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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 281945 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0245 PM CDT THU MAR 28 2013 VALID 282000Z - 291200Z ...NO SVR TSTM AREAS FORECAST... THE OUTLOOK LOOKS TO BE ON TRACK FOR THIS ISSUANCE AND NO CHANGES HAVE BEEN MADE TO THE LINES. ..BROYLES.. 03/28/2013 .PREV DISCUSSION... /ISSUED 1118 AM CDT THU MAR 28 2013/ ...SWRN TX NEWD INTO THE MID MS VALLEY THIS AFTERNOON INTO TONIGHT... AS QUASI-ZONAL MID-LEVEL FLOW OCCURS DOWNSTREAM OF A WEAKLY AMPLIFYING RIDGE OVER THE INTERMOUNTAIN WEST...A SFC TROUGH WILL STRENGTHEN IN THE LEE OF THE SRN ROCKIES. THIS WILL ENHANCE SLY/SELY SFC FLOW OVER THE PLAINS...WHERE THE INFLUX OF PARTIALLY MODIFIED GULF MOISTURE WILL CONTINUE TO THE W/NW OF A N-CNTRL/NERN GULF RIDGE AND TO THE E OF A MODESTLY SHARPENING DRYLINE. A DIFFUSE FRONT CURRENTLY STRETCHES FROM NW TX NEWD INTO THE MO OZARKS...AND WILL MOVE LITTLE THROUGH THIS EVENING. THE DRYLINE IS FORECAST TO INTERSECT THE FRONT AT A TRIPLE POINT OVER THE TX S PLAINS THIS AFTERNOON. THE STRONGEST LOW-LEVEL ASCENT WILL BE FOCUSED INVOF THE DRYLINE -- NEAR AND S/SSW OF THE TRIPLE POINT TO THE MOUNTAINS OF SW TX. THIS MAY SUPPORT AN ISOLATED THUNDERSTORM OR TWO OVER THE ERN FRINGES OF A STEEP -- NEAR DRY ADIABATIC -- LOW-LEVEL LAPSE RATE PLUME WHERE MARGINAL INSTABILITY WILL BE PRESENT THIS AFTERNOON. GUSTY WINDS AND PERHAPS SMALL HAIL WILL BE THE PRIMARY CONCERN WITH THIS ACTIVITY. HOWEVER...CONVECTIVE COVERAGE AND INTENSITY WILL BE GREATLY LIMITED BY THE LACK OF APPRECIABLE MID-LEVEL ASCENT...LIMITED LOW-LEVEL AND DEEP MOISTURE...LIMITED BUOYANCY...AND ONLY WEAK LOW-LEVEL ASCENT. A RELATIVE SPATIAL MINIMUM IN THUNDERSTORM ACTIVITY IS ANTICIPATED THROUGH TONIGHT FROM SWRN OK INTO PORTIONS OF CNTRL OK...WHERE EVEN WEAKER LOW-LEVEL ASCENT WILL BE PRESENT AMIDST AN ONLY WEAKLY CONVERGENT SFC FRONT. FARTHER NE INTO NERN OK...NWRN/N-CNTRL AR...CNTRL/SWRN MO...AND ERN KS...THUNDERSTORM CHANCES WILL NOT INCREASE UNTIL THIS EVENING...WHEN A STRENGTHENING LOW-LEVEL JET STREAM SUPPORTS INCREASING ELEVATED WAA/ISENTROPIC ASCENT. ASCENT WILL BE MAXIMIZED AT THE TERMINUS OF A 25-35-KT LOW-LEVEL JET MAXIMUM...OVER THE ERN EDGE OF A STEEP MID-LEVEL LAPSE RATE PLUME ACCOMPANYING AN EML OVERSPREADING THE SRN/CNTRL PLAINS. ELEVATED RETURN MOISTURE WILL SUPPORT SUFFICIENT BUOYANCY WITHIN THE WARM ADVECTION REGIME FOR ISOLATED TO SCATTERED ELEVATED THUNDERSTORMS ROOTED AROUND 850 MB -- POTENTIALLY ORGANIZING INTO ONE OR TWO CLUSTERS -- DURING THE LATE EVENING AND ESPECIALLY DURING THE OVERNIGHT HOURS. SMALL HAIL WILL BE THE GREATEST CONCERN WITH THIS ACTIVITY. THE SPATIAL DISPLACEMENT OF THE STRONGER FORCING FOR ASCENT FROM THE STEEPER MID-LEVEL LAPSE RATE PLUME WILL LIKELY MITIGATE THE POTENTIAL FOR SVR CONVECTION. ...PARTS OF THE NRN GREAT BASIN THIS AFTERNOON INTO THIS EVENING... ISOLATED WEAK THUNDERSTORMS MAY OCCUR AS MINOR MID-LEVEL IMPULSES MOVE THROUGH THE NRN FRINGES OF THE WRN CONUS RIDGE AMIDST MARGINAL INSTABILITY AND TERRAIN-DRIVEN ASCENT. STORMS SHOULD DIMINISH DURING THE EVENING AS STABILITY INCREASES OWING TO BOUNDARY-LAYER NOCTURNAL COOLING. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |
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