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

   SPC AC 061232
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0732 AM CDT THU APR 06 2006
   
   VALID 061300Z - 071200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS OVER NERN KS INTO SERN NEB AND
   FAR NWRN MO LATER TODAY AND THIS EVENING...
   
   ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK FROM
   ERN NEB/WRN IA INTO WRN MO...ERN OK AND WRN AR...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK OVER
   PORTIONS OF THE SRN/CENTRAL PLAINS EWD ACROSS THE MID MS RIVER
   VALLEY...
   
   ...SIGNIFICANT SEVERE WEATHER OUTBREAK /INCLUDING NUMEROUS TORNADIC
   SUPERCELLS/ IS EXPECTED TO EVOLVE ACROSS EASTERN PORTIONS OF THE
   CENTRAL PLAINS STATES LATER TODAY AND THIS EVENING...
   
   ...SYNOPSIS...
   POTENT MID/UPPER LEVEL LOW NOW OVER THE FOUR-CORNERS REGION WILL
   RAPIDLY EJECT NEWD INTO THE CENTRAL PLAINS TODAY...WITH 210M HEIGHT
   FALLS AT H5 SPREADING ACROSS ERN KS BY 00Z.  SIGNIFICANT MID TO
   UPPER LEVEL JET MAX WILL ACCOMPANY THIS SYSTEM WITH H5 WINDS IN
   EXCESS OF 100 KT /115+ KT AT H25/ SHIFTING ACROSS OK.  ASSOCIATED
   SURFACE LOW NOW TAKING SHAPE OVER CENTRAL NEB WILL DEEPEN AS IT
   BECOMES BETTER DEFINED NEAR THE N-CENTRAL KS/SERN NEB BORDER LATER
   THIS AFTERNOON.  AS THIS OCCURS...VERY STRONG DRY LINE WILL MIX TO
   NEAR THE I-35 CORRIDOR BY 18Z AND THEN SHIFT RAPIDLY EWD INTO WRN
   MO/WRN AR THIS EVENING.  AHEAD OF THIS...MODEST LOW LEVEL MOISTURE
   WILL REMAIN IN PLACE WITH AXIS OF AROUND 60F SURFACE DEW POINTS
   EXTENDING INTO ERN KS AND FAR SERN NEB THIS AFTERNOON. IN
   ADDITION...VERY STEEP LAPSE RATES /I.E. 8.5+ C/KM FROM H7-H5/ ARE
   ALREADY OBSERVED ACROSS THE REGION AND WILL REMAIN IN PLACE TODAY.
   
   ...ERN SD/NEB INTO KS/MO/IA...
   MORNING CONVECTION WITH THREAT OF ISOLATED LARGE HAIL WILL LIKELY
   INCREASE WITHIN BROAD UPPER DIFFLUENCE ACROSS SD AND INTO PORTIONS
   OF IA THIS MORNING.  IN ADDITION...WITH H85 FLOW REMAINING VEERED TO
   SWLY OVER THE SRN PLAINS...LOW LEVEL WAA AND ASCENT AHEAD OF SUBTLE
   DISTURBANCE EVIDENT ON WV IMAGERY MOVING INTO SWRN OK WILL LIKELY
   INCREASE CLOUDS AND MOIST CONVECTION ACROSS CENTRAL OK AND INTO THE
   OZARKS THIS MORNING.  THIS ACTIVITY WILL ALSO LIKELY REMAIN ELEVATED
   ABOVE STRONGLY CAPPED BOUNDARY LAYER...THOUGH CLOUD LAYER SHEAR AND
   STEEP LAPSE RATES COULD SUPPORT LARGE HAIL.
   
   PRIMARY SEVERE THREAT IS STILL EXPECTED TO ERUPT ALONG THE DRY LINE
   ALONG LEADING EDGE OF STRONG ASCENT FROM CENTRAL NEB INTO N-CENTRAL
   OK...POSSIBLY AS EARLY AS 18Z...AND EVOLVE INTO AN OUTBREAK OF
   SEVERE THUNDERSTORMS THROUGH 02-03Z ACROSS MUCH OF ERN KS AND
   PORTIONS OF SERN NEB/WRN MO.  WARM SECTOR IS FORECAST TO BECOME
   MODERATELY UNSTABLE WITH MLCAPE TO 2000 J/KG INTO THE CENTRAL
   PLAINS.  VERY STRONG SHEAR REMAINS SUPPORTIVE OF SUPERCELLS...WITH A
   VARIETY OF STORM MOTIONS.  CELLS INTO ERN NEB WILL TEND TO DEVELOP
   NWD AND ROTATE NWWD TOWARDS CENTRAL NEB...WHILE DEVELOPMENT SOUTH OF
   THE SURFACE LOW WILL TEND TO SHIFT RAPIDLY ENEWD ACROSS ERN KS AND
   INTO WRN MO WHERE AIR MASS WILL LIKELY DESTABILIZE IN WAKE OF ANY
   EARLY DAY ACTIVITY.  SOUNDINGS CONTINUE TO SUPPORT VERY LARGE AND
   DAMAGING HAIL WITH SOME HAIL STONES EXCEEDING 3-4 INCHES IN
   DIAMETER.  SUPERCELLS ARE ALSO EXPECTED TO BECOME
   TORNADIC...ESPECIALLY INTO NERN KS/FAR SERN NEB/NWRN MO WHERE STRONG
   PRESSURE FALLS AND BACKED SURFACE WINDS WILL ENHANCE LOW LEVEL
   HELICITIES AND LCLS REMAIN MORE FAVORABLE ESE OF THE LOW CENTER. 
   CONVECTIVE MODE/STORM-SCALE EVOLUTION STILL HARD TO DETERMINE
   ATTM...AS SOME OF THE ACTIVITY MAY EVOLVE INTO LEWP/BOW
   ECHOES...ESPECIALLY INTO THE EVENING.  REGARDLESS...SUPERCELL
   STRUCTURES ARE EXPECTED TO REMAIN WIDESPREAD WITH ATTENDANT THREAT
   OF TORNADOES...SOME OF WHICH COULD BE QUITE STRONG GIVEN MAGNITUDE
   OF SHEAR AND STRONG SURFACE PRESSURE FALLS.  STORMS ARE EXPECTED TO
   EVENTUALLY OUTRUN INSTABILITY NEAR THE LOWER MO/MID-MS RIVER VALLEYS
   AND BECOME INCREASINGLY ELEVATED NORTH OF THE WARM FRONT LATER THIS
   EVENING/OVERNIGHT...THOUGH LARGE HAIL POTENTIAL MAY SPREAD ACROSS
   THE MID MS RIVER VALLEY AND INTO THE OH RIVER VALLEY LATE TONIGHT.
   
   ...ERN OK/WRN AR INTO FAR NERN TX...
   SIGNIFICANT MID/UPPER LEVEL SHEAR WILL DEVELOP ACROSS THE DRY LINE
   INTO ERN OK/NERN TX LATER TODAY...WHERE MLCAPES SHOULD APPROACH 2500
   J/KG ALONG WRN EDGE OF MID LEVEL CLOUD SHIELD NOW EXTENDING NE-SW
   ACROSS CENTRAL OK.  CAPPING WILL BE MORE PROBLEMATIC SOUTH OF UPPER
   JET AND WITHIN WEAKER ASCENT THAN COMPARED TO AREAS FARTHER NORTH. 
   HOWEVER...FORECAST SOUNDINGS CONTINUE TO INDICATE DANGEROUS
   COMBINATION OF LONG HODOGRAPHS AND MODERATE INSTABILITY.  STORMS MAY
   REMAIN MORE ISOLATED ACROSS THIS REGION...THOUGH PARAMETERS REMAIN
   QUITE FAVORABLE FOR LONG-LIVED SUPERCELLS... INCLUDING STRONG AND
   DAMAGING TORNADOES...WITH STORMS THAT DO DEVELOP.  THIS ACTIVITY
   WILL LIKELY BECOME ELEVATED DURING THE MID/LATE EVENING INTO CENTRAL
   AR AND SPREAD ISOLATED DAMAGING WIND/LARGE HAIL THREAT TOWARDS THE
   LOWER OH RIVER VALLEY LATER TONIGHT.
   
   ..EVANS/CROSBIE.. 04/06/2006
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z