SPC AC 032000
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Thu Apr 03 2025
Valid 032000Z - 041200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS
AFTERNOON/EVENING FROM NORTHEAST TX TO MIDDLE TN...
...SUMMARY...
Severe thunderstorms will continue to form and move along a stalled
frontal zone from northeast Texas into middle Tennessee and southern
Kentucky through late evening, with the possibility of very large
hail and a couple of strong tornadoes. Very large hail will be
possible after midnight from southwest Texas into cnetral Texas and
southern Oklahoma.
...Northeast TX to middle TN/southern KY this afternoon/evening...
Severe storms are developing along and to the immediate cool side of
a rain-reinforced baroclinic zone from northeast TX across AR and
middle TN/southern KY. Initial storm motions will tend to carry the
convection to the cool side of the boundary (especially across AR),
though there is some potential for surface-based supercells to form
and move along the wind shift. The warm sector to the south is
characterized by boundary-layer dewpoints ranging from mid 60s F
across TN/KY to low 70s F from northeast TX into southern AR. The
rich moisture and surface temperatures warming into the low-mid 80s
beneath 7-8.5 C/km midlevel lapse rates maintain MLCAPE ranging from
1500 J/kg east to 3000+ in northeast TX/northern LA. Deep-layer
vertical shear/hodograph length is more than sufficient for
sustained supercells, while substantial low-level hodograph
curvature (effective SRH of 200-300 m2/s2) and the moist boundary
layer will support the potential for a couple of strong tornadoes
with supercells moving along the boundary. Otherwise, large hail of
1.5-2.5 inches in diameter will be possible with both the
surface-based and elevated supercells, as well as isolated wind
damage as storms train along and just north of the boundary.
...SW into central TX and southern OK overnight...
Within the large-scale trough over the Southwest, an embedded jet
streak will move through the base of the trough from Baja to
southwest TX by the end of the period. Mass response to the
approaching jet streak will result in strengthening warm advection
and the likelihood of elevated thunderstorm development over
southwest TX after 06z. Storms will subsequently spread
northeastward, with additional storm development expected by 12z
from northwest TX into southern OK. Steep midlevel lapse rates, a
rapid increase in moisture above the surface, and strong deep-layer
shear will favor elevated supercells capable of producing very large
hail (2-3 inches in diameter), as well as isolated damaging surface
winds.
..Thompson.. 04/03/2025
.PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Apr 03 2025/
...Southern Plains/Mid-South/Tennessee Valley...
With a prominent upper trough over the West, strong southwesterly
winds aloft will overlie areas along/north of a frontal zone
extending from the middle part of Texas into the ArkLaTex/Mid-South,
east-northeastward to the central Appalachians and Mid-Atlantic
States. With neutral to slightly rising mid-level heights, the
convectively reinforced front is forecast to move little today
across the ArkLaTex, Mid-South, and Tennessee Valley.
Even though large-scale ascent will tend to remain somewhat nebulous
near the front and southward into the warm sector, persistent
low-level warm advection should aid in renewed thunderstorm
development along/near the stalled front through the afternoon and
evening. Any convection which can form on or just south of this
boundary will have a rather favorably moist low-level airmass, steep
lapse rates aloft, and strong deep-layer shear to support organized
updrafts.
A notable diurnal strengthening of the low-level jet /45-55 kt/ is
expected today across the ArkLaTex to the Mid-South/Lower
Mississippi Valley, where it will impinge on the west/southwest to
east/northeast-oriented effective front. This is concerning
regarding supercell tornado potential later today, some of which
could be strong (EF2+) given the magnitudes of the
deep-layer/low-level shear and moisture-rich environment with
surface dewpoints in the upper 60s/near 70F. That said, some
modal/mesoscale uncertainties still persist as to warm-sector
development and the coverage and longevity of surface-based
supercells, with convection potentially tending to be more
prevalent/likely just north of the effective front. Otherwise, large
to very large hail will be a threat with the expected supercellular
development along/north of the front, with upscale-growing clusters
posing a damaging wind threat as well.
...West-central/North Texas and southern Oklahoma late tonight...
Elevated supercells are expected to again develop late tonight
(after midnight CDT) and early Friday as forcing for ascent
increases to the north of the surface front. These storms will pose
a large hail threat, and possibly some severe-wind potential as
well, particularly if elevated bow echo development occurs as storms
spread northeastward within a highly sheared environment.
...Central Appalachians to Mid-Atlantic/Delmarva...
Remnants of convection and related outflow boundaries will serve as
a northern limit to any appreciable severe threat today. While some
details remain uncertain, any storms that develop along/south of the
front could pose risks for hail and damaging winds.
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
SPC AC 031730
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Thu Apr 03 2025
Valid 041200Z - 051200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THE ARKLATEX
INTO WESTERN ARKANSAS...
...SUMMARY...
Several clusters of strong to severe storms are possible from
central Texas across the ArkLaTex and into the lower Ohio Valley
Friday and Friday night. The greatest threat for tornadoes, large
hail and damaging winds will be from the ArkLaTex across western
Arkansas, including potential for strong to potentially intense
tornadoes.
...Synopsis...
A mid-level trough, centered across the Southwest and northern New
Mexico, will start to shift east on Friday. As this occurs a broad,
strong low-level jet will develop across eastern Texas and into
Louisiana, Arkansas, and Mississippi. This strengthening lower
tropospheric flow will aid in the northward advancement of a warm
front, located from central Texas to the Mid-Mississippi Valley at
the beginning of the period, to eastern Oklahoma an near the MO/AR
border by 00Z Sat. This reorientation of the frontal boundary should
be favorable for supercells with the potential for large hail (some
2+ inch), damaging wind gusts, and tornadoes (some potentially
EF3+).
...ArkLatex to Western Arkansas...
As a warm front lifts north across Arkansas through the day, a very
unstable environment (2500-4000 J/kg MLCAPE) will develop from the
ArkLaTex into western Arkansas as temperatures warm into the mid 80s
with dewpoints in the low 70s. Some weak convection may maintain
along the frontal zone in eastern Oklahoma during the morning and
early afternoon. However, more robust convective development is not
anticipated until mid-afternoon when height falls start to
overspread the region, and the influence of the entrance region of
the upper-level jet increases ascent. In addition, most high
resolution guidance indicates a local area of low pressure may
traverse the frontal zone to near northwest Arkansas by 21Z. The
combination of these factors, which have decent agreement among 12Z
guidance, points toward multiple supercells along the frontal zone
during the mid to late afternoon and into the evening. These
supercells, in an environment featuring 2500-3500 J/kg MLCAPE and
0-1km SRH ~400 m2/s2, will support the potential for strong to
intense tornadoes. Messy storm mode could limit the longevity of any
of these supercells/tornadoes, but even with limited duration, the
environment supports a tornado threat.
A more conditional long-track tornado threat, which would also bring
greater opportunity for EF3+ tornadoes, exists east of the frontal
boundary. Synoptic forcing ahead of the boundary is relatively weak,
but very strong instability (3000-4000 J/kg MLCAPE) is forecast with
minimal inhibition across the warm sector. Therefore, more discrete,
open warm-sector supercell development is possible, but will be more
dependent on mesoscale details which will become more clear in the
Day 1 timeframe.
...Missouri into the Ohio Valley...
Storm mode and destabilization will be a lot more unclear farther
northeast along the frontal zone from southern Missouri and into
western Ohio. Multiple rounds of ongoing storms and new development
are anticipated through the period in a strongly sheared
environment, but storm motion will likely keep the majority of
storms on the cool side of the boundary. Any storms which can stay
along or south of the boundary will pose some severe weather threat
with all hazards possible, particularly farther southwest, closer to
the richer low-level moisture. However, hail, and perhaps some wind
gusts will be possible with any storms in this region.
...West Texas to Central Texas...
Strong elevated instability (2500-3000 J/kg MUCAPE) is forecast
across central Texas and into portions of west Texas Friday night
and into early Saturday morning. This instability, combined with
very strong shear (70-80 knots per NAM forecast soundings), will
support elevated supercells capable of large hail (perhaps 2+")
early Saturday morning as the low-level jet reintensifies and
orients into central Texas ahead of the approaching mid-level
trough.
..Bentley.. 04/03/2025
WUUS02 PTSDY2
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
SPC AC 031923
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0223 PM CDT Thu Apr 03 2025
Valid 051200Z - 061200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR EASTERN
TEXAS TO WESTERN MISSISSIPPI...
...SUMMARY...
Severe storms producing damaging winds and a few tornadoes are
forecast Saturday and Saturday night from the Sabine Valley to the
Tennessee Valley.
...Synopsis...
A mid-level speed max across northern Mexico, rounding the base of a
larger scale trough, will emerge and strengthen into a 100 knot jet
streak across the southern Plains on Saturday. As this occurs, a
closed surface low is forecast to develop somewhere near the
ArkLatex Saturday afternoon/evening and move along the pre-existing
frontal zone to northern Mississippi by Sunday morning. An
unseasonably warm/moist airmass will be in place south of this front
which will support potentially multiple rounds of severe storms on
Saturday and Saturday night.
...Eastern Texas to the Mid-Mississippi Valley...
A cluster of storms, emanating from initial elevated supercells
across central Texas, will likely be ongoing at the beginning of the
period across east Texas. The very moist airmass, featuring
dewpoints in the low 70s, and the strong wind field, will likely
support some severe threat from this activity through the morning as
it moves east. Guidance remains unclear whether this convection will
strengthen through the day and pose some severe weather threat (such
as shown by the ECMWF), or if it weakens and moves into
Arkansas/northern Mississippi and reinforces the baroclinic zone.
The evolution of this morning activity will affect both the timing
and the intensity of the severe weather threat as a more robust
morning MCS through the warm sector would probably inhibit a greater
supercell tornado threat later in the day with a much reduced
available warm sector. Despite these uncertainties, an ejecting
mid-level trough with a very strong jet streak, a developing surface
low, and an unseasonably warm/moist airmass will support a
significant severe weather threat on Saturday.
...Mid-Mississippi Valley to the Upper Ohio Valley...
Mid 60s dewpoints are expected along and ahead of the cold front
from northeast Arkansas to western Pennsylvania on Saturday morning.
Expansive cloud cover will likely inhibit significant
destabilization. However, weak instability associated with the moist
airmass could support maintenance of a squall line along and south
of the Ohio River and perhaps a few stronger, more cellular storms
from eastern Ohio into western Pennsylvania.
..Bentley.. 04/03/2025
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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