Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 041551
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1051 AM CDT SAT JUN 04 2005
   
   VALID 041630Z - 051200Z
   
   THERE IS A HIGH RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM BIE 30
   SSE SUX 30 NNW DSM 40 NE P35 25 NNE SZL 60 SSE OJC CNU 40 SW EMP
   BIE.
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 15 SSE
   MSP 40 NE RST 45 W LNR 10 S MLI COU UMN 10 S MKO ADM FSI SLN OFK 25
   WSW OTG 15 SSE MSP.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 35 ESE
   P07 65 NW ABI 25 NNW LTS P28 RSL MCK LBF ANW 35 SSE FAR 50 N BRD 40
   E DLH 40 NE RHI 35 ENE GRB CGX DEC HRO PRX TPL 50 SSE DRT.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 SSW HUM 45 N LFT
   35 WSW MLU 20 ENE SHV 35 SSW GGG 20 SSE SAT 30 NW LRD.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 40 SSW HUM 45 N LFT
   35 WSW MLU 20 ENE SHV 35 SSW GGG 20 SSE SAT 30 NW LRD ...CONT... 75
   SSW P07 10 WNW BGS 15 E CDS 45 W CSM 25 SSE LBL 20 SE EHA 25 NE DHT
   35 WSW DHT 35 NW TCC 20 NE SAF 35 SSW FMN 35 S U17 35 N BCE 15 S DPG
   50 ENE SUN 45 W BTM 30 NW CTB ...CONT... 25 ESE OLF 40 N MLS 10 E
   SHR 40 WSW GCC 35 S GCC 30 SSE 81V 30 ENE REJ 20 NNW DIK 25 S ISN 25
   ESE OLF ...CONT... 55 NNE CLE 20 WNW MGW 40 E EKN 15 NE ECG.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 SW BHB 20 SSE BTV
   15 W MSS.
   
   ...THERE IS A HIGH RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
   PARTS OF SOUTHEAST NEB...SOUTHWEST IA...EASTERN KS...AND WESTERN
   MO...
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM SOUTHERN OK NORTHWARD INTO
   FAR SOUTHERN MN...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF TX INTO MN/WI...
   
   ...OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS FORECAST TODAY
   OVER PARTS OF THE CENTRAL PLAINS...
   
   
   ...SYNOPSIS...
   
   SCENARIO OF A POTENTIALLY SIGNIFICANT PERIOD OF SEVERE THUNDERSTORMS
   CONTINUES TO UNFOLD ACROSS THE CENTRAL U.S. AS LARGE SCALE TROUGH
   MOVES INTO PLAINS TODAY.  TWO IMPORTANT S/WV TROUGHS WILL PLAY A
   ROLE... WITH EJECTING IMPULSE MOVING NEWD INTO UPPER MS VALLEY AND
   WEAKENING THIS AFTERNOON AND STRONGER TROUGH CURRENTLY ENTERING
   CENTRAL HIGH PLAINS.  WHILE SURFACE FEATURES THIS MORNING HAVE
   SEVERAL WEAK LOWS...BY THIS AFTERNOON EXPECT A LOW MOVING NWD THRU
   SRN MN AND ANOTHER LOW KS/OK BORDER AHEAD OF APPROACHING TROUGH.
   
   
   ...ERN NEB/IA/ERN KS/MO...
   LATEST SURFACE ANALYSIS SHOWS A VERY MOIST LOW LEVEL AIRMASS IN
   PLACE THIS MORNING ACROSS MUCH OF OK/TX AND WESTERN AR...WITH
   DEWPOINTS RISING INTO THE LOWER 70S. THUNDERSTORMS ONGOING MOVING
   NEWD ACROSS MID MS VALLEY  TIED TO S/WV TROUGH LIFTING NEWD INTO
   UPPER MS VALLEY.  STRONG SOUTHERLY LOW LEVEL WINDS AT AND ABOVE THE
   SURFACE WILL HELP TRANSPORT MARITIME AIR MASS NORTHWARD TODAY...WITH
   HIGH THETA-E AIR EXPECTED INTO MUCH OF EASTERN NEB AND IA BY MID
   AFTERNOON.  VERY STRONG DIURNAL HEATING IS ALSO EXPECTED THROUGHOUT
   THIS REGION AFTER MORNING CLOUDS ERODE...RESULTING IN AN EXTREMELY
   UNSTABLE AIRMASS /MLCAPE VALUES OF 3000-4000 J/KG POSSIBLE/. 
   SHORTWAVE RIDGING IN WAKE OF LEAD SHORTWAVE TROUGH IS TEMPORARILY
   PROVIDING A STRONG CAPPING INVERSION ACROSS THE WARM SECTOR
   ...SUPPRESSING DEEP CONVECTION.
   
   AS PRIMARY SHORTWAVE TROUGH APPROACHES THE WARM SECTOR BY LATE
   AFTERNOON...CAP IS EXPECTED TO ERODE ALONG SURFACE DRYLINE EXTENDING
   FROM SOUTHERN NEB INTO EAST-CENTRAL KS.  EXPLOSIVE THUNDERSTORM
   DEVELOPMENT IS FORECAST IN THIS AREA.  STRENGTHENING WIND FIELDS AT
   ALL LEVELS DURING THE LATE AFTERNOON...COUPLED WITH EXTREME
   INSTABILITY...WILL PROMOTE THE HIGH PROBABILITY OF SUPERCELL
   THUNDERSTORMS CAPABLE OF VERY LARGE HAIL AND TORNADOES.  STORMS ARE
   EXPECTED TO TRACK EAST-NORTHEASTWARD INTO PARTS OF WESTERN AND
   SOUTHERN  IA AND WESTERN AND NORTHERN MO DURING THE EVENING WITH A
   CONTINUED THREAT OF SIGNIFICANT SEVERE.  FORECAST SOUNDINGS ACROSS
   THE HIGH RISK AREA SHOW EFFECTIVE DEEP LAYER SHEAR VALUES OF 40-50
   KNOTS...AND EFFECTIVE HELICITY VALUES OF 200-300 M2/S2 DURING THE
   EVENING AS LOW LEVEL WINDS BACK AND STRENGTHEN IN RESPONSE TO
   APPROACHING UPPER TROUGH.  COMBINATION OF VERY FAVORABLE VERTICAL
   SHEAR PARAMETERS...LOW LCL HEIGHTS...RICH LOW LEVEL MOISTURE...AND
   EXTREME INSTABILITY INDICATE THE THREAT OF STRONG TORNADOES THIS
   EVENING.
   
   ...OK/TX...
   SURFACE DRYLINE IS FORECAST TO EXTEND FROM NORTH CENTRAL OK INTO
   CENTRAL TX BY LATE AFTERNOON.  FULL SUNSHINE...AMPLE MOISTURE...AND
   STEEP MID LEVEL LAPSE RATES WILL YIELD AN EXTREMELY  UNSTABLE
   AIRMASS ALONG AND EAST OF DRYLINE THIS AFTERNOON WITH MLCAPE VALUES
   PUSHING 4000 J/KG.  PRIMARY DYNAMIC FORCING ASSOCIATED WITH CENTRAL
   PLAINS TROUGH WILL BE FROM SOUTHERN KS NORTHWARD.  HOWEVER...MODEL
   FORECAST SOUNDINGS SUGGEST THAT CONVECTIVE TEMPERATURES WILL LIKELY
   BE REACHED ALONG THE DRYLINE ACROSS PARTS OF TX/OK BY LATE THIS
   AFTERNOON...WITH THE DEVELOPMENT OF  SCATTERED THUNDERSTORMS. 
   VERTICAL SHEAR PROFILES IN THIS REGION WILL SUPPORT SUPERCELLS
   CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS. TORNADOES ALSO
   APPEAR POSSIBLE...MAINLY ALONG OK PORTION OF DRYLINE...WHERE STRONG
   WIND FIELDS WILL BE PRESENT.  THERE WILL BE A THREAT OF AN ISOLATED
   STRONG TORNADO AT LEAST AS FAR S AS N CENTRAL OK THIS EVENING GIVEN
   THE EXTREME INSTABILITY...PROXIMITY TO MID AND UPPER JET AND
   FAVORABLE DEEP LAYER VEERING SHEAR PROFILES.
   
   ...UPPER MS VALLEY...
   AS LEAD S/WV TROUGH LIFTS NEWD ACROSS THIS AREA DURING
   AFTERNOON...MID LEVEL FLOW VEERS TO SWLY WHICH WILL ENHANCE SHEAR
   PROFILES. WITH S/SELY BOUNDARY LAYER FLOW TO E OF MN SURFACE LOW
   ONLY QUESTION AS TO POTENTIAL FOR SUPERCELLS AND TORNADO THREAT WILL
   BE SUFFICIENT AVAILABLE INSTABILITY.  CURRENT CLOUD COVER SHOULD
   THIN DURING AFTERNOON ALLOWING DEVELOPMENT OF SURFACE BASED
   THUNDERSTORMS FROM SURFACE LOW EWD INTO WI.  A FEW SUPERCELLS ARE
   LIKELY ASSOCIATED WITH AT LEAST AN ISOLATED TORNADO THREAT.
   CONSIDERED EXTENDING MDT RISK INTO WI...HOWEVER TOO MUCH UNCERTAINTY
   AS TO HOW MUCH INSTABILITY WILL BE AVAILABLE TO DO SO ATTM.
   
   ...CENTRAL NEB/EASTERN SD/MN...
   WITH APPROACH OF CENTRAL HIGH PLAINS S/WV ALONG WITH BACKED LOW
   LEVEL WINDS PROGD ACROSS MUCH OF CENTRAL NEB INTO SOUTHEAST SD...
   SCATTERED THUNDERSTORMS WILL FORM THIS AFTERNOON IN THIS REGION. 
   SUFFICIENT INSTABILITY AND ENHANCED DEEP LAYER VERTICAL SHEAR WILL
   PROMOTE A RISK OF LARGE HAIL AND DAMAGING WINDS IN STRONGER CELLS. 
   ACTIVITY MAY ALSO SPREAD INTO PARTS OF MN THIS EVENING.
   
   
   ...A PUBLIC SEVERE WEATHER OUTLOOK WILL BE ISSUED SHORTLY..
   
   ..HALES/GUYER.. 06/04/2005
   
   ...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 WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z