SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Thu May 19 2022
Valid 192000Z - 201200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY INTO THE LOWER OHIO
VALLEY...
...SUMMARY...
Isolated very large hail, damaging winds, and a couple of tornadoes
remain possible this afternoon into early tonight across northern
Iowa, southeastern Minnesota and western Wisconsin. Scattered to
numerous damaging winds, large hail, and a couple of tornadoes
should also occur this afternoon from southern Missouri into parts
of Illinois, Indiana, and Kentucky.
...20Z Update...
Primary change with this update was to expand the Enhanced Risk
westward to account for the current position of a compact bowing
cluster in southern MO associated with an MCV. Radar presentation of
this cluster, especially recent velocity data from KSGF, shows
potential for numerous severe winds, some potentially 75+ mph. Have
included a significant wind area across parts of southeastern MO and
continuing into southern IL, as the airmass downstream has become
moderately to strongly unstable. Father east, more cellular
convection has developed over parts of southern IN into KY and
northeastern TN to the south of a diffuse warm front. This activity
should pose a threat for mainly large hail and damaging winds, but a
couple of tornadoes will remain possible across this entire region,
especially with the cluster tied to the MCV where low-level shear is
locally enhanced. See Mesoscale Discussion 831 for more details.
No changes have been made to the risk areas across the Upper
Midwest. It appears likely that intense convection will develop by
21-22Z, with an increasing threat for very large hail, damaging
winds, and perhaps a couple of tornadoes. Mesoscale Discussion 830
has more information on the short-term severe threat across MN/IA.
..Gleason.. 05/19/2022
.PREV DISCUSSION... /ISSUED 1124 AM CDT Thu May 19 2022/
...Upper MS Valley...
Latest surface analysis shows a low over southeast SD, with a warm
front extending eastward along the IA/MN border. This boundary will
lift slightly northward today, with a warm and moderately moist
airmass along and south of the front. A southerly low-level jet
will strengthen by mid-afternoon, enhancing convergence/lift along
the boundary and result in the development of intense thunderstorms.
Supercells map develop across the ENH risk area, capable of very
large hail and a tornado or two. During the evening, storms will
likely develop southwestward across western IA into eastern NE, with
a more localized risk of large hail and damaging winds.
...Lower OH Valley...
Satellite imagery shows a pronounced MCV over southwest MO. A
cluster of lead thunderstorms over eastern MO will limit northward
destabilization this afternoon, but a corridor of moderate/strong
instability will likely form ahead of the MCV from southern MO into
southern IL/IN and western KY. Thunderstorms are expected to form
in this area, posing an initial risk of large hail and a tornado or
two. 12z CAM solutions suggest the activity will grow upscale
during the evening with an increasing risk of damaging winds as the
storms move into IN/KY. Activity may remain locally severe as far
east as OH/WV later tonight before weakening as they track into the
mountains.
...Carolinas...
The environment from the western Carolinas to the coast will be
moderately unstable this afternoon, with a conditional risk of
damaging winds and hail in persistent/robust thunderstorm clusters.
However, 12z model guidance suggests very few storms will develop
due to weak forcing aloft. Therefore will maintain only MRGL risk
for today.
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SQj4W1
