[MCD] SWOMCD

Mon Jul 31 00:08:19 UTC 2006

ACUS11 KWNS 310010
SWOMCD
SPC MCD 310009 
NDZ000-MTZ000-310145-

MESOSCALE DISCUSSION 1680
NWS STORM PREDICTION CENTER NORMAN OK
0709 PM CDT SUN JUL 30 2006

AREAS AFFECTED...PORTIONS NERN MT...NWRN ND.

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 310009Z - 310145Z

CAP HAS BROKEN ACROSS NERN MT N-NE OF OLF...WITH RAPID TSTM
DEVELOPMENT/INTENSIFICATION UNDERWAY AS OF 2350Z.  POTENTIAL EXISTS
FOR LARGE HAIL AND SVR GUSTS WITH THIS ACTIVITY...SOME OF WHICH MAY
REMAIN S OF CANADIAN BORDER AND MOVE INTO NWRN ND.  AREA WILL BE
MONITORED FOR POSSIBLE WW...ALTHOUGH AREA OF CONUS AFFECTED WOULD BE
RELATIVELY SMALL.

SFC DATA AND GGW LOW-DBZ REFLECTIVITIES INDICATE QUASISTATIONARY AND
NE-SW ORIENTED CONVERGENCE BAND FROM SERN VALLEY COUNTY NEWD ACROSS
WRN SHERIDAN COUNTY MT.  ALTHOUGH LOW LEVEL HODOGRAPHS ARE SMALL
GIVEN VERY LIGHT/NELY FLOW OVER MUCH OF THIS AREA...VERTICAL SHEAR
PROFILES IN PROSPECTIVE INFLOW REGION ARE FAVORABLE FOR SOME
SUPERCELL AND BOW STRUCTURES WITH 55-65 KT EFFECTIVE SHEAR
INDICATED.  DEVIANT RIGHTWARD MOTIONS FOR MATURE STORMS WOULD
MAINTAIN THREAT OVER NARROW AREA JUST S OF CANADIAN BORDER INTO NWRN
ND...THOUGH SOME POTENTIAL ALSO EXISTS FOR ACTIVITY TO CROSS INTO
CANADA BEFORE SUCH RIGHTWARD TURN.  AIR MASS WILL REMAIN FAVORABLY
BUOYANT...AS SFC DEW POINTS AND MLCAPES EACH INCREASE WITH EWD
EXTENT TO OFFSET EFFECTS OF WEAKENING DIABATIC HEATING.  MLCAPES
AROUND 2000 J/KG ARE EVIDENT BASED ON MODIFIED POINT SOUNDINGS FROM
RUC MODEL.  ALTHOUGH THIS AREA IS POLEWARD OF SFC FRONT...EFFECTIVE
PARCELS STILL WILL REMAIN SFC-BASED FOR A FEW MORE HOURS WITH
WELL-MIXED SUBCLOUD LAYERS SUPPORTING MAINTENANCE OF GUSTS/HAIL TO
SFC.

..EDWARDS.. 07/31/2006

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

ATTN...WFO...BIS...GGW...

48990134 48510218 48220355 48240473 48450565 49010442 

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