MD 0417 CONCERNING TORNADO WATCH 96… FOR NORTHERN AND EASTERN ILLINOIS…SOUTHEAST WISCONSIN…WESTERN INDIANA…FAR SOUTHWESTERN LAKE MICHIGAN
Mesoscale Discussion 0417
NWS Storm Prediction Center Norman OK
0754 PM CDT Fri Mar 31 2023
Areas affected...Northern and Eastern Illinois...Southeast
Wisconsin...Western Indiana...Far Southwestern Lake Michigan
Concerning...Tornado Watch 96...
Valid 010054Z - 010300Z
The severe weather threat for Tornado Watch 96 continues.
SUMMARY...A threat of tornadoes, wind damage and large hail will
continue across much of WW 96 over the next 2 to 3 hours. Parts of
WW 96 may need to be extended in time, beyond the 03Z expiration.
DISCUSSION...The latest radar imagery from Chicago shows a line of
severe storms moving eastward at nearly 70 knots across northern
Illinois. This line is located within the nose of a 500 mb jet,
which is creating very strong large-scale ascent across central and
northern Illinois. This combined with about 75 knots of deep-layer
shear, evident on the Chicago WSR-88D VWP, will be very favorable
for severe storms. In addition, RAP forecast soundings near Chicago
increase 0-3 km storm-relative helicity into the 300-350 m2/s2 range
by 02Z. This suggests that the tornado threat will continue early
this evening as the line approaches the western Chicago Metro.
Tornadoes will be most likely with supercells embedded in the line,
and with rotating elements associated with short bowing line
segments. As the line moves eastward into the Chicago and Milwaukee
metro areas, wind speeds could reach as high as 80 knots along the
leading edge of the line.
To the south, other more discrete storms are located to the east of
Lincoln, Illinois. This area is just to the north of an 850 mb jet.
For this reason, a tornado threat will likely be maintained with
these storms. A widespread wind-damage threat will also be likely
with the stronger cells, especially if a nearly continuous line
segment can organize.
..Broyles.. 04/01/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...IND...LOT...ILX...MKX...DVN...
LAT...LON 42128689 42688719 42938754 43058819 43028883 42888928
42658957 42358967 41788968 41028954 40438936 39618902
39218851 39218787 39458730 39998696 41118678 42128689
