May 12, 2010 2000 UTC Day 1 Convective Outlook
Updated: Wed May 12 22:24:27 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20100512 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20100512 2000 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20100512 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20100512 2000 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 122221
   
   DAY 1 CONVECTIVE OUTLOOK AMEND 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0521 PM CDT WED MAY 12 2010
   
   VALID 122215Z - 131200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN KS/MO AND VICINITY
   SSWWD INTO PARTS OF W CENTRAL TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS VA AND VICINITY...
   
   AMENDED FOR ADJUSTMENT OF SLIGHT RISKS IN TX PNHDL/S PLAINS AND THE
   MID-ATLANTIC
   
   .UPDATE DISCUSSION... /ISSUED 0515 PM CDT WED MAY 12 2010/
   
   ...TX PNHDL/S PLAINS...
   PRESSURE FALLS OVER THE HIGH PLAINS HAVE CAUSED LLVL SELY BOUNDARY
   LAYER FLOW TO INCREASE OVER THE TX PNHDL/S PLAINS.  DRYLINE HAS
   CONTINUED TO RETREAT TO THE S OF A CDFNT WITH TSTMS DEVELOPING
   FARTHER W THAN EARLY ANTICIPATED.  /JPR
   
   .PREV DISCUSSION... /ISSUED 0258 PM CDT WED MAY 12 2010/
   ...CENTRAL AND SRN PLAINS...
   ELEVATED CONVECTION -- AND A LOW-END HAIL THREAT -- CONTINUES FROM
   PORTIONS OF CENTRAL IA SSWWD INTO NWRN MO/NERN KS.  MEANWHILE...
   SURFACE-BASED DEVELOPMENT IS BEGINNING TO OCCUR FROM S CENTRAL KS --
   INVOF THE SURFACE COLD FRONT -- SSWWD INTO W CENTRAL TX ALONG THE
   DRYLINE.  SHEAR QUITE FAVORABLE FOR SUPERCELLS COUPLED WITH
   MIXED-LAYER CAPE NOW IN THE 3000 TO 4000 J/KG RANGE AHEAD OF THE
   FRONT/DRYLINE SUGGEST THAT SEVERE POTENTIAL WILL CONTINUE TO
   INCREASE THIS AFTERNOON AND EVENING IN CONJUNCTION WITH FURTHER CAP
   EROSION/STORM DEVELOPMENT.
   
   WHILE LOW-LEVEL SHEAR REMAINS SOMEWHAT WEAK...ISOLATED/CELLULAR
   STORM MODE...A MOIST BOUNDARY LAYER...AND FAVORABLE DEEPER-LAYER
   SHEAR WILL SUPPORT A THREAT FOR ISOLATED TORNADOES...WHILE
   LOCALLY-DAMAGING WINDS WILL ALSO BE POSSIBLE WITH STRONGER CELLS. 
   HOWEVER...PRIMARY SEVERE POTENTIAL REMAINS VERY LARGE HAIL...WITH
   THE THREAT LIKELY TO CONTINUE THROUGH THIS EVENING AND PERHAPS
   OVERNIGHT AS CONVECTION SPREADS EWD/NEWD ACROSS N CENTRAL
   TX...OK...ERN KS...AND NRN AND WRN MO.
   
   ...WV/VA AND VICINITY...
   MCS CONTINUES SPREADING SEWD ACROSS WRN AND CENTRAL VA ATTM...WITH
   NEW STORMS FORMING OVER PARTS OF NERN KY AND VICINITY IN THE WAKE OF
   THE EARLIER CONVECTION.  WITH 1500 TO 2000 J/KG MIXED-LAYER CAPE NOW
   INDICATED E OF THE MOUNTAINS AND WLY MID-LEVEL FLOW NEAR 50 KT
   PROVIDING FAVORABLE SHEAR...THREAT FOR DAMAGING WINDS AND/OR HAIL
   SHOULD CONTINUE/SPREAD EWD ACROSS VA THROUGH THE AFTERNOON AND INTO
   THIS EVENING BEFORE DIMINISHING. /GOSS
   
   ..JPR/GOSS.. 05/12/2010
   
   .PREV DISCUSSION... /ISSUED 1129 AM CDT WED MAY 12 2010/
   
   ...CENTRAL/SOUTHERN PLAINS...
   A LARGE UPPER TROUGH REMAINS OVER THE WESTERN STATES TODAY...WITH
   BAND OF 70-90 KNOT MID LEVEL WINDS EXTENDING FROM AZ/NM INTO THE
   CENTRAL PLAINS.  THE MAIN SURFACE BAROCLINIC ZONE LIES FROM CENTRAL
   MO INTO SOUTH CENTRAL KS WHERE A WEAK SURFACE LOW IS EVIDENT.  THIS
   BOUNDARY WILL PROVIDE THE PRIMARY FOCUS FOR STRONG/SEVERE
   THUNDERSTORM DEVELOPMENT LATER TODAY AND TONIGHT.  12Z RAOBS IN THE
   WARM SECTOR SUGGEST THAT THE STRONG CAP WILL INHIBIT DEEP CONVECTION
   AWAY FROM THE BOUNDARY THROUGH MOST OF THE DAY. 
   HOWEVER...INCREASING LOW LEVEL WARM ADVECTION AND LIFT ASSOCIATED
   WITH WEAK SHORTWAVE TROUGH OVER EASTERN NM/WEST TX MAY EVENTUALLY
   ERODE THE CAP OVER NORTHERN OK/SOUTHERN KS.  THIS WILL LEAD TO
   SCATTERED SEVERE STORMS ALONG THE FRONT...AND THE POTENTIAL FOR AT
   LEAST ISOLATED CELLS FORMING DISCRETELY IN THE WARM SECTOR. 
   THERMODYNAMIC PROFILES IN THIS AREA WILL BE VERY UNSTABLE WITH
   DEWPOINTS NEAR 70F AND MLCAPE VALUES OF 3000-4000 J/KG.  FORECAST
   SOUNDINGS SUGGEST STRONG EFFECTIVE SHEAR /OVER 50 KNOTS/ WILL
   SUPPORT SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL AND DAMAGING
   WINDS.  ANY DISCRETE STORM THAT FORMS OFF THE FRONT WILL ALSO HAVE
   SUFFICIENT LOW LEVEL VERTICAL SHEAR /ESPECIALLY AFTER 00Z/ FOR THE
   THREAT OF A FEW TORNADOES.  ACTIVITY SHOULD TRACK/DEVELOP
   NORTHEASTWARD ACROSS SOUTH CENTRAL KS AND INTO WESTERN MO THROUGH
   THE EVENING WITH THE RISK OF RATHER WIDESPREAD HAIL.
   
   FARTHER SOUTHWEST...IT APPEARS LIKELY AT LEAST ISOLATED
   THUNDERSTORMS WILL DEVELOP ALONG THE SURFACE DRYLINE OVER WESTERN OK
   AND WESTERN NORTH TX.  THESE STORMS WILL TRACK EAST-NORTHEASTWARD
   THIS EVENING AND WILL ALSO POSE A RISK OF LARGE HAIL AND DAMAGING
   WINDS.
   
   ...KY/WV INTO VA...
   A LARGE MCS IS ONGOING THIS MORNING OVER PARTS OF KY/WV.  GIVEN THE
   MESOSCALE ORGANIZATION OF THIS SYSTEM...IT APPEARS LIKELY TO
   MAINTAIN ITS INTENSITY THROUGH THE DAY AS IT CROSSES THE
   APPALACHIANS INTO VA.  SUNNY SKIES AHEAD OF THE STORMS...COMBINED
   WITH DEWPOINTS CLIMBING THROUGH THE 60S WILL PROVIDE SUFFICIENT
   DESTABILIZATION FOR THE RISK OF SEVERE STORMS.  DAMAGING WINDS
   APPEAR TO BE THE MAIN THREAT.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z