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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 092000 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0300 PM CDT THU MAY 09 2013 VALID 092000Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN PLNS ENE INTO THE ARKLATEX... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE MID MS AND LWR OH VLYS... ...SOUTHERN PLAINS/ARKLATEX TO LOWER MS VALLEY... FOR ADDITIONAL SHORT-TERM DETAILS REGARDING AN ONGOING MCS ACROSS CENTRAL TX...SEE MESOSCALE DISCUSSION 610. DAMAGING WINDS AND SEVERE HAIL IS EXPECTED TO REMAIN A CONCERN AS IT PERSISTS SOUTHEASTWARD ACROSS SOUTHEAST TX INTO THIS EVENING. FARTHER WEST...ADDITIONAL STORM DEVELOPMENT IS EXPECTED THROUGH LATE AFTERNOON/EARLY EVENING FROM PORTIONS OF OK SOUTHWESTWARD INTO WEST/SOUTHWEST TX IN VICINITY OF FRONT/DRYLINE. LITTLE OUTLOOK ADJUSTMENTS NEEDED FOR THIS SCENARIO...ALTHOUGH ADDITIONAL PARTS OF THE TX RIO GRANDE VICINITY WERE ADDED TO THE SLIGHT RISK. SEE PRIOR OUTLOOK DISCUSSION BELOW AND SUBSEQUENT MESOSCALE DISCUSSIONS. ...MIDDLE MS VALLEY/OH VALLEY... SOME SOUTHWARD SPATIAL ADJUSTMENTS WERE MADE TO SLIGHT RISK TO ACCOUNT FOR PRIMARY /ALBEIT MODEST/ DESTABILIZATION FOCUSED ACROSS DOWNSTATE IL/INDIANA...IMMEDIATELY AHEAD OF EAST-NORTHEASTWARD MOVING VORT ACROSS FAR EASTERN MO/SOUTHWEST IL THIS AFTERNOON. BOUTS OF DAMAGING WINDS/HAIL WILL BE POSSIBLE...AT LEAST ON AN ISOLATED BASIS INTO THIS EVENING. ..GUYER.. 05/09/2013 .PREV DISCUSSION... /ISSUED 1130 AM CDT THU MAY 09 2013/ ...SYNOPSIS... WEAK SPLIT FLOW PATTERN WILL PREVAIL OVER THE LWR 48 THIS PERIOD AS FOUR CORNERS/CNTRL RCKYS UPR LOW CONTINUES TO DEVOLVE INTO AN ELONGATED POSITIVE-TILT TROUGH...AND NE U.S. LOW ACCELERATES ENE TO BECOME REABSORBED IN THE WLYS. MODERATE WSW FLOW WILL PREVAIL FROM THE SRN PLNS/OZARKS INTO THE OH/TN VLYS ON SRN FRINGE OF ELONGATING TROUGH. NRN STREAM COLD FRONT WILL CONTINUE TO ADVANCE S/SE ACROSS THE CNTRL/SRN PLNS...DELIMITING THE NRN AND WRN EXTENT OF A RATHER LARGE AREA EXTENDING FROM PARTS OF TX AND OK NEWD INTO THE OH VLY/MIDWEST THAT WILL HAVE AT LEAST A CONDITIONAL RISK FOR SVR TSTMS THROUGH TNGT. THE FRONT...AND CONFLUENCE AXES/OUTFLOW BOUNDARIES TO ITS S AND E...SHOULD BE THE MAIN LOW-LVL FOCUS FOR STORM DEVELOPMENT THROUGH THE PERIOD. ...SRN PLNS/ARKLATEX TODAY/TNGT... SATELLITE SHOWS AN UPR DISTURBANCE NOW OVER THE TX BIG BEND THAT SHOULD CONTINUE ENE ACROSS THE REMAINDER OF TX TODAY AND INTO AR/W TN TNGT/EARLY FRI. ASCENT WITH THIS FEATURE...AND MODEST SFC HEATING OF RATHER MOIST AND CONDITIONALLY UNSTABLE ENVIRONMENT ON ITS PERIPHERY...SHOULD SUPPORT INTENSIFICATION AND AREAL EXTENSION OF EXISTING TSTMS CLUSTER NOW OVER CNTRL TX. CLOUDS WILL LIMIT SFC HEATING...BUT GIVEN QUALITY OF MOISTURE INFLOW /PW VARYING FROM AROUND 1.00 INCH IN THE EDWARDS PLATEAU TO ABOVE 1.50 IN E CNTRL AND SE TX/...DEEP EML...AND PERSISTENT ASCENT...POTENTIAL WILL EXIST FOR STRONG UPDRAFTS WITH LARGE HAIL AND LOCALLY DMGG WIND. THE CURRENT AREA OF STORMS APPEARS TO BE ASSOCIATED WITH A SFC-850 MB CONFLUENCE ZONE AHEAD OF SRN PLNS COLD FRONT. THIS CONFLUENCE ZONE SHOULD SHIFT ENE ACROSS CNTRL TX THROUGH THE DAY...WITH THE GREATEST POTENTIAL FOR SVR STORMS POSSIBLY OCCURRING AS THE CONFLUENCE ZONE REACHES AND MOVES E BEYOND THE I-35 CORRIDOR LATER TODAY INTO TNGT. 40-45 KT WSWLY DEEP SHEAR...COUPLED WITH MOISTURE AVAILABILITY...MAY SUPPORT FORWARD-PROPAGATING/BOWING SEGMENTS WITH HIGH WIND EWD ACROSS THE MID/UPR TX CSTL PLN...THE SABINE RVR VLY...AND PARTS OF AR/LA BY EARLY FRI. N AND W OF THE ABOVE ACTIVITY...TSTMS ALSO MAY FORM ALONG COLD FRONT LATE THIS AFTN FROM CNTRL OK SWWD INTO W TX. A FEW STORMS ALSO COULD FROM NEAR INTERSECTION OF THE FRONT WITH LEE TROUGH/DRY LINE IN W TX. POCKETS OF AMPLE SHEAR/INSTABILITY SHOULD EXIST IN THESE AREAS TO SUPPORT A CONDITIONAL RISK FOR SUSTAINED UPDRAFTS/SUPERCELLS WITH SVR HAIL/WIND. ABSENCE OF STRONG FORCING FOR ASCENT AND MODEST LLJ SUGGEST THAT THESE STORMS SHOULD WEAKEN BY MID TO LATE EVE. ...MID MS/LWR OH VLYS THIS AFTN/EVE... A BELT OF ENHANCED /30+ KTS AT 500 MB/ WSWLY LOW TO MID-LVL FLOW WILL PERSIST OVER THE MID MS/LWR OH VLYS TODAY...ASSOCIATED WITH NRN STREAM TROUGH NOW OVER IA...AND CONVECTIVELY-INDUCED CIRCULATIONS LEFT FROM OVERNIGHT MCSS. COUPLED WITH SFC HEATING...THIS MAY SUPPORT ONE OR TWO CORRIDORS OF STRONGER STORM DEVELOPMENT THIS AFTN FROM PARTS OF ERN MO ENE INTO CNTRL/SRN IL...IND...AND PERHAPS NRN/WRN KY. WHILE THE LWR LVLS ARE NOT PARTICULARLY MOIST...AREA 850 MB/VWP DATA SUGGEST THAT SUFFICIENT MOISTURE ADVECTION WILL OCCUR TO SUPPORT SUSTAINED STORMS S AND E OF THE ERN EXTENSION OF PLNS COLD FRONT. RELATIVELY MODEST MID-LVL LAPSE RATES SHOULD MITIGATE OVERALL SVR RISK...BUT A CONDITIONAL RISK FOR SVR WIND GUSTS AND HAIL WILL NEVERTHELESS EXIST...ESPECIALLY IN IL. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |