SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0258 PM CDT Sun Jul 10 2022
Valid 102000Z - 111200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
NORTHERN PLAINS...CENTRAL PLAINS...AND UPPER MIDWEST...
...SUMMARY...
Isolated to scattered severe thunderstorms are expected across the
Upper Midwest and parts of the northern and central Plains into
tonight.
...20Z Update...
A Slight Risk has been added across portions of western/central NE,
where scattered thunderstorm development is expected later this
afternoon near and north of a weak frontal zone, and perhaps also
within a very hot and well-mixed environment south of the front. One
or more clusters may spread eastward into this evening, with a
threat of severe wind gusts and perhaps some isolated hail. Eventual
weakening is expected late tonight as storms encounter stronger
convective inhibition, but an isolated severe-wind risk may
eventually reach the MO Valley overnight.
Considerable uncertainty remains regarding the evolution of an
ongoing storm cluster across western MN, as well as the potential
for substantial redevelopment in its wake. Since some
heating/destabilization is occurring across ND into far northern MN,
and deep-layer shear will remain favorable for organized convection,
have opted to leave the Slight Risk in place across this area.
Substantial cloudiness downstream of the ongoing western MN cluster
may tend to limit the short-term severe threat to some extent, but
very favorable midlevel lapse rates and sufficient deep-layer shear
will continue to support a threat of hail and isolated strong wind
gusts, even if convection remains somewhat elevated. More vigorous
redevelopment remains possible along the southern/southwestern flank
of this cluster, but confidence is low regarding any particular
scenario in association with this ongoing cluster.
No substantive changes have been made elsewhere with the outlook.
Severe potential remains evident from far southeast MT/northeast WY
into western SD, where a few stronger cells/clusters are expected to
develop and move toward the Black Hills this evening.
..Dean.. 07/10/2022
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Jul 10 2022/
...MN and vicinity through late evening...
The ongoing MCS across northern MN has been more resilient than all
recent numerical model guidance (both mesoscale and CAM), and it may
persist eastward into northeast MN through early afternoon as
surface heating/destabilization continues to its east. Given the
organized nature of the cold pool and its relatively fast motion,
damaging gusts will remain possible into early afternoon.
Additional thunderstorm development is possible this afternoon along
the outflow boundary trailing west/southwestward from the MCS into
west central MN and southeast ND. This area will likely remain
capped until mid afternoon as a result of the warm elevated mixed
layer noted in the 12z ABR sounding. Still, boundary-layer
dewpoints of 68-70 F beneath 8-9 C/km midlevel lapse rates, in
concert with daytime heating, should weaken convective inhibition
and allow thunderstorm development around 21-22z. The storm
environment will conditionally favor supercells capable of producing
isolated very large hail and a tornado or two. Some upscale growth
into a small cluster will be possible, with an attendant threat for
damaging winds as the convection moves southeastward toward east
central MN.
...NE WY and vicinity late this afternoon through early tonight...
A midlevel shortwave trough over northwest MT this morning will
crest the midlevel ridge and begin to move east-southeastward by
early tonight. Residual low-level moisture, steep midlevel lapse
rates, and a reinforcing cold frontal surge may be sufficient for
high-based thunderstorm development by this evening, with storms
subsequently spreading southeastward into early tonight. Buoyancy
will be modest, but vertical shear will be favorable for
supercells/small bowing segments capable of producing damaging winds
and marginally severe hail.
...NE late this afternoon into early tonight...
Strong surface heating and deep mixing along a cold front will
promote high-based thunderstorm development late this afternoon, and
storms will spread east-northeastward along the front toward IA into
early tonight. Vertical shear will generally be weak, but
inverted-v profiles and large DCAPE (~1500 J/kg) will favor
strong-severe outflow gusts.
...Northwest Gulf Coast this afternoon...
A weak cold front is sagging southward across the Gulf Coast states
in association with a weak midlevel trough moving southward around
the eastern periphery of a midlevel high over the southern High
Plains. A hot/humid boundary layer persists south of the front from
southeast TX into southern LA, where Large CAPE (> 3000 J/kg) and
DCAPE > 1000 J/kg will support isolated strong/damaging downbursts
with pulse-type cells and loosely organized, southward moving
clusters this afternoon.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/STgQ8F
