MESO: Mesoscale Discussion 1515

ACUS11 KWNS 252024
SWOMCD
SPC MCD 252024
KSZ000-NEZ000-OKZ000-TXZ000-COZ000-NMZ000-252200-

MESOSCALE DISCUSSION 1515
NWS STORM PREDICTION CENTER NORMAN OK
0324 PM CDT THU JUL 25 2013

AREAS AFFECTED...PORTIONS CENTRAL/SWRN NEB...WRN/CENTRAL
KS...EXTREME SERN CO...OK PANHANDLE...EXTREME NERN NM...EXTREME NWRN
TX PANHANDLE.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 252024Z - 252200Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...SVR POTENTIAL FCST TO INCREASE OVER DISCUSSION AREA
THROUGH REMAINDER AFTN AS TSTMS DEVELOP AND GROW UPSCALE...MOVING
INTO DESTABILIZING INFLOW-LAYER AIR MASS. INITIAL THREAT WILL BE
BLEND OF DAMAGING GUSTS AND LARGE HAIL...TRANSITIONING MORE TOWARD
WIND WITH ANY COLD-POOL AGGREGATION AND FORWARD PROPAGATION.

DISCUSSION...SFC MESOANALYSIS SHOWS WEAK FRONTAL-WAVE LOW OVER SWRN
NEB NEAR LBF WITH OUTFLOW-REINFORCED FRONT EXTENDING SWWD ACROSS
NWRN KS TO JUST S LHX. FRONT SHOULD CONTINUE SEWD ABOUT 15
KT...SERVING AS FOCUS FOR TSTM FORMATION FROM CENTRAL NEB TO NWRN KS
AND ERN CO. COMBINED OUTFLOW/DIFFERENTIAL-HEATING BOUNDARY WAS
DRAWN FROM FRONTAL INTERSECTION NEAR GLD...SEWD ACROSS W-CENTRAL KS
TO PTT-ICT CORRIDOR. THIS BOUNDARY SHOULD REMAIN QUASISTATIONARY
OVER SRN KS...WHILE SLOWLY RETREATING NWD ACROSS WRN KS AS STG SFC
HEATING OCCURS ON BOTH SIDES. AIR MASS NE OF BOUNDARY IS MORE MOIST
AND HAS EXPERIENCED LESS VERTICAL MIXING...LEADING TO LOWER LCL AND
SOMEWHAT BACKED NEAR-SFC WINDS.
MEANWHILE...QUASISTATIONARY/PREFRONTAL SFC TROUGH WAS EVIDENT FROM
NEAR GLD SSWWD THROUGH WEAK LOW NEAR LAA...THEN SWWD OVER UNION
COUNTY NM. STRONGLY HEATED/MIXED AND SLIGHTLY CONVERGENT CONDITIONS
ALONG SERN CO/EXTREME NERN NM SEGMENT OF THIS BOUNDARY HAVE
CONTRIBUTED TO DEVELOPMENT OF LINE OF TSTMS THAT MAY OFFER EITHER
1. NONSUPERCELL TORNADO IN PRE OUTFLOW-DOMINANT STAGES...AMIDST
JUXTAPOSITION OF STG LOW-LEVEL CAPE/VORTICITY AND/OR
2. RELATIVELY SHORT-LIVED THREAT OF DAMAGING GUSTS.

BETTER-ORGANIZED THREAT MAY BE NEAR KS BOUNDARY. MODIFIED FCST
SOUNDINGS SUGGEST OVERLAP OF STRONGER HEATING ON SW SIDE AND HIGHER
MOISTURE CONTENT ON NE SIDE OFFSET MODEST MIDLEVEL LAPSE RATES
ENOUGH TO YIELD CORRIDOR OF 1500-2000 J/KG MLCAPE. VIS IMAGERY
SHOWS CUMULIFORM CONVECTION THICKENING HORIZONTALLY AND VERTICALLY
OVER NWRN KS...WHERE APCH OF MCV FROM NERN CO MAY BE CONTRIBUTING
LARGE-SCALE ASCENT. MCV ALSO MAY ENHANCE DEEP SHEAR ON MESO-BETA
SCALE BEYOND 30-35 KT EFFECTIVE SHEAR MAGNITUDES NOW EVIDENT IN
AMBIENT ENVIRONMENT. AS SUCH...BLEND OF MULTICELL AND SUPERCELL
STRUCTURES MAY OCCUR INITIALLY...FOLLOWED BY POTENTIAL FOR TSTMS TO
MERGE/GROW UPSCALE INTO WIND-DAMAGE PRODUCING MCS MOVING SSEWD TO
SEWD OVER REGION.

..EDWARDS/THOMPSON.. 07/25/2013

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

ATTN...WFO...ICT...GID...LBF...DDC...GLD...AMA...PUB...ABQ...

LAT...LON 37150281 37570242 39340176 41460057 42449868 41259828
39589945 38629835 37619861 35950305 36160391 37050288
37150281

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