Apr 13, 2012 1730 UTC Day 2 Convective Outlook
Updated: Fri Apr 13 17:33:37 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120413 1730 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20120413 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
   SPC AC 131731
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1231 PM CDT FRI APR 13 2012
   
   VALID 141200Z - 151200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS OVER ERN NEB AND FAR WRN IA...
   
   ...THERE IS A HIGH RISK OF SVR TSTMS FROM S CNTRL KS INTO W CNTRL
   OK...
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM WRN OK INTO NEB AND IA...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM NW TX NWD INTO SRN MN AND
   WRN IL...
   
   ...SYNOPSIS...
   A LARGE UPPER TROUGH WILL EXIST OVER THE WRN U.S. WITH UPPER LOW
   CENTER NEAR THE FOUR CORNERS AREA AT 00Z...THEN CONTINUING INTO THE
   CNTRL PLAINS BY SUN MORNING. AROUND THE BASE OF THIS TROUGH...A
   MIDLEVEL JET CORE IN EXCESS OF 100 KT WILL BE NOSING INTO THE OK/TX
   PANHANDLE BY 00Z...TIGHTENING FURTHER AS THE UPPER LOW ROTATES NEWD
   ACROSS KS AND NEB. THIS BROAD BELT OF SWLY FLOW ALOFT WILL CREATE
   FAVORABLE SHEAR FOR SEVERE WEATHER OVER A LARGE PART OF THE PLAINS.
   
   AT THE SURFACE...A LOW WILL DEEPEN DURING THE DAY OVER ERN CO INTO
   SWRN NEB...WITH THE 00Z DRYLINE POSITION ROUGHLY FROM CNTRL NEB NEAR
   THE LOW SWD ACROSS KS AND INTO WRN OK AND NW TX. DURING THE
   AFTERNOON AND EVENING...A WARM FRONT WILL EXTEND FROM THE LOW NEWD
   ACROSS SERN SD INTO SRN MN. 
   
   SLY LOW LEVEL FLOW IN ANTICIPATION OF THE UPPER TROUGH WILL MAINTAIN
   FAVORABLE MOISTURE TRAJECTORIES...WITH A NARROW AXIS OF MID 60S F
   BOUNDARY LAYER DEWPOINTS EXTENDING FROM CNTRL TX ACROSS OK AND INTO
   SRN KS AT 00Z. DEWPOINTS NEAR 60 F WILL BE POSSIBLE AS FAR N AS THE
   WARM FRONT. COMBINED WITH COOL TEMPERATURES ALOFT...AMPLE
   INSTABILITY WILL BE PRESENT FOR SEVERE STORMS FROM TX TO NEB.
   
   ...CNTRL NEB INTO WRN IA...
   A STRONG SLY LOW LEVEL JET WILL HELP FORCE MORNING RAIN AND STORMS
   OVER MUCH OF THE AREA...AND WILL ALSO ALLOW FOR DESTABILIZATION
   DURING THE DAY BEHIND THIS INITIAL ACTIVITY. WITH THE SURFACE LOW
   DEEPENING JUST TO THE W...AND A BROAD WARM FRONT AND/OR OUTFLOWS IN
   PLACE...LOW LEVEL WINDS WILL REMAIN BACKED AND RH LEVELS SHOULD
   REMAIN RELATIVELY SHELTERED AS WELL...PROVIDING A FAVORABLE AREA FOR
   STRONG TORNADOES. CELLS WOULD LIKELY FORM OVER WRN SECTIONS OF THE
   HIGH RISK AREA WHERE HEATING WILL STEEPEN LOW LEVEL LAPSE
   RATES...THEN WOULD PROCEED RAPIDLY NEWD WITH AN INCREASING TORNADO
   THREAT. VERY LARGE HAIL WILL ALSO BE LIKELY. THE NRN EXTENT OF THE
   TORNADO THREAT WILL DEPEND ON THE ACTUAL LOCATION OF THE PRIMARY
   BOUNDARIES.
   
   ...CNTRL KS...WRN AND CNTRL OK...NWRN TX...
   SUBSTANTIAL UNCERTAINLY EXISTS IN REGARD TO STORM COVERAGE ALONG THE
   DRYLINE DURING THE DAY FROM KS INTO OK AND NW TX. HOWEVER...HIGH END
   SEVERE POTENTIAL EXISTS AND WILL MAINTAIN CATEGORICAL HIGH.
   
   LOW CLOUDS AND SCATTERED SHOWERS ARE EXPECTED EARLY ON SAT...WITH
   ONLY SLIGHT CAPPING IN PLACE EARLY. BREAKS IN THE CLOUDS AND HEATING
   SHOULD QUICKLY ERODE MOST INHIBITION BY AFTERNOON...WHEN WITH
   MODERATE INSTABILITY DEVELOPING WITH MUCAPE GENERALLY 2000-2500
   J/KG.
   
   STRONG HEATING AND STEEPENING OF LOW LEVEL LAPSE RATES WILL OCCUR
   ALONG AND W OF THE DRYLINE. HOWEVER...CONVERGENCE WILL BE RELATIVELY
   WEAK...WHICH MAY ACTUALLY HELP KEEP STORMS DISCRETE. FAVORABLY
   ORIENTED DEEP LAYER SHEAR ALONG THE DRYLINE...AS WELL AS VEERING AND
   INCREASING WINDS WITH HEIGHT WILL STRONGLY FAVOR SUPERCELLS. 
   
   THERMODYNAMIC PROFILES SHOULD BE SUFFICIENT FOR VERY LARGE
   HAIL...AND LOW LEVEL SHEAR WILL FAVOR TORNADOES AS WELL. LAPSE RATES
   ALOFT ARE MARGINAL FOR TYPICAL PLAINS VIOLENT TORNADO DAYS...BUT
   SHEAR PROFILES WOULD CERTAINLY FAVOR A FEW STRONG TORNADOES.
   
   CURRENT THINKING IS FOR ISOLATED TORNADIC SUPERCELLS WITH VERY LARGE
   HAIL TO FORM ALONG THE DRYLINE...AND TO PROCEED NEWD ACROSS THE HIGH
   RISK AREA LATE AFTERNOON INTO THE EVENING. THEN...THE PACIFIC FRONT
   WILL MOVE IN FROM THE W...LIKELY RESULTING IN A SQUALL LINE CAPABLE
   OF DAMAGING WINDS WITH EMBEDDED AREAS OF ROTATION CAPABLE OF DAMAGE.
   
   
   FARTHER S INTO TX...DAYTIME DRYLINE ACTIVITY IS LESS LIKELY...WITH
   THE MAIN SEVERE THREAT COMING FROM THE OVERNIGHT SQUALL LINE WITH
   DAMAGING WINDS AND PERHAPS TORNADOES WITH SUPERCELLS EMBEDDED WITHIN
   THE LINE.
   
   ..JEWELL.. 04/13/2012
   
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