Apr 9, 2013 1300 UTC Day 1 Convective Outlook
Updated: Tue Apr 9 12:47:34 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130409 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130409 1300 UTC Day 1 Tornado Probabilities 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
20130409 1300 UTC Day 1 Damaging Wind Probabilities 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
20130409 1300 UTC Day 1 Large Hail Probabilities 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.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 17,394 1,749,781 Oklahoma City, OK...Norman, OK...Wichita Falls, TX...Ardmore, OK...
SLIGHT 207,741 17,932,417 Dallas, TX...Ft. Worth, TX...Kansas City, MO...Tulsa, OK...Wichita, KS...
   SPC AC 091243
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0743 AM CDT TUE APR 09 2013
   
   VALID 091300Z - 101200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT FROM
   CNTRL OK INTO N-CNTRL TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
   FROM THE MID-MS/LOWER-MO VALLEY REGION SWWD INTO THE SRN PLAINS...
   
   ...SYNOPSIS...
   
   A VORTICITY MAXIMUM ALONG THE POLEWARD SIDE OF MID TO UPPER-LEVEL
   JET STREAKS CURRENTLY ROUNDING THE LARGE-SCALE TROUGH BASE OVER NWRN
   MEXICO AND FAR SRN AZ/NM WILL EJECT NEWD INTO THE CNTRL HIGH PLAINS
   TODAY...IN ADVANCE OF AN UPSTREAM JET STREAK DIGGING SEWD THROUGH
   SRN CA AND BAJA INTO NWRN MEXICO.  THIS PATTERN EVOLUTION WILL
   RESULT IN A CORRIDOR OF MODEST /I.E. 30-60 M/ 12-HR HEIGHT FALLS AT
   500 MB SPREADING INTO THE SRN AND CNTRL HIGH PLAINS IN CONJUNCTION
   WITH A BELT OF 70-90 KT SWLY WINDS AT THIS SAME LEVEL.
   
   IN THE LOW LEVELS...A FRONTAL WAVE OVER THE SRN HIGH PLAINS WILL
   DEVELOP NEWD INTO THE LOWER MO VALLEY WHILE A TRAILING...INTENSE
   COLD FRONT SURGES SEWD THROUGH MUCH OF THE SRN PLAINS BY WEDNESDAY
   MORNING.  A DRYLINE WILL MIX EWD ACROSS WRN TX TODAY AND WILL LIKELY
   EXTEND FROM THE COLD FRONT OVER SWRN OK INTO W-CNTRL TX BY LATE
   AFTERNOON OR EARLY EVENING.  AHEAD OF THE FRONTAL WAVE...A
   BAROCLINIC ZONE WILL REMAIN QUASI-STATIONARY ACROSS THE MIDWEST/OH
   VALLEY. 
   
   ...CNTRL/SRN PLAINS THIS AFTERNOON INTO TONIGHT...
   
   LATEST MODEL GUIDANCE REMAINS IN GOOD AGREEMENT IN SUGGESTING THAT
   INCREASING HEIGHT FALLS AND LOW-LEVEL UPLIFT/CONVERGENCE ALONG THE
   COLD FRONT WILL FOSTER THE DEVELOPMENT OF SURFACE-BASED TSTMS BY MID
   TO LATE AFTERNOON FROM CNTRL/ERN KS INTO SWRN OK.  AIDED BY STEEP
   LAPSE RATES...BOUNDARY LAYER DEWPOINTS IN THE LOWER /TO POSSIBLY
   MID/ 60S...AND MLCAPE RANGING FROM 1000-1500 J/KG NORTH TO 2000-2500
   J/KG SOUTH...EXPECT TSTMS TO QUICKLY BECOME SEVERE WITH AN ATTENDANT
   RISK FOR DAMAGING WINDS...LARGE HAIL /SOME POTENTIALLY
   SIGNIFICANT/...AND PERHAPS A FEW TORNADOES.
   
   THE LARGELY PARALLEL ORIENTATION OF THE DEEP-LAYER SHEAR VECTOR TO
   THE COLD FRONT AND IT/S STRONGLY ANAFRONTAL CHARACTERISTICS SUGGEST
   A FAIRLY RAPID TRANSITION OF STORMS TO OUTFLOW DOMINANT CLUSTERS OR
   LINES.  THOUGH CAPPING WILL REMAIN PROBLEMATIC...THE GREATEST RISK
   FOR SUPERCELLS WILL EXIST WITHIN THE DRYLINE CIRCULATION FROM SWRN
   OK INTO NWRN TX.  
   
   AN AMALGAMATION OF STORMS INTO MULTIPLE BANDS/CLUSTERS IS
   ANTICIPATED TONIGHT INVOF OF THE COLD FRONT WITH PRIMARILY A
   DAMAGING WIND AND HAIL THREAT DEVELOPING EWD/NEWD INTO THE LOWER MO
   RIVER VALLEY AND OZARKS...AND SEWD TOWARD THE ARKLATEX AND TX HILL
   COUNTRY.
   
   ...IA EWD ACROSS THE OH VALLEY THIS AFTERNOON AND EVENING...
   
   A FAIRLY WELL-DEFINED MCV HAS EVOLVED EARLY THIS MORNING OVER THE
   MID MO VALLEY IN ASSOCIATION WITH AN MCS IN PROGRESS TO THE NORTH OF
   THE SURFACE STATIONARY FRONT.  HEATING ALONG AND/S OF THE STATIONARY
   FRONT COUPLED WITH THE GLANCING INFLUENCE OF THE MCV AND ANY
   ADDITIONAL PERTURBATIONS EMBEDDED WITHIN THE ZONAL FLOW REGIME WILL
   GIVE RISE TO MULTIPLE TSTM CLUSTERS THIS AFTERNOON.  THE COMBINATION
   OF MODEST INSTABILITY /I.E. MLCAPE OF 1000-1500 J PER KG/ AND 40-45
   KT OF DEEP-LAYER SHEAR SUGGEST THE POTENTIAL FOR ORGANIZED STORM
   MODES CAPABLE OF DAMAGING WINDS AND SEVERE HAIL.  UNCERTAINTY IN A
   MORE SPECIFIC TIMING AND LOCATION OF THIS SEVERE THREAT PRECLUDES
   THE INCLUSION OF A CATEGORICAL SLIGHT RISK FARTHER EAST INTO THE OH
   VALLEY ATTM.
   
   ..MEAD/ROGERS.. 04/09/2013
   
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