890
ACUS02 KWNS 240537
SWODY2
SPC AC 240536

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1236 AM CDT Fri May 24 2024

Valid 251200Z - 261200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SATURDAY
EVENING THROUGH SATURDAY NIGHT ACROSS PARTS OF NORTHWESTERN
OKLAHOMA...CENTRAL AND EASTERN KANSAS INTO WESTERN MISSOURI...

...SUMMARY...
Severe thunderstorm development appears likely across parts of the
central and southern Great Plains by Saturday evening.  This
probably will include a few supercells initially, before storms
gradually evolve into an organizing cluster overnight, accompanied
by a risk for large hail, a few tornadoes and severe wind gusts
across parts of Kansas and Oklahoma into western Missouri.

...Synopsis...
The most prominent mid-level short wave perturbations have mostly
become confined to the northern mid-latitudes.  This includes one
forecast to dig southeast of the Canadian Maritimes and northern New
England coast, another pivoting northeast and east of the Great
Lakes region, and a third digging along/southeast of the western
Canadian/U.S. border area.  However, models indicate that
subtropical ridging, centered over central Mexico and the
southwestern Gulf of Mexico, will remain suppressed, with several
lower-amplitude waves progressing around its periphery.  This will
include mid-level troughing likely to progress east of the south
Atlantic Seaboard, and another perturbation accelerating out of the
Southwest trailed by a similar strength perturbation accelerating
east of the Great Basin.

It appears that the latter two impulses will contribute to
larger-scale troughing progressing across the lower Missouri Valley
and central Great Plains by 12Z Sunday, accompanied by a deepening
surface cyclone emerging from the lee of the Colorado Rockies.  In
the wake of a preceding cold front associated with the Great Lakes
perturbation, which appears likely to stall southeast of the lower
Great Lakes through the Ohio Valley, rapid low-level moisture return
is forecast through the developing warm sector across the southern
through much of central Great Plains by late Saturday evening.  It
appears this will reach much of the lower Missouri Valley by late
Saturday night.  Beneath a plume of warm and capping elevated
mixed-layer air overspreading much of the central/southern Great
Plains and lower Mississippi Valley, models suggest that the
seasonably moist air will support large CAPE on the order of
2000-4000 J/kg.

...Great Plains...
While the general synoptic evolution appears fairly certain, there
is notable spread within/among the various model output concerning
the details, and smaller-scale evolution.  With low-level moisture
return ongoing from the southeastern Great Plains during day, model
output indicating later timing (probably after 26/00z) of the more
appreciable increase in thunderstorm initiation seems likely to
verify best.

By early Saturday evening, it appears that the deeper boundary-layer
moistening may become focused in a narrow corridor across
northwestern Oklahoma into central Kansas, along/west of a
strengthening southerly 850 mb jet (in excess of 50 kt by late
evening).  This may become the focus for the most intense potential
supercell development, posing a risk for large, damaging hail and
perhaps a strong tornado or two.  This activity will tend to develop
northeastward and eastward within the warm sector through mid to
late evening, before forcing associated with lower/mid-tropospheric
warm advection provides a potential focus for an upscale growing and
organizing cluster near a warm front across central/eastern Kansas
into western Missouri overnight.  As this occurs, damaging surface
gusts are expected to become the most prominent potential severe
hazard.

...Lower Great Lakes/Allegheny Plateau into Ohio Valley...
Deep-layer shear may be modest, but CAPE on the order of 1000-2000
J/kg ahead of the slowing front may become supportive of storms with
potential to produce severe hail and wind during the day Saturday,
before the onset of more substantive mid-level height rises in the
wake of the mid-level short wave trough.

...Eastern Gulf States...
It is possible that a convectively generated or enhanced
perturbation, digging around the northeastern periphery of
low-amplitude ridging, may contribute to vigorous renewed
thunderstorm development by late Saturday afternoon and evening.  In
the presence of a seasonably moist boundary layer with sizable CAPE,
stronger storms may be accompanied by a risk for potentially
damaging wind gusts.

..Kerr.. 05/24/2024

$$