[MCD] SWOMCD

Wed Aug 16 23:20:12 UTC 2006

ACUS11 KWNS 162321
SWOMCD
SPC MCD 162321 
MNZ000-SDZ000-NDZ000-170045-

MESOSCALE DISCUSSION 1825
NWS STORM PREDICTION CENTER NORMAN OK
0621 PM CDT WED AUG 16 2006

AREAS AFFECTED...NERN SD...ERN ND AND NWRN MN

CONCERNING...SEVERE THUNDERSTORM WATCH 724...

VALID 162321Z - 170045Z

WATER VAPOR IMAGERY SHOWS THAT THE LEAD MID-LEVEL SHORTWAVE TROUGH
AXIS WAS MOVING ENEWD ACROSS THE RED RIVER VLY THIS EVE.  FORCING
FOR ASCENT ASSOCD WITH THIS IMPULSE AND HEATING CONTRIBUTED TO
WEAKENING CINH TO SUPPORT SCT TSTMS ALONG THE NE-SW ORIENTED SFC
TROUGH SITUATED ACROSS NWRN MN SWWD TO NCNTRL SD.  THE GRAND FORKS
VWP SHOWED 35-40 KT OF MID-LEVEL FLOW ATOP SSELY BOUNDARY LAYER
WINDS OF 15-20 KTS.  THIS WAS BOOSTING VERTICAL SHEAR TO VALUES
SUFFICIENT FOR SUPERCELLS AND GIVEN THE STEEP LAPSE RATES OF 7.5 DEG
C/KM... LARGE HAIL WILL BE THE PRIMARY THREAT INITIALLY ALONG WITH
DAMAGING WIND GUSTS.  AN ISOLD TORNADO IS ALSO POSSIBLE THROUGH
EARLY THIS EVE...PRIMARILY ACROSS SERN ND...WHERE THE LOW-LEVEL FLOW
WAS LOCALLY BACKED INVOF A WEAK SFC LOW.  

THE STRONGEST LOW-LEVEL FLOW SHOULD TRANSLATE QUICKLY NEWD IN TANDEM
WITH THE UPPER WAVE LATER THIS EVENING...LESSENING THE OVERALL
LOW-LEVEL SHEAR.  THE WEAKER SHEAR COMBINED WITH NOCTURNAL BOUNDARY
LAYER COOLING AND INCREASED RIDGING ALOFT DOWNSTREAM FROM THE MT
WAVE SHOULD STRENGTHEN INHIBITION AND LESSEN THE SEVERE RISKS IN THE
03-06Z TIME FRAME.  TSTMS WILL CONTINUE TO TRANSLATE ENEWD ACROSS
NWRN MN INTO NWRN ONTARIO THROUGH THE OVERNIGHT HOURS.

..RACY.. 08/16/2006

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

ATTN...WFO...FGF...FSD...ABR...BIS...

44659938 45059983 46599952 48239820 49569622 49979464
48419495 47029606 45489730 44579805 

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