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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 021921 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0221 PM CDT SAT NOV 02 2013 VALID 022000Z - 031200Z ...NO SVR TSTM AREAS FORECAST... ...FL PENINSULA... MARGINAL POTENTIAL FOR LIGHTNING STRIKES WILL EXIST FOR AREAS ALONG AND IMMEDIATELY AHEAD OF A SWD MOVING COLD FRONT. THREAT IS EXPECTED TO BECOME NEGLIGIBLE AFTER SUNSET. ...KY/TN AND SRN APPALACHIANS... LOW TOPPED CONVECTION IS DEVELOPING THIS AFTERNOON BENEATH AND IMMEDIATELY AHEAD OF COLD UPPER TROUGH MOVING ACROSS THE AREA. SOME OF THIS ACTIVITY IS PRODUCING LIGHTNING...AND WILL CONTINUE TO DO SO DURING THE REMAINDER OF THE AFTERNOON. POTENTIAL FOR LIGHTNING WILL DIMINISH AFTER SUNSET AS BOUNDARY LAYER COOLS AND STABILIZES. ...COASTAL ORE/WA... PREVIOUS FORECAST THINKING IS STILL ON TRACK. ...SRN AZ... AN ISOLATED LIGHTNING STRIKE OR TWO WILL BE POSSIBLE LATE IN THE FORECAST PERIOD AS A SRN STREAM DISTURBANCE APPROACHES THE AREA. HOWEVER...COVERAGE IS NOT EXPECTED TO BE SUFFICIENT FOR A CATEGORICAL THUNDER DELINEATION ATTM. ..GARNER.. 11/02/2013 .PREV DISCUSSION... /ISSUED 1102 AM CDT SAT NOV 02 2013/ ...SYNOPSIS... A LARGER-SCALE TROUGH...WITH EMBEDDED SPEED MAXIMA...WILL CONTINUE TO MOVE EWD FROM THE OH/TN VALLEYS TO THE ATLANTIC COAST BY SUNDAY MORNING...AS AN ASSOCIATED COLD FRONT MOVES SEWD FROM CENTRAL FL TO THE FL STRAITS. 12Z SOUNDINGS REVEALED POOR MIDLEVEL LAPSE RATES ACROSS FL...WHICH WILL TEND TO LIMIT BUOYANCY AND THE POTENTIAL FOR SURFACE-BASED CONVECTION. WILL MAINTAIN A MARGINAL RISK FOR THUNDERSTORMS ACROSS CENTRAL FL TODAY...BUT THE RISK SHOULD SLOWLY DIMINISH WITH TIME AND SWD EXTENT. OTHERWISE...SOME LOW-TOPPED CONVECTION IS EXPECTED THIS AFTERNOON AS THE MIDLEVEL THERMAL TROUGH CROSSES KY AND VICINITY. LAPSE RATES NEAR 7 C/KM FROM THE SURFACE TO 500 MB AND COLD MIDLEVEL TEMPERATURES WILL RESULT IN MUCAPE OF 100-200 J/KG AND EL TEMPERATURES AOB -20 C...BOTH OF WHICH ARE SUFFICIENT FOR LIGHTNING PRODUCTION. ACROSS THE PAC NW...A STRONG SHORTWAVE TROUGH IS MOVING INLAND THIS MORNING. THE STEEPEST LAPSE RATES AND WEAK SURFACE-BASED BUOYANCY ARE EXPECTED TO LIKEWISE SPREAD INLAND TODAY IN THE POST-FRONTAL ENVIRONMENT...WITH THE RISK FOR ISOLATED LOW-TOPPED THUNDERSTORMS. THE ONLY OTHER POTENTIAL CONCERN FOR DEEP CONVECTION WILL BE ACROSS SRN AZ NEAR THE END OF THE PERIOD...AS A WEAK SRN STREAM LOW EVOLVES INTO MORE OF AN OPEN WAVE AND EJECTS ENEWD OVER NW MEXICO IN ADVANCE OF THE PAC NW TROUGH. AT THIS POINT...CONFIDENCE IS LOW THAT MIDLEVEL MOISTENING OVER AZ WILL BE SUFFICIENT TO SUPPORT WEAK ELEVATED CAPE...SO WILL NOT ADD A GENERAL THUNDERSTORM AREA IN THIS UPDATE. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |
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