SPC AC 091316
   
   DAY 1 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0816 AM CDT FRI APR 09 2004
   
   VALID 091300Z - 101200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 NNE
   JCT 35 NNE SJT 55 N ABI 40 SSW LTS CDS 45 SSW GAG GAG END BVO FYV 10
   SE LIT ELD GGG 60 NW AUS 40 NNE JCT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 60 W MIA 10 N VRB.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 SE P07 MAF 25 WNW
   CNM 30 NW ELP 35 NNE DUG 45 NW TUS 25 S BLH 25 NW BLH 35 NNW EED 35
   WSW SGU 25 NNE CDC 35 S SLC 30 E BYI 75 NE BOI 60 ESE S80 25 SW HLN
   30 SSE BIL 40 NNW CPR 40 ESE CYS 30 SSE AKO 40 NW GCK 50 E ICT 35 NW
   UNO PAH 30 SW CKV 25 WSW MSL 20 SSW CBM 30 NW HEZ 30 WNW POE 45 WSW
   GLS.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING
   ACROSS THE SOUTHERN PLAINS...
   
   CORRECTED FOR SLIGHT RISK AREA ARROW DIRECTION
   
   UPPER FLOW REGIME HAS BECOME AMPLIFIED FROM THE EASTERN PACIFIC INTO
   THE ROCKIES.  MODELS SUGGEST THIS WILL REMAIN THE CASE THROUGH THIS
   FORECAST PERIOD...WITH SHARP UPPER RIDGE PERSISTING NEAR THE PACIFIC
   COAST. MULTIPLE BELTS OF STRONGER FLOW DOWNSTREAM OF RIDGE AXIS
   WILL MERGE IN CONFLUENT REGIME ACROSS THE PLAINS/MISSISSIPPI VALLEY
   ...BEFORE CONTINUING IN MORE OR LESS ZONAL FASHION  ACROSS THE
   ATLANTIC SEABOARD.
   
   ...CENTRAL ROCKIES INTO LOWER MISSISSIPPI VALLEY...
   WHILE A COLD SURFACE RIDGE HAS ALREADY NOSED SOUTHWARD BENEATH
   CONFLUENT UPPER FLOW REGIME FROM THE NORTHERN PLAINS INTO THE
   CENTRAL GULF COAST STATES...A WEAK SURFACE LOW HAS FORMED IN THE LEE
   OF THE CENTRAL ROCKIES.  THIS IS IN RESPONSE TO SHORT WAVE TROUGH
   NOW MIGRATING ACROSS THE TEXAS/OKLAHOMA PANHANDLE REGION...AND
   PROGGED TO CONTINUE EAST NORTHEASTWARD ACROSS THE SOUTH CENTRAL
   PLAINS TODAY...BEFORE ACCELERATING THROUGH THE MIDDLE MISSISSIPPI
   VALLEY TONIGHT.
   
   WITH UPPER SYSTEM WEAKENING IN CONFLUENT UPPER FLOW REGIME...ONLY A
   WEAK WAVE IS PROGGED TO MIGRATE SOUTHEASTWARD THEN EASTWARD ALONG
   TIGHTENING BAROCLINIC ZONE ACROSS THE SOUTHERN PLAINS RED RIVER
   VALLEY AREA.  PRIMARY LOW THROUGH EARLY EVENING WILL REMAIN
   UPSTREAM...IN THE LEE OF THE CENTRAL ROCKIES/SOUTHERN HIGH
   PLAINS...AS ANOTHER SHORT WAVE DIGS INTO THE GREAT BASIN.  THEN...
   AS ANOTHER POLAR AIR MASS SURGES SOUTHWARD IN THE LEE OF THE ROCKIES
   TONIGHT...SURFACE LOW WILL WEAKEN/REDEVELOP SOUTHEASTWARD INTO NORTH
   TEXAS.
   
   GIVEN COMPLEXITY OF EVOLVING PATTERN...CONSIDERABLE UNCERTAINTY
   EXISTS WITH REGARD TO SEVERE POTENTIAL TODAY.  THIS IS FURTHER
   COMPLICATED BY RELATIVELY MARGINAL LOW-LEVEL MOISTURE NOW IN PLACE
   ACROSS THE SOUTHERN PLAINS.  SURFACE DEW POINTS ARE GENERALLY ONLY
   IN THE LOWER/MID 50S SOUTH OF THE RED RIVER...AND WITH NO
   SUBSTANTIAL INFLUX OF MOISTURE OFF THE GULF OF MEXICO...SLOW
   NORTHWARD ADVECTION WILL ONLY RESULT IN SLIGHT MOISTURE INCREASES
   THROUGH THE DAY.
   
   STILL...WITH A CONSIDERABLE AMOUNT OF SURFACE HEATING LIKELY ACROSS
   WEST TEXAS/WESTERN AND SOUTHERN OKLAHOMA...MEAN MIXED LAYER CAPE IN
   EXCESS OF 1000 J/KG APPEARS POSSIBLE WITH MID 50S DEW POINTS. 
   DESTABILIZATION WILL BECOME MAXIMIZED AROUND PEAK HEATING
   ...NEAR/JUST AHEAD OF WAVE ALONG SURFACE FRONT ACROSS SOUTH CENTRAL
   OKLAHOMA...AS WELL AS ALONG DIFFUSE DRY LINE EXTENDING SOUTHWESTWARD
   TOWARD THE ABILENE AREA.
   
   WITH CAPPING STRONGER ALONG DRY LINE...AND LOW-LEVEL CONVERGENCE
   PROGGED TO REMAIN WEAK...CONVECTIVE DEVELOPMENT APPEARS MOST LIKELY
   NEAR FRONTAL ZONE ALONG/NORTH OF THE RED RIVER.  WHILE MID/UPPER
   FORCING FOR UPWARD VERTICAL MOTION WILL BE WEAK AT BEST...LOW-LEVEL
   WARM ADVECTION/CONVERGENCE SHOULD PROVIDE SUFFICIENT FORCING FOR
   THUNDERSTORMS...A FEW OF WHICH LIKELY WILL BE SEVERE.  DESPITE ONLY
   MODERATE WIND FIELDS...VEERING WINDS WITH HEIGHT NEAR SURFACE WAVE
   WILL CONTRIBUTE TO SUFFICIENT SHEAR FOR SUPERCELLS.  WHILE AN
   ISOLATED TORNADO IS POSSIBLE...PRIMARY THREAT WILL BE LARGE
   HAIL...ALONG WITH POTENTIAL FOR DAMAGING WIND GUSTS.
   
   DURING THE MID/LATE EVENING HOURS...MORE INTENSE CONVECTION LIKELY
   WILL BEGIN DEVELOPING SOUTH OF FRONTAL ZONE ALONG STRENGTHENING WEST
   SOUTHWESTERLY LOW-LEVEL JET AXIS INTO NORTH CENTRAL TEXAS.  LOWER
   LEVELS SHOULD REMAIN WARM...POTENTIALLY UNSTABLE ENOUGH TO SUPPORT
   CONTINUING RISK OF LARGE HAIL/DAMAGING WIND GUSTS THROUGH AROUND
   10/05-06Z...BEFORE DIMINISHING IN STRENGTH OVERNIGHT.
   
   OTHER SCATTERED STRONG/ISOLATED SEVERE STORMS ARE POSSIBLE NEAR
   PRIMARY SURFACE LOW ACROSS THE TEXAS/OKLAHOMA PANHANDLE REGION. 
   LOW-LEVELS WILL BE SUBSTANTIALLY DRIER ACROSS THIS REGION...WHICH
   WILL RESULT IN SHORTER DURATION SEVERE THREAT THAN FARTHER EAST.
   HOWEVER...DIGGING GREAT BASIN SHORT WAVE TROUGH MAY CONTRIBUTE TO
   INCREASINGLY DIVERGENT UPPER FLOW FIELD ACROSS THIS REGION... BEFORE
   BOUNDARY LAYER QUICKLY STABILIZES WITH LOSS OF DAYTIME HEATING BY
   THE 10/02-03Z TIME FRAME.
   
   ...INTERMOUNTAIN WEST/ROCKIES...
   COOL MID-LEVELS ASSOCIATED WITH WEAKENING TROUGH/SHEAR AXIS ACROSS
   THE FOUR CORNERS REGION/SOUTHERN PLATEAU WILL CONTRIBUTE TO
   DESTABILIZATION/CONVECTIVE DEVELOPMENT WITH DAYTIME HEATING. OTHER
   SCATTERED THUNDERSTORMS ARE LIKELY IN ASSOCIATION WITH COOLING/LIFT
   IN EXIT REGION OF UPPER JET STREAK DIGGING INTO THE GREAT BASIN THIS
   AFTERNOON.  WHILE COVERAGE OF STORMS WILL DIMINISH WITH LOSS OF
   DAYTIME HEATING...FORCING ASSOCIATED WITH DIGGING JET MAY BE
   SUFFICIENT FOR CONTINUATION OF A FEW THUNDERSTORMS ACROSS THE
   CENTRAL ROCKIES INTO THE OVERNIGHT HOURS.
   
   ...FLORIDA...
   IMPULSE EVIDENT IN WATER VAPOR IMAGERY...ALONG SUBTROPICAL JET OVER
   THE GULF OF MEXICO...WILL PROGRESS EASTWARD ACROSS THE FLORIDA
   PENINSULA TODAY.  MODELS SUGGEST THIS WILL RESULT IN INCREASING
   LOW-LEVEL CONVERGENCE ALONG THE SOUTHERN FLORIDA ATLANTIC COAST
   DURING PEAK HEATING...WHEN MEAN MIXED LAYER CAPE WILL EXCEED 1000
   J/KG.  THOUGH LOW-LEVEL FLOW WILL BE FAIRLY WEAK...MODERATE SHEAR
   AND UNSATURATED LOW/MID-LEVEL ENVIRONMENT MAY SUPPORT A FEW VIGOROUS
   CELLS WITH GUSTY WINDS APPROACHING OR BRIEFLY EXCEEDING SEVERE
   LIMITS.
   
   ..KERR.. 04/09/2004
   
   ...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 1630Z