[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 211403
SWOMCD
SPC MCD 211403 
MIZ000-INZ000-ILZ000-IAZ000-211600-

MESOSCALE DISCUSSION 1748
NWS STORM PREDICTION CENTER NORMAN OK
0903 AM CDT WED JUL 21 2004

AREAS AFFECTED...ERN IA...NRN/CNTRL IL...NRN/CNTRL IND AND EXTREME
SWRN LOWER MI

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 211403Z - 211600Z

THERE WILL BE AN INCREASING THREAT FOR A BOW ECHO WITH DAMAGING
WINDS FROM ERN IA EWD INTO THE MIDWEST.  A SEVERE TSTM WATCH WILL
LIKELY BE REQUIRED BY 16Z.

SATELLITE LOOPS SHOW A WELL-DEFINED MCV VCNTY OMA THAT WILL BE
MOVING EWD THROUGH CNTRL IA THROUGH MID-DAY.  12Z ETA FORECAST
SOUNDINGS SUGGEST THAT THE MIDLEVEL FLOW ASSOCIATED WITH THIS
FEATURE WILL INCREASE DOWNSTREAM INTO THE 40-50 KT RANGE BY 18Z. 
THIS SEEMS REASONABLE CONSIDERING 40-45 KT FLOW IN THE 4-5 KM RANGE
ON THE OMAHA VWP.  

MESOANALYSIS DEPICTS AN OUTFLOW BOUNDARY BECOMING SITUATED W-E
ACROSS CNTRL IA INTO NRN IL/SRN LAKE MI AREA.  THOUGH THERE WILL BE
CIRRUS/AC DEBRIS COVERING THE AREA THROUGH MIDDAY...IT APPEARS TO BE
SUFFICIENTLY THIN FOR AIR MASS DESTABILIZATION.  AS CINH
ERODES...AIR MASS ALONG/SOUTH OF THIS BOUNDARY WILL BECOME VERY
UNSTABLE BY EARLY AFTERNOON.  

TSTMS SHOULD INCREASE IN INTENSITY LATE THIS MORNING ACROSS ERN IA
AND/OR NWRN IL ALONG THE PERIPHERY OF CURRENT ACTIVITY.  MAGNITUDE
OF WLY MIDLEVEL FLOW...STRONG INSTABILITY AND LARGE SCALE ASCENT
AHEAD OF THE MCV SHOULD AID IN UPSCALE GROWTH INTO A POTENTIAL BOW
ECHO.  FEATURE SHOULD TRACK ALONG THE 850-500 THICKNESS VECTORS
ESEWD ACROSS NRN/CNTRL IL INTO NRN/CNTRL IND AND PERHAPS A SMALL
PART OF SWRN LOWER MI THIS AFTERNOON WITH DAMAGING WINDS/HAIL.

..RACY.. 07/21/2004

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

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

40869292 41819317 42229176 42448922 42468888 42288475
39898507 39848814 

WWWW