Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0702 AM CDT Tue May 27 2025
Valid 271300Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS AND SOUTHEAST...
...SUMMARY...
Scattered strong to severe thunderstorms should occur today across
parts of the southern Plains and the Southeast. Large to very large
hail and severe winds should be the main threats across portions of
Texas, while damaging winds will be the primary concern across the
Southeast.
...Lower Mississippi Valley/Southeast...
The northern portion of a long-lived MCS has maintained its
structure through the early morning hours across LA into western MS,
with occasional strong to severe gusts observed. The airmass
downstream of this small bowing complex is not overly unstable at
the moment. But, filtered daytime heating of a moist low-level
airmass across southern MS into AL/GA is expected to aid the
development of weak to moderate instability by late morning/early
afternoon. Current expectations are for this bow (or new updrafts
along its outflow) to gradually intensify into the afternoon as it
tracks east-northeastward in tandem with a weak mid-level shortwave
trough embedded within larger cyclonic flow over the
north-central/eastern CONUS. Deep-layer shear is forecast to remain
adequate for continued organization with this cluster, and the
threat for isolated to scattered damaging winds should increase by
this afternoon across parts of the central Gulf Coast states as the
boundary layer gradually destabilizes. There may also be some chance
for additional cells/clusters to develop ahead of the ongoing
activity across the lower MS Valley this morning. Isolated hail and
damaging winds may also occur with these thunderstorms if they form.
...Southern Plains...
An extensive area of thunderstorms moved offshore from the TX Gulf
Coast region earlier this morning and subsequently weakened. In its
wake, a convectively reinforced front has settled well south into TX
and parts of northern Mexico. Isolated cells which have developed
this morning across parts of south-central TX may pose some risk for
hail over the next few hours. Otherwise, more substantial convective
development should occur over portions of west/south TX later this
afternoon and evening, 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 TX 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 still
foster 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 across south-central and possibly
deep south TX.
...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 of the central/southern Rockies 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 with this activity.
..Gleason/Leitman.. 05/27/2025
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