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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 131630 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1130 AM CDT SAT JUL 13 2013 VALID 131630Z - 141200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE OH AND TN VLYS... ...SYNOPSIS... IN RESPONSE TO STRENGTHENING WRN ATLANTIC/NEW ENGLAND ANTICYCLONE...KY UPR LOW EXPECTED TO CONTINUE WWD THIS PERIOD...REACHING SRN IL THIS EVE AND SRN MO EARLY SUN...AS STRONG/ELONGATED RIDGE PERSISTS FROM THE FOUR CORNERS ACROSS THE NRN PLNS TO THE UPR GRT LKS. THE SRN STREAM OF THE WLYS WILL CONTINUE ALONG THE NRN FRINGE OF THE RIDGE...EXTENDING FROM THE PACIFIC NORTHWEST THROUGH THE CANADIAN PRAIRIES TO THE LABRADOR CST. SHORTWAVE IMPULSE THAT CROSSED WA YESTERDAY SHOULD DEAMPLIFY AS IT CONTINUES ENE ACROSS SRN SK/MB LATER TODAY. FARTHER S...A WEAKER DISTURBANCE NOW NEAR SLC SHOULD TRACK NE TO THE NRN HIGH PLNS. COLD FRONT ASSOCIATED WITH THE CANADIAN IMPULSE WILL ADVANCE SLOWLY SE ACROSS ERN MT/ND...ACCOMPANIED BY WEAK LEE CYCLOGENESIS. MEANWHILE...FRONT ASSOCIATED WITH YESTERDAY'S STORMS IN ND/MN SHOULD DISSIPATE OVER SD...WHILE LEE TROUGH PERSISTS FROM WRN NEB INTO FAR WRN KS. ...NRN PLNS THIS AFTN/EVE... SATELLITE SHOWS THAT STRONG HEATING WILL OCCUR OVER ERN MT AND WRN ND TODAY...ALONG/AHEAD OF FRONT ASSOCIATED WITH CANADIAN SHORTWAVE IMPULSE. CURRENT OBSERVATIONS AND DEVELOPMENT OF WEAK LEE LOW IN SE MT ALSO SUGGEST THAT SFC WINDS LIKELY WILL REMAIN SELY ACROSS REGION. COUPLED WITH TERRAIN-INDUCED CIRCULATIONS AND ASCENT ASSOCIATED WITH UT UPR IMPULSE...CONFIDENCE FAIRLY HIGH FOR THE DEVELOPMENT OF STRONG AFTN/EVE STORMS...ESPECIALLY OVER FAR ERN MT AND WRN ND. 35-40 KT WSWLY 500 MB FLOW IN CONJUNCTION WITH 15-20 KT SLY 850 MB WINDS WILL YIELD FAIRLY LONG...SLIGHTLY ELONGATED HODOGRAPHS THAT COULD FOSTER SUSTAINED STORMS/SUPERCELLS AND SUPERCELL SPLITS WITH LARGE HAIL AND LOCALLY DMGG WIND. A TORNADO OR TWO ALSO COULD OCCUR...ESPECIALLY IN THE WRN DAKOTAS WHERE TEMP/DEW POINT SPREADS SHOULD BE LEAST. THE STORMS MAY EVOLVE SMALL LINES OR CLUSTERS THIS EVE...BUT SHOULD NOT PERSIST TOO LATE INTO THE NIGHT GIVEN MODEST LLJ. THE SVR WEATHER RISK APPEARS MORE CONDITIONAL FARTHER S AND SE...WHERE WEAKER DEEP SHEAR WILL EXIST INVOF DISSIPATING SFC FRONT AND LEE TROUGH. NEVERTHELESS...RATHER RICH MOISTURE WILL LINGER INVOF THESE FEATURES /WITH PW AOA 1.50 INCHES AND SFC DEWPOINTS IN THE UPR 60S TO LOW 70S F/. COUPLED WITH STRONG HEATING...EXPECT MLCAPE TO BE AOA 3000 J/KG BY LATE AFTN. WEAK ASCENT MAY OCCUR ON SRN FRINGE OF PASSING UPR IMPULSE...BUT OVERALL LARGE SCALE SUPPORT WILL BE MINIMAL. NEVERTHELESS...GIVEN DEGREE OF SFC-BASED BUOYANCY AND LIKELIHOOD FOR AT LEAST MODEST LOW-LVL CONVERGENCE...SETUP APPEARS TO WARRANT A SLIGHT RISK FOR MULTICELLS AND PERHAPS A TRANSIENT SUPERCELL OR TWO CAPABLE OF SVR WIND/HAIL. ...LWR OH VLY TO SOUTHEAST THIS AFTN/EVE... KY UPR LOW IS RETROGRESSING RATHER QUICKLY WWD ATTM...AND SHOULD MAINTAIN THIS SPEED THROUGH THE PERIOD. THIS WILL RESULT IN FAIRLY RAPID AND SUBSTANTIAL SPATIAL-TEMPORAL CHANGES IN THE ASSOCIATED WIND AND THERMODYNAMIC FIELDS ACROSS THE REGION FROM ERN KY TO SRN IL/MO. IN THE SHORT TERM...MODERATE DESTABILIZATION APPEARS TO BE IN PROGRESS OVER PARTS OF KY AND IND AS SFC HEATING OCCUR BENEATH MID-LVL COLD POCKET /WITH 500 MB TEMP AROUND MINUS 13 C/. WHILE LOW-LVL MOISTURE IS MODEST BY JULY STANDARDS...IT IS SUFFICIENT FOR STRONG STORMS GIVEN COOL AIR ALOFT AND PRESENCE OF AT LEAST WEAK CONVERGENCE ALONG ASSOCIATED SFC TROUGH. WITH AREA VWP DATA ALREADY SHOWING AN INCREASE IN LOW TO MID-LVL FLOW...AND SOME DEGREE OF LOW TO MID-LVL VEERING...WITH 700 MB WINDS AROUND 25 KTS AT LOUISVILLE...THERE IS SOME CONCERN THAT A FEW STORMS COULD BECOME SUSTAINED ENOUGH TO POSE A RISK FOR SVR HAIL...LOCALLY DMGG WIND...AND PERHAPS A TORNADO OR TWO. ANY SUCH THREAT SHOULD BE GREATEST DURING THE EARLY STAGES OF STORM DEVELOPMENT...WITH THE ACTIVITY TENDING TO MERGE INTO SMALL CLUSTERS LATER TODAY INTO TNGT. FARTHER SE...BELT OF DEEP...CONFLUENT SSELY FLOW EXTENDING S AND SE OF UPR LOW MAY YIELD SUFFICIENT DEEP SHEAR TO PRODUCE A FEW MULTICELL CLUSTERS WITH A CONDITIONAL DMGG WIND THREAT...ESPECIALLY ALONG THE S ATLANTIC CST...WHERE PW IS GREATEST AND SFC HEATING WILL BE MAXIMIZED. ..CORFIDI/MOSIER.. 07/13/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z |