Oct 13, 2012 0600 UTC Day 1 Convective Outlook | |
Updated: Sat Oct 13 05:35:32 UTC 2012 | |
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic |
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Probabilistic Tornado Graphic |
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
Probabilistic Damaging Wind Graphic |
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
Probabilistic Large Hail Graphic |
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
SPC AC 130532 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1232 AM CDT SAT OCT 13 2012 VALID 131200Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS SRN/CENTRAL PLAINS TO PORTIONS UPPER MS VALLEY REGION... ...SYNOPSIS... SPLIT-FLOW PATTERN NOW OVER WRN CONUS IS FCST TO DEAMPLIFY THROUGH PERIOD. WELL-DEFINED MID-UPPER LEVEL CYCLONE -- INITIALLY OVER ERN UT/WRN CO REGION -- IS FCST TO MOVE ENEWD ACROSS CO BY START OF PERIOD...DEVOLVING TO OPEN-WAVE TROUGH AS IT CROSSES CENTRAL PLAINS. BY 14/00Z...EXPECT HIGH-AMPLITUDE SHORTWAVE TROUGH WITH SLGT POSITIVE TILT...FROM S-CENTRAL/SERN NEB ACROSS WRN KS...TX PANHANDLE...AND TX SOUTH-PLAINS REGION. THIS PERTURBATION WILL BECOME MORE NEUTRALLY TILTED WITH TIME THEREAFTER...BUT ALSO...WILL LINK WITH NRN-STREAM FLOW BELT AND DEAMPLIFY. TROUGH SHOULD BE CROSSING WRN OZARKS...WRN MO...AND IA BY 14/12Z. AT SFC...PAC COLD FRONT IS FCST TO MOVE EWD OUT OF ROCKIES...WITH ATTACHED FRONTAL-WAVE LOW OVER ERN NEB/WRN IA REGION BY 14/00Z...AND FRONT SWWD ACROSS N-CENTRAL KS...NWRN OK AND TRANS-PECOS AREA OF W TX. BY LATE AFTERNOON...DRYLINE SHOULD INTERSECT PAC FRONT OBLIQUELY OVER NWRN OR WRN OK...AND EXTEND SSWWD ACROSS NW TX AND PERMIAN BASIN REGION. DRYLINE AND PAC FRONT SHOULD MERGE THROUGH REMAINDER PERIOD. MEANWHILE...DIFFUSE WARM FRONT -- NOW LOCATED OVER PORTIONS CENTRAL/SRN OK AND SRN AR -- IS FCST TO MOVE OR REDEVELOP NWD RAPIDLY ACROSS LOWER MO VALLEY REGION EARLY IN PERIOD. WARM FRONT SHOULD EXTEND FROM SFC LOW ACROSS NRN IA AND SRN WI BY 14/00Z. BY END OF PERIOD...EXPECT PRIMARY SFC LOW OVER NWRN IL/SWRN WI REGION...WITH WARM FRONT ENEWD OVER LOWER MI...AND COLD FRONT OVER NRN/WRN MO...ERN OK...AND W-CENTRAL TX. ...PORTIONS SRN/CENTRAL PLAINS... BAND OF TSTMS SHOULD BE ONGOING AT START OF PERIOD FROM PORTIONS W-CENTRAL TX NNEWD ACROSS NW TX AND WRN OK...INTO PORTIONS CENTRAL KS AND PERHAPS FARTHER NE. RELATED ANVIL SHIELD WILL SUBDUE PACE OF INSOLATION IN ITS INFLOW REGION. HOWEVER...COMBINATION OF SLOW SFC HEATING AND BOUNDARY-LAYER THETAE ADVECTION SHOULD YIELD FAVORABLY LARGE BUOYANCY TO SUPPORT GROWING SVR THREAT WITH TIME THROUGHOUT DAYLIGHT HOURS...AS BAND MOVES EWD ACROSS OUTLOOK AREA. BACKBUILDING WITH TIME ALSO IS POSSIBLE ACROSS PORTIONS W-CENTRAL/SW TX ALONG/AHEAD OF DRYLINE...PERHAPS AS FAR S AS RIO GRANDE. FURTHERMORE...SOME PROGS SUGGEST MID-LATE AFTERNOON QUASI-LINEAR TSTM DEVELOPMENT BEHIND INITIAL ACTIVITY AND ALONG/AHEAD OF COLD FRONT OVER PORTIONS KS/NWRN OK. WIDTH AND MAGNITUDE OF ANY DESTABILIZATION CORRIDOR BEHIND INITIAL/PRIMARY TSTM BAND IS QUITE QUESTIONABLE ATTM...THOUGH THIS AREA GENERALLY IS COVERED BY UNCONDITIONAL...MRGL TO SLGT-RISK LEVEL PROBABILITIES THAT ALREADY ACCOUNT FOR EARLIER TSTMS. PRIMARY THREAT FROM ANY OF THE ABOVE CONVECTION WILL BE DAMAGING GUSTS...WITH QUASI-LINEAR MODES DOMINANT FOR MOST OF PERIOD. NONETHELESS...FAVORABLE DEEP SHEAR AND POTENTIAL FOR AT LEAST A FEW SUPERCELLS SUGGESTS CATEGORICAL HAIL RISK. ANY SUCH SUPERCELLS...ALONG WITH EMBEDDED QLCS CIRCULATIONS...COLLECTIVELY OFFER RELATIVELY MAXIMIZED TORNADO POTENTIAL AT LEAST BETWEEN NW TX AND WRN MO...WHERE ENLARGED LOW-LEVEL HODOGRAPHS ARE MOST LIKELY TO JUXTAPOSE WITH FAVORABLE DESTABILIZATION. TORNADO THREAT FARTHER NE AND SW...WHILE NONZERO...IS MORE CONDITIONAL. OVERALL SVR POTENTIAL SHOULD DIMINISH FROM LATE EVENING ONWARD OVER MOST OF THIS AREA AS BOUNDARY LAYER SLOWLY STABILIZES...AND AS PRIMARY MID-UPPER WAVE DEAMPLIFIES. THREAT MAY PERSIST LONGEST OVERNIGHT ACROSS PORTIONS S TX INTO N-CENTRAL/NE TX AND SERN OK...WHERE LOW-LEVEL THETAE WILL REMAIN HIGHEST IN ABSENCE OF SUBSTANTIAL CAPPING. ...NRN MO/ERN NEB TO SWRN WI...NWRN IL... SCATTERED TSTMS MAY MOVE NEWD ACROSS THIS REGION EARLY IN PERIOD...PERHAPS AS EXTENSION OF ACTIVITY NOW CROSSING PORTIONS CENTRAL/SRN HIGH PLAINS. SOME ACTIVITY MAY PERSIST OR REDEVELOP INTO AFTERNOON HOURS WHEN BOUNDARY-LAYER THETAE ADVECTION COULD INTRODUCE SFC-BASED PARCELS TO CONVECTIVE INFLOW REGION. SEPARATE/NNE-SSW ALIGNED BELT OF TSTMS ALSO MAY DEVELOP AHEAD OF SFC COLD FRONT OVER PORTIONS MO/IA AND SHIFT EWD. AFTERNOON/EVENING WIND PROFILES WILL BE FAVORABLE FOR SVR OVER WARM SECTOR IN THIS REGION...ALBEIT EXHIBITING SOME BACKING WITH HEIGHT IN MIDLEVELS COMMON TO QUASI-LINEAR EVENTS. FCST SOUNDINGS SUGGEST 35-45 KT EFFECTIVE SHEAR...ALONG WITH ENHANCED LOW-LEVEL HODOGRAPHS INVOF WARM FRONT AND SFC LOW. MOST PROGS ALSO INDICATE SOME DEGREE OF SUFFICIENT SFC-BASED DESTABILIZATION ACROSS THIS REGION...E.G. 1000-1500 J/KG MLCAPE PREDICTED BY NAM. HOWEVER...SUBSTANTIAL DESTABILIZATION MAY BE PRECLUDED BY PRECURSORY PRECIP AND CLOUD COVER MOVING INTO THIS REGION FROM UPSHEAR AREAS OF CENTRAL PLAINS DURING MORNING/EARLY AFTERNOON HOURS. WHILE CORRIDOR OF RELATIVELY ENHANCED SVR WIND POTENTIAL YET MAY DEVELOP POLEWARD OF PRESENT 30% LINE...EXTENT/TIMING REMAINS TOO UNCERTAIN TO EXTEND THAT PROBABILITY FARTHER NNE ATTM. ..EDWARDS/ROGERS.. 10/13/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z