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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 141245 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0745 AM CDT FRI JUN 14 2013 VALID 141300Z - 151200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF ERN SD AND WRN MN INTO THE MID-MO VALLEY AND CNTRL PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF NRN FL... ...SYNOPSIS... A SLIGHT DE-AMPLIFICATION OF THE LARGE-SCALE PATTERN IS FORECAST DURING THE D1 PERIOD WITH THE PRIMARY FEATURE OF INTEREST BEING A MIGRATORY SHORT-WAVE TROUGH THAT WILL TRANSLATE NEWD THROUGH THE NRN HIGH PLAINS INTO THE CANADIAN PRAIRIE PROVINCES. THIS SYSTEM WILL BE ATTENDED BY MID AND UPPER-LEVEL JET STREAKS AND A CORRIDOR OF MODEST HEIGHT FALLS THAT WILL GLANCE AN ASSOCIATED SURFACE COLD FRONT ADVANCING EWD FROM THE NRN HIGH PLAINS. BY 15/00Z...THIS FRONT IS EXPECTED TO LIE IN N-S FASHION ACROSS CNTRL PARTS OF THE DAKOTAS AND NEB BEFORE ARCING SWWD TO A LEE LOW OVER NWRN KS. THIS BOUNDARY WILL CONJOIN WITH A WARM FRONT OVER ERN NEB WHICH WILL TRAIL SSEWD INTO THE OZARK PLATEAU. ...MID-MO VALLEY INTO CNTRL HIGH PLAINS THIS AFTERNOON INTO TONIGHT... WAA/ISENTROPIC ASCENT ENHANCED BY A NOCTURNAL LOW-LEVEL WIND MAXIMUM TO THE N OF SFC WARM FRONT IS SUPPORTING ONGOING...ELEVATED TSTMS FROM S-CNTRL NEB INTO CNTRL IA AND NWRN MO. THIS ACTIVITY WILL LIKELY PERSIST...PERHAPS INTENSIFYING BY LATE MORNING INTO AFTERNOON ACROSS PARTS OF SRN IA/NRN MO WHERE ISOLATED OCCURRENCES OF HAIL AND DAMAGING WINDS WILL BE POSSIBLE. IN THE WAKE OF THE INITIAL STORMS....STEEP LAPSE RATES AND INCREASING BOUNDARY LAYER MOISTURE CONTENT WILL YIELD A MODERATELY TO STRONGLY UNSTABLE WARM SECTOR BY AFTERNOON WITH MLCAPE VALUES APPROACHING 2000-3000+ J/KG. LATEST MODEL GUIDANCE SUGGESTS AN INCREASED LIKELIHOOD FOR SURFACE-BASED STORM DEVELOPMENT BY MID AFTERNOON FROM THE VICINITY OF THE NWRN KS LEE LOW NEWD ALONG THE COLD FRONT INTO CNTRL NEB WHERE STRONG HEATING WILL BOOST SFC TEMPERATURES IN THE 90S TO LOW 100S. GIVEN FAIRLY LARGE T-TD SPREADS AND MODEST /30-35 KT/ DEEP-LAYER SHEAR...HIGH-BASED MULTICELLS CAPABLE OF DAMAGING WINDS AND HAIL APPEAR PROBABLE. IN SITU STORM DEVELOPMENT NEAR THE SFC TRIPLE POINT SSEWD ALONG THE WARM FRONT OVER ERN NEB REMAINS MORE UNCERTAIN OWING TO THE POSSIBILITY OF LINGERING CLOUDS ASSOCIATED WITH ONGOING STORMS. HOWEVER...SHOULD SURFACE-BASED TSTMS DEVELOP AND BECOME SUSTAINED...THE COMBINATION OF STRONG INSTABILITY AND MODERATELY STRONG LOW-LEVEL AND DEEP-LAYER SHEAR WILL BE SUPPORTIVE OF SUPERCELLS CAPABLE OF LARGE HAIL AND POSSIBLY A FEW TORNADOES. THE REDEVELOPMENT OF A NOCTURNAL LOW-LEVEL WIND MAXIMUM WILL PROMOTE THE UPSCALE GROWTH OF DIURNAL STORMS INTO CLUSTERS BY LATE EVENING WITH THE RISK FOR DAMAGING WINDS AND HAIL CONTINUING INTO THE OVERNIGHT HOURS ACROSS PARTS OF THE MID AND LOWER-MO VALLEY. ...ERN SD INTO THE RED RIVER VALLEY THIS AFTERNOON AND EVENING... ELEVATED TSTMS OVER THE WRN DAKOTAS ARE LIKELY BEING FORCED BY HEIGHT FALLS/DCVA ATTENDANT TO THE NRN HIGH PLAINS SHORT-WAVE TROUGH. A SUBSET OF THESE STORMS MAY PERSIST TODAY...SHIFTING NEWD WITH TIME WITH SOME RISK FOR HAIL. BY MID TO LATE AFTERNOON...LOW-LEVEL CONVERGENCE ALONG THE COLD FRONT COUPLED WITH THE GLANCING INFLUENCE OF THE SHORT-WAVE TROUGH WILL FOSTER WIDELY SCATTERED...SURFACE-BASED STORMS ACROSS THE ERN DAKOTAS. WHILE ISOLATED OCCURRENCES OF DAMAGING WINDS AND HAIL WILL BE THE PRIMARY HAZARDS...A TORNADO IS POSSIBLE OWING TO THE ENHANCEMENT OF LOW-LEVEL SHEAR ALONG THE NRN EXTENT OF THE LLJ. ...NRN FL THIS AFTERNOON AND EVENING... THE 12Z TLH/JAX SOUNDINGS SHOWED THE PRESENCE OF A VERY MOIST BOUNDARY LAYER /I.E. LOWEST-100-MB MEAN MIXING RATIOS OF AROUND 18 G PER KG/ BENEATH MODERATELY STEEP MIDLEVEL LAPSE RATES WHICH WHEN COUPLED WITH DIURNAL HEATING WILL RESULT IN A STRONGLY UNSTABLE AIR MASS LATER TODAY. WHILE LARGE-SCALE FORCING FOR ASCENT WILL DIMINISH TODAY WITH THE PASSAGE OF THE MIDLEVEL TROUGH TO THE E...UPLIFT ALONG THE SWD-SAGGING COLD FRONT AND DEVELOPING SEA BREEZE CIRCULATIONS SHOULD BE SUFFICIENT TO FOSTER SCATTERED TSTMS BY AFTERNOON. GIVEN THE DEGREE OF INSTABILITY AND 40-45 KT OF DEEP NLY SHEAR...THE SETUP APPEARS FAVORABLE FOR A FEW ORGANIZED/ROTATING STORMS CAPABLE OF DAMAGING WINDS AND PERHAPS SOME HAIL. ..MEAD/COHEN.. 06/14/2013 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z |