, another shortwave trough associated
with convection over East Texas is edging eastward. It`s expected
that at least isolated to scattered storms should redevelop in the
unstable air mass to our west with SBCAPE over 4000 J/kg and
increasing shear with that next wave. A Slight Risk for severe
thunderstorms remains in place into this evening for areas in far
northeast LA, far southeast AR, and MS near Greenville and
Cleveland. A broader Marginal Risk for severe storms extends farther
south and east to encompass more of the Natchez Trace corridor and
areas northwest from there. There is also a chance that heavy rain
could cause isolated flash flooding problems if storms train over
the same areas, or a quick downpour of 2-3 inches is observed like
happened in northeast Louisiana this morning. Will carry a Limited
threat area for flash flooding in the ArkLaMiss Delta regions
through tomorrow morning.

Confidence in exact timing is low, but it appears that we should
have a relative lull in severe weather and flooding threats through
most of the daytime tomorrow. Then during the evening and overnight
hours Friday night, a shortwave interacting with a frontal boundary
over KS/MO/AR areas should trigger additional rounds of
thunderstorms that have the potential to spread southeast toward our
forecast area through early Saturday morning. A Slight Risk for
severe thunderstorms has been extended into southeast Arkansas and
northern Mississippi to cover this potential round of severe
weather. Some continued threat for strong to severe storms will
exist across those same areas on Saturday, so a Marginal Risk for
severe storms is advertised on Saturday. Given the holiday weekend
and some uncertainty in forecasted impacts and timing, please
continue to stay aware of any updates to the forecast over the
next few days. /NF/

Sunday through Thursday:

The overall active pattern will continue into early week before
seeing a reprieve for the mid week period. Starting with Sunday,
the main weather focus will be north of our area and things should
be warm/hot but basically quiet. PoPs on Sunday are 10% or less,
but chances do increase some (20-30%) for later Sunday night.
There remains quite a bit of variability for Sunday night into
Monday night as there are timing differences with the surface
front location and southward progression and being aligned with
the upper support. Due to this, confidence is not overly high
with PoPs from Sunday night into Monday night. Additionally, same
reasoning is lowering confidence in severe storm potential. While
confidence is on the low side for these time periods, there`s a
bit more of the guidance that is on the side of slower with the
front and thus the area holds more in the favorable parameter side
for getting severe storms. So while some probability exists for
severe storms at some point Monday, will allow a few more runs to
come in and build confidence in either way.

For Tuesday into Thursday...good agreement from the global guidance
of deep layer dry air filtering into the region with PWs <1.2 or sub
1.0 inch. This will help take the edge off the warmth and humidity,
but look for modification and the boundary trying to return by later
Thursday into Friday. This is typical and having a lower level
boundary to focus moisture and convergence fits the late May type of
front supports increasing storm potential by late Thursday and by
Friday. /CME/

&&

.AVIATION...
(00Z TAFS)
Issued at 740 PM CDT Thu May 23 2024

SHRA & TSRA are slow to materialize this evening, with scattered
SHRA west of the MS River corridor. Expect this to push eastward &
some late evening to overnight development at GLH, GWO & psbl, at
GTR. Confidence is too low at other TAF sites to introduce this
TAF cycle. Some low MVFR stratus is psbl overnight between
24/08-15Z Friday, with some potential IFR stratus at southeast TAF
sites. Expect mixing & lifting to VFR flight categories after
24/15Z Friday. Any low probs of aftn convection is psbl again at
GTR. Light southerly winds, generally around 10mph & gusts up to
20mph, are psbl through Friday aftn. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       72  91  72  92 /  20  10  10  10
Meridian      71  91  71  93 /  20  10  10  10
Vicksburg     72  92  72  92 /  20  10  10  10
Hattiesburg   72  92  73  94 /  10  10   0   0
Natchez       73  91  72  93 /  20  10   0  10
Greenville    72  90  72  90 /  50  10  40  30
Greenwood     71  90  71  90 /  40  20  40  30

&&

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

$$

DC/CME/DC