SPC 1730Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK CORR 1 NWS STORM PREDICTION CENTER NORMAN OK 1236 PM CDT SAT JUN 02 2012 VALID 031200Z - 041200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN KS...PARTS OF NRN OK AND WRN MO... CORRECTED FOR WORDING IN FOURTH PARAGRAPH ...SYNOPSIS... A DOWNSTREAM REX BLOCK OVER THE NRN ATLANTIC/GREENLAND PERSISTING FOR AT LEAST ONE MORE DAY...AND HEIGHT RISES WSWWD INTO NRN QUEBEC/HUDSON BAY AND ADJACENT NRN ONTARIO ON SUNDAY...WILL ALLOW THE CLOSED LOW LOCATED JUST N OF THE GREAT LAKES TO PROGRESS SEWD ACROSS THE NERN STATES. MEANWHILE...A PACIFIC SHORTWAVE TROUGH... CURRENTLY LOCATED AT 39 N/147 W PER WATER VAPOR IMAGERY...WILL MOVE INTO THE BASE OF THE GULF OF AK CLOSED LOW...AIDING THE AMPLIFICATION OF THESE SYSTEMS TOWARD THE WRN CONUS. THE SLOW EWD PROGRESSION OF THE NERN U.S. TROUGH AND AMPLIFICATION OF THE PACIFIC LONGWAVE TROUGH SUPPORT RIDGING ACROSS THE ROCKIES AND PLAINS STATES. AT THE SURFACE...A BOUNDARY...ATTENDANT TO A SHORTWAVE TROUGH MOVING INTO THE LOWER OH VALLEY TODAY...CURRENTLY EXTENDED FROM WRN IL WSWWD THROUGH CENTRAL MO TO KS. THE SEWD PROGRESSION OF THE EWD EXTENT OF THIS BOUNDARY INTO THE TN VALLEY AND A NWD MOVING WARM FRONT FROM OK AND AR ARE EXPECTED TO FORM THE EFFECTIVE SURFACE BOUNDARY FOR DAY 2. THE PRIMARY FOCUS FOR TSTM DEVELOPMENT IS EXPECTED TO BE THIS BOUNDARY EXTENDING NWWD FROM NRN AL/MS THROUGH NRN AR/SWRN MO TO A DEVELOPING SURFACE LOW/TRIPLE POINT OVER NORTH CENTRAL KS BY SUNDAY AFTERNOON. ...KS/NRN OK...MID-LOWER MO VALLEY...AND PART OF TN VALLEY... A SHORTWAVE TROUGH WITH A COUPLE OF EMBEDDED MID/UPPER LEVEL IMPULSES CURRENTLY UNDERCUTTING THE RIDGE AXIS INTO THE FOUR CORNERS REGION SHOULD BE LOCATED IN THE CENTRAL PLAINS AT THE START OF DAY 2. MODELS TEND TO AGREE WITH THE PLACEMENT AND TRACK OF THESE WEAK IMPULSES ON SUNDAY...MOVING ESEWD WITHIN NWLY FLOW REGIME ALONG THE ERN EXTENT OF THE ROCKIES/PLAINS RIDGE. THESE FEATURES SHOULD MOVE ACROSS KS AND LOWER MO/MID MS VALLEYS AREAS SUNDAY AFTERNOON AND INTO OK...OZARKS TO TN VALLEY LATE SUNDAY NIGHT. A STRONG EML SPREADING EWD ATOP MOISTENING LOW LEVELS AND SURFACE HEATING WILL RESULT IN A VERY UNSTABLE AIR MASS ACROSS THE WARM SECTOR /KS INTO OK/ AND MODERATE INSTABILITY EXTENDING SEWD ACROSS THE OZARKS TO WRN TN/NRN MS/NRN AL AND ALSO NWD THROUGH THE MID MO VALLEY. WHILE THE STRONG CAP/EML SHOULD LIMIT WARM SECTOR CONVECTION...CONVERGENCE AND LOW LEVEL WAA ALONG THE SE-NW ORIENTED SURFACE BOUNDARY WILL LIKELY SUPPORT TSTM DEVELOPMENT. PERSISTENT DEVELOPMENT SHOULD RESIDE ACROSS ERN KS/WRN MO INTO NERN OK WHERE A SLY LLJ WILL BE LOCATED. THUS...STRONGEST BULK SHEAR IS EXPECTED ACROSS THE SLIGHT RISK AREA WITH THE POTENTIAL FOR SUPERCELLS. MULTICELLS SHOULD BE THE PRIMARY STORM MODE BOTH WITH SEWD EXTENT INTO TN/NRN MS/NRN AL AND NWD INTO THE MID MO VALLEY WHERE BULK SHEAR WILL TEND TO BE WEAKER. A VEERING LLJ INTO MO/OZARKS/ERN OK SUNDAY NIGHT SUGGESTS AN MCS MAY PERSIST AFTER DARK WITH SOME THREAT FOR ADDITIONAL SEVERE STORMS. ...PARTS OF SRN PA...ERN WV...FAR NRN VA AND NRN MD... DAYTIME HEATING BENEATH COOL MID-LEVEL TEMPERATURES ASSOCIATED WITH THE UPPER LOW WILL RESULT IN MODEST/LOW-TOPPED CONVECTION PER GREATEST DESTABILIZATION NEAR PEAK HEATING. GIVEN THE POTENTIAL FOR STRONGER DESTABILIZATION...THOUGH STILL WEAK WITH EWD EXTENT INTO SERN PA AND NRN MD...THE 5 PERCENT SEVERE PROBABILITY HAS BEEN EXTENDED EWD WITH THIS OUTLOOK ISSUANCE. CURRENT MODELS SUGGEST AN EWD SHIFT FOR THE GREATER POTENTIAL OF A FEW STRONGER STORMS TO DEVELOP WITHIN NWLY FLOW AND AROUND 30 KT OF BULK SHEAR. MIDLEVEL LAPSE RATES CLOSE TO 7 C/KM AND STEEP LOW LEVEL LAPSE RATES... ESPECIALLY OVER NRN VA TO SERN PA...SUGGEST HAIL AND STRONG WIND GUSTS WILL BE POSSIBLE WITH THE MORE ROBUST UPDRAFTS. WEAK INSTABILITY WILL PRECLUDE INTRODUCING HIGHER PROBABILITIES/ CATEGORICAL RISK AT THIS TIME. ..PETERS.. 06/02/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_1730.html
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