573
ACUS02 KWNS 050602
SWODY2
SPC AC 050600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Sun May 05 2024

Valid 061200Z - 071200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WESTERN/CENTRAL OKLAHOMA AND SOUTH-CENTRAL KANSAS...

...SUMMARY...
Numerous severe thunderstorms are expected to develop and move
eastward Monday afternoon through Monday night across parts of the
southern/central Plains. Multiple strong/potentially long-track
tornadoes, very large to giant hail, and severe/damaging winds all
appear likely.

...Synopsis...
A negatively tilted upper trough with embedded 50-70 kt mid-level
speed maximum will eject northeastward across the northern/central
Plains on Monday. At the surface, the primary low will consolidate
over the northern High Plains of eastern MT into western ND/SD and
vicinity, with a secondary surface low forecast to develop over the
central High Plains by Monday evening. A rather moist low-level
airmass, with surface dewpoints generally in the mid 60s to low 70s,
will spread northward across the southern/central Plains ahead of an
eastward-mixing dryline and southeastward-moving cold front. A warm
front should eventually reach eastward across parts of NE/IA. This
warm front should be the northern limit of appreciable
severe-thunderstorm potential through Monday night.

...Southern/Central Plains...
Confidence has increased in a corridor of greater potential for
strong tornadoes and very large hail, with multiple supercells
likely to develop across south-central KS and western/central OK
late Monday afternoon and continuing through much of the evening.
Accordingly, a Moderate Risk has been introduced for this area.

Daytime heating of the moist low-level airmass, coupled with steep
mid-level lapse rates, will foster moderate to strong instability
developing along/east of the dryline Monday afternoon. Peak
pre-convective MLCAPE will likely reach 2500-4000 J/kg across much
of central KS into western/central OK and northwest TX. Strong
deep-layer shear of 40-50 kt will easily support supercells with
initial thunderstorm development. Convective initiation appears
likely by early Monday afternoon as ascent with the lead shortwave
trough overspreads NE/KS. Very large hail will be a threat
initially, but most guidance suggests a fairly quick transition to a
more linear mode with time Monday afternoon/evening, especially as
the cold front overtakes the dryline. An increasing threat for
damaging winds and embedded tornadic circulations will likely occur
as this mode transition occurs, in tandem with strengthening
boundary-layer shear associated with a strengthening southerly
low-level jet. This damaging-wind/tornado threat may continue into
the overnight hours into parts of IA/MO, and the Slight Risk has
been expanded eastward to account for this potential.

Farther south across western OK and south-central KS, more modest
large-scale ascent and related mid-level height falls associated
with a more westerly mid/upper-level jet will eventually overspread
the dryline and warm sector by late Monday afternoon. Although
overall convective coverage will likely be lower compared to
locations farther north, there should be a better chance for
supercell structures to be maintained, as deep-layer shear vectors
appear more orthogonal to the initiating boundary (dryline). A
southerly low-level jet should strengthen to around 40-45 kt through
early Monday evening across this area, greatly enhancing
corresponding low-level shear and effective SRH. The best chance for
strong, potentially long-track tornadoes and giant hail (3-4 inches)
should exist with any supercells that can persist Monday evening in
a very favorable thermodynamic and kinematic parameter space.
Similar to locations farther north in KS/NE, upscale growth should
eventually occur across central/eastern OK. A threat for damaging
winds and tornadoes (some potentially strong) should continue Monday
night into early Tuesday with eastward extent across the southern
Plains given a sufficiently unstable and strongly sheared
environment.

..Gleason.. 05/05/2024

$$