Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Fri May 23 2025
Valid 232000Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
AND SOUTHERN GREAT PLAINS...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected across parts
of the southern and central Plains this afternoon through the
overnight hours, with large hail and severe wind gusts the main
threats. Isolated very large hail greater than 2 inches in diameter
may occur.
...20Z Updates...
Only minor changes to the MRGL risk area in southeast Colorado where
dewpoints have held in the upper 50s F. The outlook is otherwise
unchanged. See the previous discussion for greater details.
..Wendt.. 05/23/2025
.PREV DISCUSSION... /ISSUED 1137 AM CDT Fri May 23 2025/
...Central High Plains to Kansas/Oklahoma/Ozarks...
Multiple low-amplitude mid-level shortwave troughs will progress
east-southeastward from the southern/central Rockies across the
adjacent High Plains by this evening. Corresponding weak
cyclogenesis over the central High Plains will encourage modest
low-level moisture transport northward into parts of eastern
Colorado/western Kansas by peak afternoon heating. A narrow corridor
of sufficient destabilization, along with 35-45 kt of deep-layer
shear, should support organized convection.
Initial development over the central High Plains late this
afternoon, most likely across the Nebraska/Colorado/Kansas border
region, should become supercellular and pose a threat for large hail
and severe wind gusts as it spreads southeastward through the
evening. Given steep lapse rates aloft and elongated hodographs at
mid/upper levels, isolated very large hail may occur, with some
tornado risk as well. It remains unclear whether this convection
will grow upscale into a cluster across southern Kansas/northern
Oklahoma later in the evening/early overnight hours as a southerly
low-level jet gradually strengthens, or if separate clusters will
eventually develop as warm advection/moisture transport increases.
Regardless, the airmass across this region will be at least
moderately unstable, with sufficient deep-layer shear to support
continued updraft organization and a continued threat for hail and
damaging winds with convection that can persist east-southeastward
this evening/overnight across Kansas/Oklahoma and eventually the
Ozarks.
...Southern High Plains including Texas Panhandle/South Plains...
A subtle mid-level disturbance/speed max over New Mexico/southern
Colorado, as inferred from Water Vapor/Infrared satellite imagery,
may be an influence on late-day severe storm development. At least
isolated to widely scattered high-based thunderstorm development
seems plausible near the dryline. While warm mid-level temperatures
exist, sufficient near-dryline confluence/convergence and ample
post-dry line mixing (surface temperatures reaching mid/upper 90s F
with CAPE persisting atop the boundary layer in forecast soundings)
should be sufficient for the initiation of sustained deep
convection. Especially with some expected increase in mid-level
westerlies late today, wind profiles/moderate buoyancy will support
high-based supercells capable of large hail, with damaging winds
also possible, particularly across the Texas South Plains given the
well-mixed environment.
...Florida...
To the south of a remnant front, at least scattered thunderstorms
should develop this afternoon across parts of the southeast Florida
Peninsula. This activity should preferentially form on/near the
Atlantic Coast sea breeze. While mid-level winds are not forecast to
be overly strong, sufficient instability and vertical shear should
exist for modest updraft organization. Any cells/clusters that
develop could produce isolated hail and/or damaging winds. For
additional short-term details, see Mesoscale Discussion 939.
...Southern Louisiana...
A moist/very unstable environment near a northward-returning
old/near-coastal front may be conducive to a very isolated damaging
wind and marginally severe hail risk this afternoon through around
sunset.
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