681
ACUS01 KWNS 271627
SWODY1
SPC AC 271625

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1125 AM CDT Sat Apr 27 2024

Valid 271630Z - 281200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PORTIONS OF SOUTHERN KANSAS...MUCH OF
OKLAHOMA...AND NORTHWEST TEXAS....

...SUMMARY...
Severe thunderstorms are likely today and tonight across the
southern and central Plains into the lower to mid Missouri Valley.
The most numerous/intense storms are expected from north Texas into
Oklahoma and southeast Kansas, where strong tornadoes, very large
hail of 2-3 inches in diameter and damaging winds of 60-80 mph are
all possible.

...A regional outbreak of severe thunderstorms is forecast for this
afternoon and evening across parts of KS/OK.  Very large hail and
strong tornadoes are possible..

...OK/northwest TX/south-central KS...
Water vapor imagery shows the main upper trough is still back over
southern AZ, with a rapidly ejecting mid/upper level jet streak
nosing into OK/TX.  This lead feature has aided in the development
of severe storms this morning over parts of west TX/OK.  Storms will
develop northeastward through the afternoon into central KS, despite
an expansive anvil shield from the morning convection.  These storms
will pose a risk of very large hail and a few tornadoes through the
afternoon and early evening.

Farther south, the air mass across much of central/western OK and
northwest TX continues to warm/destabilize as temperatures rise
through the mid/upper 70s - eliminating CINH.  Only weak upper
forcing through the afternoon will result in chaotic development of
discrete supercells in a very strongly sheared and very unstable
environment.  Forecast soundings show very steep mid-level lapse
rates, ample low-level moisture, and strong/increasing shear
profiles through the day.  Details of timing and location are
nebulous, but those storms that develop will pose a risk of very
large hail and strong and possibly long-track tornadoes.  The
stronger large-scale forcing will arrive around/after dark, with a
greater eastward surge of storms across central OK expected.  This
activity may organize upscale in bowing segments will an increasing
risk of damaging winds along with hail and tornadoes into southeast
KS and northeast OK tonight.

...Southeast CO into northern KS...
A rather strong surface boundary extends from southeast CO across
much of northern KS.  Relatively strong heating along this boundary
and moderate instability will lead to scattered thunderstorm
development by mid-afternoon along the entire corridor.  Steep
mid-level lapse rates, strong deep-layer shear, and favorable
low-level wind profiles in vicinity of the boundary will pose a risk
of very large hail and a few tornadoes through the afternoon and
early evening.  This activity is expected to build eastward this
evening along the same boundary into parts of southern IA/northern
MO, with a continued risk of large hail along with an increasing
threat of damaging winds.

..Hart/Jewell.. 04/27/2024

$$