Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Tue May 27 2025
Valid 272000Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
SOUTHWESTERN INTO DEEP SOUTH TEXAS...AND PARTS OF THE GULF COAST
STATES...
...SUMMARY...
Scattered strong to severe thunderstorms remain possible across
parts of the southern Plains to the Southeast. Large to very large
hail and severe winds should be the main threats across western and
southern portions of Texas, with damaging winds the primary concern
across the Southeast.
...20Z Update...
The previous forecast remains on track. Consideration was given to
trim the Slight Risk across portions of eastern LA into southern MS
with the passage of an earlier QLCS. However, surface observations
show temperatures reaching 90 F in spots, indicating robust enough
modification of the boundary layer to support some organized severe
potential with an expected second round of storms this evening.
Severe wind and hail is still expected to accompany the stronger
storms that form to the lee of the central/southern Rockies, with
potentially 2+ inch hail possible with storms closer to the Rio
Grande.
..Squitieri.. 05/27/2025
.PREV DISCUSSION... /ISSUED 1139 AM CDT Tue May 27 2025/
...Southeast States...
A modestly organized quasi-linear cluster persists at midday across
east-central/southwest Alabama, with a trailing MCV near the
Mississippi and Alabama border. These storms will continue generally
eastward and potentially intensify along the composite outflow
through the afternoon into areas along/south of a front across
Georgia, with at least isolated damaging wind potential. While not
certain, some short-term guidance suggests that a degree of air mass
recovery and abatement of outflow could allow for strong/localized
severe storm redevelopment near the synoptic front later today
farther west across southern Mississippi and possibly nearby
Louisiana.
...Southern Plains including West/South Texas...
In the wake of last night's extensive storms and prominent outflow
now over the western Gulf, substantial convective development should
focus later today over portions of west/south Texas, as a weak
mid-level shortwave trough moves from northwest/north-central Mexico
into the Southwest and southern High Plains. Weak low-level upslope
flow against the higher terrain in west Texas and northern Mexico
may also aid thunderstorm development. Most guidance suggests that
moderate to locally strong instability will exist by peak afternoon
heating, with steep mid-level lapse rates once again overspreading
the warm sector from higher terrain to the south/west.
Mid-level westerly flow is expected to remain fairly modest, but
veering and gradual strengthening with height through mid/upper
levels should support around 30-40 kt of deep-layer shear.
Slow-moving supercells posing a threat for large to very large hail
(2+ inches) should be the main threat with initial development. A
transition to one or more bowing clusters with a greater severe wind
threat appears possible through the evening and overnight hours as
convection spreads generally southeastward toward and across
south-central/Deep South Texas including the Rio Grande vicinity.
...Central/Southern High Plains...
On the back side of an upper trough/low over the north-central
states, isolated/high-based thunderstorms should initially form over
the higher terrain this afternoon before spreading southeastward
over the adjacent High Plains. While instability should tend to
remain fairly weak, steepened low-level lapse rates this
afternoon/evening and sufficient deep-layer shear to support modest
updraft organization may support occasional hail and severe wind
gusts.
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