818
ACUS02 KWNS 300551
SWODY2
SPC AC 300549

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1249 AM CDT Tue Apr 30 2024

Valid 011200Z - 021200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE
CENTRAL PLAINS...WITH SCATTERED SEVERE STORMS FROM WESTERN TEXAS
INTO SOUTHERN NEBRASKA...

...SUMMARY...
Scattered severe thunderstorms will be possible across parts of the
central and southern Plains on Wednesday. A few tornadoes (including
potential for a strong tornado), very large hail and damaging winds
are expected.

...Synopsis...
On Wednesday, an upper trough will extend from MT into the Great
Basin by late afternoon, with increasing west/southwest flow aloft
spreading into the central and northern Plains. Height falls with
this trough will occur mainly overnight and into Thursday morning
over the Plains, with 500 mb southwesterlies increasing all the
while. Farther south, modest midlevel westerlies will exist from
western TX into northern Mexico, the upper-level winds more
prominent at over 60 kt at 300 mb.

At the surface, low pressure will deepen over the central High
Plains in advance of the upper trough, with a warm front lifting
north across KS during the day. This front will reach into far
southern NE during the late evening and overnight, with 60s F
dewpoints possibly reaching I-80 into eastern NE by 12Z Thursday.
Backed surface winds north of the warm front will also lead to
rising dewpoints into western KS and far eastern CO toward the low,
while robust moisture builds east of the dryline from southwest KS
into western TX.

Aiding both moisture advection and shear will be an increasing
low-level jet which will exceed 50 kt Wednesday evening, affecting
the majority of the central and southern Plains. Finally, a cold
front will move into western NE and KS by around 06Z, and surge east
toward the MO Valley into Thursday morning, augmented with
thunderstorm outflow.

...Central Plains...
Several possible severe-weather regimes may occur Wednesday into
Wednesday night, with initial activity expected along the warm front
during the day from south-central into eastern KS. This early
activity will begin elevated, but instability may be strong and
support occasional hail. With time, additional activity could
develop along any outflow boundaries as theta-e advection persists,
and a few surface-based cells may result by afternoon with hail or
tornado risk.

Later in the day and coincident with peak heating, widely spaced
supercells are anticipated along the dryline from western KS into
northwest TX. Given that this area will be well ahead of the upper
trough, large-scale support will be minimal.  However, strong
heating and mid to upper 60s F dewpoints will still lead to at least
isolated supercells capable of very large hail, and tornado risk
within a relatively narrow zone.

Farther north, the plume of backed moisture may lead to storms
developing over eastern CO into western KS.  This convection will
eventually interact with the cold front by late evening. Depending
on how uncapped the air mass is at that time, cells may congeal into
a line of storms, which will be limited on the northern end by
cooler air into NE, and on the southern end by possible capping.
However, with very steep lapse rates aloft, a strong low-level jet
and the frontal forcing, a few significant wind gusts cannot be
ruled out along the NE/KS border overnight.

...Western TX...
Strong heating will occur near the dryline, where an uncapped and
very unstable air mass will develop. As dewpoints rise well into the
60s F, MLCAPE may exceed 4000 J/kg. Ample low-level convergence
along the boundary will lead to scattered afternoon storms, some of
which will be slow-moving supercells. Increasing and backing 850 mb
winds with time may support a few east/southeast cell motions, with
localized very large hail. In addition, hail-laden outflows may lead
to wind damage.

..Jewell.. 04/30/2024

$$