SPC AC 090545
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1245 AM CDT SAT APR 09 2005
   
   VALID 101200Z - 111200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM RSL
   OTG BRD 30 SSW DLH 60 NNE EAU 40 ESE OMA STJ 15 N SZL UNO PBF POE
   BPT HOU 35 NNE VCT SAT BWD FSI CSM 55 NE AMA LBL RSL.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 45 ENE ELO RHI RFD
   SPI MKL JAN BTR 30 SSE 7R4 ...CONT... 35 S CRP COT JCT ABI INK ELP
   GNT 4BL 15 NNE CNY 20 NNE RWL CYS LIC GLD EAR YKN ATY 70 W RRT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 N CLM SEA RDM MFR
   15 WSW CEC.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SUNDAY/SUNDAY NIGHT FROM THE
   SOUTHERN PLAINS INTO PARTS OF THE UPPER MISSISSIPPI VALLEY....
   
   MODELS CONTINUE TO INDICATE UPPER FLOW PATTERN WILL BEGIN TO
   TRANSITION TOWARD A LESS PROGRESSIVE REGIME DURING THIS FORECAST
   PERIOD.  A BLOCKING UPPER RIDGE DEVELOPING ACROSS ONTARIO AND THE
   UPPER GREAT LAKES WILL GRADUALLY BECOME MORE PROMINENT...AND THIS IS
   EXPECTED TO SIGNIFICANTLY IMPACT EVOLUTION OF CYCLONE AS IT SHIFTS
   EAST OF THE SOUTHERN ROCKIES.
   
   SURFACE PRESSURES ASSOCIATED WITH CYCLONE DEVELOPING ACROSS
   SOUTHEAST COLORADO TODAY...IN RESPONSE TO STRONG TROUGH DIGGING INTO
   THE FOUR CORNERS REGION/SOUTH CENTRAL ROCKIES...ARE PROGGED TO
   BOTTOM OUT BY 12Z SUNDAY.  STILL...MODELS SUGGEST A DEEP SURFACE
   CYCLONE WILL ACCOMPANY EVOLVING MID-LEVEL CIRCULATION EAST OF THE
   SOUTHERN ROCKIES INTO SOUTH CENTRAL PLAINS SUNDAY/SUNDAY NIGHT. 
   THIS WILL OCCUR AS ANOTHER STRONG UPPER JET NOSES INTO THE PACIFIC
   NORTHWEST.  IN RESPONSE TO LATTER FEATURE...CLOSED LOW... ALREADY
   BEGINNING TO EVOLVE ACROSS THE NORTHERN HIGH PLAINS...WILL WEAKEN
   AND LIFT INTO THE CENTRAL CANADIAN PROVINCES...AROUND WESTERN
   PERIPHERY OF UPPER RIDGE.
   
   EVOLVING SYNOPTIC PATTERN WILL CONTRIBUTE TO INCREASING INSTABILITY
   BY SUNDAY AFTERNOON ALONG A QUASI-STATIONARY FRONT...FROM CENTRAL
   MINNESOTA INTO VICINITY OF SURFACE LOW ACROSS THE TEXAS
   PANHANDLE/WESTERN OKLAHOMA...AND ALONG A SURFACE DRY LINE ARCING
   SOUTHWARD THROUGH CENTRAL OKLAHOMA/TEXAS.  WITH SIGNIFICANT RETURN
   FLOW OF MOISTURE OFF THE WESTERN GULF OF MEXICO STILL NOT LIKELY
   NORTH OF SOUTHEAST TEXAS BY THE BEGINNING OF THE PERIOD...MAGNITUDE
   OF DESTABILIZATION IS STILL IN QUESTION.  THIS...IN CONJUNCTION WITH
   UNCERTAINTIES ASSOCIATED WITH SMALLER SCALE PERTURBATIONS WITHIN
   BROADER...SOUTHERN CYCLONIC CIRCULATION PROVIDES CONSIDERABLE
   UNCERTAINTY ABOUT EXPECTED AREAL COVERAGE/ INTENSITY OF SEVERE
   THREAT SUNDAY.
   
   MODELS HAVE GENERALLY BEEN CONSISTENT IN INDICATING A 70 TO 90 KT
   MID-LEVEL JET STREAK WILL REDEVELOP AROUND SOUTHERN/EASTERN
   PERIPHERY OF SOUTHERN CLOSED LOW.  THIS FEATURE IS PROGGED TO
   MIGRATE NORTH/EAST OF THE TEXAS BIG BEND REGION AROUND/SHORTLY AFTER
   PEAK HEATING SUNDAY...AND APPEARS LIKELY TO GENERATE BEST CHANCE OF
   SEVERE STORMS ACROSS THE SOUTHERN PLAINS.
   
   ...SOUTHERN PLAINS...
   FORCING NEAR/EAST OF SURFACE LOW OVER WESTERN OKLAHOMA...AND SURFACE
   DRY LINE SETTING UP ROUGHLY ALONG THE INTERSTATE 35 CORRIDOR OF
   CENTRAL OKLAHOMA/NORTH CENTRAL TEXAS...MAY PROVIDE MAIN FOCUS FOR
   INTENSE CONVECTIVE DEVELOPMENT.  MODELS SUGGEST AT LEAST NARROW
   INSTABILITY AXIS ALONG/EAST OF THESE FEATURES BY LATE AFTERNOON. 
   SURFACE DEW POINTS NEAR 60F APPEAR POSSIBLE...AND STRONG HEATING MAY
   CONTRIBUTE TO MIXED LAYER CAPE IN EXCESS OF 1000 J/KG...PERHAPS
   LOCALLY AS HIGH AS 2000 J/KG.
   
   AS STORMS INITIATE LATE SUNDAY AFTERNOON...STRONG VERTICAL SHEAR
   WILL BE SUPPORTIVE OF SUPERCELLS WITH POTENTIAL FOR VERY LARGE
   HAIL/DAMAGING WIND GUSTS.  ISOLATED TORNADOES WILL ALSO BE
   POSSIBLE...PARTICULARLY IN CLOSER PROXIMITY TO SURFACE LOW...WHERE
   LOW-LEVEL HODOGRAPHS WILL BE ENLARGED AND AMBIENT VERTICAL VORTICITY
   ALREADY MOST FAVORABLE.  HOWEVER...TORNADO THREAT MAY BE MITIGATED
   BY RATHER RAPID EVOLUTION OF SQUALL LINE BY EARLY SUNDAY
   EVENING...PARTICULARLY IF NAM SOLUTION OF FASTER MID-LEVEL COOLING
   ALONG DRY LINE COMES CLOSEST TO VERIFYING.
   
   STRONG FORCING MAY MAINTAIN SQUALL LINE WITH A DAMAGING WIND/HAIL
   THREAT EASTWARD THROUGH PARTS OF SOUTHWEST MISSOURI/WESTERN ARKANSAS
   AND THE ARKLATEX SUNDAY NIGHT.
   
   ..KERR.. 04/09/2005
   
   ...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 1730Z