[MCD] SWOMCD

Tue Jul 18 18:55:46 UTC 2006

ACUS11 KWNS 181854
SWOMCD
SPC MCD 181854 
ILZ000-MOZ000-182030-

MESOSCALE DISCUSSION 1551
NWS STORM PREDICTION CENTER NORMAN OK
0154 PM CDT TUE JUL 18 2006

AREAS AFFECTED...CNTRL IL INTO CNTRL MO

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 181854Z - 182030Z

THE POTENTIAL FOR SEVERE STORMS CAPABLE OF LARGE HAIL AND DAMAGING
WINDS APPEARS TO BE INCREASING ACROSS DISCUSSION AREA. CONVECTIVE
TRENDS ARE BEING MONITORED FOR A WW ISSUANCE.

RECENT VISIBLE SATELLITE IMAGERY SHOWS A DEEPENING CUMULUS FIELD
FROM NEAR UIN TO N OF SPI...TO THE N OF FRONTAL ZONE EXTENDING FROM
SUB-SYNOPTIC LOW N OF STL ENEWD INTO CNTRL IL. AMBIENT AIR MASS HAS
BECOME STRONGLY UNSTABLE /MLCAPES OF 3500-4500 J/KG/ THIS AFTERNOON
OWING TO TEMPERATURES IN THE UPPER 80 TO MID 90S AND DEWPOINTS OF
70-75 F.  

WATER VAPOR IMAGERY SUGGESTS THAT THIS REGION OF AGITATED CUMULUS
DEVELOPMENT IS OCCURRING IN THE WAKE OF A WEAK MID-LEVEL IMPULSE
SHIFTING SEWD THROUGH NRN IND INTO CNTRL IL.  THEREFORE...SOME
DEGREE OF LARGE-SCALE SUBSIDENCE AND DRY AIR ENTRAINMENT ABOVE THE
PBL MAY TEND TO SLOW TSTM DEVELOPMENT. HOWEVER...SHOULD STORMS
INITIATE AND BECOME SUSTAINED...THE DEGREE OF INSTABILITY WILL BE
SUPPORTIVE OF INTENSE UPDRAFTS...SOME OF WHICH MAY EXHIBIT SUPERCELL
CHARACTERISTICS AS NNWLY MID-LEVEL WINDS STRENGTHEN TO 30-35 KTS. 
THE STRONGEST STORMS WILL BE CAPABLE OF LARGE HAIL AND DAMAGING
WINDS.

..MEAD.. 07/18/2006

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

ATTN...WFO...ILX...LSX...DVN...SGF...EAX...

38379048 38059318 38579323 39419150 40259053 40518990
40608923 40278858 39508867 38818925 

WWWW