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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 141955 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0255 PM CDT FRI JUN 14 2013 VALID 142000Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CNTRL PLAINS...NRN PLAINS AND LOWER TO MID MO VALLEY... SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS ISSUANCE. THE FIRST CHANGE IS TO EXTEND THE SLIGHT RISK AREA SEWD A FEW COUNTIES ACROSS NW MO. SEVERAL SHORT-TERM HIGH RES MODELS SUGGEST A LINE SEGMENT WILL MOVE SEWD INTO NW MO THIS EVENING. HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE WITH THIS LINE IF A CONVECTIVE SYSTEM CAN ORGANIZE. THE SECOND CHANGE TO THE OUTLOOK IS TO REMOVE THE SLIGHT RISK AREA FROM NRN FL. CELLS DEVELOPING IN NRN FL SHOULD HAVE A WIND DAMAGE POTENTIAL DUE TO MODERATE INSTABILITY AND STEEP LOW-LEVEL LAPSE RATES. HOWEVER...THE THREAT IS NOT EXPECTED TO INCREASE MARKEDLY THIS AFTERNOON. THE THIRD CHANGE TO THE OUTLOOK IS TO EXTEND THE 5 PERCENT WIND DAMAGE PROBABILITY WWD TO THE FRONT RANGE OF ECNTRL CO WHERE THE STRONGER CELLS COULD HAVE A MARGINAL SEVERE THREAT THIS AFTERNOON. ..BROYLES.. 06/14/2013 .PREV DISCUSSION... /ISSUED 1107 AM CDT FRI JUN 14 2013/ ...SYNOPSIS... A MIDLEVEL SHORTWAVE TROUGH WILL CONTINUE TO PROGRESS EWD OFF THE MID ATLANTIC COAST...AS A TRAILING COLD FRONT SAGS SWD INTO N FL AND THE N CENTRAL/NE GULF COAST. THE WRN PORTION OF THE BAROCLINIC ZONE WILL DRIFT SWWD INTO EXTREME E TX AND ERN OK...AND THEN TRANSITION INTO A WARM FRONT ALIGNED PRIMARILY NW-SE BY LATER THIS AFTERNOON FROM ERN NEB TO NEAR THE KS/MO BORDER. FARTHER N...A COLD/OCCLUDED FRONT WILL MOVE EWD ACROSS THE DAKOTAS TO WRN MN BY TONIGHT...IN ASSOCIATION WITH A MIDLEVEL TROUGH EJECTING FROM WY/MT. THE SURFACE BAROCLINIC ZONE WILL BE THE PRIMARY FOCUS FOR STRONG/SEVERE THUNDERSTORM DEVELOPMENT THIS AFTERNOON/EVENING. ...MID MO VALLEY THIS AFTERNOON/EVENING... AN MCV PERSISTS THIS MORNING OVER ERN NEB...WITHIN THE REMNANTS OF OVERNIGHT CONVECTION. DOWNSTREAM FROM THE MCV...A NEW CLUSTER OF ELEVATED STORMS HAS FORMED IN SW IA/NRN MO. THESE STORMS WILL POSE A MARGINAL RISK OF HAIL/DAMAGING WINDS AS THE LOW LEVELS DESTABILIZE THROUGH THIS AFTERNOON ACROSS SW IA/NW MO. FARTHER W/NW...ADDITIONAL THUNDERSTORM DEVELOPMENT IS EXPECTED ALONG THE SYNOPTIC COLD FRONT FROM NW KS INTO S CENTRAL NEB...WHERE STRONG SURFACE HEATING S OF THE FRONT ERODES CONVECTIVE INHIBITION. THE INITIAL HIGH-BASED CONVECTION WILL POSE A RISK FOR DAMAGING OUTFLOW GUSTS AS IT SPREADS NEWD INTO NEB. FARTHER E INTO ERN NEB...RICHER MOISTURE /BOUNDARY LAYER DEWPOINTS OF 68-70 F/ WILL SUPPORT LARGER CAPE...IN AN ENVIRONMENT WITH STRONGER LOW-LEVEL SHEAR NEAR THE SYNOPTIC WARM FRONT. STORMS THAT SPREAD INTO OR DEVELOP WITHIN THE ERN NEB ENVIRONMENT WILL HAVE THE POTENTIAL TO BECOME SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL...AND POSSIBLY A TORNADO OR TWO WITH THE MORE DISCRETE/PERSISTENT STORMS. ...ERN ND THIS AFTERNOON/EVENING... LOW-LEVEL MOISTURE WILL BE MORE LIMITED ACROSS ERN ND...AND CLOUDS WILL LIMIT SURFACE HEATING...COMPARED TO AREAS FARTHER S IN SD/NEB. STILL...DEEP-LAYER VERTICAL SHEAR WILL BE SUFFICIENT FOR SUPERCELLS WITH THE EJECTING MIDLEVEL TROUGH/SPEED MAX. GIVEN QUESTIONS ABOUT THE MAGNITUDE OF THE INSTABILITY THIS AFTERNOON...WILL MAINTAIN LOW SEVERE PROBABILITIES IN THIS UPDATE. ...N FL TODAY... DEEP CONVECTION HAS ALREADY DEVELOPED NEAR CTY AS OF 15Z...AND ADDITIONAL STORMS ARE LIKELY THIS AFTERNOON ACROSS N FL ALONG A DIFFUSE PRE-FRONTAL TROUGH...AND PERHAPS FARTHER N ALONG THE SYNOPTIC COLD FRONT. THE COMBINATION OF MODEST DEEP-LAYER SHEAR WITH THE SWRN FRINGE OF THE MID ATLANTIC SHORTWAVE TROUGH AND STRONG INSTABILITY /MLCAPE AOA 300O J PER KG/ WILL SUPPORT ORGANIZED MULTICELL CLUSTERS CAPABLE OF PRODUCING A FEW DAMAGING OUTFLOW GUSTS AND MARGINALLY SEVERE HAIL THROUGH THE AFTERNOON. ...SRN LA/EXTREME SE TX THIS AFTERNOON/EVENING... STRONG SURFACE HEATING /TEMPERATURES WELL INTO THE 90S/ AND RICH BOUNDARY LAYER MOISTURE /DEWPOINTS IN THE MID-UPPER 70S/ WILL CONTRIBUTE TO MLCAPE NEAR 4000 J/KG AND SUPPORT THUNDERSTORM DEVELOPMENT THIS AFTERNOON ALONG THE WNW-ESE ORIENTED SYNOPTIC FRONT. THOUGH VERTICAL SHEAR WILL BE RELATIVELY WEAK...THE STRONG INSTABILITY WILL SUPPORT A FEW MULTICELL CLUSTERS WITH STRONG UPDRAFTS/PRECIPITATION LOADING...WHILE DCAPE OF 1250-1500 J/KG WILL BE FAVORABLE FOR ISOLATED DAMAGING DOWNBURSTS. THE INITIAL STORMS SHOULD FORM BY 21-22Z IN SRN LA...AND THEN SPREAD WWD-WSWWD TOWARD THE SABINE RIVER THIS EVENING. ...RIO GRANDE VALLEY IN TX TODAY... A PLUME OF RICH TROPICAL MOISTURE /PW VALUES AOA 2 INCHES/ HAS SPREAD NWD OVER THE RIO GRANDE VALLEY...TO THE E OF A WEAK MIDLEVEL LOW OVER THE BIG BEND. THOUGH WIDESPREAD CLOUDS WILL LIMIT SURFACE HEATING...THE DRT VWP SHOWS SUFFICIENT LOW-LEVEL SHEAR FOR WEAKLY ROTATING STORMS. THUS...WILL ADD LOW TORNADO PROBABILITIES FOR A BRIEF/WEAK TORNADO TODAY /SEE MD 1078 FOR ADDITIONAL INFORMATION/. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |