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| Probabilistic Tornado Graphic | |||||||||
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| 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. |
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| Probabilistic Damaging Wind Graphic | |||||||||
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| 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. |
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| Probabilistic Large Hail Graphic | |||||||||
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| 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. |
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SPC AC 041251 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0751 AM CDT TUE JUN 04 2013 VALID 041300Z - 051200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE HIGH PLAINS OF CO EWD/SEWD ACROSS THE KS/OK/NWRN TX VICINITY... ...SYNOPSIS... BETWEEN A MID-LEVEL RIDGE /EXTENDING NEWD FROM MEXICO ACROSS THE RIO GRANDE VALLEY/ AND A SLOW-MOVING CLOSED LOW OVER THE NRN PLAINS...A BROAD BELT OF ENHANCED WLY/ZONAL FLOW IS FORECAST TO SPREAD OUT OF THE ROCKIES AND ACROSS THE CENTRAL PORTION OF THE U.S. THIS PERIOD. AT THE SURFACE...A LOW CURRENTLY CENTERED OVER SWRN KS IS PROGGED TO SHIFT/REDEVELOP SWD ACROSS THE OK/TX PANHANDLES INTO NWRN TX BY LATE AFTERNOON. THE PRIMARY ZONE OF SEVERE POTENTIAL THIS PERIOD IS PROGGED TO EXIST NEAR/N OF THIS FEATURE -- WITHIN SELY/UPSLOPE LOW-LEVEL FLOW REGIME. ELSEWHERE...A WEAK COOL FRONT ASSOCIATED WITH A WEAKENING LOW OVER THE NRN PLAINS WILL CONTINUE SHIFTING SLOWLY SEWD ACROSS THE MID MO VALLEY/CENTRAL PLAINS...WHILE THE OCCLUDED/NRN PORTION OF THE BOUNDARY CROSSES THE ERN DAKOTAS. THIS FRONTAL ZONE WILL FOCUS CONVECTION -- AND LIKELY ISOLATED SEVERE POTENTIAL -- THIS AFTERNOON AND EVENING. ...CENTRAL HIGH PLAINS SEWD INTO WRN KS/WRN OK... A LARGE MCS CONTINUES MOVING SEWD ACROSS OK THIS MORNING...WHILE SCATTERED SHOWERS/THUNDERSTORMS PERSIST NWD ACROSS KS AND THE MID MO VALLEY INTO THE NRN PLAINS/UPPER MS VALLEY. WHILE THE AFTER-EFFECTS OF THE OK MCS IN PARTICULAR CAST SOME UNCERTAINTY ON THE LOCATION AND DEGREE OF SEVERE POTENTIAL THIS AFTERNOON...IT APPEARS THAT AS THE SYSTEM WEAKENS/DEPARTS THE AREA...CONVECTIVELY-ALTERED AIRMASS TO THE COOL SIDE OF THE OUTFLOW BOUNDARY SHOULD HEAT/DESTABILIZE RAPIDLY. WITH KAMA MORNING RAOB REVEALING VERY STEEP LAPSE RATES ABOVE H7...DIURNAL HEATING OF THE RELATIVELY MOIST BOUNDARY LAYER SHOULD YIELD MODERATE INSTABILITY ACROSS WRN KS/WRN OK BY AFTERNOON. HOWEVER...CAPPING SHOULD ACT TO HINDER DEVELOPMENT ACROSS MUCH OF THE REGION THOUGH MUCH OF THE AFTERNOON. INITIAL STORM DEVELOPMENT WILL LIKELY OCCUR WITHIN THE LOW-LEVEL ESELY UPSLOPE FLOW REGIME ACROSS THE CO FRONT RANGE -- N OF THE SURFACE LOW INVOF NWRN TX. AMPLE INSTABILITY AND FAVORABLE SHEAR WILL SUPPORT SUPERCELLS -- AND ASSOCIATED THREATS FOR LARGE HAIL...LOCALLY DAMAGING WINDS...AND POSSIBLY A TORNADO. FORECAST FOR MORE WIDESPREAD SEVERE POTENTIAL FROM SERN CO INTO NWRN OK STILL SEEMS REASONABLE...INITIALLY AS ISOLATED STORMS DEVELOP WITH LOCAL BREACHING OF THE CAP NEAR AN AXIS OF CONVERGENCE EXTENDING NWD FROM THE NWRN TX LOW ACROSS THE WRN OK/SWRN KS VICINITY. WITH FAVORABLE SHEAR AND INSTABILITY EXPECTED...THESE STORMS WOULD LIKELY BE SUPERCELLULAR...CAPABLE OF PRODUCING VERY LARGE HAIL ALONG WITH LOCALLY DAMAGING WIND GUSTS AS WELL AS A TORNADO OR TWO. BY EVENING...COVERAGE OF THE THREAT MAY INCREASE ACROSS THIS REGION...AS STORMS EMERGING FROM THE CO FRONT RANGE POTENTIALLY GROW UPSCALE IN RESPONSE TO DIURNALLY STRENGTHENING LOW-LEVEL SELYS. ALONG WITH HAIL RISK AND POSSIBLY A TORNADO...THREAT FOR DAMAGING WINDS MAY INCREASE PRESUMING UPSCALE GROWTH/MCS DEVELOPMENT. THREAT FOR THIS MORE ORGANIZED/WIDESPREAD WIND POTENTIAL WOULD LIKELY EXTEND FROM SERN CO ACROSS PARTS OF WRN KS AND THE OK/NRN TX PANHANDLES INTO NWRN OK. ...ERN KS/SERN NEB VICINITY... ONGOING CONVECTION ACROSS THE SERN NEB/ERN KS VICINITY SHOULD INCREASE IN COVERAGE AND INTENSITY THIS AFTERNOON AS THE WEAK SURFACE COLD FRONT SHIFTS SEWD. A FEW OF THE STORMS WILL LIKELY BECOME SEVERE -- PRESUMING AMPLE HEATING CAN OCCUR AWAY FROM THE VICINITY OF ONGOING CONVECTION. WITH THIS REGION LYING ON THE SRN FRINGE OF THE MID-LEVEL JET CORE PROGGED ACROSS NRN NEB/SERN SD...SHEAR SUPPORTIVE OF UPDRAFT ROTATION SUGGESTS THREAT FOR LARGE HAIL AND/OR LOCALLY DAMAGING GUSTS WITH THE STRONGEST CELLS. STORMS MAY INCREASE SOME IN COVERAGE INTO THE EVENING...AS THE NOSE OF THE DEVELOPING LOW-LEVEL JET ACROSS NWRN TX/OK EXTENDS NWD TOWARD SERN KS. SEVERE THREAT SHOULD LINGER THROUGH THE EVENING WITH THESE STORMS...BEFORE A LIKELY OVERNIGHT/DIURNAL WEAKENING TREND. ...ERN DAKOTAS/WRN MN VICINITY... AS THE UPPER LOW AND ASSOCIATED/WEAKENING SURFACE LOW SHIFT SLOWLY EWD ACROSS THE DAKOTAS...THE OCCLUDED FRONT FORECAST TO LIE N-S ACROSS THE ERN DAKOTAS DURING THE AFTERNOON SHOULD BECOME A FOCUS FOR DEVELOPMENT OF SHOWERS AND SCATTERED/LOW-TOPPED THUNDERSTORMS. THOUGH THE LOW-LEVEL FLOW SHOULD REMAIN RELATIVELY WEAK AS THE LOW FILLS...DEEP-LAYER VEERING/SHEAR COMBINED WITH STEEP MID-LEVEL LAPSE RATES /OWING TO THE PRESENCE OF THE UPPER LOW/ SUGGEST A COUPLE OF STRONG/POSSIBLY SEVERE CELLS. THREAT FOR LOCALLY GUSTY/DAMAGING WINDS...MARGINAL HAIL...AND POSSIBLY AN ISOLATED TORNADO REMAIN APPARENT -- UNTIL CONVECTION WEAKENS THROUGH SUNSET. ..GOSS/GARNER.. 06/04/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |