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 221957
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0157 PM CST SUN JAN 22 2012
   
   VALID 222000Z - 231200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS EVENING AND TONIGHT ACROSS
   ERN AR...SERN MO...SRN PARTS OF IL/IND...WRN PARTS OF KY/TN...NRN
   MS...NWRN AL AND FAR NERN LA......
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM A LARGE PART OF THE OH
   VALLEY TO ARKLATEX/CNTRL GULF COAST...
   
   ...FORECAST...
   A POTENTIALLY SIGNIFICANT SEVERE WEATHER EPISODE IS LIKELY TO UNFOLD
   TONIGHT ACROSS THE MID-SOUTH/LOWER AND MIDDLE MS VALLEY TO TN
   VALLEY/LOWER OH VALLEY. FORECAST REASONING GENERALLY REMAINS
   UNCHANGED BASED ON LATEST OBSERVATIONS/SHORT-TERM GUIDANCE...SEE
   PRIOR DISCUSSION BELOW FOR ADDITIONAL/BROADER PERSPECTIVE.
   
   LATEST HIGH-RES DETERMINISTIC AND ENSEMBLE GUIDANCE /SUCH AS
   EXPERIMENTAL SPC SSEO/ REFLECT THAT DEEP CONVECTION IS MOST LIKELY
   TO INITIALLY DEVELOP TOWARD /AND ESPECIALLY AFTER/ THE 23Z-02Z TIME
   FRAME WITHIN A CORRIDOR ACROSS SOUTHWEST/CENTRAL/NORTHEAST PORTIONS
   OF AR INTO SOUTHEAST MO. CONFIDENCE REMAINS HIGH IN A MIXED-MODE OF
   SUPERCELLS AND FAST-MOVING QLCS DEVELOPMENT TONIGHT AS STORMS
   DRAMATICALLY INCREASE IN COVERAGE/INTENSITY THIS EVENING IN
   ACCORDANCE WITH A STEADILY STRENGTHENING DEEP TROPOSPHERIC WIND
   FIELD/AMPLE FORCING FOR ASCENT.
   
   ..GUYER.. 01/22/2012
   
   .PREV DISCUSSION... /ISSUED 1027 AM CST SUN JAN 22 2012/
   
   ...ENVIRONMENTAL CONDITIONS STILL APPEAR TO BE COMING TOGETHER FOR A
   POTENTIALLY SIGNIFICANT SEVERE WEATHER EVENT BEGINNING BY LATE
   AFTERNOON OR EARLY EVENING AND CONTINUING INTO MONDAY MORNING...
   
   ...SYNOPSIS...
   
   INTENSE MID- AND UPPER-LEVEL TROUGH OVER THE CNTRL/SRN HIGH PLAINS
   WILL ASSUME AN INCREASING NEGATIVE TILT WHILE MOVING INTO THE OZARK
   PLATEAU BY THIS EVENING...BEFORE EJECTING NEWD ACROSS THE OH AND TN
   VALLEYS OVERNIGHT INTO MON MORNING.  THIS TROUGH WILL BE ATTENDED BY
   100+ KT JET STREAKS AT 500 AND 250 MB WITH A CORRIDOR OF 12-HR
   HEIGHT FALLS OF 150-200 M AT 500 MB FORECAST ALONG SYSTEM TRACK.  IN
   THE LOW LEVELS...CYCLONE OVER WRN KS WILL DEVELOP EWD TO ERN KS BY
   23/00Z BEFORE ACCELERATING NEWD INTO NRN IL BY 23/12Z.  THIS LOW
   PRESSURE WILL BE ACCOMPANIED BY A STRENGTHENING COLD FRONT WHICH
   WILL SWEEP EWD THROUGH THE PLAINS AND MS VALLEY BY THE END OF THE
   FORECAST PERIOD.  MEANWHILE...WARM FRONT ANALYZED FROM NERN TX EWD
   ACROSS CNTRL PARTS OF MS/AL/GA WILL DEVELOP NWD THROUGH THE
   LOWER/MID MS VALLEY INTO THE OH VALLEY AHEAD OF THE MIGRATORY
   SURFACE LOW.
   
   ...OH VALLEY SWD TO THE CNTRL GULF COAST...
   
   12Z SOUNDINGS OVER THE SRN PLAINS EWD ACROSS THE GULF COAST INDICATE
   THE PRESENCE OF ROBUST LOW-LEVEL MOISTURE AT COASTAL LOCATIONS WITH
   BOUNDARY LAYER DEWPOINTS IN THE 60S AND 100-MB MEAN MIXING RATIOS OF
   13-14 G/KG.  THE INTENSIFICATION AND BROADENING OF A 50+ KT LLJ WILL
   ALLOW FOR THE NWD ADVECTION OF THIS MOISTURE WITH DEWPOINTS
   INCREASING THROUGH THE 50S BY TONIGHT INTO SRN PARTS OF THE OH
   VALLEY.  THIS MOISTURE FLUX WILL OCCUR BENEATH STEEPENING MIDLEVEL
   LAPSE RATES ATTENDANT TO AN EWD/NEWD-ADVECTING EML...CONTRIBUTING TO
   RAPID AIR MASS DESTABILIZATION TODAY INTO TONIGHT ACROSS THE
   EXPANDING WARM SECTOR.  EXPECT MLCAPE TO INCREASE TO 500-1000 J/KG
   OVER PORTIONS OF THE LOWER OH VALLEY...WITH VALUES APPROACHING
   1000-1500 J/KG ACROSS PARTS OF FAR ERN TX INTO THE LOWER MS VALLEY.
   
   LATEST MODEL GUIDANCE INDICATES THAT INCIPIENT STORM DEVELOPMENT AND
   ISOLATED SEVERE WEATHER POTENTIAL WILL BE POSSIBLE THIS AFTERNOON
   OVER PORTIONS OF MS AND AL ALONG RETREATING WARM FRONT.  THE MORE
   SIGNIFICANT TSTM INITIATION IS ANTICIPATED BETWEEN 22/21Z-23/00Z
   ACROSS PORTIONS OF CNTRL OR ERN AR AS THE LEADING EDGE OF STRONGER
   HEIGHT FALLS OVERSPREAD THE DESTABILIZING/EXPANDING WARM SECTOR. 
   BETWEEN 23/00Z-23/06Z...EXPECT THE RAPID EXPANSION IN SEVERE TSTMS
   ACROSS THE LOWER MS INTO LOWER OH/MID MS VALLEYS WITH STORMS
   SPREADING ACROSS THE OH/TN VALLEYS AND MS INTO AL THROUGH 23/12Z.
   
   LOCATIONS FROM THE LOWER OH VALLEY INTO LOWER MS VALLEY WILL HAVE
   THE HIGHEST LIKELIHOOD OF EXPERIENCING TORNADOES /SOME
   SIGNIFICANT/...POTENTIALLY WIDESPREAD DAMAGING WINDS AND LARGE HAIL.
   HERE...FORECAST SOUNDINGS INDICATE THAT A MODERATELY UNSTABLE AIR
   MASS WILL ALIGN WITH 50-60 KT OF DEEP LAYER SHEAR AND 0-1 KM SRH OF
   250-400 M2/S2...CONTRIBUTING TO THE DEVELOPMENT OF SUPERCELLS AND
   BOWING STRUCTURES EMBEDDED WITHIN AN EVOLVING QLCS.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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