AREAS AFFECTED...SRN WI/NRN IL INTO SRN LOWER MI AND FAR NRN IND
CONCERNING...SEVERE THUNDERSTORM WATCH 520...522...523...
VALID 260640Z - 260745Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
520...522...523...CONTINUES.
SUMMARY...A LOCAL WW EXTENSION OF WW 520 MAY BE NEEDED FOR PARTS OF
SERN WI INTO LOWER MI PRIOR TO ITS 07Z EXPIRATION. MEANWHILE...A
NEW WW IS BEING CONSIDERED FOR PARTS OF NERN IL INTO FAR NRN IND AND
FAR SRN LOWER MI.
DISCUSSION...AT 06-0630Z...SURFACE ANALYSIS COMBINED WITH TRENDS IN
REGIONAL RADAR IMAGERY AND WSR-88D VWPS AND WIND PROFILER INDICATED
A COMPOSITE OUTFLOW BOUNDARY HAS MOVED SWD AND EXTENDED FROM FAR
SERN LOWER MI /JUST S OF MTC/ WSWWD TO THE N OF JXN TO NEAR 25 S RAC
IN FAR NERN IL. THIS BOUNDARY THEN EXTENDED SWWD THROUGH NORTH
CENTRAL IL WHERE WIND GUSTS WERE REPORTED AT 49 KT AT KRFD AT 0550Z.
THE DEPTH OF THIS BOUNDARY APPEARS TO BE AROUND 0.5 KM AGL PER
WSR-88D VADS IN SRN LOWER MI. OBJECTIVE ANALYSES INDICATED A
MODERATELY UNSTABLE AIR MASS RESIDING OVER AND S OF THE ONGOING
TSTMS IN SRN WI TO LOWER MI...WHILE A 45-50 KT SWLY LLJ EXTENDED
INTO CHICAGO AREA TO NRN IND.
GIVEN THESE FACTORS AND THE EWD MOVEMENT OF A CLUSTER OF STORMS IN
SRN LOWER MI AT 40 KT...THE POTENTIAL FOR ADDITIONAL STRONG WIND
GUSTS REMAINS ACROSS SRN WI...NRN IL INTO SRN LOWER MI AND NRN IND
OVERNIGHT.
..PETERS/THOMPSON.. 07/26/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CLE...DTX...APX...IWX...GRR...GRB...LOT...ILX...
MKX...DVN...
LAT...LON 43748215 42458263 41818302 41608428 41458639 41298746
40689039 41299064 42528903 43038915 43758922 44488709
44038378 43958270 43748215
