SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT SUN JUL 07 2013 VALID 091200Z - 101200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE CNTRL AND NRN PLAINS INTO THE UPPER MS VALLEY AND WRN GREAT LAKES... ...SYNOPSIS... TYPICAL SUMMER SYNOPTIC PATTERN WITH EXPANSIVE UPPER RIDGE OVER THE SRN TWO THIRDS OF THE COUNTRY AND BELT OF STRONGER WLYS OVER THE NRN TIER STATES WILL PREVAIL TUESDAY. A LOW AMPLITUDE SHORTWAVE TROUGH EMBEDDED WITHIN THIS BELT OF STRONGER FLOW IS FORECAST TO MOVE FROM ERN MT EARLY TUESDAY TO THE WRN GREAT LAKES BY THE END OF THE PERIOD. THERE IS ALSO SOME INDICATION AMONG MODELS THAT AN MCV OR TWO MIGHT DEVELOP AHEAD OF THE SHORTWAVE TROUGH IN ASSOCIATION WITH ONGOING CONVECTION. AT THE SFC A QUASISTATIONARY FRONT /PORTIONS OF WHICH MAY BE CONVECTIVELY REINFORCED/ WILL LINGER FROM THE GREAT LAKES WWD THROUGH IA AND NEB. THE NRN STREAM SHORTWAVE TROUGH WILL PROVIDE THE IMPETUS FOR A COLD FRONT TO ACCELERATE SEWD THROUGH THE NRN/CNTRL PLAINS AND UPPER MS VALLEY. BY THE END OF THE PERIOD THIS BOUNDARY IS FORECAST TO EXTEND FROM THE GREAT LAKES SWWD THROUGH KS. ...CNTRL/NRN PLAINS THROUGH UPPER MS VALLEY AND GREAT LAKES... MAIN COMPLICATING FACTOR THIS FORECAST IS POTENTIAL FOR WIDESPREAD CONVECTION TO BE ONGOING EARLY TUESDAY. MCS MAY BE IN PROGRESS FROM ND INTO NRN MN AND FARTHER SOUTH FROM IA INTO THE SRN GREAT LAKES OR NRN OH VALLEY WITHIN A BROAD ZONE OF WARM ADVECTION. THIS ACTIVITY SHOULD CONTINUE EAST ALLOWING POTENTIAL FOR THE UPSTREAM BOUNDARY LAYER TO DESTABILIZE. WHILE SOME CONVECTIVE DEBRIS MIGHT LINGER A PORTION OF THE DAY...AT LEAST PARTIAL CLEARING SHOULD DEVELOP FROM THE WEST. A BROAD FETCH OF MULTI-DAY SLY WINDS AND EVAPOTRANSPIRATION WILL CONTRIBUTE TO UPPER 60S DEWPOINTS IN PRE-FRONTAL WARM SECTOR...WHILE PLUME OF STEEPER LAPSE RATES ADVECT EWD ABOVE THE MOIST AXIS. ASSUMING THE EARLY CONVECTION IS NOT TOO WIDESPREAD AND CONTINUES EAST...POTENTIAL WILL EXIST FOR A RESERVOIR OF STRONG INSTABILITY TO DEVELOP FROM ERN NEB...SERN SD...SRN MN INTO IA WITH MLCAPE FROM 2000-3000 J/KG POSSIBLE. STORMS SHOULD REDEVELOP DURING THE AFTERNOON ALONG RESIDUAL PRE-FRONTAL OUTFLOW BOUNDARIES AND SEWD ADVANCING COLD FRONT. THIS REGION WILL EXIST WITHIN BELT OF MODERATE WLY FLOW AOA 500 MB WITH 30-45 KT EFFECTIVE SHEAR SUPPORTIVE OF ORGANIZED STORMS INCLUDING SUPERCELLS AND LINES WITH BOWING SEGMENTS. DAMAGING WIND AND LARGE HAIL WILL BE THE MAIN THREATS...BUT A CONDITIONAL THREAT WILL ALSO EXIST FOR ISOLATED TORNADOES...ESPECIALLY OVER THE UPPER MS VALLEY REGION. ..DIAL.. 07/07/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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