ACUS01 KWNS 261936
SWODY1
SPC AC 261934

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0234 PM CDT Thu Sep 26 2024

Valid 262000Z - 271200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
AREAS OF NORTHEAST FLORIDA...GEORGIA...SOUTH CAROLINA...AND FAR
SOUTHERN NORTH CAROLINA...

...SUMMARY...
Several tornadoes remain possible this afternoon into tonight across
the coastal Southeast in association with Hurricane Helene. The
greatest threat is expected across parts of Florida into southeast
Georgia, the Midlands and Low Country of South Carolina, and
southern North Carolina.

...20Z...
The Day 1 Convective Outlook remains on track. Multiple rainbands
with embedded low-topped, rotating storms continue to progress
across the FL Panhandle into central GA and SC. As the center of
Hurricane Helene approaches the FL coastline later this evening, the
vertical wind (and associated shear) profiles should increase
further across northern FL into the Carolinas. Large, curved
hodographs will support tornado potential with any embedded
supercell structures that can develop amid surface-based buoyancy.
The latest CAM guidance depicts an arc of low-topped supercells to
the northeast of Helene's center moving across central and eastern
SC between 06-12Z, when tornado potential will be maximized. If
enough surface-based buoyancy can advect inland, a strong tornado
could develop closer to the SC coastline.

..Squitieri.. 09/26/2024

.PREV DISCUSSION... /ISSUED 1127 AM CDT Thu Sep 26 2024/

...Florida/Georgia into the Carolinas...
Hurricane Helene is currently centered about 200 miles southwest of
SRQ. This system is characterized by a very broad/expansive wind
field, with the VAD profiles at JAX and CLX showing 50 and 35 kt at
2 km, respectively. Stronger low-level winds are already in place
across FL. Rotation has been noted in cells both off the central FL
Panhandle south of TLH as well as from coastal GA into the SC Low
Country.

The general trend of rotation within the deeper, more cellular
convection is expected to continue throughout the day into the
evening across the entire region, with some chance for an increased
frequency of rotating cells given the strengthening wind profiles.
Best overlap between modest buoyancy and veering low-level wind
profiles is still expected to occur from southeast GA northward into
coastal SC and far southern NC (i.e. ILM vicinity). For much of this
region, the higher dewpoints currently remain offshore, but
additional advection inland is anticipated as the system moves
northward. This additional low-level moisture should increase
buoyancy slightly, which is expected to result in a relatively
higher tornado threat. This relatively higher tornado risk is
expected from 04Z to 18Z Friday, which bridges the Day 1 and Day 2
periods. As such, additional information regarding the tornado risk
for this area can be found in the Day 2 Convective Outlook.

$$
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ACUS01 KWNS 041259
SWODY1
SPC AC 041257

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0657 AM CST Tue Mar 04 2025

Valid 041300Z - 051200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
SOUTHEASTERN OKLAHOMA/NORTHEASTERN TEXAS EAST-SOUTHEASTWARD TO
SOUTHERN ALABAMA AND WESTERN PARTS OF THE FLORIDA PANHANDLE...

...SUMMARY...
Severe thunderstorms with a threat for tornadoes, damaging winds,
and isolated hail are possible today from eastern portions of the
southern Plains into the lower Mississippi Valley and Southeast. A
couple strong tornadoes will be possible.

...North and East Texas and Oklahoma eastward to the southern Appalachians/Southeast...

Water-vapor imagery shows a large-scale mid to upper-level trough
moving east across the central and southern High Plains this
morning. Several embedded perturbations are rotating through the
larger-scale upper feature with the most notable feature being a
100+ kt 500-mb speed max forecast to move from south-central TX
through the lower MS Valley and into the TN Valley/Mid South
tonight. Meanwhile a deepening surface low will move from KS into
the mid MS Valley during the period as a cold front sweeps east
across the Mid South and central Gulf Coast later today/tonight.

A severe squall line is ongoing this morning from central TX north-northeastward into eastern OK. Intense shear profiles within
an adequately unstable warm/moist sector will favor severe gusts
with the bowing segments as this mature squall line rapidly moves
east across eastern OK/TX this morning. A risk for a few tornadoes
will accompany the band of storms as this activity moves east across
the Ark-La-Tex and into the Ark-La-Miss during the day. Forecast
soundings show very large hodographs which will support storm-scale
rotation with the stronger cells either embedded within or that can
develop ahead of the squall line. Strong tornado potential exists
given the wind field across the lower MS Valley where diurnal
destabilization and northward-returning Gulf moisture will aid in
storm intensity/coverage.

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 tornadoes will become the
primary severe hazards. Have expanded Slight-Risk and Enhanced-Risk
equivalent severe probabilities farther east across southern AL and southwestern GA where confidence in a surface-based severe threat
appear greatest.

...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.

Farther east, across Missouri and into western Illinois, elevated
storms east of the primary zone of convection may pose limited/local
risk for marginal hail during the morning and into the afternoon hours.

..Smith/Bentley.. 03/04/2025

$$
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ACUS01 KWNS 041947
SWODY1
SPC AC 041945

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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ACUS01 KWNS 051300
SWODY1
SPC AC 051258

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0658 AM CST Wed Mar 05 2025

Valid 051300Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN
SOUTH CAROLINA INTO CENTRAL AND EASTERN NORTH CAROLINA AND INTO
SOUTHERN AND SOUTHEAST VIRGINIA...

...SUMMARY...
Severe thunderstorms capable of producing scattered damaging-wind
gusts and a few tornadoes are possible today across parts of the
eastern Carolinas into southeast Virginia. Other strong to severe
storms may occur across parts of Florida and east Georgia, and also
from the Allegheny Plateau into the Mid Atlantic.

...VA south to north FL...
Water-vapor imagery this morning shows a mid-level low meandering
east over the mid MS Valley towards the southern Great Lakes. The
larger-scale trough will shift eastward from the lower OH
Valley/central Gulf Coast through the Carolinas/Mid-Atlantic states
by daybreak Thursday.

An ongoing convective band in the form of a broken QLCS structure
extends from western NC southward into north FL. Strong southerly
low-level flow is aiding in the transport of richer moisture (lower
60s dewpoints into SC) northward ahead of the convective band.
Little to no lightning has been observed with the band this morning,
but as it moves eastward into a slightly more buoyant airmass from
central SC east/northeast into VA, the squall line is forecast to
intensify coincident with modest diurnal heating. Very strong low
to deep-layer shear will support storm organization mainly in the
form of bowing structures/mesovortices. An attendant threat for
tornadoes will probably develop with the more persistent/long-lived
embedded circulations in addition to wind damage focused near
inflections and bowing segments of the band.

While weak instability is forecast farther south over GA/FL,
large-scale ascent will be lifting north of this region. Strong
deep-layer flow will still be in place, and coupled with
modest instability, this should result in some continued organized
convection capable of strong to severe gusts.

...Upper OH Valley/PA vicinity...
Farther north, instability will be quite limited given a cooler
boundary layer and dewpoints generally in the mid 40s to mid 50s F.
However, cold temperatures aloft will result in steep midlevel lapse
rates and MUCAPE 250-500 J/kg. Additionally, closer to the surface
low, vertically veering wind profiles with effective shear values
near 40 kt, will support isolated low-topped transient supercells
and perhaps linear segments. Strong to severe gusts, isolated hail
and perhaps a tornado will be possible with this activity this
afternoon before weakening this evening.

..Smith/Jewell.. 03/05/2025

$$
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