MD 0453 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR EASTERN IA…NORTHWEST IL…SOUTHERN WI
Mesoscale Discussion 0453
NWS Storm Prediction Center Norman OK
0800 AM CDT Tue Apr 04 2023
Areas affected...eastern IA...northwest IL...southern WI
Concerning...Severe potential...Watch possible
Valid 041300Z - 041530Z
Probability of Watch Issuance...40 percent
SUMMARY...The threat for isolated large hail may continue and
increase through the mid-late morning. A severe thunderstorm watch
is possible and largely dependent on evolving convective trends.
DISCUSSION...Radar mosaic shows a couple of vigorous thunderstorms
developing north of a surface warm front over southeast IA as of 8am
CDT. The 12 UTC Davenport, IA raob indicated the storms are likely
rooted near 850mb with increasing moisture surging northward this
morning above a cool/stable layer near the surface, to the north of
the warm front. Around 900 J/kg MUCAPE was observed on the
Davenport, IA raob with around 40-kt effective shear. 700-500mb
lapse rates will continue to steepen during the morning (reference
upstream raobs at Omaha/Topeka). As a result, increasing elevated
instability and deep-layer shear will at least support a conditional
risk for strong to severe thunderstorms across eastern IA and
eventually moving into adjacent parts of southern WI/northern IL.
Uncertainty remains regarding storm coverage, and in turn, the
potential severe threat. Convective trends will be monitored for a
possible severe thunderstorm watch this morning.
..Smith/Edwards.. 04/04/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...MKX...DVN...ARX...
LAT...LON 41759226 42729148 43148964 42998821 42538789 42238845
41059134 41149198 41759226
