SPC AC 191636
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1036 AM CST FRI MAR 19 2004
   
   VALID 191630Z - 201200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM END 15
   SW EMP 10 E OJC IRK OTM 30 NNE MLI MMO LAF 10 SSE CKV MEM 55 NE LIT
   PGO DUA 35 ENE SPS END.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SSE MTC 30 SW UNI
   35 SSE JKL 20 SSE TYS 10 W GAD CBM 40 N MWL 35 SSW LTS 35 W CSM 25 E
   DDC 10 SW SLN 15 W FNB 15 WSW ALO 10 NNE LNR 45 SSE IMT 55 NE ESC 45
   NNW ANJ.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS TODAY/TONIGHT FROM PARTS OF THE
   SRN PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY....
   
   INTENSE ZONAL MID/UPPER JET CONTINUES TO NOSE EASTWARD ALONG THE
   WESTERN CANADIAN/U.S. BORDER.  FORCING ASSOCIATED WITH THIS FEATURE 
   HAS ALREADY SUPPORTED CYCLOGENESIS IN THE LEE OF THE CANADIAN
   ROCKIES.  MODELS INDICATE SURFACE CYCLONE WILL MIGRATE EASTWARD
   ACROSS THE CENTRAL CANADIAN PRAIRIES...INTO ONTARIO BY LATE
   TONIGHT...AS UPPER JET STREAK PROGRESSES EASTWARD INTO THE VICINITY
   OF THE CENTRAL CANADIAN/U.S. BORDER.  SLIGHT AMPLIFICATION OF UPPER
   FLOW REGIME IS FORECAST TO OCCUR TONIGHT ACROSS THIS REGION...WHICH
   WILL BE ACCOMPANIED BY A SOUTHWARD SURGE OF COLD FRONT INTO THE
   UPPER MISSISSIPPI VALLEY/GREAT LAKES REGION.
   
   IN RESPONSE TO EVOLVING LARGE-SCALE PATTERN...TONGUE OF LOW-LEVEL
   MOISTURE...NOW IN PLACE FROM THE SOUTHERN PLAINS INTO THE OZARKS...
   WILL CONTINUE TO ADVECT NORTHEASTWARD THROUGH THE MIDDLE MISSISSIPPI
   VALLEY.  AT THE SAME TIME...WESTERLY FLOW ABOVE RETURNING MOISTURE
   WILL ADVECT INCREASINGLY WARM ELEVATED MIXED LAYER FROM THE PLAINS
   INTO THE MISSISSIPPI VALLEY.
   
   GIVEN PRESENCE OF MID-LEVEL CAPPING...AND LACK OF MORE READILY
   APPARENT SIGNIFICANT FORCING FOR UPWARD VERTICAL MOTION...THERE
   REMAINS CONSIDERABLE UNCERTAINTY WITH REGARD TO CONVECTIVE POTENTIAL
   TODAY. HOWEVER...EVOLUTION OF WEAK TO MODERATE POTENTIAL CONVECTIVE
   INSTABILITY OVER FAIRLY BROAD AREA OF THE CENTRAL U.S. SUPPORTS AT
   LOW PROBABILITY SEVERE THREAT.
   
   ...SOUTHERN PLAINS INTO MIDDLE MISSISSIPPI VALLEY...
   LATEST WATER VAPOR IMAGERY SUPPORTS MODELS WHICH INDICATE MID-LEVEL
   WAVE MIGRATING OUT OF THE GREAT BASIN INTO THE SOUTH CENTRAL PLAINS
   TODAY...ON NORTHERN PERIPHERY OF SUBTROPICAL RIDGE.  WHILE FORCING
   WITH THIS FEATURE WILL BE WEAK...SUFFICIENT WEAKENING OF CAP MAY
   OCCUR IN CONJUNCTION WITH DAYTIME HEATING TO SUPPORT CONVECTIVE
   INITIATION ALONG DRY LINE...FROM PARTS OF WESTERN OKLAHOMA INTO
   SOUTH CENTRAL KANSAS...LATE THIS AFTERNOON.  ALTHOUGH VERTICAL SHEAR
   PROFILES WILL ONLY BE MODERATE IN STRENGTH...THIS SHOULD BE
   SUFFICIENT...GIVEN FAVORABLE THERMODYNAMIC ENVIRONMENT...FOR
   SUPERCELLS.  ANY ACTIVITY WHICH DEVELOPS LIKELY WILL BE ISOLATED TO
   WIDELY SCATTERED IN COVERAGE AT BEST...AND SHOULD WEAKEN AS
   INHIBITION INCREASES WITH LOSS OF DAYTIME HEATING.
   
   NOCTURNAL STRENGTHENING OF LOW-LEVEL JET THIS EVENING...ALONG
   NORTHERN FRINGE OF SOUTHEASTERN STATES LOW-LEVEL RIDGE...WILL FOCUS
   LOW-LEVEL WARM ADVECTION ALONG AN AXIS FROM EASTERN OKLAHOMA INTO
   THE MISSOURI OZARKS.  THIS MAY SUPPORT ADDITIONAL VIGOROUS
   CONVECTIVE DEVELOPMENT...BUT LOW-LEVEL FORCING MAY BE OFFSET BY
   FURTHER STRENGTHENING OF MID-LEVEL CAP.
   
   IT CURRENTLY APPEARS BEST CHANCE FOR STRONG/SEVERE THUNDERSTORM
   ACTIVITY WILL BE LATER TONIGHT...AS VEERING LOW-LEVEL FLOW FOCUSES
   WARM ADVECTION ON EASTERN PERIPHERY OF ELEVATED MIXED LAYER.  THIS 
   LIKELY WILL SET UP SOMEWHERE NEAR/JUST EAST OF THE MISSISSIPPI
   RIVER...FROM MISSOURI/ILLINOIS INTO THE VICINITY OF THE ARKANSAS/
   TENNESSEE BORDER.  PRIMARY SEVERE THREAT WILL BE  LARGE HAIL AS CAPE
   FOR PARCELS LIFTED ABOVE SURFACE INVERSION INCREASES INTO THE 1000
   TO 2000 J/KG RANGE.
   
   ...UPPER MISSISSIPPI VALLEY INTO GREAT LAKES...
   FORCING FOR UPWARD VERTICAL MOTION AND DESTABILIZATION WILL INCREASE
   ACROSS THIS REGION...ALONG/JUST NORTH OF SOUTHWARD ADVANCING COLD
   FRONT. THIS SHOULD BE SUFFICIENT FOR THE DEVELOPMENT OF A LINE OF
   THUNDERSTORMS. WHILE INSTABILITY WILL BE WEAKER THAN AREAS TO THE
   SOUTH...LAPSE RATES/CAPE AND SHEAR ABOVE FRONTAL INVERSION MAY BE
   SUFFICIENT FOR MARGINALLY SEVERE HAIL IN MORE VIGOROUS CELLS.
   
   ..KERR/JEWELL.. 03/19/2004
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 2000Z