[MCD] SWOMCD

Tue Jun 20 22:19:19 UTC 2006

ACUS11 KWNS 202219
SWOMCD
SPC MCD 202219 
ILZ000-WIZ000-IAZ000-MNZ000-210015-

MESOSCALE DISCUSSION 1262
NWS STORM PREDICTION CENTER NORMAN OK
0519 PM CDT TUE JUN 20 2006

AREAS AFFECTED...CNTRL THROUGH NERN IA...SERN MN...SWRN WI AND NWRN
IL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 202219Z - 210015Z

POTENTIAL FOR THUNDERSTORM INITIATION MAY INCREASE NEXT FEW HOURS
ACROSS PORTIONS OF THE UPPER MS VALLEY FROM CNTRL AND NERN IA INTO
SERN MN...SWRN WI AND NWRN IL. A FEW SUPERCELLS CAPABLE OF PRODUCING
LARGE HAIL...ISOLATED TORNADOES AND ISOLATED DAMAGING WIND WILL BE
POSSIBLE. A WW WILL BE NEEDED IF IT BEGINS TO APPEAR INITIATION IS
IMMINENT.

A WARM FRONT EXTENDS FROM WRN IA SEWD THROUGH CNTRL IL. THIS
BOUNDARY IS LIFTING SLOWLY NWD THIS EVENING ALONG A 40+ KT SLY LOW
LEVEL JET. PARTIAL CLEARING IN WAKE OF MCS THAT MOVED THROUGH THE
AREA THIS MORNING HAS CONTRIBUTED TO STRONG INSTABILITY ALONG AND S
OF THE WARM FRONT. STEEP LAPSE RATES...LOW LEVEL DEWPOINTS IN THE
UPPER 60S AND TEMPERATURES IN THE LOW 80S HAVE RESULTED IN AN AXIS
OF 2500 MLCAPE FROM WRN AND S CNTRL IA SEWD THROUGH CNTRL AND SRN
IL. PLUME OF WARM AIR IN THE 850 MB TO 700 MB LAYER HAS ADVECTED
NEWD CONTRIBUTING TO A CAP. THIS LENDS UNCERTAINTY REGARDING WHEN
AND IF STORMS WILL INITIATE. MCV THAT ACCOMPANIED THE MORNING
CONVECTION HAS MOVED EWD INTO IL AND WI WITH TEMPORARY SUBSIDENCE IN
ITS WAKE. HOWEVER...ISENTROPIC LIFT ASSOCIATED WITH THE SWLY LOW
LEVEL JET INTERACTING WITH THE WARM FRONT AND INCREASING LARGE SCALE
ASCENT ASSOCIATED WITH SHORTWAVE TROUGH MOVING EWD THROUGH THE UPPER
MS VALLEY MAY ENHANCE POTENTIAL FOR INITIATION NEXT FEW HOURS. MOST
LIKELY AREAS FOR DEVELOPMENT INCLUDE NRN IA...SRN MN INTO SWRN WI ON
NRN EDGE OF THE STRONGER CAP. LOW LEVEL HODOGRAPHS AND FAVORABLE
DEEP LAYER SHEAR WILL SUPPORT THE POTENTIAL FOR SUPERCELLS
CONTAINING LOW LEVEL MESOCYCLONES WITH ANY SURFACE BASED STORMS NEAR
AND N OF THE WARM FRONT.

..DIAL.. 06/20/2006

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

ATTN...WFO...LOT...ILX...MKX...DVN...ARX...MPX...DMX...FSD...

40559021 41699280 42979626 44659285 42538929 40778898 

WWWW