| Categorical Graphic |
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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. |
| 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. |
| 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. |
SPC AC 180456 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1156 PM CDT SAT MAR 17 2012 VALID 181200Z - 191200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL AND SRN PLAINS... ...SYNOPSIS... A FULL LATITUDE UPPER TROUGH WILL GRADUALLY SHIFT EWD FROM THE GREAT BASIN ACROSS THE ROCKIES DURING THE DAY...EMERGING INTO THE HIGH PLAINS BY MON MORNING. WHILE THE PRIMARY VORTICITY CENTER WILL BE MOVING ACROSS THE FOUR CORNERS AREA DURING THE DAY...A LEAD SHORTWAVE TROUGH IS EXPECTED TO MOVE OUT OF NRN MEXICO NEWD ACROSS TX EARLY SUN AND INTO OK AND KS FROM MID TO LATE AFTERNOON. BEHIND THIS LEAD WAVE...GRADUAL HEIGHT FALLS WILL PERSIST WITH THE MAIN BODY OF THE TROUGH. AT THE SURFACE...A BROAD AREA OF LOW PRESSURE WILL CONSOLIDATE OVER THE NRN HIGH PLAINS...WITH A DISTINCT LOW PRESSURE TROUGH EXTENDING SWD INTO W TX AND A COLD FRONT DEVELOPING OVER WY...CO AND NM. AHEAD OF THIS TROUGH...BROAD SLY FLOW WILL BRING LOWER 60S F DEWPOINTS AS FAR N AS IA AND IL. AN EML WILL EXIST OVER THE WARM SECTOR...PREVENTING SURFACE BASED DEVELOPMENT FOR MUCH OF THE DAY. TO THE E...A WEAK VORTICITY CENTER...ENHANCED BY ONGOING CONVECTION THIS EVENING OVER IL AND IND...WILL PERSIST AS IT TRAVELS EWD ALONG AND N OF THE OH RIVER. THIS FEATURE IS LIKELY TO FOCUS ADDITIONAL THUNDERSTORM DEVELOPMENT DURING THE DAY. ...OK INTO ERN KS MIDDAY INTO AFTERNOON... LIFT WITH THE LEAD SHORTWAVE IS LIKELY TO RESULT IN SCATTERED RAIN AND STORMS DEVELOPING OVER NWRN TX INTO OK NEWD INTO SRN/ERN KS BY LATE AFTERNOON. FORECAST SOUNDINGS INDICATE THAT THIS ACTIVITY COULD BE ELEVATED ABOVE THE CAPPING INVERSION...WHERE STEEP LAPSE RATES WILL EXIST. EVEN SO...WITH FAVORABLE EFFECTIVE SHEAR...SOME OF THIS ACTIVITY COULD PRODUCE SOME HAIL. ...NWRN TX INTO WRN OK AND KS... CONVERGENCE ALONG THE DRYLINE IS EXPECTED TO INCREASE AFTER ABOUT 21Z AS MASS FIELDS READJUST TOWARD THE WRN TROUGH AND AWAY FROM THE LEAD SHORTWAVE. WITH STRONG HEATING AND NEARLY DRY ADIABATIC LAPSE RATES THROUGH A DEEP LAYER W OF THE DRYLINE...A NARROW ZONE OF STRONG INSTABILITY IS EXPECTED FROM WRN KS INTO THE ERN OK/TX PANHANDLE SWD INTO NWRN TX. HERE...SHEAR PROFILES WILL STRONGLY FAVOR SUPERCELLS...CAPABLE OF LARGE...PERHAPS VERY LARGE HAIL...DAMAGING WIND GUSTS AND A COUPLE TORNADOES. WHILE LOW LEVEL HODOGRAPHS DO ENLARGE AFTER 00Z...SO WILL CONVECTIVE INHIBITION WITH BACKING SURFACE WINDS BRINGING RELATIVELY COOLER...YET STILL MOIST AIR NWWD MEETING WITH THE COLD FRONT AROUND 03Z. ADDITIONAL ACTIVITY IS LIKELY DUE TO STRONG FORCING...BUT MORE OF A LINEAR STORM MODE IS EXPECTED...WITH PERHAPS HYBRID SUPERCELLS AND BOWING SEGMENTS CAPABLE OF WIND AND HAIL. THE SEVERE THREAT APPEARS MORE CONDITIONAL FARTHER N INTO NEBRASKA WHERE STORMS MAY BE MORE ISOLATED. ...IL...IND...OH...NRN KY... CONVECTION WILL BE ONGOING ACROSS THE OH VALLEY EARLY SUNDAY...AND MAY REJUVENATE ESPECIALLY ON THE WRN FRINGE AS SWLY 850 MB FLOW MAINTAIN A MOIST AND UNSTABLE FEED OF AIR INTO THE BACK SIDE OF THIS SYSTEM. AREAS OF HEATING ARE EXPECTED...AND OVERALL LAPSE RATES PROFILES MAY FAVOR SEVERE HAIL IN THE STRONGER CORES...ESPECIALLY NEAR PEAK HEATING. DEEP LAYER SHEAR WILL BE WEAK...SUGGESTING PULSE OR MULTICELLS. AS SUCH...A SLIGHT RISK IS NOT WARRANTED. ..JEWELL/HURLBUT.. 03/18/2012 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z