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ACUS03 KWNS 280730
SPC AC 280729

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0229 AM CDT Tue May 28 2024

Valid 301200Z - 311200Z


Severe thunderstorms are possible across parts of the central and
southern High Plains Thursday afternoon through Thursday night. 
This may include a few supercells initially, before one or two
thunderstorm clusters develop and organize, posing a risk for severe
wind gusts in addition to large hail.

Large-scale mid-level troughing on the leading edge of stronger
westerlies emanating from the northern mid-latitude Pacific may
linger across the northern U.S. Rockies and Great Plains through
this period.  However, it appears that the primary embedded
perturbation will be forced to pivot north of the international
border through the eastern Canadian Prairies, accompanied by
continuing surface cyclogenesis centered over northern Saskatchewan.
As this occurs, initially prominent downstream ridging will become
suppressed southeastward across the Lake Superior and adjacent
northwestern Ontario vicinity, and amplified troughing further
downstream may slowly begin to shift across the Atlantic Seaboard.

In the southern mid- into subtropical latitudes, broad weak
mid-level troughing probably will linger across the northeastern
Gulf of Mexico and Florida vicinity, downstream of suppressed
subtropical ridging.  At least a couple of weak waves are forecast
to continue migrating around the periphery of this ridge, including
one slowly across and east of the southern Rockies Thursday through
Thursday night.

Seasonably high boundary-layer moisture content appears likely to
remain confined to the southern Great Plains into deepening surface
troughing to the lee of the southern Rockies through this period. 
It appears that warm elevated mixed-layer air will slowly advect to
the east of the southern Rockies, and contribute to a strengthening
lower/mid-level baroclinic zone roughly from the lee of the Front
Range and Sangre de Cristo Mountains into northwestern Texas by late
Thursday afternoon.  Along and to the southwest of this zone, steep
lower/mid-tropospheric lapse rates may contribute to sizable
mixed-layer CAPE on the order of 2000-4000 J/kg with daytime

...Central/Southern High Plains...
Early period warm advection driven convection preceding the eastward
advection of the elevated mixed-layer air could be a complicating
factor with regard to destabilization and subsequent convective
development through Thursday and Thursday night.  However, the
strengthening baroclinic zone may become the focus for organizing
upscale growing convection, initially forming within the lee surface
troughing and/or propagating off the higher terrain to the west. 
Given the potential instability, this could include the evolution of
one or two prominent mesoscale convective vortices with
strengthening mid-level rear inflow contributing to potential for
sustained strong to severe surface gusts as the storms clusters and
associated surface cold pools tend to propagate southeastward along
the baroclinic zone.  

It is possible that this may become particularly focused across the
Texas Panhandle into northwest Texas by late Thursday evening, aided
by forcing associated with the short wave impulse emerging from the
Southwest.  Severe wind probabilities might need to be increased
across this region in later outlooks for this period.

..Kerr.. 05/28/2024