SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Mon Jun 06 2022
Valid 062000Z - 071200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
HIGH PLAINS TO NORTH-CENTRAL KANSAS...FROM SOUTHEASTERN COLORADO
INTO NORTHWESTERN OKLAHOMA...AND OVER PORTIONS OF THE MID
MISSISSIPPI...MID OHIO...AND TENNESSEE VALLEYS...
...SUMMARY...
Multiple rounds of severe thunderstorms are possible from the Lower
Ohio Valley to Mid-South this afternoon and evening. Scattered
severe thunderstorms are also possible from the Black Hills vicinity
to the central Great Plains and south-central High Plains this
afternoon and evening.
...Discussion..
No substantive outlook area changes appear necessary at this time,
with ongoing convective evolution largely in line with the existing
forecast. Main changes in this update are to expand the MRGL area
and associated probabilistic forecasts eastward across more of
northern Illinois, and a similar areal expansion over central Ohio.
Meanwhile, the SLGT risk in Nebraska/northern Kansas is being
expanded eastward, to include the ongoing supercell over the Boone
County vicinity. Otherwise, only minor line adjustments are being
implemented.
Storms are developing over the northern High Plains area, with
initiation spreading southeastward with time, while central High
Plains development has also begun. These areas of development
should expand to overspread much of the SLGT risk areas over the
next several hours. Meanwhile, some increase in convection is
occurring over western portions of Tennessee and Kentucky, within
the SLGT risk across this area.
..Goss.. 06/06/2022
.PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Jun 06 2022/
...Mid-South and TN/Lower OH Valleys...
Visible satellite and regional radar imagery show a well-defined MCV
over southern MO. Thunderstorm coverage has increased over the
Mid-South within the warm-air advection wing preceding this MCV. The
air mass downstream into more of the TN and Lower OH Valleys
continues to destabilize amid diurnal heating and modest low-level
moisture. As such, the expectation is for the ongoing activity to
persist and likely increase in coverage over the next few hours.
Area VAD profiles and recent mesoanalysis show relatively weak shear
ahead of the MCV. As such, the overall expectation is for the
majority of this activity preceding the MCV to remain sub-severe and
multicellular, although a few instances of hail and a water-loaded
downburst are possible.
Higher severe potential appears to exist along the outflow in the
wake of this MCV later this afternoon. Temperatures are expected to
climb into the 80s in the wake of the MCV, while dewpoints reach the
upper 60s to low 70s. These thermodynamic conditions coupled with
moderately enhanced low-level flow throughout the southern periphery
of the MCV should support the potential for a few severe storms.
Primary hazards should be damaging wind gusts, although the
potential for hail and a tornado or two also exists.
...Northern High Plains and Black Hills to central NE...
A modest shortwave trough currently over the northern Rockies will
continue eastward throughout the day, reaching the Dakotas by this
evening. Low-level moisture will be limited across southeast
MT/eastern WY, but ascent attendant to this shortwave coupled with
low-level convergence near a modest surface low is still expected to
be enough to initiate thunderstorms during this afternoon. Moderate
mid-level flow accompanying the shortwave will contribute to long
hodographs supportive of supercells, and a weak front will provide a
favored corridor for southeasterly storm progression into central
NE. These storms will likely develop and progress to the north and
east of the steeper mid-level lapse rates, but the wind profiles are
still favorable for large to very large hail within any more robust
updrafts.
...South-Central High Plains...
High-based thunderstorms are expected to develop this afternoon amid
strong diurnal heating and low-level convergence (as well as some
glancing influence from the northern High Plains shortwave trough).
Storms should intensify/mature as they gradually move southeastward
into the greater low-level moisture/buoyancy. Deep-layer shear
appears strong enough for a few supercells capable of damaging wind
gusts and/or hail.
...Southern IA/Northern MO...
Predominantly multicellular thunderstorms are anticipated in the
vicinity of the weak frontal zone across southern IA and northern MO
this afternoon. Even with a mostly multicellular mode, a few
stronger updrafts, and potentially even a supercell or two, may
develop. Isolated hail is possible with any more robust updrafts.
...FL and southeast GA...
A low-amplitude mid-level trough over the northeast Gulf will drift
east today. This feature will aid in a pocket of -10 C 500-m
temperatures across north FL and southeast GA this afternoon. As
MLCAPE reaches 1500-2000 J/kg, scattered thunderstorms should
develop along the sea breezes. While lower-level flow will be quite
weak, 25-40 kt effective bulk shear will support mid-level updraft
rotation. Isolated severe hail and locally damaging wind gusts are
possible.
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