SPC AC 111745
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1245 PM CDT WED MAY 11 2005
   
   VALID 121200Z - 131200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 90 SW
   P07 15 S HOB 25 W GCK 35 SW GLD 40 N GLD 15 SSW HSI 10 E OMA 35 S
   FOD 25 NW CID 25 SSE DBQ 35 SW RFD 20 SSW MMO 20 SW BMI 40 S UIN 30
   NNW TBN 25 N FYV 15 ESE TUL 40 SSE OKC 10 WNW BWD 65 W COT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 W MRF 45 N ROW 15
   SE LHX 20 WSW COS 35 N 4BL 55 W U24 45 SSE TWF 25 SSW MQM 30 S BIL
   40 WSW PHP 45 ENE PIR 60 SSW BJI 10 NE IWD 30 S TVC 20 NE CLE HLG 15
   SSW SHD 25 ENE ECG ...CONT... 20 SSE SAV 20 WSW ATL 35 S LUL 50 W
   MLU 25 ESE FSM 30 N DUA 10 SE TPL 25 ESE MFE.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE
   CENTRAL/SRN PLAINS TO THE UPPER MIDWEST...
   
   ...SYNOPSIS...
   LARGE UPPER LOW OVER THE WRN STATES WILL DE-AMPLIFY FROM DAY 1 INTO
   DAY 2 AS IT TRACKS NEWD TOWARD THE NRN PLAINS ON THURSDAY.  THIS LOW
   WILL EVOLVE INTO AN OPEN WAVE ACROSS THE DAKOTAS THURSDAY NIGHT AS
   IT BEGINS TO MERGE WITH NRN STREAM FLOW OVER CANADA.  A COUPLE OF
   SHORT WAVE TROUGHS ASSOCIATED WITH THE UPPER LOW ARE PROGGED TO MOVE
   ENEWD ACROSS THE CENTRAL PLAINS TO UPPER MIDWEST BEGINNING LATE
   THURSDAY AFTERNOON...WITH STRONGEST HEIGHT FALLS EXPECTED GENERALLY
   AFTER 00Z.
   
   AT THE SURFACE...A LOW INITIALLY OVER SRN NEB WILL WEAKEN AS IT
   TRACKS EWD TOWARD SRN IA BY 13/00Z...WITH A TRAILING COLD FRONT
   MOVING SLOWLY EWD ACROSS CENTRAL KS.  DRY LINE EXTENDING SWD ACROSS
   THE OK/TX PANHANDLES TO WRN TX WILL REMAIN QUASI-STATIONARY THIS
   PERIOD.  MEANWHILE...A BOUNDARY EXTENDING ESEWD TO THE OH VALLEY
   FROM THE NEB SURFACE LOW SHOULD REMAIN MAINLY STATIONARY...BUT
   RETREAT NWD OVER MID MS AND LOWER OH VALLEYS.
   
   ...CENTRAL/SRN PLAINS EWD INTO THE UPPER MIDWEST...
   ELEVATED MCS...POTENTIALLY SEVERE...SHOULD BE ONGOING AT THE START
   OF THE PERIOD ACROSS PORTIONS OF CENTRAL/ERN NEB AND NRN KS ALONG
   NOSE OF SWLY LLJ.  THIS ACTIVITY IS EXPECTED TO DIMINISH IN
   INTENSITY AS THE LLJ WEAKENS/REDEVELOPS FROM THE SRN PLAINS TO LOWER
   MO RIVER VALLEY BY AFTERNOON.  AXIS OF RICH MOISTURE WILL REMAIN
   ACROSS THE WARM SECTOR WITH SURFACE DEWPOINTS IN THE UPPER 60S
   CONTRIBUTING TO STRONG INSTABILITY.  SURFACE HEATING IS EXPECTED TO
   BE THE PRIMARY IMPETUS FOR THUNDERSTORM DEVELOPMENT ALONG THE DRY
   LINE AND NEWD ALONG THE COLD FRONT TO THE SURFACE LOW...GIVEN THE
   LACK OF A WELL DEFINED MID LEVEL SYSTEM MOVING OVER THIS REGION
   DURING THE AFTERNOON.
   
   LARGE SCALE ASCENT WITHIN THE ENTRANCE REGION OF A 50-60 KT SSWLY
   MID LEVEL JET...TRANSLATING NEWD ACROSS THE CENTRAL PLAINS TO NRN MS
   VALLEY...WILL AID IN SUSTAINED UPDRAFTS AS STORMS BECOME RAPIDLY
   SEVERE ALONG THE DRY LINE FROM NWRN TX INTO WRN OK AND SWRN-SOUTH
   CENTRAL KS WITHIN A VERY UNSTABLE AIR MASS.  DEEP LAYER SHEAR
   VECTORS CROSSING THE DRY LINE WILL SUPPORT SUPERCELLS WITH VERY
   LARGE HAIL...DAMAGING WINDS AND TORNADOES POSSIBLE.  STORMS WILL
   ALSO DEVELOP NEWD ALONG THE COLD FRONT TO THE VICINITY OF THE
   SURFACE LOW AS IT TRACKS INTO SRN IA.  MODERATE INSTABILITY AND DEEP
   LAYER SHEAR VECTORS ORIENTED ALONG THE BOUNDARY WOULD FAVOR A
   GREATER POTENTIAL FOR LINE SEGMENTS OVER THIS AREA.
   
   AS HEIGHT FALLS SPREAD EWD ACROSS THE CENTRAL PLAINS TO UPPER
   MIDWEST...SWLY LLJ WILL STRENGTHEN TO 40-45 KT NOSING INTO NRN
   OK/SRN KS.  THIS SUGGESTS UPSCALE DEVELOPMENT INTO AN MCS WITH HAIL
   AND DAMAGING WINDS BEING THE PRIMARY THREATS AS ACTIVITY SPREADS EWD
   TOWARD WRN MO BY 12Z FRIDAY.
   
   ...MID MS/OH VALLEYS...
   MODELS SUGGEST CONVECTION WILL DEVELOP ALONG THE SURFACE BOUNDARY
   FROM SRN WV/SWRN VA WNWWD ACROSS KY TO SRN IL/SERN IA. ALTHOUGH THE
   AIR MASS WILL BE MODERATELY UNSTABLE...MODEST DEEP LAYER SHEAR
   SHOULD SUPPORT MULTICELLS.  PINPOINTING A HIGHER RISK FOR SEVERE
   POTENTIAL IS DIFFICULT ATTM GIVEN SOME UNCERTAINTY WITH LOCATION OF
   SURFACE BOUNDARY.  THUS HAVE MAINTAINED FORECAST OF LOW
   PROBABILITIES.
   
   ..PETERS.. 05/11/2005
   
   ...NOTICE...
   THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
   SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
   WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
   IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
   CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
   WILL PROVIDE DETAILS ON THE TRANSITION.
   
   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z