Jun-26-2004 1300 UTC Day 1 Convective Outlook
Updated: Sat Jun 26 12:57:44 UTC 2004
Categorical Graphic
20040626 1300 UTC Day 1 Outlook Graphic
Probablistic Tornado Graphic
20040626 1300 UTC Day 1 Tornado Probabilities Graphic
Probablistic Damaging Wind Graphic
20040626 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probablistic Large Hail Graphic
20040626 1300 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 261251
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0751 AM CDT SAT JUN 26 2004
   
   VALID 261300Z - 271200Z
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 70 NW
   FCA 15 NNW HLN 25 W BTM 27U 80 NNE BOI BKE 30 ESE PDT EPH 20 SW 4OM
   40 NNW 4OM.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 S FHU 10 NNW SOW
   SGU 70 WNW P38 TPH BIH 35 NNE FAT 40 NNE MER 35 WSW TVL RNO LOL 40
   SE YKM 40 ESE SEA 30 NE BLI ...CONT... 80 N GFK DLH 30 NW LSE OTM 50
   NE FNB 35 WSW FNB EMP BVO 10 ESE FSM MKL TRI 10 S DCA 20 NNE TTN 15
   SW PSF 30 ENE EFK.
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS ERN WA...NRN ID...NERN
   ORE...WRN MT...
   
   ...SYNOPSIS...
   RELATIVELY STABLE MID-UPPER LEVEL PATTERN WILL CONTINUE TO BE
   CHARACTERIZED BY HIGHLY AMPLIFIED NRN STREAM...WITH OMEGA BLOCK OVER
   NWRN NORTH AMERICA AND ADJACENT PACIFIC.  ANCHORING THIS BLOCK IS
   STRONG ANTICYCLONE OVER NWRN CANADA...WITH RIDGE SSEWD ACROSS ID TO
   NWRN MEX.  STRONG SHORTWAVE TROUGHS ARE EVIDENT ATTM ON MOISTURE
   CHANNEL IMAGERY...OVER S-CENTRAL SASK/ALTA BORDER AND OFFSHORE WA
   COAST. SASK/ALTA TROUGH IS FCST TO MOVE SWD TOWARD NRN MT THIS
   AFTERNOON...THEN TURN SEWD ACROSS NRN HIGH PLAINS OVERNIGHT. 
   EXTENSIVE CYCLONIC GYRE WILL REMAIN CENTERED OVER HUDSON BAY/WRN QUE
   REGION...WHILE BROAD/WEAK SRN STREAM TROUGH DRIFTS EWD/NEWD ACROSS
   CENTRAL TX.
   
   AT SFC...WAVY/QUASISTATIONARY FRONTAL ZONE FROM TIDEWATER REGION
   WSWWD ACROSS ARKLATEX WILL MOVE OFFSHORE NC...BUT WILL ACT AS BOTH
   FOCUS AND EFFECTIVE NRN BOUND FOR SUBTROPICAL/GULF AIR MASS AND
   GREATEST CONVECTIVE POTENTIAL OVER DIXIE.
   
   ...INTERIOR PACIFIC NW...NRN ROCKIES...
   WIDELY SCATTERED TSTMS -- SOME AGGREGATING INTO ORGANIZED MULTICELL
   CLUSTERS OR BANDS -- ARE POSSIBLE THIS AFTERNOON INTO EARLY EVENING.
    CONVECTION SHOULD INITIATE BOTH OVER DIABATICALLY HEATED HIGHER
   TERRAIN OF ROCKIES...AND IN REGION OF WEAK LOW LEVEL UPSLOPE FLOW
   ALONG ERN FLANK OF MTNS.  MAIN THREAT WILL BE DAMAGING WIND...WITH
   ISOLATED LARGE HAIL AS WELL.  A FEW NON-SUPERCELL TORNADOES ALSO
   REMAIN POSSIBLE...MAINLY OVER BASINS/VALLEYS AND RELATIVELY EARLY IN
   CONVECTIVE EVOLUTION...IN ASSOCIATION WITH STRONGEST THERMAL FORCING
   AND VERTICAL STRETCHING OF BOUNDARY LAYER VORTICITY.
   
   BOUNDARY LAYER MOISTURE SHOULD REMAIN FAVORABLE GIVEN
   EVAPOTRANSPIRATIVE EFFECTS RELATED TO RECENT PRECIP.  INSTABILITY
   ALOFT -- ALREADY FAVORABLE ACROSS THIS REGION -- MAY BE ENHANCED BY
   WEAK LARGE SCALE LIFT ON WRN FRINGES OF UPPER TROUGH APCHG NRN MT. 
   STEEP MIDLEVEL LAPSE RATES -- I.E. 7.5-8.5 DEG C/KM -- AND SFC DEW
   POINTS AS HIGH AS 50S F WILL CONTRIBUTE TO MLCAPES UP TO NEAR 1000
   J/KG.  ALTHOUGH WEAK LOW LEVEL FLOW AND LOW-MIDLEVEL SHEAR ARE
   FCST...ENOUGH COVERAGE OF CONVECTION WITH POTENTIAL FOR DAMAGING
   GUSTS IS EXPECTED TODAY TO WARRANT CATEGORICAL SEVERE RISK.
   
   ...GULF COAST STATES...
   CLUSTER OF TSTMS MOVING ONSHORE W-CENTRAL LA COAST MAY PRODUCE
   STRONG/ISOLATED SEVERE GUSTS NEXT HOUR OR TWO...REF SPC MESOSCALE
   DISCUSSION 1424 FOR NOWCAST DETAILS.  OTHERWISE...WIDELY SCATTERED
   TO SCATTERED TSTMS IN CLUSTERS AND BANDS SHOULD DEVELOP THROUGHOUT
   AFTERNOON AND EVENING...INITIALLY INVOF NUMEROUS OUTFLOW BOUNDARIES
   LEFT BEHIND BY CONVECTION FROM PREVIOUS DAY.  MOST VIGOROUS ACTIVITY
   SHOULD OCCUR ALONG OUTFLOW INTERSECTIONS WHERE CONVERGENCE AND STORM
   SCALE ASCENT WILL BE MAXIMIZED.  GREATEST CONVECTIVE COVERAGE BY
   MID-LATE AFTERNOON MAY BE ACROSS ARKLATEX REGION EWD OVER LOWER MS
   VALLEY...WHERE WEAK FRONTAL CONVERGENCE IS JUXTAPOSED WITH LARGE
   SCALE ASCENT NE OF UPPER TROUGH OVER CENTRAL TX...SFC DEW POINTS 70S
   F...AND FAVORABLE DIABATIC DESTABILIZATION.  MLCAPE 2000-3000 J/KG
   ARE POSSIBLE...HOWEVER WEAK LOW-MIDLEVEL FLOW AND WEAK DEEP-LAYER
   SHEAR ARE LIKELY...PRECLUDING OUTLOOK OF WELL ORGANIZED SEVERE
   EVENT.
   
   ...FL...
   SCATTERED TSTMS POSSIBLE BY EARLY-MID AFTERNOON INVOF SEA BREEZE
   FRONTS...AUGMENTED LOCALLY BY INTERACTIONS OF OUTFLOW AND OTHER
   BOUNDARIES.  A FEW OF THE STRONGEST TSTMS MAY PRODUCE DAMAGING WET
   MICRO BURSTS.  GIVEN WEAK AMBIENT FLOW WITH SLY LOW-MIDLEVEL
   COMPONENT...BOTH COASTAL SEA BREEZES SHOULD YIELD CONVECTION
   TODAY...AND ASSOCIATED BOUNDARIES MAY INTERSECT OVER SOME PORTIONS
   CENTRAL/N-CENTRAL FL.  MLCAPE 2500-3000 J/KG IS POSSIBLE BASED ON
   MODIFIED BBW RAOB.
   
   ..EDWARDS/GUYER.. 06/26/2004
   
   ...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