[MCD] SWOMCD

Tue Apr 18 00:36:03 UTC 2006

ACUS11 KWNS 180033
SWOMCD
SPC MCD 180033 
NDZ000-SDZ000-MTZ000-WYZ000-180200-

MESOSCALE DISCUSSION 0540
NWS STORM PREDICTION CENTER NORMAN OK
0733 PM CDT MON APR 17 2006

AREAS AFFECTED...PORTIONS EXTREME NERN WY...WRN SD...SWRN ND

CONCERNING...SEVERE THUNDERSTORM WATCH 198...

VALID 180033Z - 180200Z

BAND OF SEVERE TSTMS WILL MOVE NEWD FROM HARDING COUNTY SD INTO
BOWMAN COUNTY ND WITHIN NEXT HOUR...WITH POTENTIAL FOR SEVERE
HAIL/GUSTS.  ADDITIONAL/ISOLATED TSTMS ARE MOVING NWD INTO SRN
HARDING COUNTY AND DEVELOPING FARTHER SW INVOF SD/WY BORDER. 
MIDLEVEL CONVECTION OVER ERN WY IS ASSOCIATED WITH BAND OF ENHANCED
LARGE SCALE ASCENT MOVING EWD AHEAD OF INTENSE NRN ROCKIES/NRN GREAT
BASIN TROUGH ALOFT.  THIS ACTIVITY IS CHARACTERIZED BY INCREASING CG
LIGHTNING...BUILDING REFLECTIVITIES...AND COOLING IR CLOUD TOPS. 
BOUNDARY LAYER ACROSS SRN PORTIONS WW...AND REMAINDER SWRN
SD...REMAINS RELATIVELY DRY WITH SFC DEW POINTS MID 40S ON PLAINS
AND 30S IN BLACK HILLS.  HOWEVER...MOIST ADVECTION AND STRENGTHENING
LLJ MAY RESULT IN SOME OF THIS ACTIVITY BECOMING ROOTED NEAR SFC. 
MODIFIED 00Z RAP RAOB AND RUC SOUNDINGS INDICATE WELL MIXED SUBCLOUD
LAYER CONDUCIVE TO MAINTAINING SEVERE DOWNDRAFTS AND HAIL TO
SFC...IN FAVORABLE VERTICAL SHEAR PROFILES FOR BOTH SUPERCELLS AND
BOW FORMATIONS.

53 KT GUST AND THREE REPORTS OF .75-1.75 INCH HAIL HAVE BEEN
RECEIVED COMBINED AS OF 0030Z...OVER HARDING/BOWMAN COUNTIES.  THIS
REPRESENTS STRONG CLIMATOLOGICAL ANOMALY. SPC SEVERE DATABASE
INDICATES THESE ARE FIRST RECORDED APRIL SEVERE EVENTS IN THEIR
COUNTIES...AND HALF THE TOTAL OF EIGHT APRIL REPORTS FOR ALL
COUNTIES IN WW...SINCE RECORDS BEGAN IN 1950.

..EDWARDS.. 04/18/2006

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

ATTN...WFO...BIS...UNR...BYZ...

44160252 44180435 47050357 47060168 

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