[MCD] SWOMCD

Tue May 23 22:42:54 UTC 2006

ACUS11 KWNS 232240
SWOMCD
SPC MCD 232240 
MNZ000-IAZ000-NEZ000-SDZ000-240045-

MESOSCALE DISCUSSION 0955
NWS STORM PREDICTION CENTER NORMAN OK
0540 PM CDT TUE MAY 23 2006

AREAS AFFECTED...PORTIONS CENTRAL/ERN SD...CENTRAL-ERN NEB...SWRN
MN...EXTREME WRN IA.

CONCERNING...TORNADO WATCH 380...

VALID 232240Z - 240045Z

CONTINUE WW ALONG/AHEAD OF PRIMARY CONVECTIVE BAND...WHICH AT 2220Z
WAS INDICATED NEAR A LINE FROM ABR...50 S ONL...EAR.  WLY BOUNDARY
LAYER WINDS AND DRYING ASSOCIATED WITH COMBINED DRYLINE/FRONT SHOULD
REDUCE INSTABILITY...SHEAR AND CONVERGENCE W OF THIS
ACTIVITY....MARKEDLY DIMINISHING SVR POTENTIAL. ANOTHER WW MAY BE
REQUIRED WITHIN NEXT COUPLE HOURS...E OF THIS ONE ACROSS PORTIONS
IA/MN AND/OR REMAINDER ERN NEB.

TORNADO POTENTIAL MAY INCREASE LATER THIS EVENING ONCE DEW POINT
DEPRESSIONS DROP...WHEN EFFECTIVE PARCELS STILL ARE BASED AT SFC. 
IN MEANTIME...MAIN THREAT NEXT 1-2 HOURS IS SEVERE DOWNDRAFT
WIND...GIVEN LARGE SFC DEW POINT DEPRESSIONS IN INFLOW LAYER AND
DEEPLY HEATED/MIXED SUBCLOUD PROFILES. HAIL THREAT OF CONSEQUENCE
SHOULD BE ASSOCIATED WITH ANY EMBEDDED SUPERCELLS.  MODIFIED 18Z OMA
RAOB AND RUC FCST SOUNDINGS INDICATE MLCAPES INCREASING TO AROUND
1500 J/KG NEAR ERN EDGE OF WW IN ASSOCIATION WITH SOMEWHAT MORE
ROBUST SFC MOISTURE.  VERTICAL SHEAR PROFILES ARE STRENGTHENING FROM
W-E ACROSS PRE CONVECTIVE AIR MASS AND WILL FAVOR BOTH BOW ECHO AND
SUPERCELL PROCESSES.  ANY SUSTAINED SUPERCELLS EMBEDDED IN LINE WILL
HAVE POTENTIAL TO BECOME SOMEWHAT OUTFLOW DOMINANT AND EVOLVE INTO
LEWPS/BOWS.  STRONGEST PRESSURE FALLS THIS HOUR EXTEND FROM NERN NEB
NWD THROUGH ERN SD...AND SHOULD SHIFT NEWD ACROSS WW
AREA....INDICATING POTENTIAL FOR BACKED SFC WINDS AND ENLARGED LOW
LEVEL HODOGRAPHS NOW OVER NERN NEB TO SHIFT/EXPAND OVER MORE OF ERN
SD.  EXPECT EFFECTIVE SHEARS STRENGTHENING TO 40-50 KT AHEAD OF
TSTMS...AND 200-300 J/KG SRH IN 0-3 KM LAYER FROM NERN NEB INTO ERN
SD.

..EDWARDS.. 05/23/2006

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

ATTN...WFO...MPX...FSD...OAX...ABR...GID...LBF...

40939916 42439863 43949841 44789885 45839846 45559655
42949594 41089681 