Apr 9, 2013 0600 UTC Day 1 Convective Outlook
Updated: Tue Apr 9 06:03:36 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130409 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130409 1200 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 1200 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 1200 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 22,252 2,602,099 Oklahoma City, OK...Tulsa, OK...Norman, OK...Wichita Falls, TX...Broken Arrow, OK...
SLIGHT 214,297 16,725,209 Dallas, TX...Ft. Worth, TX...Kansas City, MO...Wichita, KS...Arlington, TX...
   SPC AC 090600
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT TUE APR 09 2013
   
   VALID 091200Z - 101200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL OK...SRN
   OK AND NORTH TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
   PLAINS...CNTRL PLAINS...NW AR...MO...SRN IA AND WRN IL...
   
   ...SRN AND CNTRL PLAINS...
   AN UPPER-LEVEL LOW OVER THE FOUR CORNERS REGION WILL MOVE NEWD INTO
   THE CNTRL ROCKIES ON TUESDAY. AT THE SFC...A COLD FRONT WILL ADVANCE
   QUICKLY SEWD ACROSS THE SRN HIGH PLAINS AND CNTRL PLAINS. AHEAD OF
   THE FRONT...SFC DEWPOINTS SHOULD REACH THE LOWER 60S F ACROSS ERN KS
   WITH MID TO UPPER 60S F ACROSS CNTRL OK AND NORTH TX. MODERATE TO
   STRONG INSTABILITY IS FORECAST TO DEVELOP ALONG THIS CORRIDOR WITH
   CONVECTIVE INITIATION BEGINNING FIRST IN NRN KS DURING THE
   MID-AFTERNOON. THUNDERSTORM DEVELOPMENT SHOULD TAKE PLACE ALONG THE
   COLD FRONT...QUICKLY EXPANDING SSWWD ACROSS SRN KS AND CNTRL OK
   DURING THE LATE AFTERNOON INTO NCNTRL TX BY EARLY EVENING. THE
   STRONG INSTABILITY ALONG WITH COUPLED LOW AND MID-LEVEL JETS WILL BE
   FAVORABLE FOR A SIGNIFICANT SEVERE WEATHER EVENT FROM LATE TUESDAY
   AFTERNOON INTO TUESDAY EVENING.
   
   FORECAST SOUNDINGS AT OKLAHOMA CITY AND WICHITA FALLS AT 00Z/WED
   SHOW MLCAPE VALUES OF 2500 TO 3000 J/KG WITH AN IMPRESSIVE SHEAR
   ENVIRONMENT. 0-6 KM SHEAR IS FORECAST TO INCREASE DURING THE LATE
   AFTERNOON INTO THE 50 TO 60 KT RANGE AS A MID-LEVEL JET MOVES INTO
   THE SRN PLAINS. THE SHEAR ALONG WITH MID-LEVEL LAPSE RATES AROUND
   8.0 C/KM SHOULD BE FAVORABLE FOR SUPERCELL DEVELOPMENT WITH LARGE
   HAIL. THE MORE DOMINANT SUPERCELLS SHOULD BE CAPABLE OF PRODUCING
   HAIL GREATER THAN 2 INCHES IN DIAMETER. 0-1 KM SHEAR IS FORECAST TO
   INCREASE INTO THE 25 TO 30 KT RANGE DURING THE EARLY EVENING AS THE
   LOW-LEVEL JET STRENGTHENS MAKING CONDITIONS FAVORABLE FOR TORNADOES.
   A FEW STRONG TORNADOES COULD OCCUR FROM THE OKLAHOMA CITY AREA SSWWD
   TO AROUND WICHITA FALLS WHERE THE COMBINATION OF PARAMETERS APPEARS
   TO BE MOST IDEAL. ALTHOUGH SOME CONCERN EXISTS ABOUT THE TIMING OF
   INITIATION IN SRN OK AND NORTH TX...THE CURRENT THINKING IS THE
   THREAT FOR SUPERCELL DEVELOPMENT WILL PERSIST WELL INTO THE EVENING
   DUE TO THE STRONG INSTABILITY THAT IS FORECAST.
   
   FURTHER TO THE NORTH FROM ECNTRL KS SWD INTO NERN OK...THE MODELS
   APPEAR TO QUICKLY ORGANIZE A LINE OF THUNDERSTORMS ALONG THE FRONT.
   THIS SUGGESTS THAT THE POTENTIAL FOR SIGNIFICANT SEVERE MAY BE
   SOMEWHAT LESS THERE. HOWEVER...THE LINE SHOULD BE INTENSE WITH
   ROTATING CELL ELEMENTS. SEVERE THREAT COVERAGE COULD BE EXTENSIVE
   WITH A POTENTIAL FOR LARGE HAIL...WIND DAMAGE AND TORNADOES AS WELL.
   
   
   ...MID-MO VALLEY/MO/SRN IA/WRN IL...
   A SHORTWAVE UPPER-LEVEL RIDGE IS FORECAST TO MOVE NNEWD ACROSS THE
   UPPER MIDWEST AS AN UPPER-LEVEL LOW MOVES INTO THE CNTRL ROCKIES. A
   MID-LEVEL JET TO THE EAST OF THE UPPER-LEVEL SYSTEM IS FORECAST TO
   NOSE INTO THE MID-MO VALLEY LATE TUESDAY AFTERNOON. AT THE SFC...A
   COLD FRONT WILL ADVANCE SEWD ACROSS SERN NEB WITH A WARM FRONT
   EXTENDING EWD NEAR THE IA-MO STATE LINE INTO NCNTRL IL. ALONG AND
   SOUTH OF THE WARM FRONT...SFC DEWPOINTS ARE FORECAST TO BE IN THE
   LOWER 60S F WITH MODERATE INSTABILITY DEVELOPING BY MID-AFTERNOON. A
   LACK OF A CAPPING INVERSION COULD ENABLE THUNDERSTORMS TO DEVELOP
   ALONG AND SOUTH OF THE BOUNDARY AROUND MID-DAY WITH A GRADUAL
   INCREASE IN CONVECTIVE COVERAGE TAKING PLACE DURING THE AFTERNOON
   AND EARLY EVENING.
   
   FORECAST SOUNDINGS AT 00Z/WED FROM NEAR KANSAS CITY EWD TO NEAR
   SPRINGFIELD IL SHOW MLCAPE VALUES AROUND 1500 J/KG WITH 40 KT OF 0-6
   KM SHEAR. THIS ENVIRONMENT SHOULD SUPPORT SEVERE STORM DEVELOPMENT.
   THE MORE DISCRETE CELLS ALONG AND TO THE SOUTH OF THE BOUNDARY WHERE
   MODERATE INSTABILITY IS FORECAST...MAY OBTAIN BETTER ORGANIZATION.
   ROTATING STORMS AND/OR BOWING LINE-SEGMENTS SHOULD BE CAPABLE OF
   PRODUCING ISOLATED LARGE HAIL AND WIND DAMAGE. A FEW TORNADOES COULD
   OCCUR WITH THE GREATEST POTENTIAL EXISTING WITH CELLS THAT CROSS THE
   WARM FRONT DURING THE EARLY EVENING WHEN LOW-LEVEL FLOW SHOULD
   BECOME ENHANCED.
   
   ..BROYLES/GARNER.. 04/09/2013
   
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