[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 211802
SWOMCD
SPC MCD 211801 
INZ000-MIZ000-ILZ000-IAZ000-MOZ000-211930-

MESOSCALE DISCUSSION 1751
NWS STORM PREDICTION CENTER NORMAN OK
0101 PM CDT WED JUL 21 2004

AREAS AFFECTED...SERN IA INTO NRN IL

CONCERNING...SEVERE THUNDERSTORM WATCH 661...

VALID 211801Z - 211930Z

SO FAR...ORGANIZED TSTMS HAVE NOT DEVELOPED AS PLANNED...BUT SHOULD
INCREASE THIS AFTERNOON.  ENVIRONMENT IS STILL CONDUCIVE TO A BOW
ECHO SITUATION WITH DAMAGING WIND THE PRIMARY THREAT.

18Z DAVENPORT SOUNDING SHOWED A WARM LAYER IN THE H85-H7 LAYER AND
IS LIKELY THE MAIN INHIBITING FACTOR IN SUSTAINED SURFACE BASED TSTM
DEVELOPMENT THUS FAR.  MODIFYING THE SOUNDING FOR CONDITIONS
DOWNSTREAM ACROSS NRN ILL WITH 85/77 STILL INDICATES ABOUT 75 J/KG
INHIBITION.  CONTINUED HEATING...HOWEVER...AND INCREASING
CONVERGENCE ALONG W-E ORIENTED OUTFLOW BOUNDARY WILL LIKELY LEAD TO
ADDITIONAL TSTM DEVELOPMENT/INTENSIFICATION ACROSS EXTREME SERN IA
OR NWRN IL THIS AFTERNOON.

WIND FIELDS REMAIN VERY FAVORABLE FOR BOW ECHO FORMATION.  DAVENPORT
SOUNDING SHOWED BETTER THAN 30 KTS OF UNIDIRECTIONAL FLOW ABOVE 2 KM
AGL.  AS STORMS DEVELOP AND BECOME ALIGNED WITH THE WLY SHEAR
VECTORS...A BOW ECHO IS LIKELY TO EVOLVE AND TRACK EWD ACROSS NRN
IL...NRN IND AND EXTREME SRN LOWER MI THROUGH LATE AFTERNOON. 
DAMAGING WINDS WILL BE THE PRIMARY THREAT WITH SOME GREATER THAN 70
KT GUSTS POSSIBLE.  HAIL COULD ALSO OCCUR.

AS THE SITUATION EVOLVES...WW MAY NEED TO BE REALIGNED/REISSUED FOR
THE AREA AND DOWNSTREAM.

..RACY.. 07/21/2004

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

ATTN...WFO...IWX...GRR...IND...LOT...ILX...DVN...DMX...EAX...

40589330 42219332 42428597 40598612 

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