[MCD] SWOMCD

Wed Apr 20 00:12:12 UTC 2005

ACUS11 KWNS 200021
SWOMCD
SPC MCD 200021 
NEZ000-KSZ000-COZ000-SDZ000-WYZ000-200215-

MESOSCALE DISCUSSION 0599
NWS STORM PREDICTION CENTER NORMAN OK
0721 PM CDT TUE APR 19 2005

AREAS AFFECTED...PORTIONS ERN NEB...NERN CO...SERN WY

CONCERNING...SEVERE THUNDERSTORM WATCH 163...

VALID 200021Z - 200215Z

CONTINUE WW.  SFC MESOANALYSIS SHOWS SEVERAL CRITICAL
BOUNDARIES...BEGINNING WITH POLAR FRONT FROM S-CENTRAL SD SWWD
ACROSS WRN CHERRY COUNTY NEB...TO NEAR SNY...THEN WSWWD ACROSS
EXTREME N-CENTRAL CO.  THIS FRONT SEPARATES SFC-BASED PARCELS TO ITS
S FROM COLD/STABLE BOUNDARY LAYER TO ITS N...AND SHOULD MOVE SLOWLY
SSEWD...AIDED BY EFFECTS OF CONVECTIVE OUTFLOWS FROM STRONG-SEVERE
TSTMS ONGOING ALONG AND JUST N OF IT OVER NEB AND S OF CYS.  DENSE
CLUSTER OF SEVERE TSTMS WITH EMBEDDED SUPERCELLS -- NOW EVIDENT
ALONG THAT FRONT BETWEEN CHERRY COUNTY AND SNY...PRODUCED 2.5 INCH
HAIL JUST BEFORE 00Z.  DAMAGING HAIL/GUST POTENTIAL WILL
CONTINUE...AND A TORNADO CANNOT BE RULED OUT GIVEN FAVORABLE STORM
INTERACTIONS AND AMBIENT SHEAR FOR SUPERCELLS.

SECOND FRONTAL ZONE EXTENDS AS WARM FRONT FROM SFC LOW E OF
PUB...NEWD TO NEAR OGA...THEN ENEWD TOWARD OLU.  THIS DEMARCATES 
SOMEWHAT WARMER/MORE DEEPLY MIXED AND HIGHER LCL AIR TO ITS S. 
PRONOUNCED ELY/UPSLOPE COMPONENT OF BOUNDARY LAYER FLOW BETWEEN
FRONTS HAS INITIATED/SUPPORTED SCATTERED STRONG-SEVERE STORMS
BETWEEN DEN-LIC.  ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG OUTFLOWS
PRODUCED BY THAT ACTIVITY FOR ANOTHER COUPLE HOURS...BEFORE AIR MASS
BEGINS STABILIZING FROM CUMULATIVE EFFECTS OF OUTFLOWS AND DIABATIC
COOLING.  PRECONVECTIVE AIR MASS BETWEEN FRONTS REMAINS
CHARACTERIZED BY 1000-2000 J/KG MLCAPE BASED ON COMBINATION OF 00Z
LBF RAOB...AND 00Z DEN RAOB MODIFIED TO REMOVE SPURIOUS DEW POINT
NEAR 800 MB.  VERY STRONG DIRECTIONAL SHEAR RESULTS IN 300-400 J/KG
SRH IN 0-3 KM AGL LAYER.

OCCASIONAL LARGE HAIL POSSIBLE FROM SCATTERED TSTMS N OF NRN FRONTAL
BOUNDARY AS WELL...ACROSS SERN WY AND WRN NEB PANHANDLE...SUPPORTED
BY 30-40 KT EFFECTIVE LAYER SHEAR AND ELEVATED MUCAPES 500-1000
J/KG.

..EDWARDS.. 04/20/2005

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

ATTN...WFO...LBF...UNR...GLD...PUB...BOU...CYS...

42860212 42879917 39130268 39090554 39680505 40120489
40580493 40810507 41000524 41200546 41500567 41730567
42140548 42610497 42850439 43000398 43030371 42940252 

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