[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 202337
SWOMCD
SPC MCD 202336 
SDZ000-NEZ000-210100-

MESOSCALE DISCUSSION 0940
NWS STORM PREDICTION CENTER NORMAN OK
0636 PM CDT FRI MAY 20 2005

AREAS AFFECTED...SCENTRAL/CENTRAL SD...FAR NCENTRAL NEB

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 202336Z - 210100Z

ISOLATED STG/SVR STORM OVER TODD COUNTY WILL MOVE SLOWLY ENEWD OVER
THE NEXT 2 HOURS. ADDITIONAL ISOLATED SVR STORMS MAY DEVELOP OVER
SCENTRAL SD. TRENDS WILL CONTINUE TO BE MONITORED...BUT IF SEVERAL
STORMS CAN ORGANIZE INTO A CLUSTER IN THE NEXT 2-4 HOURS...THEN
INCREASING LOW LEVEL JET WOULD SUPPORT A LONGER LIVED SEVERE THREAT
AND THE NEED FOR A WW.

SFC ANALYSIS INDICATES SFC PRESSURE FALL/INSTABILITY AXIS EXTENDING
FROM CENTRAL SD SWD INTO NCENTRAL NEB. WEAKENING INHIBITION AND
SUSTAINED CONVERGENCE ALONG NW-SE ORIENTED SFC PRESSURE TROUGH OVER
SCENTRAL SD/NWRN NEB HAS SUPPORTED ISOLATED STORM DEVELOPMENT IN THE
LAST HOUR. MERRIMAN PROFILER SHOWS MODERATE /40 KT/ WLY MID LEVEL
FLOW ABOVE BACKED LOW LEVEL FLOW. THE COMBINATION OF MODERATE DEEP
LAYER SHEAR/INSTABILITY OF AROUND  2000 J/KG OF MUCAPE...WILL
SUPPORT AT LEAST AN ISOLATED SVR THREAT WITH ANY STORM OVER THE AREA
INTO THE EVENING HOURS. LACK OF LARGER SCALE LIFT IN THE MID LEVELS
SUGGESTS THAT CONVECTION MAY DISSIPATE SHORTLY AFTER SUNSET /02Z/.
HOWEVER...IF CONVECTION CAN SUSTAIN ITSELF BEYOND THAT TIME
FRAME...THEN AN INCREASING LOW LEVEL JET MAY BE SUFFICIENT FOR A
GREATER ORGANIZED SVR THREAT IF MORE THAN ONE STORM DEVELOPS. TRENDS
WILL CONTINUE TO BE MONITORED FOR THIS POSSIBILITY AND THE NEED FOR
A WW AFTER 01Z.

..CROSBIE.. 05/20/2005

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

ATTN...WFO...FSD...ABR...LBF...UNR...

43009921 43939936 44560006 44720094 44450157 43730203
43280200 42850169 42590074 42709981