MD 1554 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PARTS OF IA…NORTHWEST IL…AND FAR SOUTHWEST WI
Mesoscale Discussion 1554
NWS Storm Prediction Center Norman OK
1022 PM CDT Fri Jul 22 2022
Areas affected...Parts of IA...northwest IL...and far southwest WI
Concerning...Severe potential...Watch unlikely
Valid 230322Z - 230515Z
Probability of Watch Issuance...20 percent
SUMMARY...The risk of severe storms capable of strong to severe
gusts could increase into the overnight hours. The need for a watch
is uncertain, and trends will continue to be monitored.
DISCUSSION...Latest IR satellite imagery shows gradually cooling
cloud tops over central IA in association with a 30 kt low-level jet
(sampled by regional VWP) and related isentropic ascent
overspreading the area. The OAX/DVN 00Z soundings show steep
midlevel lapse rates atop middle 70s dewpoints, which is resulting
in a reservoir of strong instability along and south of a warm front
draped across northern IA. While lingering low-level inhibition and
generally weak large-scale ascent have tempered convective
development thus far, continued isentropic ascent coupled with a
subtle midlevel impulse approaching the area (per water vapor
imagery) could result in increasing convective coverage during the
next several hours.
While initially cellular (potentially elevated) development may be
accompanied by a risk of marginally severe hail, 30-40 kt of
effective shear oriented parallel to the warm frontal zone could
eventually favor clustering and upscale growth. If an organized cold
pool can become established and track east-southeastward from parts
of IA into southwest WI and northwest IL, strong to severe gusts
could become a growing concern given the favorable buoyancy/shear in
place. Ultimately, convective evolution remains unclear and trends
will be monitored.
..Weinman/Thompson.. 07/23/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MKX...DVN...ARX...DMX...
LAT...LON 42949329 43009200 42969086 42789016 42288971 41508987
41199044 40959191 41129367 41479433 42259463 42729422
42949329
