Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0746 AM CDT Tue Apr 22 2025
Valid 221300Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS...
...SUMMARY...
Isolated to scattered severe thunderstorms will be possible across
parts of the southern/central Plains, mainly this afternoon and
evening. Large hail and severe gusts should be the main threats.
...Southern/Central Plains...
Stronger westerly flow aloft should remain confined to the northern
tier of the CONUS today, and to the north of the surface warm
sector. Multiple weak mid-level disturbances may drift eastward
across the southern/central High Plains through this evening, with
fairly modest mid-level flow for late April standards. At the
surface, a front will extend from parts of the Upper Midwest to
southwest KS near a weak surface low. A dryline will extend
southward from this low over the southern High Plains. Some eastward
mixing of the dryline is forecast by late afternoon, especially
across the OK/TX Panhandles. Otherwise, little movement of the front
is anticipated through this evening.
Both of these surface boundaries should provide some focus for
convective development this afternoon and evening, even with
large-scale forcing for ascent remaining rather nebulous. Weak to
locally moderate instability should develop through the afternoon
with diurnal heating of a partially modified Gulf airmass. Even
though west-southwesterly mid-level flow is expected to remain
fairly modest, weak low-level winds gradually veering/strengthening
with height though mid/upper levels should support sufficient
deep-layer shear for some updraft organization. A mix of widely
spaced supercells and multicells may eventually develop along both
the front and dryline, with uncertainty remaining rather high about
favored locations for robust convective development. Regardless,
this activity could pose a threat for isolated to scattered large
hail given steep lapse rates aloft. Any clusters that can evolve
through the late afternoon and evening may also have some severe
wind threat given steep low-level lapse rates. Some trimming was
made to the northwest extent of severe probabilities based on the
forecast position of the front/dryline later today.
...Southeast to the Carolinas...
A weak front draped southwest to northeast is forecast to move
little today across the Southeast. Generally modest
west-southwesterly mid-level flow is expected to prevail, with
slightly stronger winds aloft forecast over the Carolinas. This
should tend to limit deep-layer shear and convective
organization/intensity. Still, with some destabilization forecast
and fairly cool temperatures aloft, any clusters of convection that
can develop along/south of the front may pose an isolated threat for
damaging winds and perhaps marginally severe hail. Based on latest
observational and guidance trends showing greater thunderstorm
coverage this afternoon across parts of AL into northern GA, have
connected the two Marginal Risk areas with this update.
..Gleason/Broyles.. 04/22/2025
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