SPC 0730Z Day 3 Outlook
DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0236 AM CDT SUN APR 29 2012 VALID 011200Z - 021200Z ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL AND NRN PLAINS INTO THE UPPER MS VALLEY... ...SYNOPSIS... SYNOPTIC PATTERN WILL REMAIN DOMINATED BY A BROAD LOW AMPLITUDE CYCLONIC FLOW REGIME OVER MUCH OF THE COUNTRY TUESDAY. UPPER JET STREAK AND ATTENDANT SHORTWAVE TROUGH LOCATED ABOUT 600 SM SOUTH OF THE ALEUTIAN ISLANDS AS OF EARLY SUNDAY MORNING WILL REACH THE NRN PLAINS TUESDAY. THIS FEATURE WILL BE ACCOMPANIED BY A COLD FRONT THAT WILL MOVE SEWD THROUGH THE NRN/CNTRL PLAINS AND UPPER MS VALLEY. A DRYLINE WILL STRETCH FROM THE SRN THROUGH THE CNTRL HIGH PLAINS DURING THE DAY. FARTHER EAST A WARM FRONT WILL LIFT NWD THROUGH THE UPPER MS AND OH VALLEYS. ...UPPER MS VALLEY THROUGH NRN AND CNTRL PLAINS REGIONS... LEE TROUGHING WILL HAVE BECOME ESTABLISHED OVER THE HIGH PLAINS WITHIN THE QUASI-ZONAL UPPER FLOW REGIME. AS THE WARM FRONT LIFTS NWD A BROAD...MOIST WARM SECTOR WILL ADVECT THROUGH THE REMAINDER OF THE PLAINS AND UPPER MS VALLEY WITH UPPER 50S DEWPOINTS AS FAR NORTH AS THE ERN DAKOTAS INTO MN AND LOW 60S FARTHER SOUTH. ZONE OF MODERATE INSTABILITY IS LIKELY OVER THIS REGION AS PLUME OF STEEP MID LEVEL LAPSE RATES ADVECT EWD ABOVE RETURNING MOIST AXIS AND AS THE BOUNDARY LAYER WARMS DURING THE AFTERNOON. STORMS MAY DEVELOP WITHIN ZONE OF DEEPER FORCING ALONG THE SEWD ADVANCING COLD FRONT ACROSS THE ERN DAKOTAS INTO NEB WITH MORE ISOLATED ACTIVITY POSSIBLE FARTHER SOUTH ALONG THE DRYLINE ACROSS KS. VERTICAL SHEAR FROM 35-45 KT WILL SUPPORT ORGANIZED STORMS INCLUDING SUPERCELLS. HOWEVER...SOME OF THE STORMS DEVELOPING ALONG THE FRONT FROM NEB INTO THE DAKOTAS MAY EVENTUALLY EVOLVE INTO LINES AS THEY ADVANCE TOWARD THE UPPER MS VALLEY...WHILE FARTHER SOUTH ACTIVITY WILL LIKELY REMAIN DISCRETE. LARGE HAIL AND DAMAGING WIND SHOULD BE THE MAIN THREATS...BUT ISOLATED TORNADOES WILL ALSO BE POSSIBLE. ...SRN HIGH PLAINS... A FEW STORMS MAY DEVELOP ALONG THE DRYLINE AS THE CAP WEAKENS DURING PEAK HEATING...BUT LACK OF FORCING FOR DEEP ASCENT AND A STRONG CAP SUGGEST ACTIVITY WILL REMAIN SPARSE. VERTICAL SHEAR IN MUCH OF THIS REGION WILL REMAIN MODEST...BUT THE THERMODYNAMIC ENVIRONMENT WILL SUPPORT A THREAT OF ISOLATED DAMAGING WIND AND HAIL WITH ANY STORM THAT DEVELOPS. ..DIAL.. 04/29/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html
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