SPC May 24, 2025 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0742 AM CDT Sat May 24 2025

Valid 241300Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS INTO THE LOWER MISSISSIPPI VALLEY AND
SOUTHEAST...

...SUMMARY...
Scattered severe thunderstorms should occur across parts of the
southern Plains to the Southeast today. Damaging winds, large hail
and a few tornadoes are all possible. Isolated very large hail
greater than 2 inches in diameter may also occur across the southern
Plains.

...Southern/Central Plains to the Southeast...
Aided by a 30-40 kt south-southwesterly low-level jet, a small but
intense cluster is ongoing this morning across parts of eastern OK.
Several reports of severe wind gusts and large hail have been noted
over the past several hours with this convection. Current
expectations are for the primary cluster to continue posing some
threat for mainly scattered severe/damaging winds as it spreads
east-southeastward into the ArkLaTex this morning into the early
afternoon, generally along/south of an instability gradient/remnant
front. The potential for this activity to persist and/or its related
outflow to generate new convection through the afternoon/evening
across parts of the lower MS Valley and Southeast remains unclear.
Even so, a moderately to strongly unstable airmass will likely be in
place by this afternoon across these regions ahead of the ongoing
convection. While low/mid-level flow and related deep-layer shear
are forecast to only be modestly enhanced, they should still be
sufficient to support a continued threat for scattered
severe/damaging winds and some hail as thunderstorms continue
east-southeastward. Based on observational and short-term guidance
trends, southward and eastward expansions have been made to the
severe hail/wind probabilities across the lower MS Valley and
central Gulf Coast states.

Behind the initial morning activity, a strongly unstable airmass is
forecast to be in place this afternoon/evening over the southern
Plains to the east of a surface dryline, and south of the
convectively reinforced outflow boundary/front. With upper-level
ridging forecast to remain over much of the southern/central Plains
through the day, it remains uncertain whether additional intense
convection will develop along either the dryline or outflow
boundary/front across western/central OK and vicinity late this
afternoon or evening. Strong to locally extreme instability is
forecast to be in place across this area, and a conditionally very
favorable environment will exist for severe thunderstorms. If robust
convection can develop, then sufficient deep-layer shear and steep
lapse rates aloft will support supercells capable of producing very
large hail (2-3+ inches in diameter). A gradual increase in
low-level shear will occur this evening in tandem with a gradually
strengthening low-level jet, and a few tornadoes may occur with any
supercells that can remain surface based. Otherwise, additional
rounds of mainly elevated convection may occur tonight into early
Sunday morning across parts of the southern/central Plains, with a
continued threat for large to very large hail and perhaps occasional
severe winds.

...Central High Plains/Rockies...
Aided by modest low-level upslope flow, isolated strong to severe
thunderstorms may develop against the higher terrain of the eastern
slopes of the central Rockies this afternoon and evening. While
instability is forecast to remain fairly modest, adequate deep-layer
shear will foster some supercell concern and attendant threat for
occasional large hail and severe winds. Overall coverage of severe
thunderstorms appears too isolated to include greater severe hail
probabilities at this time.

...Florida Peninsula...
Another day of seasonably cool mid-level temperatures atop a moist
low-level airmass combined with strong daytime heating will likely
support moderate to locally strong instability across parts of the
FL Peninsula this afternoon. While large-scale forcing for ascent
will remain weak, both the Gulf and Atlantic Coast sea breezes
should aid in scattered thunderstorm development by peak afternoon
heating. Modest deep-layer shear should support some updraft
organization, and isolated hail/wind gusts appear possible with any
of the stronger cores that can be sustained.

..Gleason/Leitman.. 05/24/2025

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