586
ACUS03 KWNS 200711
SWODY3
SPC AC 200711

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0211 AM CDT Sun Apr 20 2025

Valid 221200Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
WESTERN/CENTRAL TEXAS...WESTERN OKLAHOMA...AND SOUTHERN KANSAS...

...SUMMARY...
Isolated severe thunderstorms are possible on Tuesday across
portions of the southern Plains.

...Synopsis...

A low-amplitude west/southwest flow regime is expected across much
of the CONUS on Tuesday. A weak upper trough will be maintained
across the western U.S. while a belt of stronger westerly flow
envelops the north-central and northeast U.S. where a pair of modest
shortwave upper troughs will migrate east through the period. At the
surface, south/southeasterly low-level flow over the Gulf and
southern Plains will transport modified Gulf moisture northward
across TX/OK/KS.

...Western TX/OK into southern KS...

Large scale ascent is expected to remain somewhat nebulous across
the region on Tuesday. However, various forecast models suggest a
weak impulse may migrate across the southern Rockies into the
southern Plains Tuesday afternoon into evening atop the moistening
boundary layer. Modest west/southwesterly flow and strong surface
heating also may allow for weak lee low development across the
southern High Plains, and the development of a dryline extending
from the OK/TX Panhandles southward through western TX. A stalled
surface boundary is also forecast to extend across central KS. These
boundaries may provide focus for isolated thunderstorm development
by late afternoon.

A plume of steep midlevel lapse rates will reside across the region,
aiding in diurnal destabilization, with MLCAPE values around
1500-2000 J/kg possible. Additionally, forecast guidance indicates
an 25-35 kt southwesterly low-level jet will develop during the
evening. NAM forecast soundings suggest at least weak capping
between 850-700 mb may persist, though the GFS is much more mixed
with a weaker cap. Given the weak forcing regime, thunderstorm
coverage remains uncertain. Nevertheless, a few organized
thunderstorms during the late afternoon into the evening hours, with
a risk for large hail and damaging gusts, appear possible and a
Marginal (level 1 of 5) risk has been included.

..Leitman.. 04/20/2025

$$