LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Jun 30 2023
Valid 301200Z - 011200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
HIGH PLAINS EASTWARD INTO PARTS OF THE MS/OH/TN VALLEYS...
...SUMMARY...
Severe storms producing wind damage and isolated hail are expected
today mainly from Missouri and Illinois southeastward toward the
southern Appalachians. Severe storms with large hail and severe wind
are also possible over the central and southern High Plains.
...Southern IA/Northern MO into parts of the OH/MS/TN Valleys...
Another round of severe thunderstorms is possible later today along
the periphery of a weakening upper ridge over the lower MS Valley,
but uncertainty remains regarding the details. There is some
potential for convection emanating out of KS/NE early this morning
to evolve into an MCS that will move across northern MO/southern IA
later this morning, and potentially into parts of the MS/OH Valleys
this afternoon. However, early-morning convection across the central
Plains is much less intense than at this time last night, and the
immediate downstream environment is not as volatile, so the
potential for a forward-propagating MCS remains uncertain. However,
if the early-day convection is limited, then there will be greater
potential for destabilization prior to potential storm development
this afternoon and evening near the effective surface boundary.
Strong buoyancy and modest but sufficient deep-layer shear could
support a supercell threat across parts of the MS/OH Valleys, if an
early-day MCS does not occur. Under this scenario, an
upscale-growing cluster could spread into parts of the TN Valley and
Southeast, with a damaging-wind threat.
A separate area of elevated convection is possible farther east this
morning across parts of eastern KY/TN, within a warm-advection
regime. Guidance varies regarding the intensity and longevity of
this convection, but some isolated hail and wind damage will be
possible during the morning. Some clustering of this convection is
also possible with time, which could potentially move southward into
parts of AL and GA with a localized damaging wind threat.
...Central/southern High Plains and vicinity...
A positively tilted upper trough is forecast to move across the
southern/central High Plains later today. Moderate instability and
40+ kt of effective shear will again support supercell potential
across parts of eastern CO and vicinity, with a threat of very large
hail and possibly a tornado or two. With the approaching trough
arriving relatively early in the day, storm coverage may become
widespread, resulting in messier convective modes, but a continued
threat for hail and severe gusts is expected as storms spread
eastward across parts of KS/NE through the evening.
Deep-layer shear will be somewhat weaker into the southern High
Plains and west TX, but scattered storms capable of isolated hail
and severe gusts will be possible during the afternoon and evening
in this region as well.
..Dean/Weinman.. 06/30/2023
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