SPC MD 1002

MD 1002 CONCERNING SEVERE THUNDERSTORM WATCH 289… FOR PORTIONS OF ERN NEB…SWRN IA…NWRN MO…NERN KS


MESOSCALE DISCUSSION 1002
NWS STORM PREDICTION CENTER NORMAN OK
0744 PM CDT SAT JUN 08 2013

AREAS AFFECTED...PORTIONS OF ERN NEB...SWRN IA...NWRN MO...NERN KS

CONCERNING...SEVERE THUNDERSTORM WATCH 289...

VALID 090044Z - 090245Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 289
CONTINUES.

SUMMARY...THE SVR POTENTIAL IS DECREASING ACROSS WW 289. ADDITIONAL
WW ISSUANCE WILL NOT BE NEEDED.

DISCUSSION...CONVECTIVE CLUSTERS HAVE OUTRUN STRONGER/DEEPER FORCING
FOR ASCENT WHILE ADVANCING INTO AN AIR MASS CHARACTERIZED BY ONLY
MARGINAL BUOYANCY...THOUGH AN ISOLATED STRONG/SVR WIND GUST AND/OR
BRIEF/WEAK TORNADO CANNOT BE RULED OUT. THE 00Z OAX RAOB REFLECTS
WEAK TROPOSPHERIC LAPSE RATES SUPPORTING ONLY AROUND 450 J/KG OF
MLCAPE. THIS SOUNDING IS LARGELY REPRESENTATIVE OF THE AIR MASS
ACROSS REMAINING VALID PORTIONS OF THE WW AREA S OF A STATIONARY
FRONT EXTENDING FROM E-CNTRL NEB INTO SWRN IA...AS WIDESPREAD
CONVECTION AND/OR CONVECTIVE DEBRIS ARE INHIBITING MAINTENANCE OF A
WARM BOUNDARY LAYER AMIDST ONLY MODESTLY FAVORABLE MOISTURE -- I.E.
LOWEST-100-MB MEAN MIXING RATIO AROUND 12 G/KG PER OAX 00Z RAOB.
EVEN LESS BUOYANCY EXISTS FOR MIXED-LAYER PARCELS N OF THE
STATIONARY FRONT. AND...WITH NOCTURNAL COOLING/STABILIZATION
COMMENCING SHORTLY...CONVECTION SHOULD ONLY YIELD AN ADDITIONAL
DOWNWARD TREND IN INTENSITY. DESPITE SIZABLE...LOOPING LOW-LEVEL
HODOGRAPHS INVOF THE STATIONARY FRONT SUPPORTING SUBSTANTIAL 0-1-KM
SRH PER THE 00Z OAX RAOB -- WITH SOMEWHAT LOWER SRH IN THE MORE
VEERED SFC FLOW TO THE SOUTH -- THE THERMODYNAMIC PROFILES WILL
NOTABLY OFFSET THE SVR POTENTIAL.

THE SVR THREAT HAS ENDED BEHIND THE BACK EDGE OF ONGOING CONVECTION
OWING TO CONVECTIVE OVERTURNING...AND THE WW MAY BE CLEARED BEHIND
THIS CONVECTION PRIOR TO THE SCHEDULED 0400 UTC WW EXPIRATION TIME.
FURTHERMORE...ADDITIONAL/DOWNSTREAM WW ISSUANCE WILL NOT BE NEEDED.

..COHEN.. 06/09/2013

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

ATTN...WFO...DMX...EAX...OAX...TOP...

LAT...LON   41789612 41789453 40959399 39869451 39049575 38839716
            39409764 41789612

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1002.html