SPC May 31, 2025 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1225 PM CDT Sat May 31 2025

Valid 011200Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL AND EASTERN TEXAS...

...SUMMARY...
Scattered large hail and isolated damaging winds are possible on
Sunday from mid-afternoon to mid-evening Sunday in east Texas. More
isolated severe thunderstorms are possible across parts of the
mid-Tennessee River Valley into the southern Appalachians, central
High Plains, northern Rockies, and south Florida.

...Synopsis...
Little change is expected to the overall synoptic regime over the
next 48 hours across the country. Long-wave ridging will persist
across much of the Rockies/Plains with embedded shortwave troughs
propagating across the western CONUS. To the east, a long-wave
trough will undergo gradual de-amplification as it continues to
shift east/northeast. Overall, this synoptic regime will favor
multiple focused corridors of at least low-end strong to severe
thunderstorm potential, though the greatest risk will reside across
parts of TX where buoyancy/shear should be most conducive for
organized convection.

...Central to eastern Texas...
Early-morning convection associated with the progressive shortwave
trough currently over the central Plains will likely be ongoing
across parts of north/northeast TX by 12z Sunday. Recent forecast
guidance suggests this activity will weaken through morning,
possibly leaving an outflow boundary draped across parts of
eastern/central TX. Heating of a moist air mass along and west of
the boundary and/or along a weak surface trough should yield around
3000 J/kg MLCAPE by mid-afternoon with weak capping. Recent
convective allowing guidance continues to show some uncertainty
regarding convective coverage within this weakly forced regime, but
all solutions show at least a few robust cells developing along the
boundary/trough by late afternoon. 30-40 knot mid-level flow
associated with the departing upper-level perturbation will support
adequate deep-layer wind shear for supercells capable of severe
gusts and large to very large (2+ inches in diameter) hail. While
low-level wind shear is expected to generally be weak for much of
the region, a tornado threat may materialize if convection can
become rooted along the boundary where low-level vorticity may be
locally maximized.

...Tennessee to the Carolinas...
A diffuse cold front currently pushing south across the Midwest/OH
Valley is forecast to stall from southern IL into parts of KY, TN,
and the Carolinas by peak heating Sunday. A combination of moist
low-level conditions and weak capping should facilitate thunderstorm
development along the front by late afternoon. 25-30 knot mid-level
flow within the base of a mid-level trough should allow for
sufficient deep-layer wind shear for a few organized cells/clusters
capable of severe hail and sporadic damaging winds. Confidence in
the severe threat is greatest across eastern TN into the Carolinas
where mesoscale ascent along the boundary will be aided by lift
ahead of the trough axis. 

...Northern Rockies...
A shortwave trough is forecast to move across the Pacific
Northwest/northern Rockies through Sunday evening. Steepening
mid-level lapse rates and modest broad-scale ascent ahead of the
wave should promote thunderstorm development by late afternoon from
eastern ID into western MT. Although overall buoyancy will be modest
(MUCAPE approaching 200-400 J/kg), strong speed shear within the
CAPE-bearing layer (around 35-40 knots within the 0-3 km layer)
should promote some storm organization/longevity with an attendant
hail/wind risk. 

...Central High Plains...
Thunderstorm development along the eastern slopes of the central
Rockies is anticipated by mid-afternoon within a weak upslope flow
regime. 20-25 knot westerly mid-level flow will not only help
elongate hodographs, but will advect steeper mid-level lapse rates
into the region. This, combined with slightly improved low-level
moisture, should be sufficient for a few robust thunderstorms
capable of severe gusts and perhaps large hail. 

...South Florida...
The frontal boundary currently drifting southward along the FL
peninsula is forecast to stall later tonight/early Sunday morning.
Although forcing for ascent along the stalled boundary will be weak,
very moist low-level conditions and limited capping will promote
thunderstorm development across the central peninsula by late
morning. Through late afternoon, additional heating combined with
persistent 25-30 knot mid-level flow aloft should promote some storm
organization with an attendant wind threat across southern FL.

..Moore.. 05/31/2025

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