582
FXUS64 KJAN 041658
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1158 AM CDT Tue Jun 4 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE...
Issued at 1158 AM CDT Tue Jun 4 2024

Rest of this afternoon...

Active but complex convective pattern is expected today. Morning
analysis indicates quasi zonal pattern with shortwave centered
across the Ozarks into the Mid West. Convective complex to the west
is decaying, as cold cloud tops are warming, with the main focus
becoming closer to the ArkLaTex. Recent convective complex
yesterday evening really overturned a majority of the region.
Morning 12Z sounding at JAN indicate the scoured out environment,
with only 1.2 PWs & sfc mesoanalysis indicating only around 1.4 inch
PWs currently. However, low-level southerly sfc flow is picking up
south of a stationary boundary analyzed across the southern half of
the area, especially from Monroe, LA into Vicksburg to southeast
towards Hattiesburg. Cold pool dominant storms are sagging into
southeast AR, but there is good shortwave ascent/moist advection for
some sfc boundary lifting northward slightly. MLCAPE is somewhat on
the lower side in the I-20 corridor, with more focus & potential
further southwest into the Hwy 84 corridor. However, steep
mid-level lapse rates of 6-8 deg C, 30-35kts mean bulk shear &
expected 2-3k J/kg MLCAPE south & west of a line from Vicksburg-
Jackson-Brookhaven indicate potential for severe storms. Main
threats continue to be damaging winds of 60-70mph & hail. With
recent rains & expected potential for an additional 2-3 inches,
with locally higher amounts possible, some localized flash
flooding potential is possible. Added a "Limited" for areas along &
west of the I-55 corridor, mainly from Grenada to Jackson to
Brookhaven. Other than some timing of rain/storm chances &
minor updates to the forecast to adjust temperatures slightly
downward due to all of the convective cloud debris, no major changes
are needed there. Updates are out. /DC/

&&

.DISCUSSION...
Issued at 335 AM CDT Tue Jun 4 2024

Through tonight: A few areas of light to moderate rain comprise
the remaining vestiges of two MCSs that moved into the area
yesterday evening. Both of these systems have long since weakened,
but not before producing wind damage in several areas. Also of
note, a wake low developed across parts of AR and north MS behind
the first MCS and has resulted in southerly winds that have been
gusty at times overnight.

Looking ahead to today, we`re in for another complicated and low
confidence forecast heavily driven by mesoscale details.
Considerable cloud debris and perhaps some shower activity will
likely persist well into this morning. After the convective
overturning that took place overnight, there will likely need to
be some window of recovery during the day before the atmosphere
will again be primed for more widespread convection. The 00z
guidance suite zeroed in on the convective complex currently
moving into the Red River Valley of OK as the next system to bring
thunderstorms into our area from midday through the afternoon.
However, some later runs of the HRRR backed off on this solution
somewhat, weakening the storms as they move eastward, perhaps
hinting at a scenario in which the airmass has not had sufficient
time to recover. And so, these two solutions appear to represent
our best and worst case scenarios for today. If this MCS is able
to maintain progress into our area or weaken then become
reinvigorated later today into this evening, it will have the
potential to carry similar threats to last night`s storms with
damaging wind gusts being the primary concern. For this we are
highlighting SPC`s day one marginal to slight risk across our
region. If this is the scenario that prevails, localized flooding
can`t be ruled out particularly in areas that have seen similar
activity in recent days. But there is also the potential failure
mode, in which the atmosphere doesn`t sufficiently recover and
overall precip coverage is limited. We`ll watch closely how this
plays out through the morning and provide more updates along the
way. /DL/

Tuesday through early to mid next week...

High pressure over the southeastern CONUS will keep a steady
stream of moisture into the area, supportive of daily rain and
storm chances for much of the extended period. A warm moist
boundary layer beneath perturbed midlevel flow will result in a
period of enhanced activity through the remainder of the week.
With PWAT generally in excess of 1.7 inches, several rounds of
storms will be possible. Flow in the 20-30 kt range will aid in
the organization of these storms, with greatest confidence in the
extended period for a system Wednesday. A shortwave will help
drive the complex and aid in moisture recovery. Flow is ample for
organization and DCAPE around 1000 j/kg range will support
downbursts capable of damaging wind gusts. There is still a bit of
uncertainty regarding timing and evolution of these systems as a
lot depends on mesoscale features. Given the conditional nature
and overall low confidence, expect adjustments in the forecast as
more data becomes available.

Storm chances will likely continue into Thursday/Friday as a cold
front pushes south. several more complexes appear possible where
the environment remains favorable, mainly the southwest. There is
a chance that the front stalls out and should this happen, given
the lingering moisture reservoir, this may serve as a focus for
storms, however this is only speculation at this time. Storms will
continue to be possible south of the front where moisture remains
abundant, but overall confidence in their organization and
evolution remains low. In the wake of the cold front Saturday,
drier air will shift focus further south, thus limiting the chance
for storms. Moisture recovery will be possible Sunday as high
pressure shifts east and a shortwave pushes across the midsouth,
bringing a return of rain and storm chances. PoPs remain low at
this time. Early to mid next week gets a bit interesting, as a
seasonally anomalous trough digs south across the eastern CONUS.
This will likely favor below normal temperatures. Persistent
northerlies and high pressure will favor drier conditions and
perhaps a more spring-like feel./SAS/

&&

.AVIATION...
(12Z TAFS)
Issued at 637 AM CDT Tue Jun 4 2024

A patchy IFR stratus ceiling is impacting portions of north MS.
Otherwise, VFR conditions prevail across the region this morning.
Another round of TS is expected this afternoon, with 50 kt wind
gusts and 1 inch hail possible. Brief categorical reductions will
be possible in storms. Late tonight into early Wed morning, low
stratus ceilings will be possible again and patchy fog cannot be
ruled out. /DL/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       88  73  89  71 /  60  20  50  40
Meridian      89  70  91  70 /  60  30  40  60
Vicksburg     88  73  88  71 /  70  20  50  40
Hattiesburg   89  73  92  73 /  50  20  30  40
Natchez       88  73  89  71 /  60  20  40  30
Greenville    86  73  86  72 /  70  20  60  30
Greenwood     88  72  86  71 /  60  30  60  30

&&

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

$$

DC/DL/SAS20