248
ACUS02 KWNS 290505
SWODY2
SPC AC 290504

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1204 AM CDT Wed May 29 2024

Valid 301200Z - 311200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON
INTO THURSDAY NIGHT ACROSS PARTS OF EASTERN COLORADO...WESTERN
KANSAS...WESTERN OKLAHOMA...NORTHWESTERN TEXAS...PARTS OF
NORTHEASTERN NEW MEXICO...

...SUMMARY...
Severe thunderstorms are possible across parts of the central and
southern Great 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.

...Synopsis...
If a closed anticyclonic circulation forms within larger-scale
mid/upper ridging across the southern Manitoba into northwestern
Ontario vicinity, models continue to indicate that this will be
short-lived.  It appears that the ridging will begin to gradually
become suppressed southeastward across the remainder of northwestern
Ontario and the upper Great Lakes region during this period, as a
significant short wave impulse, embedded within a still slowly
progressive upstream trough, pivots north of the international
border through the eastern Canadian Prairies.  This is forecast to
be accompanied by continuing surface cyclogenesis across the
northern Canadian Prairies, but an initial cold front trailing to
its southwest may weaken across the northern U.S. Great Plains.

Downstream larger-scale mid-level troughing likely will remain
amplified across the Atlantic Seaboard, but it may slowly begin to
accelerate eastward, as one embedded short-wave turns across
southeastern Quebec toward the Canadian Maritimes, while another
perturbation digs across the Mid Atlantic coast.  Beneath and
trailing this regime, an influx of seasonably mild/dry low-level air
will be maintained across most areas east of the Mississippi Valley.


In the southern mid- to subtropical latitudes, mid/upper ridging is
forecast to remain suppressed, with broad weak troughing lingering
over the northeastern Gulf of Mexico and Florida Peninsula.
Upstream, models indicate at least a couple of weak short waves will
remain slowly progressive within weak zonal flow across southern
California/northern Baja into the southern Great Plains.  It appears
this will include one advancing across and east of the southern
Rockies Thursday through Thursday night.

Beneath this regime, a seasonably moist boundary-layer will remain
largely confined to the northwestern Gulf coastal plain
northwestward into deepening surface troughing to the lee of the
southern Rockies.  Much of this region will have been impacted by
considerable convection during preceding days.  However, models
continue to indicate that a plume of warm elevated mixed-layer air
will slow advect to the east of the southern Rockies during the day
Thursday, and contribute to a strengthening lower/mid-tropospheric
baroclinic zone somewhere to the lee of the Front Range/Sangre de
Cristo Mountains into northwest Texas by late Thursday afternoon.
Along and to the west/southwest of this zone, steep lapse rates may
contribute to large CAPE on the order of 2000-4000 J/kg with daytime
heating.

...Central/Southern Great Plains...
Early period warm advection driven convection preceding the eastward
advecting elevated mixed-layer air could still be a complication
factor with regard to destabilization and subsequent convective
development through the remainder of Thursday and Thursday night.
However, the remnant cold front across parts of the middle Missouri
Valley, the terrain near/east of the Front Range and Sangre de
Cristo Mountains and a sharpening dryline across the southern High
Plains may all become a focus for thunderstorm initiation by late
Thursday afternoon.

In the presence of weak (and modest to weakly sheared) westerly
deep-layer mean flow, storms will spread eastward and become most
numerous in advance of the short wave progressing to the east of the
Rockies.  The baroclinic zone near the leading edge of the warmer
elevated mixed-layer air may provide a focus for one or two upscale
growing and organizing clusters.  Given the environment, this could
include the evolution of increasingly prominent mesoscale convective
vortices, strengthening mid-level rear inflow and potential for
sustained strong to severe surface gusts with southeastward
propagating cold pools into Thursday night.

..Kerr.. 05/29/2024

$$