The SPC is forecasting ...severe thunderstorms expected over parts of the southern plains into the ozarks and middle mississippi valley today and tonight.... Please read the latest public statement about this event. View What is a Watch? clip.
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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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| 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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| 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 201217 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0717 AM CDT MON MAY 20 2013 VALID 201300Z - 211200Z ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER PARTS OF NORTH TX...CENTRAL AND EASTERN OK...NORTHWEST AR...EXTREME SOUTHEAST KS...AND SOUTHERN MO.... ...THERE IS A SLGT RISK OF SVR TSTMS FROM CENTRAL TX INTO MUCH OF THE UPPER MS VALLEY AND GREAT LAKES REGION.... ...TX/OK/AR/KS/MO... MORNING WATER VAPOR LOOPS SHOW A BROAD UPPER TROUGH OVER THE WESTERN AND CENTRAL STATES...WITH A PROGRESSIVE SHORTWAVE TROUGH TRACKING EASTWARD ACROSS NORTHERN NM. THIS FEATURE WILL MOVE INTO THE SOUTHERN PLAINS BY EARLY AFTERNOON...HELPING TO INITIATE ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS OVER THE SOUTHERN PLAINS. A SURFACE COLD FRONT CURRENTLY EXTENDS ROUGHLY FROM LTS-BVO. THIS FRONT IS LIKELY TO MOVE SLIGHTLY SOUTHEASTWARD TODAY AND WILL PROVIDE THE FOCUS FOR AFTERNOON THUNDERSTORM DEVELOPMENT. VARIOUS MESOSCALE MODELS DIFFER ON TIMING OF STRONG/SEVERE STORMS...BUT AGREE ON STORMS FORMING OVER CENTRAL OK BY ABOUT 20Z AND BUILDING QUICKLY NORTHEASTWARD INTO SOUTHEAST KS AND WESTERN MO. THE INITIAL STORMS WILL LIKELY BE SUPERCELLUAR WITH VERY LARGE HAIL...DAMAGING WINDS...AND TORNADOES POSSIBLE. THOSE STORMS THAT FORM OVER SOUTHERN OK INTO NORTH TX APPEAR TO HAVE THE GREATEST CHANCE OF REMAINING DISCRETE AND POSING A RISK OF SIGNIFICANT SEVERE WEATHER FOR SEVERAL HOURS INTO THE EVENING. MEANWHILE...STORMS THAT FORM FROM CENTRAL OK NORTHEASTWARD INTO SOUTHEAST KS AND MO APPEAR LIKELY TO ORGANIZE INTO BROKEN LINES AND CLUSTERS BY EARLY EVENING CAPABLE OF WIDESPREAD DAMAGING WINDS...LARGE HAIL...AND A FEW TORNADOES. SIMILAR TO YESTERDAY...MID LEVEL LAPSE RATES OF 7.5-8.0 C/KM...VERY LARGE CAPE...AND FAVORABLE SHEAR VALUES WILL POSE A RISK OF ISOLATED STRONG TORNADOES ACROSS PORTIONS OF THE MODERATE RISK AREA. ...UPPER MS VALLEY AND WESTERN GREAT LAKES... EARLY VISIBLE SATELLITE IMAGERY SHOWS ONLY BROKEN CLOUD COVER OVER PARTS OF IA/WI EASTWARD INTO MI/OH. RELATIVELY STRONG DAYTIME HEATING AND LITTLE CAP SHOULD RESULT IN SCATTERED THUNDERSTORMS TODAY AND TONIGHT TO THE EAST OF A SURFACE LOW OVER MN. MLCAPE VALUES OF 1500-2000 J/KG WILL PROMOTE VIGOROUS UPDRAFTS IN THIS REGION...WHILE SUFFICIENTLY STRONG VERTICAL SHEAR HELPS TO ORGANIZE THE CONVECTION. PRESENT INDICATIONS ARE THAT MULTIPLE LINES/CLUSTERS OF THUNDERSTORMS WILL AFFECT THIS REGION...WITH A FEW SUPERCELLS POSSIBLE. HAIL AND DAMAGING WINDS ARE THE MAIN THREATS...BUT ISOLATED TORNADOES CANNOT BE RULED OUT. ...TX... SOUTH OF THE MODERATE RISK AREA IN TX...CONFIDENCE IS A LITTLE HIGHER TODAY COMPARED TO LAST FEW DAYS THAT ISOLATED STORMS WILL FORM ALONG THE DRYLINE. ANY STORM THAT CAN FORM IN THIS AREA WILL POSE A RISK OF VERY LARGE HAIL AND DAMAGING WINDS FOR A FEW HOURS THIS EVENING. ..HART/LEITMAN.. 05/20/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |