Severe Thunderstorm Warning 20, NWS Jackson, MS

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1206 PM CST Wed Feb 12 2025

...New AVIATION...

.MESOSCALE UPDATE...
Issued at 958 AM CST Wed Feb 12 2025

A shield of light to moderate rain continues to advance across
central and northern portions of the area with a rumble of thunder
or two. This morning activity could still have a brief stronger
storm or two, but the primary window for severe storms will come
this afternoon in the airmass behind the departing showery
complex. Morning CAM guidance suggests rather robust recovery is
possible, which would be impressive given current cool
temperatures across the area with mostly variable or light
northerly component of wind. Heavy rains have had rates that have
not particularly supported flash flooding but early reports along
creeks that typically respond quickly to rainfall indicate the
totals so far, upwards of 3 inches in some places, have started to
result in areal flood impacts with some road closures. Given the
higher rates expected in some locales by afternoon, the concern
for flash flooding will remain through the evening.

Should the more aggressive modeling prove accurate, there does
exist a threat for strong tornadoes with the afternoon activity as
modeled soundings indicate large, curved hodographs, favorable
storm motions with respect to boundary orientation, potential for
discrete/semidiscrete storm modes, and instability supportive of
robust deep convection (SBCAPE approaching 2,000 J/KG and low
level, 3 KM CAPE in the 125-150 J/KG, reflective of steep low
level lapse rates).

This threat, particularly the areal/northward extent, is still
uncertain as the degree of destabilization/boundary movement
northward will serve as the primary control on the outcome. Over
the next 2-3 hours, it will likely become much more clear what the
afternoon may hold as the scenarios with most impactful outcomes
will require substantial southerlies/recovery by that time to
support such an event. We'll be closely monitoring the progress of
the potential warm sector and updates, including possible
convective watches, will be issued later today as necessary. /86/

&&

.DISCUSSION...
Issued at 409 AM CST Wed Feb 12 2025

Through tonight:

An active 12-18 hours is on tap with potential for flash flooding
and severe weather through the early evening hours. Early this
morning, moderate rain continues to spread across northwestern
portions of the forecast area. Further south, areas which have had
a break over much of the overnight are beginning to see rain and
some thunderstorms increase as the next upper disturbance
approaches the area. Since yesterday, observed 2-3" of rain have
fallen in a corridor from near Monroe LA to Belzoni to Winona to
West Point. Outside of this area, amounts vary greatly with 1-2"
amounts common north of a Natchez to Jackson to De Kalb line. This
has lowered flash flood guidance in many areas, particularly
across the northern half of the area.

Looking ahead through today, convection developing with the
approach of a strong low level jet upstream from Southeast TX into
LA will build into central and southern portions of the forecast
area this morning, setting up our next SW-NE corridors of heavy
rainfall to come. Right now, it appears the higher rain amounts
today may occur just south of where the highest rainfall totals
have been so far. While this would be good news for those areas,
it does not mean areas further south are out of the woods.
Sufficient rain has already fallen in some areas further south
that higher rain rates today could still result in flooding. After
the morning round of heavy rain, another round of storms is
increasingly possible through the afternoon which could also
result in flooding issues. We will maintain the going Flood Watch
and also expand into the Meridian area to align more closely with
where greater rain amounts are anticipated today. If trends
through the morning hours are positive, we might be able to back
off on the Flood Watch in some of our northwestern areas early in
the day.

Turning to the severe threat, we're beginning the day with stable
conditions across essentially the entire area. Thus, convection
moving into the area within the next few hours with our morning
round of storms will be elevated, at least initially. However, as
a warm front lifts northward through the morning hours, it is
possible some of these early day storms could become surface based
as a more unstable airmass advects into the area. Therefore, an
isolated severe threat could exist before these storms move out of
the area by around midday. The evolution of these morning storms
will play a big role in severe potential for this afternoon, when
another round of storms is expected to develop. If morning storms
are so numerous and organized in such a way that stable outflow
holds the unstable air further south, the severe threat will be
more limited - at least geographically - during the afternoon and
evening. However, if the main corridor of storms this morning
tends to focus further north, closer to I-20, this would make it
more likely for the airmass to recover later today over a larger
portion of the area. Uncertainty over how much of the area might
be impacted by the next round of storms aside, the afternoon
storms are more likely to have instability to work with while
shear remains rather strong. These storms also have greater
potential to be discrete, with sufficient low level flow for
damaging wind gusts and sufficient low level turning, especially
along the warm front, for tornadoes to be possible. We also can't
rule out marginally severe hail, particularly with any discrete
storms. The cold front will ultimately begin to make greater
headway through the area beginning around sunset, ending rain
chances and the storm threat from west to east before midnight.
/DL/

Thursday through Tuesday:

Surface ridging will provide a brief break from the rainfall
Thursday and Friday as it traverses over the central CONUS.
Southerly flow will help Gulf moisture return to the region and
bring afternoon temps to the lower 70s to near 80 degrees by
Saturday.

Although warm temps are expected Saturday, rain will also return
as well as an upper-lvl trough progresses east, pushing a cold
front into the area. With mid-60 dewpoints, sufficient shear and
instability in place, strong to severe storms will be possible.
Continue to check back for updates as this system is several days
away. Depending on rainfall amounts from the next couple of days,
flooding could be possible with this system as soils will be
saturated and additional 1-2 inches of rain will be likely from
this system.

Post frontal passage will bring a cooler start to the new week.
Afternoon highs will range from the upper 40s in the northwest to
lower 60s in the southeast and overnight lows are expected to drop
to the upper 20s and lower 30s. Cold overnight lows could lead to
a widespread freeze Monday and Tuesday morning. /SW/

&&

.AVIATION...
(18Z TAFS)
Issued at 1142 AM CST Wed Feb 12 2025

A mix of conditions were observed at 1730Z as the morning showers
have moved to ne MS but additional SHRA/TSRA will move back across
the area from the west through 05Z. IFR/LIFR conds are expected
to redevelop area and prevail areawide through 09Z. After 09Z
cigs wl gradually improve to MVFR from the west but MVFR cigs wl
prevail through the end of the TAF period. A gusty s-se wind to
20kts is expected this aftn but wl shift to the nw and be gusty
20-22kts tonight as a cold front moves across the region. /22/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       72  42  53  37 / 100  80   0   0
Meridian      72  44  58  34 / 100  90   0   0
Vicksburg     70  40  51  36 / 100  30   0   0
Hattiesburg   82  50  65  39 /  90  90   0   0
Natchez       75  43  53  39 / 100  50   0   0
Greenville    62  35  45  32 / 100  10   0   0
Greenwood     67  37  49  32 / 100  40   0   0

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flood Watch until 6 PM CST this evening for MSZ019-025>057-059-
     060.

LA...Flood Watch until 6 PM CST this evening for LAZ007>009-015-016-
     023>026.

AR...Flood Watch until 6 PM CST this evening for ARZ074-075.

&&

86/DL/SW/22

Preliminary Local Storm Report
National Weather Service Jackson MS
937 AM CST Wed Feb 12 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0840 AM     Flood            2 SSW Chester           33.34N 89.25W
02/12/2025                   Choctaw            MS   Trained Spotter

            Stewart road closed due to high water from
            South Union Road to Chester Mills Road due
            to swelling of Besa Chitto Creek.

&&

LP