[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 220216
SWOMCD
SPC MCD 220216 
NDZ000-SDZ000-220345-

MESOSCALE DISCUSSION 1821
NWS STORM PREDICTION CENTER NORMAN OK
0916 PM CDT THU JUL 21 2005

AREAS AFFECTED...PORTIONS WRN/CNTRL ND INTO WRN SD

CONCERNING...SEVERE THUNDERSTORM WATCH 657...658...

VALID 220216Z - 220345Z

THROUGH 04Z...GREATEST THREAT OF LARGE HAIL AND DAMAGING WINDS WILL
EXIST ACROSS CNTRL AND POSSIBLY SRN PORTIONS OF WW 658.

AS OF 0205Z...RAP RADAR IMAGERY SHOWED AN INTENSE TSTM CLUSTER WITH
AT LEAST ONE EMBEDDED SUPERCELL OVER SERN MEADE...NERN
PENNINGTON...SRN ZIEBACH AND NRN HAAKON COUNTIES MOVING 330/30-35
KTS. IT APPEARS THAT ASSOCIATED GUST FRONT HAS STARTED TO SURGE
AHEAD OF PARENT STORMS...AT LEAST ALONG WRN PORTION OF COMPLEX.
INFLOW AIR MASS REMAINS WARM AND MOIST...SUGGESTING THAT CAP LIKELY
HAS NOT STRENGTHENED TOO SIGNIFICANTLY. THEREFORE...IT APPEARS THAT
PRIMARY FAILURE MODE OF SYSTEM WOULD BE IF GUST FRONT CONTINUES TO
OUTRUN STORM CLUSTER. GIVEN THE EMBEDDED SUPERCELL STRUCTURES...HAIL
TO GOLFBALL SIZE OR LARGER IN ADDITION TO DAMAGING WINDS WILL REMAIN
POSSIBLE WITH COMPLEX AS IT MOVES ACROSS I-90.

FARTHER TO THE N...SEVERAL LEFT-MOVING SUPERCELLS HAVE BEEN OBSERVED
THIS EVENING ALONG OUTFLOW BOUNDARIES ORIGINATING FROM EARLIER
CONVECTION. CURRENTLY...THE MOST INTENSE STORM IS LEFT-MOVING
SUPERCELL OVER SRN SHERIDAN COUNTY ND WHICH IS CAPABLE OF LARGE
HAIL. AIR MASS ACROSS ND PORTION OF WW 657 HAS COOLED INTO THE
70S...LARGELY AS A RESULT OF CONVECTIVE OUTFLOW. ISOLATED LARGE HAIL
WILL REMAIN POSSIBLE WITH MOST INTENSE STORMS LIKELY SLIGHTLY
ELEVATED ABOVE STABILIZING BOUNDARY-LAYER. OVERALL SEVERE WEATHER
THREAT IS EXPECTED TO SLOWLY DIMINISH THROUGH 04Z.

..MEAD.. 07/22/2005

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

ATTN...WFO...FGF...ABR...BIS...UNR...

47660237 47659917 45100009 45140045 43570048 43610294
45150295 45160325 

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