SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0735 AM CDT Wed Jul 27 2022
Valid 271300Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATER THIS
AFTERNOON/EVENING ACROSS THE CENTRAL HIGH PLAINS...
...SUMMARY...
Large hail, severe outflow gusts, and a tornado or two will be
possible later this afternoon/evening across the central High
Plains. Isolated wind damage will be possible this afternoon from
the Ozarks to the Mid-Atlantic.
...Central High Plains late this afternoon/evening...
An embedded shortwave trough over southeast SK will rotate
southeastward over the northern Plains/upper MS Valley through
tonight, around the western and southern periphery of a deep closed
low over western ON. An associated, reinforcing surface cold front
will move southward into the central Plains by this evening. South
of this front, a corridor of mid 60s boundary-layer dewpoints has
been maintained in a weak upslope flow regime across the central
High Plains. This moisture will combine with daytime heating to the
south and west of ongoing convection over the NE Panhandle in
association with warm advection/frontogenesis near 700 mb, and will
result in MLCAPE values of 1500-2000 J/kg by mid-late afternoon.
Though midlevel lapse rates will not be particularly steep, the
moderate buoyancy and relatively long hodographs (effective bulk
shear near 40 kt) will favor a few south/southeastward-moving
supercells by late afternoon as convective inhibition is removed.
Occasional large hail and severe outflow gusts will be the main
threats, though a tornado or two may also occur with the more
persistent supercells.
...Ozarks to the Mid-Atlantic this afternoon/evening...
Overnight convection has continued to reinforce an effective frontal
zone from the Ozarks to the Mid-Atlantic, and residual
outflow/differential heating will help focus additional thunderstorm
development this afternoon along the southern fringe of the morning
convection. The stronger midlevel flow/vertical shear will tend to
remain to the cool side of the front, with weaker wind profiles in
the unstable warm sector to the south. Steepening of low-level
lapse rates with daytime heating in cloud breaks, in combination
with moderate to locally strong buoyancy, will support some threat
for isolated wind damage with downbursts in multicell clusters for a
few hours this afternoon/evening. Farther north, midlevel flow will
be stronger and there will be lingering low-level moisture (65-70 F
boundary-layer dewpoints). However, the influence of clouds and
morning convection cast substantial doubt on any threat for wind
damage this afternoon to the immediate north of the MRGL area across
IL/IN.
..Thompson/Gleason.. 07/27/2022
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