SPC AC 281240
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Sun Apr 28 2024
Valid 281300Z - 291200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH EARLY
TONIGHT FROM THE ARKLATEX SOUTHWARD INTO EAST TX...
...SUMMARY...
Clusters of severe storms are possible through early tonight, with
the most concentrated threat for wind damage, large hail and a few
tornadoes from the ArkLaTex southward into east Texas.
...MO to east TX/western LA through tonight...
Within a larger-scale trough, a primary shortwave trough will move
northeastward from the central Plains to the upper MS Valley by
tonight. A weak surface cyclone will likewise move northeastward
from KS to IA, and an associated/weak cold front will drift
southeastward across KS/OK/northwest TX.
The warm sector has been altered substantially by an extensive
overnight QLCS that is weakening but continues to move eastward
across southern MO, western AR and northeast into south central TX.
Widespread convective overturning has occurred across areas west of
the line, and many of the overnight forecast models appear too
aggressive with thermodynamic recovery today in its wake. There may
be some recovery later today from eastern OK into MO in advance of
an embedded speed max rotating northeastward from west TX over
OK/MO. However, destabilization is unlikely to be sufficient to
support more than SLGT-risk caliber severe probabilities.
Farther south, the remnant QLCS will encounter the richer
moisture/larger buoyancy in the undisturbed warm sector from the
ArkLaTex southward. Vertical shear will be sufficient for
supercells, but the stronger shear and larger, curved hodographs
appear to be in response to warm advection within the modifying cold
pool that the models appear to remove a little too quickly today
from southeast OK/western AR northward. Thus, the main threat for
any embedded supercells/tornadoes will be along the remnant outflow
from the ArkLaTex southward. It appears possible that additional
storm development by this afternoon could evolve into another linear
cluster that will spread southeastward into southeast TX and western
LA by this evening/overnight with a continued threat for wind damage
and occasional large hail.
..Thompson/Leitman.. 04/28/2024
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
SPC AC 280557
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Sun Apr 28 2024
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
CENTRAL/SOUTH TX INTO THE LOWER MS VALLEY...
...SUMMARY...
Isolated strong to severe thunderstorms will be possible on Monday
from parts of central and south Texas into the lower Mississippi
Valley.
...Synopsis...
A shortwave trough near the upper Great Lakes region at the start of
the period is forecast to gradually weaken and move northeastward on
Monday. In its wake, a low-amplitude shortwave trough is forecast to
move across the southern Plains. Across the West, a shortwave trough
and related mid/upper-level jet will move through the Northwest
toward the northern Rockies by Monday evening.
...ArkLaTex into the Lower MS Valley...
A storm cluster will likely be ongoing somewhere near or east of the
ArkLaTex region Monday morning, aided by a persistent low-level jet
and the approaching low-amplitude shortwave trough. Depending on the
timing of the cluster, some downstream diurnal destabilization could
support a threat for isolated hail, damaging wind, and possibly a
tornado into the lower MS Valley region. The threat should begin to
wane by evening as instability weakens with time and eastward
extent.
...Parts of the southern Plains...
A nebulous but nonzero severe threat appears evident over parts of
Texas on Monday. While stronger ascent will move east/northeast of
this region, strong heating of a moist airmass will result in
moderate to locally strong destabilization across parts of south and
perhaps central TX, and isolated storm development will be possible
as CINH weakens. Deep-layer shear will remain sufficient for some
storm organization, so any sustained development would pose a threat
for hail and isolated severe gusts. A broad but uncertain Marginal
Risk has been maintained for this regime.
There is some signal in guidance for isolated storm development near
the northwest fringe of returning low-level moisture into northwest
OK and southern KS, even though this region will be in the immediate
wake of the departing shortwave trough. Given the uncertainty
regarding both magnitude and northward extent of more favorable
low-level moisture, probabilities have not been introduced in this
area, but a strong storm or two cannot be ruled out within this
regime.
...Parts of the Mid MS and OH Valleys into the lower Great Lakes
region...
A weakening cold front will move through parts of the Mid MS and OH
Valleys during the day on Monday, with the front expected to reach
parts of the lower Great Lakes by Monday evening. While moderate
deep-layer flow will persist along/ahead of the front,
destabilization may be quite limited due to considerable cloudiness
and weakening midlevel lapse rates. A strong storm or two cannot be
ruled out along/ahead of the front, but confidence regarding the
development of adequate instability remains too low to include
probabilities.
..Dean.. 04/28/2024
WUUS02 PTSDY2
SPC AC 280742
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 AM CDT Sun Apr 28 2024
Valid 301200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR EASTERN
NE...WESTERN IA...NORTHWEST MO...NORTHEAST KS...
...SUMMARY...
Severe thunderstorms will be possible on Tuesday from parts of the
mid/upper Mississippi Valley into the central/southern Plains.
...Synopsis...
An amplified mid/upper-level shortwave trough is forecast to move
eastward from the northern Rockies into parts of the
northern/central Plains on Tuesday, accompanied by a strong
mid/upper-level jet. A surface wave is forecast to move from the
central Plains toward the upper MS Valley, with a separate low
expected to largely remain in place across the southern High Plains.
...Upper MS Valley into the southern Plains...
Low-level moisture will stream northward through the day from the
southern Plains into the central Plains and upper MS Valley, in
response to the approaching shortwave trough. While the richest
moisture will likely remain displaced southward of the shortwave
track, 50s to near 60F dewpoints could spread as far north as
eastern NE/western IA and southern MN by Tuesday afternoon. This
moistening beneath relatively steep midlevel lapse rates will
support diurnal destabilization, with peak MLCAPE ranging from
around 500 J/kg across southern MN to greater than 1500 J/kg across
the southern Plains.
Thunderstorm development is expected along a weak cold front Tuesday
afternoon, as diurnal heating weakens MLCINH. The greatest coverage
of storms and strongest deep-layer shear are expected from southern
MN into parts of eastern NE and western IA, in closer proximity to
stronger ascent attendant to the shortwave. A few stronger
cells/clusters will be possible, capable of producing large hail,
damaging winds, and possibly a tornado or two. Storm coverage and
deep-layer shear will likely decrease with southward extent, though
stronger instability into parts of KS/OK could support at least an
isolated severe thunderstorm threat during the afternoon and
evening.
A Slight Risk has been added where confidence is greatest in overlap
of greater storm coverage and shear with more favorable instability.
..Dean.. 04/28/2024
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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