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

   SPC AC 121708
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1108 AM CST SUN MAR 12 2006
   
   VALID 121630Z - 131200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS EASTERN KANSAS...MUCH OF
   MISSOURI...SOUTHEAST IOWA...AND WEST CENTRAL AND NORTHWESTERN
   ILLINOIS...
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS EASTERN OKLAHOMA...FAR
   NORTHEAST TEXAS..ARKANSAS..MISSOURI...SOUTHEAST NEBRASKA...SOUTHERN
   IOWA...ILLINOIS...INDIANA...AND WESTERN KENTUCKY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN PORTIONS OF THE
   CENTRAL AND SRN PLAINS EWD ACROSS THE MID MS AND OH VALLEYS...
   
   ...SYNOPSIS...
   LARGE UPPER TROUGH OVER THE WRN U.S. WILL SHIFT ENEWD ACROSS THE
   PLAINS STATES TOWARD THE MIDDLE AND UPPER MS VALLEY THIS
   PERIOD...ACCOMPANIED BY VERY STRONG DEEP-LAYER WIND FIELD /H5 JET
   100 TO 120 KT/.
   
   AT THE SURFACE...WELL-DEVELOPED LOW IS FORECAST TO SHIFT ENEWD OUT
   OF ERN CO...WHILE WARM FRONT NOW EXTENDING W-E ACROSS SRN KS/SRN MO
   MOVES NWD WITH TIME.  THIS BOUNDARY WILL CONTINUE TO SERVE AS A
   FOCUS FOR CONVECTIVE DEVELOPMENT...WITH DRYLINE ALSO FORECAST TO ACT
   AS A CONVECTIVE FOCUS LATER THIS AFTERNOON AS IT MIXES EWD ACROSS
   CENTRAL AND INTO ERN OK/SERN KS.
   
   ...CENTRAL AND SRN PLAINS EWD ACROSS THE MID MS AND OH VALLEYS...
   VERY STEEP LAPSE RATES -- 8 TO 8.5 C/KM IN THE 850 TO 500 LAYER
   ACCORDING TO MORNING RAOBS -- WILL CONTINUE TO SPREAD ENEWD ACROSS A
   MOIST WARM SECTOR /SURFACE DEWPOINTS IN THE LOW TO MID 60S/ THIS
   PERIOD.  LOW-LEVEL JET ADVECTING WARM/MOIST AIR ISENTROPICALLY NWD
   INTO NRN KS/NRN MO COMBINED WITH VERY STRONG DEEP-LAYER WIND
   PROFILES HAS YIELDED A CLUSTER OF ELEVATED SUPERCELLS...WHICH HAVE
   PRODUCED SIGNIFICANT SEVERE WEATHER.  SUPERCELLS/SEVERE THREAT
   SHOULD PERSIST/SHIFT SLOWLY EWD ALONG AND N OF RETREATING WARM FRONT
   AS UPPER TROUGH AND ASSOCIATED JET STREAK MOVES EWD INTO THE PLAINS.
   
   
   MEANWHILE...DRYLINE NOW LYING ACROSS WRN OK/WRN N TX WILL ALSO SERVE
   AS A FOCUS FOR SEVERE CONVECTIVE DEVELOPMENT LATER THIS
   AFTERNOON...AS IT MIXES EWD ACROSS N TX/OK/SERN KS INTO
   DESTABILIZING AIRMASS /1500 TO 3000 J/KG MEAN-LAYER CAPE/.  THOUGH
   WARM SECTOR AIRMASS REMAINS CAPPED ATTM...DAYTIME HEATING OF MOIST
   BOUNDARY LAYER COMBINED WITH INCREASING LARGE-SCALE ASCENT SHOULD
   WEAKEN CAP SUFFICIENTLY TO ALLOW STORM DEVELOPMENT TO OCCUR BY
   20-21Z.  
   
   AS STRONG MID-LEVEL SWLYS SHIFT EWD ACROSS THE WARM SECTOR ABOVE 35
   TO 50 KT SLY/SSWLY LOW-LEVEL JET...VERY FAVORABLE WIND SHEAR WITH
   HEIGHT WILL SUPPORT INTENSE SUPERCELLS -- PARTICULARLY GIVEN DEGREE
   OF INSTABILITY.  ATTM...AREA OF MAXIMUM SEVERE THREAT APPEARS TO
   EXIST FROM ERN KS ENEWD ACROSS CENTRAL AND NRN MO INTO SERN IA/W
   CENTRAL AND NWRN IL.  WITH SURFACE LOW FORECAST TO SHIFT ENEWD WITH
   TIME ACROSS THIS REGION...BACKING LOW-LEVEL FLOW IN THE WARM SECTOR
   -- AND ELY WINDS N OF WARM FRONT -- WILL YIELD VERY FAVORABLE
   LOW-LEVEL SHEAR SUPPORTIVE OF VIOLENT/LONG-TRACK TORNADOES ALONG A
   BROAD AXIS ON EITHER SIDE OF WARM FRONT.  ALONG WITH
   TORNADOES...VERY LARGE HAIL AND STRONG/DAMAGING WINDS CAN ALSO BE
   EXPECTED.
   
   THOUGH LOW-LEVEL FLOW SHOULD REMAIN MORE SLY -- AND MID-LEVEL FLOW
   LESS INTENSE -- FURTHER S ACROSS ERN OK AND INTO N TX...SHEAR
   PROFILES WILL REMAIN MORE THAN ADEQUATE FOR SUPERCELL STORMS.  GIVEN
   DEGREE OF SHEAR AND INSTABILITY...A FEW STRONG/DAMAGING TORNADOES
   ARE ANTICIPATED...ALONG WITH VERY LARGE HAIL AND LOCALLY DAMAGING
   WIND GUSTS.
   
   THIS EVENING/OVERNIGHT...70 KT LOW-LEVEL JET IS FORECAST TO DEVELOP
   ACROSS THE MID MS VALLEY.  EXPECT STORMS TO INCREASE IN
   COVERAGE...EVOLVING INTO ONE OR MORE SEVERE STORM CLUSTERS.  ALONG
   WITH LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES WILL BE
   POSSIBLE ALONG AND N OF WARM FRONT AS FAR E AS SRN LOWER MI/NRN OH.
   
   FURTHER S...DRYLINE WILL CONTINUE SHIFTING EWD ACROSS MO/ERN OK/NERN
   TX THIS EVENING/OVERNIGHT.  COLD FRONT SHOULD OVERTAKE THE DRYLINE
   OVERNIGHT ACROSS MO...WHERE SQUALL LINE SHOULD EVOLVE. ALONG WITH
   LARGE HAIL AND ISOLATED TORNADOES...A MORE WIDESPREAD THREAT FOR
   VERY STRONG/DAMAGING WINDS APPEARS LIKELY.  A MORE BROKEN LINE OF
   STORMS SHOULD CONTINUE EWD OVERNIGHT FROM ERN OK AND NERN TX ACROSS
   AR/NRN LA AND TO THE MS VALLEY BY THE END OF THE PERIOD.  LARGE HAIL
   AND LOCALLY DAMAGING WINDS ALONG WITH AN ISOLATED TORNADO THREAT
   SHOULD PERSIST THROUGH THE END OF THE PERIOD.
   
   ..GOSS.. 03/12/2006
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z