[MCD] SWOMCD

Sun Aug 6 00:35:12 UTC 2006

ACUS11 KWNS 060036
SWOMCD
SPC MCD 060035 
MNZ000-SDZ000-NDZ000-060130-

MESOSCALE DISCUSSION 1752
NWS STORM PREDICTION CENTER NORMAN OK
0735 PM CDT SAT AUG 05 2006

AREAS AFFECTED...ERN ND/NRN AND WRN MN/ERN SD

CONCERNING...SEVERE THUNDERSTORM WATCH 686...

VALID 060035Z - 060130Z

THREAT FOR SEVERE STORMS CONTINUES ACROSS VALID PART OF WW 686
THROUGH AT LEAST 02Z.  NEW WW MAY BE REQUIRED ACROSS PARTS OF WEST
CENTRAL MN/ERN SD IN THE NEXT 1-2 HOURS.

EARLY EVENING SURFACE ANALYSIS COMBINED WITH REGIONAL RADAR IMAGERY
SHOWED A COLD FRONT ADVANCING EWD INTO NWRN MN AND SERN ND...AND
OVERTAKING THE PRE-FRONTAL TROUGH ACROSS THESE AREAS.  AS THE COLD
FRONT MERGES WITH THE TROUGH...FORCING FOR ASCENT APPEARS TO BECOME
STRONGER ALLOWING FOR MORE ROBUST UPDRAFTS AS HAS OCCURRED ACROSS
NWRN MN /ROSEAU COUNTY/ AND OVER SERN ND /RANSOM AND RICHLAND
COUNTIES/ DURING LAST 1-2 HOURS.  WATER VAPOR IMAGERY INDICATED A
VIGOROUS SHORT WAVE TROUGH...NOW LOCATED OVER SOUTH CENTRAL
CANADA...WITH A 60-70 KT WSWLY MID LEVEL JET OVER ND INTO NWRN MN. 
ASCENT SPREADING EWD ALONG LEADING EDGE OF THIS UPPER TROUGH WILL
SUPPORT ADDITIONAL THUNDERSTORMS AS THE COLD FRONT PROGRESSES EWD
INTO NRN AND WEST CENTRAL MN TO NERN SD THIS EVENING.  

AIR MASS REMAINS MODERATELY UNSTABLE ALONG/E OF THE COLD FRONT WITH
EFFECTIVE BULK SHEAR VALUES UP TO 55 KT RESULTING IN FAVORABLE
ENVIRONMENT FOR STORM ORGANIZATION.  STRONGEST LOW LEVEL SHEAR FOR A
TORNADO POTENTIAL REMAINS ACROSS NWRN MN AS INDICATED BY THE 00Z
SOUNDING AT INL WITH SFC-3 KM SRH EXCEEDING 240 M2/S2.

ALTHOUGH FORCING FOR ASCENT AHEAD OF THE UPPER TROUGH DECREASES WITH
SWD EXTENT INTO SD AND PARTS OF WEST CENTRAL MN...STRONGER
INSTABILITY MAY COMPENSATE ALLOWING THUNDERSTORMS TO CONTINUE
DEVELOPING SWD ALONG THE COLD FRONT.  EFFECTIVE BULK SHEAR VALUES
ARE SUPPORTIVE ACROSS SD INTO CENTRAL/SRN MN FOR ORGANIZED STORMS.
FARTHER E ACROSS NERN MN...AIR MASS IS MORE STABLE WHICH SUGGESTS
EWD EXTENT FOR SEVERE STORMS SHOULD BE LIMITED WITH GREATER
POTENTIAL FOR A NEW WW SWD ACROSS PARTS OF WEST CENTRAL MN AND ERN
SD.

..PETERS.. 08/06/2006

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

ATTN...WFO...DLH...MPX...FGF...ABR...BIS...

45269876 46549734 48319587 48969576 48949401 48549348
46539403 45359472 44929632 44959816 44909867 

WWWW