SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0145 PM CST Tue Mar 04 2025
Valid 042000Z - 051200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MS VALLEY INTO THE CENTRAL GULF COAST...
...SUMMARY...
Severe thunderstorms with a threat for tornadoes, damaging winds,
and isolated hail are possible today the lower Mississippi Valley
into the Southeast. A couple strong tornadoes will be possible.
...20z Update...
In general, the ongoing forecast remains on track with only minor
adjustments needed. An organized squall line continues to push east
across the lower MS River Valley. Regional radar imagery shows
discrete/semi-discrete cells developing ahead of the line across
southeast LA into southwest MS. The greatest wind/tornado threat is
expected to remain across this region and spread into southern MS/AL
through late afternoon/evening as higher-quality moisture (denoted
by dewpoints in the 60s) spreads east in tandem with the axis of
stronger (40-50 knot) 925-850 mb flow. 5% wind/hail probabilities
were expanded slightly across parts of northern OK/southern KS where
very cold temperatures aloft coupled with surface temperatures
climbing into the low 60s along/behind a weak surface warm front.
Isolated to scattered convection is gradually developing within this
zone per recent satellite imagery, and may mature sufficiently to
pose an isolated hail/wind risk across the region. 2% tornado
probabilities were maintained along the warm frontal boundary where
low-level vorticity/CAPE may be adequate for a brief/weak tornado.
See the previous discussion below for additional details.
..Moore.. 03/04/2025
.PREV DISCUSSION... /ISSUED 1024 AM CST Tue Mar 04 2025/
...Synopsis...
Recent satellite imagery continues to depict a maturing cyclone
across the central/southern Plains with an embedded shortwave trough
moving through its southern periphery across TX. This shortwave
trough is accompanied by a strong jet streak characterized by 100+
kt at 500 mb. This shortwave and associated jet streak are forecast
to continue eastward through the Lower MS Valley during the day
before curving cyclonically overnight across the TN Valley. The
strong mid/upper flow will persist during this period, spreading
across the Lower MS Valley this afternoon and Southeast/TN Valley
this evening and overnight. This overall evolution will also help to
induce a more negative tilt to the parent upper trough throughout
the day, contributing to notable height falls across the Lower MS
Valley.
At the surface, the primary low associated with this system is
currently over central KS, while a second, triple-point low was
observed farther southeast over the Arklatex vicinity. A strong cold
front extends from this second low, extending back southwestward
into south TX. Strong to occasionally severe thunderstorms are
currently ongoing along and just ahead of this cold front, and the
expectation is for these storms to continue throughout the day as
the front progresses quickly eastward. The warm sector ahead of this
line is currently fairly narrow, with the warm front currently
analyzed approximately along the 58 deg F isodrosotherm from the low
southeastward through central LA. General expectation is for
thunderstorms to continue along the front for the next several
hours. There may be a trend towards stronger storms developing along
the southern portion of the convective line (i.e. central LA
southward/southeastward) given the narrowness of the warm sector and
limited buoyancy currently downstream across northern LA and
southern AR.
...East TX across the Lower MS Valley into the Southeast...
Influence of the more continental airmass remains in place farther
downstream across the Southeast, but this is expected to change amid
strong mass response ahead of the approaching shortwave trough.
General expectation is that low 60s dewpoints will reach the
AR/LA/MS border vicinity by the early afternoon, with mid 60s
dewpoints farther south across southwest MS and southeast LA. The
warm sector should gradually become wider as well, with 60s
dewpoints likely across southeast MS and most of southern AL by
later this evening. Given the presence of intense kinematic fields
across the entire region, the advection and extent of these
dewpoints will be key for delineating the greatest severe potential
this afternoon and evening.
A linear mode will likely be maintained throughout the period, with
some intensification expected as downstream destabilization
increases. Low-level wind fields are more than sufficient for
embedded QLCS tornadoes as well as strong gusts. Potential remains
for more discrete storm development ahead of the line, although the
coverage of these storms could be mitigated by modest but persistent
convective inhibition. Duration of any discrete storms could also be
limited by the fast progression of the cold front. However, given
the very favorable kinematic fields, quick storm maturation is
possible, and the potential for strong tornadoes still exists,
particularly across the Lower MS Valley.
This activity will likely maintain a linear mode tonight as it moves
east across the central Gulf Coast states into the TN Valley. A
continued risk for damaging gusts and line-embedded tornadoes will
remain the primary severe hazards.
...Eastern Kansas to western Illinois...
As the upper low pivots eastward across Oklahoma and Kansas through
the day, and into Missouri by evening, cold air aloft accompanying
the low will yield steep mid-level lapse rates. Any daytime heating
in the wake of initial/prior convection across the northeastern
Kansas vicinity could yield enough CAPE for isolated, low-topped
convective redevelopment. Assuming this scenario manifests, a couple
of the strongest storms could pose marginal risk for hail/wind and
possibly a tornado. Any such risk would taper by evening.
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