LIVE MAP (ABOVE) ... SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CDT Wed May 17 2023
Valid 181200Z - 191200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM OKLAHOMA
SOUTH-SOUTHWESTWARD INTO THE TRANSPECOS REGION OF WESTERN TEXAS...
...SUMMARY...
A few severe thunderstorms may occur over portions of the southern
Plains region Thursday.
...Synopsis...
An upper low initially over southern portions of the Canadian
Prairie will shift southeastward with time, crossing the
north-central U.S. through Friday morning. As this occurs, a
surface cold front is forecast to advance southeastward across the
Upper Mississippi Valley into the Upper Great Lakes region, and
southward across the Plains states. Elsewhere, northern-stream
ridging aloft will prevail over the West.
...Oklahoma southwestward to the Transpecos region of Texas...
As a cold front advances southward across the central Plains and a
weak low evolves over the Texas South Plains region along a southern
High Plains lee trough, daytime heating of the moist boundary layer
will result in mixed-layer CAPE values in the 1000 to 2000 J/kg
range to develop from parts of western Oklahoma south-southwestward
to areas near the Texas Big Bend. During the afternoon, isolated
convective development is expected to occur near the lee trough, and
later should increase in coverage across the Oklahoma vicinity as
the front advances southward, and eventually a 50 kt southerly
low-level jet develops.
Initial/more isolated convective development near peak heating may
pose a local risk for gusty winds and hail, though somewhat modest
shear should limit overall storm intensity. During the evening, as
the low-level jet develops, increasing low-level flow will
contribute to stronger low-level and deep-layer shear, sufficient to
otherwise support rotating storms. However, with instability
diminishing later in the evening, this should somewhat offset the
more favorable shear which is expected to develop. Additionally,
storms would likely grow upscale rather rapidly into a cluster/MCS,
which also may mitigate a more robust supercell severe risk.
At this time, will maintain only MRGL risk, as the degree of
potential for any one severe hazard does not appear particularly
notable at this time. Still, upgrade to SLGT may be required in
later outlooks, as cumulative threat may eventually appear
sufficient to warrant slightly higher probabilities.
...Wisconsin southwestward to northwestern Kansas...
As the cold front advances southward/southeastward through the day,
weak destabilization is forecast to occur near the boundary, where
daytime heating combined with modest (generally upper 50s dewpoints)
boundary-layer moisture allows roughly 500 J/kg mixed-layer CAPE to
evolve. This instability will likely be sufficient to allow a
broken band of storms to develop during the afternoon, but likely
insufficient enough to limit storm intensity overall -- particularly
given only modestly sufficient shear for organized updrafts. As
such, it appears that any severe potential should remain limited
enough so as to not warrant inclusion of a MRGL risk area at this
time.
..Goss.. 05/17/2023
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