AREAS AFFECTED...NERN IL /INCLUDING CHICAGO METRO AREA/...FAR NWRN
IND AND SRN LAKE MICHIGAN
CONCERNING...SEVERE THUNDERSTORM WATCH 230...
VALID 032322Z - 032345Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 230
CONTINUES.
SUMMARY...A NEW WW WILL BE COORDINATED SOON TO REPLACE PARTS OF
EXISTING WW 230...AND INCLUDE PARTS OF FAR NWRN IND.
TSTMS ARE INCREASING IN COVERAGE AND INTENSITY ALONG A LOW LEVEL
CONVERGENCE ZONE FROM SRN LAKE MICHIGAN SWWD THROUGH NERN TO CENTRAL
IL. A THREAT FOR SEVERE STORMS ARE EXPECTED TO PERSIST THROUGH THE
EVENING.
DISCUSSION...AT 2310Z...REGIONAL RADAR IMAGERY SHOWED AN INCREASING
TREND IN STORM INTENSITIES ALONG A LOW LEVEL CONVERGENCE ZONE
EXTENDING FROM SRN LAKE MI SWWD THROUGH NERN INTO CENTRAL IL. GIVEN
A MODERATELY-STRONGLY UNSTABLE AIR MASS RESIDING OVER WRN/CENTRAL TO
NERN IL TO NWRN IND AND EFFECTIVE BULK SHEAR OF 30-35 KT...A THREAT
FOR SEVERE STORMS IS EXPECTED TO PERSIST BEYOND THE 00Z EXPIRATION
TIME OF THE WW 230. MODELS TEND TO AGREE WITH THE SCENARIO SHOWING
STORMS DEVELOPING AND PERSISTING THROUGH THE EVENING ALONG THIS ZONE
OF LOW LEVEL CONVERGENCE...WHILE A SWLY LLJ AT 30-35 KT FEEDS THE
MODERATE-STRONG INSTABILITY INTO THIS REGION.
..PETERS.. 05/03/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GRR...LOT...
LAT...LON 42498624 41538723 41228799 41318826 41548869 41878931
42438824 42508695 42608663 42498624
