Sep 5, 2012 0600 UTC Day 1 Convective Outlook
Updated: Wed Sep 5 05:48:28 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120905 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120905 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
20120905 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
20120905 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.
   SPC AC 050545
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1245 AM CDT WED SEP 05 2012
   
   VALID 051200Z - 061200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID MS
   VALLEY AND GREAT LAKES REGION...
   
   ...MID MS VALLEY/GREAT LAKES....
   AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE ACROSS THE NRN PLAINS THIS
   MORNING AND INTO THE UPPER MS VALLEY THIS AFTERNOON. AHEAD OF THE
   TROUGH...AN MCS WILL LIKELY BE ONGOING ACROSS PARTS OF THE MIDWEST
   THIS MORNING. FURTHER TO THE WEST...A COLD FRONT WILL ADVANCE SEWD
   INTO CNTRL WI AND ERN IA AROUND MIDDAY. SFC HEATING AND ENHANCED
   LOW-LEVEL CONVERGENCE ALONG THE FRONT SHOULD RESULT IN THE
   DEVELOPMENT OF SCATTERED TO NUMEROUS THUNDERSTORMS LATE THIS
   AFTERNOON. AN MCS MAY AGAIN ORGANIZE ACROSS THE REGION EARLY THIS
   EVENING WITH STORMS AFFECTING AREAS FROM LOWER MI SWWD TO AROUND ST
   LOUIS.
   
   MODEL FORECASTS SUGGEST THE STRONGEST INSTABILITY WILL DEVELOP FROM
   NRN IND SWWD ACROSS CNTRL IL LATE THIS AFTERNOON. NAM FORECAST
   SOUNDINGS AROUND INDIANAPOLIS AND SPRINGFIELD IL AT 00Z/THU SHOW
   MLCAPE VALUES RANGING FROM 3000 TO 4000 J/KG. THE STRONG INSTABILITY
   COMBINED WITH MODERATE DEEP LAYER SHEAR PROFILES SHOULD BE FAVORABLE
   FOR SUPERCELLS WITH LARGE HAIL. THE PRISTINE THERMODYNAMIC
   ENVIRONMENT MAY ALSO SUPPORT HAIL GREATER THAN 2 INCHES IN DIAMETER
   ESPECIALLY WITH SUPERCELLS THAT HAVE ACCESS TO THE STRONGEST
   INSTABILITY. AS LOW-LEVEL FLOW INCREASES DURING THE EARLY
   EVENING...CELLS SHOULD CONGEAL INTO A LINEAR CONVECTIVE SYSTEM
   RESULTING IN AN INCREASED WIND DAMAGE THREAT. AN ENHANCED WIND
   DAMAGE THREAT MAY DEVELOP ACROSS THE LOWER OH VALLEY ESPECIALLY IF
   AN MCS CAN ORGANIZE AND MOVE QUICKLY SEWD ACROSS THE REGION.
   
   ...SRN PLAINS/OZARKS...
   A COLD FRONT WILL ADVANCE SEWD ACROSS THE OZARK PLATEAU AND SRN
   PLAINS TODAY. SOUTH OF THE FRONT...SFC DEWPOINTS IN THE LOWER TO MID
   60S F SHOULD RESULT IN THE DEVELOPMENT OF MODERATE INSTABILITY. AS
   SFC TEMPS WARM AND A CAP WEAKENS...SCATTERED SFC-BASED THUNDERSTORMS
   SHOULD INITIATE ALONG THE FRONT AND MOVE SEWD ACROSS THE REGION. IN
   SPITE OF THE MODERATE INSTABILITY...DEEP LAYER SHEAR SHOULD REMAIN
   RELATIVELY WEAK WITH 0-6 KM SHEAR AT OR BELOW 20 KT. THIS SHOULD
   KEEP ANY SEVERE THREAT MARGINAL. HAIL AND STRONG WIND GUSTS WILL BE
   POSSIBLE WITH THE STRONGER UPDRAFTS. 
   
   ....CNTRL GULF COAST...
   A SLOW MOVING DISTURBANCE WILL BE PRESENT ALONG THE CNTRL GULF COAST
   TODAY. THIS FEATURE ALONG WITH SFC HEATING SHOULD RESULT IN THE
   DEVELOPMENT OF NUMEROUS THUNDERSTORMS AGAIN TODAY FROM SE LA NEWD
   ACROSS SRN AL AND THE FL PANHANDLE. FORECAST SOUNDINGS ALONG THE
   CNTRL GULF COAST AT 21Z GENERALLY SHOW MLCAPE IN THE 1500 TO 2500
   J/KG RANGE WITH ABOUT 20 KT OF DEEP LAYER SHEAR. THIS ENVIRONMENT
   WOULD BE IDEAL FOR MULTICELL STORMS WITH A MARGINAL SEVERE THREAT.
   WET DOWNBURSTS WOULD LIKELY BE THE PRIMARY THREAT DUE TO THE MOIST
   BOUNDARY LAYER....STEEP LOW-LEVEL LAPSE RATES AND WARM AIR ALOFT.
   
   ..BROYLES/MOSIER.. 09/05/2012
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z