Categorical Graphic
Probabilistic Tornado Graphic
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.

   SPC AC 200600
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT MON JUN 20 2011
   
   VALID 201200Z - 211200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS CENTRAL/EASTERN NEB AND
   NORTHEAST KS/SOUTHEAST SD/WESTERN IA/NORTHWEST MO...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE PLAINS TO THE
   MIDWEST/OH VALLEY AND APPALACHIANS/CAROLINAS...
   
   ...SYNOPSIS...
   AN AMPLIFYING/SUBSTANTIAL LATE SPRING UPPER TROUGH IS EXPECTED TO
   CLOSE OFF/DECELERATE AND BEGIN TO PIVOT MORE EAST-NORTHEASTWARD OVER
   THE CENTRAL PLAINS TODAY AND TONIGHT. A VERY ACTIVE SEVERE WEATHER
   DAY IS EXPECTED ESPECIALLY ACROSS THE CENTRAL PLAINS/MIDDLE MO
   VALLEY THIS AFTERNOON/TONIGHT...WITH SEVERE TSTMS OTHERWISE POSSIBLE
   ACROSS A LARGE PART OF THE PLAINS/MIDWEST TO THE
   APPALACHIANS/CAROLINAS.
   
   ...CENTRAL PLAINS/MIDDLE MO VALLEY/MIDWEST...
   GIVEN THE AFOREMENTIONED POTENT UPPER TROUGH...AN APPRECIABLE LATE
   SPRING SURFACE LOW IS EXPECTED TO DEVELOP NORTHEASTWARD ACROSS KS
   AND EVENTUALLY SOUTHERN NEB INTO TONIGHT. GIVEN CONSIDERABLE
   CONVECTION OVERNIGHT/EARLY THIS MORNING ACROSS NEB/IA...CURRENT
   THINKING IS THAT OUTFLOW WILL PROBABLY REINFORCE A WEST-EAST
   EFFECTIVE WARM FRONT FROM SOUTH-CENTRAL NEB /IMMEDIATELY NORTH OF
   THE SURFACE LOW/ EASTWARD TO NORTHERN MO/SOUTHERN IA AND THE
   ADJACENT MIDDLE MS RIVER VALLEY. TIED TO THE ADVANCEMENT OF THE
   LARGE SCALE TROUGH/APPRECIABLE HEIGHT FALLS ACROSS THE CENTRAL
   PLAINS...A COLD FRONT WILL SPREAD EASTWARD ACROSS THE SOUTH-CENTRAL
   PLAINS AND GRADUALLY OVERTAKE A DRYLINE ACROSS KS/OK.
   
   AS STRONG DYNAMIC FORCING FOR LARGE SCALE ASCENT OVERSPREADS THE
   REGION...DEEP CONVECTION IS EXPECTED TO INITIALLY INCREASE BY
   EARLY/MID AFTERNOON ACROSS THE CENTRAL HIGH PLAINS INCLUDING WESTERN
   NEB...WITH SURFACE BASED DEEP CONVECTION BECOME MORE
   LIKELY/WIDESPREAD BY MID/LATE AFTERNOON AND CERTAINLY EARLY EVENING
   NEAR THE SURFACE TRIPLE POINT ACROSS CENTRAL/EASTERN NEB AND
   NORTHEAST KS.
   
   BACKING/STRENGTHENING MID LEVEL FLOW /SOUTH-SOUTHWESTERLIES
   INCREASING TO 50-70 KT/ WILL BE HIGHLY SUPPORTIVE OF SUPERCELLS
   ESPECIALLY IN VICINITY OF THE TRIPLE POINT/ADJACENT FRONTAL
   ZONE...WHERE MODERATE TO STRONG INSTABILITY /3000+ PER KG MLCAPE/ IS
   LIKELY TO BE IN PLACE. VERY LARGE HAIL WILL BE POSSIBLE IN ADDITION
   TO TORNADOES /A STRONG TORNADO CANNOT BE RULED OUT/ ESPECIALLY
   ACROSS CENTRAL/EASTERN NEB AND FAR NORTHEAST KS. THE SEVERE THREAT
   WILL SHIFT EASTWARD THROUGH THE EVENING INTO PORTIONS OF IA/MO WITH
   AT LEAST A DAMAGING WIND/SEVERE HAIL THREAT CONTINUING MUCH OF THE
   NIGHT.
   
   ...CENTRAL/EASTERN KS TO OK/NORTH TX...
   SCATTERED HIGHER BASED STORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON
   ALONG THE DRYLINE/OVERTAKING COLD FRONT FROM EAST-CENTRAL KS INTO
   OK...WITH MORE ISOLATED DEEP CONVECTION POSSIBLE ACROSS NORTH/WEST
   TX. DEEP LAYER SHEAR WILL BE SUPPORTIVE OF SUPERCELLS...WITH LARGE
   HAIL AND PERHAPS A TORNADO OR TWO POSSIBLE...ALTHOUGH HIGH
   BASES/RELATIVELY LARGE LOW LEVEL TEMPERATURE-DEWPOINT SPREADS WILL
   TEND TO MITIGATE A MORE CONSEQUENTIAL TORNADO THREAT. FACTORS SUCH
   AS THE ENTRANCE REGION OF THE UPPER JET/DEEP LAYER SHEAR ORIENTED
   PARALLEL TO THE DRYLINE/COLD FRONT IMPLY THAT STORMS MAY TEND TO
   CONGEAL/CLUSTER BY EVENING...WITH AN APPRECIABLE DAMAGING WIND
   THREAT GIVEN THE STEEP LAPSE RATES/WATER LOADING ASSOCIATED
   DOWNDRAFT POTENTIAL.
   
   ...MUCH OF THE MIDWEST/OH VALLEY TO APPALACHIANS/CAROLINAS...
   WITH THE POTENTIAL FOR AN MCS TO BE ONGOING EARLY THIS MORNING
   ACROSS PORTIONS OF THE MIDWEST/LAKE MI VICINITY...REMNANTS OF THIS
   ACTIVITY AND/OR ONE OR TWO ADDITIONAL CLUSTERS OF TSTMS MAY
   DEVELOP/INCREASE THROUGH THE AFTERNOON ACROSS THE UPPER OH VALLEY
   AND/OR PORTIONS OF THE CENTRAL/SOUTHERN APPALACHIANS TO CAROLINAS.
   THIS WILL BE WITHIN A RELATIVELY MOIST/UNSTABLE WARM SECTOR AMID
   MODERATELY STRONG WEST-NORTHWESTERLY FLOW ALOFT. ONE OR MORE
   CORRIDORS OF DAMAGING WIND GUSTS AND OCCASIONAL HAIL WILL BE
   POSSIBLE ACROSS THESE REGIONS.
   
   ..GUYER/GRAMS.. 06/20/2011
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z