SPC 0600Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0100 AM CDT SUN APR 29 2012 VALID 301200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN AND CNTRL PLAINS... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE MID MS VALLEY INTO THE OH VALLEY... ...SYNOPSIS... BLOCKING PATTERN WILL BREAK DOWN AND TRANSITION TO QUASI-ZONAL WITH SEVERAL LOW AMPLITUDE IMPULSES MOVING THROUGH THIS REGIME. QUASI-STATIONARY FRONT SHOULD EXTEND FROM THE CAROLINAS WWD INTO THE MID MS VALLEY AND CNTRL/SRN PLAINS EARLY MONDAY. THE BOUNDARY MAY LIFT SLOWLY NWD DURING THE DAY WITHIN BROAD ZONE OF SLY FLOW ESTABLISHED BY GRADIENT BETWEEN HIGH PRESSURE EXITING THE ERN SEABOARD AND DEVELOPING LEE TROUGH OVER THE HIGH PLAINS. HOWEVER...NWD ADVANCE AND EVOLUTION OF THIS FRONT WILL LIKELY BE MODULATED BY ONGOING CONVECTION EARLY MONDAY FROM PORTIONS OF OK AND KS NEWD THROUGH THE OH VALLEY. FARTHER SOUTH A DRYLINE WILL SHARPEN FROM WRN KS THROUGH WRN TX. ...SRN AND CNTRL PLAINS AREA... STORMS SHOULD BE ONGOING WITHIN ZONE OF WARM ADVECTION AND ISENTROPIC ASCENT FROM PARTS OF OK INTO KS AND THE MS VALLEY REGION. TIMING OF INDIVIDUAL IMPULSES WILL BE DIFFICULT...BUT MODELS INDICATE A LEAD SHORTWAVE TROUGH WILL MOVE THROUGH THE CNTRL PLAINS INTO THE MID MS VALLEY EARLY IN THE PERIOD. THIS SHOULD RESULT IN AT LEAST A TEMPORARY VEERING AND WEAKENING OF LOW LEVEL WINDS OVER THE CNTRL/SRN PLAINS AS PRIMARY LLJ SHIFT NEWD TOWARD THE OH VALLEY. THUS EARLY CONVECTION MAY GRADUALLY DIMINISH FROM THE WEST ALLOWING FOR AT LEAST PARTIAL CLEARING IN WRN PORTIONS OF WARM SECTOR FROM WRN KS SWD THROUGH WRN OK AND WRN TX. IF THIS OCCURS...MODERATE INSTABILITY WILL DEVELOP WHERE THE EML PLUME WILL ADVECT EWD ABOVE AXIS OF LOW 60S DEWPOINTS SUPPORTING 1500-2000 J/KG MLCAPE. POTENTIAL WILL EXIST FOR STORMS TO REDEVELOP ESPECIALLY WHERE DRYLINE INTERSECTS RESIDUAL OUTFLOW BOUNDARIES OR WRN EXTENT OF CONVECTIVELY REINFORCED FRONT AS WELL AS SOME DISTANCE DOWN THE DRYLINE DURING THE AFTERNOON. ACTIVITY WILL SUBSEQUENTLY SPREAD EWD THROUGH KS INTO PORTIONS OF THE TX PANHANDLE AND OK. VERTICAL SHEAR FROM 40-50 KT WILL SUPPORT SUPERCELLS WITH ISOLATED LARGE HAIL AND DAMAGING WIND THE MAIN THREATS...BUT A COUPLE OF TORNADOES CANNOT BE RULED OUT. OTHER STORMS WILL BE POSSIBLE OVERNIGHT OVER CNTRL/NRN KS AS THE LLJ STRENGTHENS AND AUGMENTS ISENTROPIC ASCENT AND DESTABILIZATION NORTH OF THE FRONT. THESE STORMS COULD POSE A THREAT FOR LARGE HAIL. CONSIDERABLE UNCERTAINTY STILL EXISTS WITH REGARD TO THE EVOLUTION OF THE EARLY CONVECTION WHICH LOWERS CONFIDENCE IN INTRODUCING MORE THAN A 15% COVERAGE AREA AT THIS TIME. ...MID MS VALLEY THROUGH OH VALLEY... STORMS WILL BE ONGOING AND DEVELOP NEWD THROUGH THE MID MS AND OH VALLEY REGIONS IN ASSOCIATION WITH AN EJECTING LOW AMPLITUDE WAVE. WARM SECTOR SOUTH OF THIS ACTIVITY WILL BECOME MODERATELY UNSTABLE...AND THE STORMS WILL REMAIN EMBEDDED WITHIN SUFFICIENT UNIDIRECTIONAL SHEAR FOR ORGANIZATION AND A POTENTIAL SEVERE THREAT. IT IS POSSIBLE THAT ADDITIONAL STORMS DEVELOPING ALONG THE SRN EDGE OF THE ONGOING ACTIVITY MAY INTENSIFY DURING THE AFTERNOON AS THE BOUNDARY LAYER DESTABILIZES. SOME OF THE STORMS MAY BECOME CAPABLE OF PRODUCING ISOLATED DAMAGING WIND AND HAIL THROUGH EARLY EVENING. ..DIAL.. 04/29/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_0600.html
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