SPC MD 1362

MD 1362 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS NRN KS…SRN NEB.


MESOSCALE DISCUSSION 1362
NWS STORM PREDICTION CENTER NORMAN OK
0608 PM CDT TUE JUL 09 2013

AREAS AFFECTED...PORTIONS NRN KS...SRN NEB.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 092308Z - 100115Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...INITIALLY SEPARATE AREAS OF STG-SVR TSTMS OVER NERN KS AND
S-CENTRAL NEB ARE OCCURRING IN DIFFERENT ENVIRONMENTS...BUT MAY
MERGE WITH CONDITIONAL POTENTIAL FOR DAMAGING GUSTS DOWNSHEAR ACROSS
N-CENTRAL/NERN KS AND S-CENTRAL/SERN NEB.

DISCUSSION...SFC MESOANALYSIS SHOWED WEAK/HEAT-AIDED SFC LOW NEAR
RSL...WITH TROUGH SWWD ACROSS SWRN KS NEAR GCK AND NEWD OVER SERN
NEB NEAR BIE.  SLOW-MOVING COLD FRONT EXTENDED FROM CENTRAL IA SWWD
ACROSS LNK AREA THEN WWD THROUGH WEAK FRONTAL WAVE INVOF LBF AND
INTO NERN CO.  FRONT SHOULD CONTINUE TO MOVE SLOWLY SEWD THROUGH
EVENING...WITH SOMEWHAT LESS WELL-MIXED BOUNDARY LAYER AND HIGHER
SFC DEW POINTS TO ITS IMMEDIATE N.  IN THAT ENVIRONMENT...STG-SVR
TSTM QUICKLY DEVELOPED N LXN...YIELDING REPORT OF 1.75 INCH HAIL AND
BRIEF TORNADO AROUND 2217Z...WHILE NONSUPERCELL CHARACTER WAS
EVIDENT EARLY IN ITS LIFESPAN.  THIS ACTIVITY CURRENTLY RESIDES IN
SMALL AREA WHERE OBJECTIVE ANALYSES SHOW MAXIMA IN SFC VORTICITY AND
0-3 KM AGL CAPE JUXTAPOSED INVOF FRONT.  HOWEVER...FAVORABLE DEEP
SHEAR -- E.G. 40-50 KT EFFECTIVE SHEAR MAGNITUDES INDICATED BY
MODIFIED MODEL SOUNDINGS -- INDICATES SOME POTENTIAL FOR THIS OR
OTHER CONVECTION OVER THIS AREA TO BECOME SUPERCELLULAR...WITH
RELATED ENHANCEMENT TO LARGE HAIL RISK.  SUPERCELL TORNADO POTENTIAL
IS MUCH MORE MRGL/CONDITIONAL BECAUSE OF WEAK LOW-LEVEL WINDS
LIMITING HODOGRAPH SIZE...AND RELATED LACK OF SUBSTANTIAL SRH.
INSTEAD...CONCERN IS THAT THIS ACTIVITY MAY INCREASE IN COVERAGE
INVOF 2500-3500 J/KG MLCAPE AXIS THAT EXTENDS EWD ACROSS
S-CENTRAL/SERN NEB...POSSIBLY ORGANIZING UPSCALE AND MERGING WITH
INITIALLY SEPARATE NWRN KS CONVECTION.

LATTER TSTMS ARE OCCURRING IN MUCH HOTTER/MORE DEEPLY MIXED
ENVIRONMENT WITH WEAKER VERTICAL SHEAR.  AS SUCH...KS CONVECTION HAS
MORE POTENTIAL FOR SHORT-FUSED PRODUCTION OF STG-SVR OUTFLOW
POOLS...BUT ALSO...GUST FRONTS MOVING QUICKLY AWAY FROM ORIGINATING
CONVECTION.  IN BETWEEN THESE TWO AREAS...MODIFIED RAOBS AND FCST
SOUNDINGS SUGGEST RELATIVE MAX IN MLCINH...CASTING FURTHER
UNCERTAINTY ON EVOLUTION OF CONVECTION ACROSS THIS REGION INTO EARLY
EVENING.  HOWEVER...WW MAY BE REQUIRED IF CONVECTIVE TRENDS INDICATE
LIKELIHOOD FOR UPSCALE GROWTH INTO FORWARD-PROPAGATING MCS WITH
FORCED ASCENT AND ENHANCED WIND-DAMAGE THREAT...AS INDICATED BY SOME
HIGH-RES MODELS.

..EDWARDS/GOSS.. 07/09/2013

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

ATTN...WFO...OAX...TOP...ICT...GID...LBF...DDC...GLD...

LAT...LON   38319847 38430006 39160081 41000003 41129921 41049613
            39919583 38519619 38319847

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