SPC MD 1629

MD 1629 CONCERNING SEVERE THUNDERSTORM WATCH 468… FOR PORTIONS WRN/SRN KS…SRN NEB…EXTREME NRN OK.


MESOSCALE DISCUSSION 1629
NWS STORM PREDICTION CENTER NORMAN OK
0608 PM CDT MON AUG 05 2013

AREAS AFFECTED...PORTIONS WRN/SRN KS...SRN NEB...EXTREME NRN OK.

CONCERNING...SEVERE THUNDERSTORM WATCH 468...

VALID 052308Z - 060045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 468
CONTINUES.

SUMMARY...WW MAY BE REPLACED TO ACCOMMODATE SEWD SHIFT IN SVR THREAT
ACROSS MAINLY KS...IN STEP WITH SVR TSTM CLUSTER MOVING SSEWD ACROSS
EXISTING WW 468 AND ADDITIONAL ACTIVITY DEVELOPING ALONG FRONT NEAR
KS/OK BORDER.

DISCUSSION...SFC MESOANALYSIS SHOWS LARGE/ROUGHLY SEMICIRCULAR
OUTFLOW POOL EMANATING FROM ORIGINAL LOCUS OF NWRN KS CONVECTION.
ASSOCIATED  BOUNDARY WAS DRAWN AT 23Z FROM EXISTING TSTM CLUSTER
OVER NESS/LANE COUNTIES THROUGH FINNEY/HAMILTON COUNTIES...THEN
ACROSS E-CENTRAL/NERN CO...BACK NEWD OVER IML AREA TO SRN LINCOLN
COUNTY NEB.  WITH SFC DEW POINTS 70S F...MLCAPE 2500-3500 J/KG AND
35-40 KT EFFECTIVE SHEAR MAGNITUDES IN PRECONVECTIVE/PRE-OUTFLOW
ENVIRONMENT OVER SWRN NEB...ISOLATED SVR HAIL/GUSTS ARE PSBL FROM
TSTMS ERUPTING ALONG NEB SEGMENT OF BOUNDARY...BEFORE THAT ACTIVITY
IS UNDERCUT BY OUTFLOW.  ADDITIONAL WW IS NOT ANTICIPATED ATTM OVER
THAT AREA DUE TO MORE DISORGANIZED/SHORTER-DURATION NATURE OF SVR
THREAT.

HOWEVER...CONVECTION WITH WELL-DEVELOPED COLD POOL OVER WRN KS
SHOULD CONTINUE TO MOVE SEWD INTO RICHLY MOIST/UNSTABLE AIR LOCATED
N OF SFC WARM FRONT THAT WAS ANALYZED NEAR OK BORDER.  S OF THAT
FRONT...HOT/DEEPLY MIXED AIR MAY SUPPORT SVR GUST POTENTIAL WITH ANY
CONVECTION MOVING SEWD INTO THAT AIR MASS.  UPSCALE EXPANSION OF
WARM-FRONTAL CONVECTION MAY MERGE WITH WRN KS TSTM COMPLEX DURING
01Z-03Z TIME FRAME OVER S-CENTRAL KS...ENLARGING MCS AND FURTHER
REINFORCING ITS COLD POOL FOR FORCED ASCENT OF HIGH-THETAE AIR TO
ITS E...OVER S-CENTRAL/SERN KS AND NERN OK.  GIVEN THIS
POTENTIAL...AND STABILIZATION OF MUCH OF NWRN KS FOR SFC-BASED
PARCELS CAUSED BY COLD POOL...ADDITIONAL WW IS BEING CONSIDERED THAT
WOULD INCLUDE MORE OF CENTRAL/SRN KS AND PERHAPS EXTREME NRN
OK...POSSIBLY AS REPLACEMENT FOR WW 468.

..EDWARDS.. 08/05/2013

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

ATTN...WFO...TSA...ICT...OUN...GID...LBF...DDC...GLD...AMA...

LAT...LON   36469721 36659887 37130053 39160179 40580104 41479950
            41089823 40249994 39269938 38459768 38019650 36809623
            36469721

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1629.html