[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 031034
SWOMCD
SPC MCD 031033 
MIZ000-OHZ000-INZ000-031230-

MESOSCALE DISCUSSION 1723
NWS STORM PREDICTION CENTER NORMAN OK
0533 AM CDT THU AUG 03 2006

AREAS AFFECTED...NRN IL...NWRN IN...SRN LAKE MI...SWRN LOWER MI

CONCERNING...SEVERE THUNDERSTORM WATCH 679...

VALID 031033Z - 031230Z

BOW SHAPED SQUALL LINE IS PROGRESSING ENEWD ACROSS NERN IL AT 40 KT
PRODUCING DAMAGING WINDS GUSTS ACROSS THE REGION.  LINEAR
EXTRAPOLATION OF THIS SYSTEM WOULD PLACE THE LEADING EDGE OF THE
STORMS ACROSS LAKE MI AND INTO SWRN LOWER MI AND PARTS OF NRN
INDIANA BY 12-13Z.  AREA DOWNSTREAM FROM WW 679 IS BEING MONITORED
FOR A POSSIBLE WW.

SQUALL LINE CONTINUES TO EXHIBIT RADAR SIGNATURES INDICATING SEVERE
WIND POTENTIAL...WITH PERIODIC WEAK ECHO REGIONS EVIDENT SUGGESTING
THE PRESENCE OF DESCENDING REAR INFLOW JET STRUCTURES INTO THE BACK
SIDE OF THE LINE.  IR IMAGERY ALSO SHOWS WARMING CLOUD TOPS WHICH
CAN BE ASSOCIATED WITH INTENSIFICATION OF DOWNDRAFT STRENGTH.  THE
STRONGEST STORMS WILL MOVE THROUGH THE REMAINDER OF THE CHICAGO AREA
WITHIN THE NEXT HOUR AND INTO SWRN LAKE MI AND EXTREME NWRN INDIANA.
ALTHOUGH THE SYSTEM MAY REMAIN SLIGHTLY ELEVATED AS IT MOVES ACROSS
SRN LAKE MI TOWARD SWRN LOWER MI...PERSISTENT 40-50 KT WESTERLY
WINDS EVIDENT ON AREA VAD PROFILES AT 1-2 KM AGL SUGGEST CONTINUED
DOWNWARD TRANSFER OF STRONG HORIZONTAL MOMENTUM IS LIKELY WITHIN THE
SQUALL LINE.  THUS...AND A NEW WW MAY BE NEEDED DOWNSTREAM FROM WW
679 WITHIN THE NEXT HOUR OR SO.

..WEISS.. 08/03/2006

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DTX...IWX...GRR...

42518689 43028608 43328516 43338452 42408425 41658448
40938592 40738691 

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