Mar 12, 2006 1300 UTC Day 1 Convective Outlook
Updated: Sun Mar 12 12:32:17 UTC 2006
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting an outbreak of severe thunderstorms today and tonight across portions of the United States. This is an extremely dangerous situation. Please read the latest public statement about this event.

Categorical Graphic
20060312 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20060312 1300 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20060312 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20060312 1300 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 121229
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0629 AM CST SUN MAR 12 2006
   
   VALID 121300Z - 131200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS OVER NRN/CENTRAL MO...FAR SERN
   IA INTO W-CENTRAL IL...
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM ERN PORTIONS OF THE
   SRN/CENTRAL PLAINS INTO THE MID SOUTH/OH RIVER VALLEY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PORTION OF THE
   NATION/S MID SECTION...
   
   ...SIGNIFICANT SEVERE THUNDERSTORM OUTBREAK STILL ANTICIPATED
   TODAY... 
   
   OVERNIGHT MODELS ARE CONSISTENT IN SLOWING DOWN APPROACHING
   SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW.  06Z NAM AND GFS ALONG
   WITH 09Z RUC DEVELOP SURFACE LOW INTO NWRN KS THRU 21Z...WHICH WILL
   MOVE ACROSS NWRN MO EARLY THIS EVENING AND INTO SRN WI OVERNIGHT. 
   THUS WILL SHIFT SEVERE THREAT AREAS A BIT WEST AS COMPARED TO
   EARLIER OUTLOOK.
   
   ELEVATED SUPERCELLS AND MULTICELL CLUSTERS ONGOING ACROSS PORTIONS
   OF CENTRAL AND ERN KS THIS MORNING WILL LIKELY PERSIST AND SPREAD
   ENEWD ACROSS THE MO RIVER VALLEY THIS AFTERNOON ALONG LLJ AXIS.
   LARGE HAIL...SOME OF WHICH COULD BE VERY LARGE...MAY ACCOMPANY THIS
   ACTIVITY.  THE EARLY DEVELOPMENT EAST OF THE DRY LINE RAISES SOME
   CONCERN ABOUT QUALITY OF AIR MASS AVAILABLE FOR LATER SEVERE THREAT.
    HOWEVER...AIR MASS WILL RECOVER QUICKLY EAST AND SOUTH OF THIS
   ACTIVITY WITH SURFACE DEW POINTS WELL INTO THE 60S EXPECTED ALONG
   AND NORTH OF THE MO RIVER VALLEY BY 21Z...AS WRN END OF OUTFLOW
   BOUNDARY CURRENTLY NEAR THE OZARKS ERODES.  WITH AFTERNOON
   HEATING...SRN AND ERN MOST STORMS WILL BECOME INCREASINGLY SURFACE
   BASED DURING THE EARLY TO MID AFTERNOON...WITH ADDITIONAL
   DEVELOPMENT INTO SERN KS/NERN OK ALONG DRY LINE.  LOW AND DEEP LAYER
   SHEAR REMAINS MORE THAN OPTIMAL FOR TORNADIC SUPERCELLS WITH VERY
   LARGE HODOGRAPHS.  THEREFORE...THE POTENTIAL FOR LONG-TRACK
   TORNADOES WILL SPREAD EWD ACROSS MUCH OF MO/POSSIBLY FAR SERN IA AND
   INTO WRN IL THROUGH THE EVENING.  MOST LIKELY AREA WILL CONTINUE TO
   BE NEAR AND JUST SOUTH OF EFFECTIVE WARM FRONT WHICH IS EXPECTED TO
   LIFT NWD AHEAD OF APPROACHING LOW CENTER TO NEAR THE IA/MO BORDER BY
   THIS EVENING. HERE LOW LEVEL SSELY WINDS WILL BE MAXIMIZED...AND AN
   OUTBREAK OF DAMAGING TORNADIC SUPERCELLS IS MORE LIKELY.  AS STORMS
   CROSS THE WARM FRONT AND DEVELOP NWD WITHIN ENHANCED ASCENT INTO
   MORE OF IA...EFFECTIVE SHEAR WILL REMAIN SUFFICIENT FOR ELEVATED
   SUPERCELLS ENHANCING THE THREAT OF VERY LARGE HAIL.  ACTIVITY WILL
   CONTINUE WELL INTO THE NIGHT EWD ACROSS THE MID MS RIVER
   VALLEY...WITH CONTINUED THREAT OF TORNADOES WHERE STORMS CAN ROOT
   NEAR THE SURFACE ALONG AND SOUTH OF THE WARM FRONT.
   
   FARTHER SOUTH INTO ERN OK AND NERN TX...INITIATION SHOULD BE DRIVEN
   BY HEATING AND CONVERGENCE ALONG AND AHEAD OF DRY LINE AS CAPPING
   HOLDS FOR MUCH OF THE DAY.  THOUGH THIS REGION WILL REMAIN REMOVED
   FROM GREATEST LARGE SCALE ASCENT...FORECAST SOUNDINGS INDICATE A
   VERY VOLATILE COMBINATION OF 2000+ J/KG MLCAPES AND 50+ KT EFFECTIVE
   BULK SHEAR.  IN ADDITION...STORMS SHOULD REMAIN DISCRETE. 
   THEREFORE...TORNADIC SUPERCELL THREAT...INCLUDING THE THREAT OF
   LONG-LIVED TORNADOES AND VERY LARGE HAIL WILL SPREAD ACROSS SRN
   MO/AR AND INTO THE LOWER OH RIVER VALLEY WELL AFTER DARK.
   
   ..EVANS/GRAMS.. 03/12/2006
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z