Apr 5, 2012 1300 UTC Day 1 Convective Outlook
Updated: Thu Apr 5 12:57:30 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120405 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120405 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
20120405 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
20120405 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.
   SPC AC 051254
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0754 AM CDT THU APR 05 2012
   
   VALID 051300Z - 061200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PART OF THE SERN
   U.S....
   
   ...SYNOPSIS...
   AN AMPLIFIED PATTERN WILL PREVAIL OVER THE LWR 48 THROUGH FRI.
   TROUGHS OVER THE PACIFIC NW/NRN GRT BASIN AND THE LWR GRT LKS/NEW
   ENGLAND WILL BOUND A RIDGE BUILDING N FROM THE PLNS STATES INTO
   CNTRL CANADA.  JUST E OF THE RIDGE...AR CLOSED LOW SHOULD ACCELERATE
   ESE AS IT BEGINS TO BE ABSORBED BY THE NERN TROUGH.  THE LOW SHOULD
   REACH THE MS/AL BORDER THIS EVE...AND ERN GA EARLY SAT.
   
   AT LWR LVLS...WEAK FRONT EXTENDING ESE FROM SE MO SFC LOW SHOULD
   CONTINUE DRIFTING S ACROSS THE TN VLY...THE SRN APPALACHIANS...AND
   SC TODAY AS SFC HIGH BUILDS INTO THE OH VLY FROM THE UPR GRT LKS. 
   AT THE SAME TIME...DIFFUSE COLD FRONT NOW EXTENDING SW FROM THE LOW
   SHOULD ADVANCE STEADILY E ACROSS THE GULF CST STATES.  FARTHER
   S...REMNANT COLD POOL LEFT BY YESTERDAY'S GULF OF MEXICO MCS
   EXPECTED TO GRADUALLY DISSIPATE OVER THE N CNTRL AND NERN GULF.
   
   SEVERAL AREAS OF STRONG TO POTENTIALLY SVR TSTMS APPEAR LIKELY
   THROUGH THE PERIOD IN ASSOCIATION WITH THE AR UPR LOW AND RELATED
   FEATURES.
   
   ...SERN STATES TODAY INTO TNGT...
   ONGOING SVR STORMS OVER LA/MS APPEAR RELATED TO VORT LOBE ROTATING
   AROUND SE QUADRANT OF AR UPR LOW /REF MCD 454/.  THIS ACTIVITY MAY
   SPREAD ENE ACROSS THE REMAINDER OF MS AND POSSIBLY WRN AL LATER THIS
   MORNING AS THE LOBE PIVOTS NEWD.  MUCH OF THE ACTIVITY LIKELY WILL
   REMAIN SOMEWHAT ELEVATED.  BUT GIVEN COOL MID LVL TEMPS /AROUND
   MINUS 18C AT 500 MB/ AND MODERATE...UNIDIRECTIONAL CLOUD LAYER
   SHEAR...EXPECT THE STORMS TO CONTINUE TO YIELD SPORADIC LARGE HAIL. 
   THE SVR THREAT COULD INCREASE LATER TODAY FROM ERN MS INTO CNTRL/NRN
   AL EWD AND NEWD INTO ADJACENT PARTS OF TN AND GA AS SFC HEATING
   FOSTERS DEVELOPMENT OF NEW STORMS...OR THE EXISTING ACTIVITY BECOMES
   SFC-BASED.  COMBINATION OF SBCAPE AROUND 1000 J/KG S AND E OF THE
   AFOREMENTIONED FRONTS AND 40+ KT DEEP WSWLY SHEAR MAY YIELD A FEW
   SUPERCELLS OR OTHER SUSTAINED STORMS WITH LARGE HAIL AND AN
   INCREASING RISK FOR DMGG WIND...ESPECIALLY IN AL/GA.
   
   FARTHER S...ONGOING LOOSELY ORGANIZED WAA STORMS NOW OVER SE LA AND
   ADJACENT SRN MS/NRN GULF OF MEXICO SHOULD ALSO SPREAD EWD
   AS FLOW/ASCENT INCREASE OVER THE CNTRL GULF CST.  STRENGTHENING DEEP
   UNIDIRECTIONAL WSW FLOW ACROSS THE REGION...AND SFC HEATING/EROSION
   OF SHALLOW COOL DOME E OF THE STORMS...SUGGEST THAT NEW CELLS MAY
   DEVELOP ON THE E SIDE OF EXISTING ACTIVITY.  THIS COULD YIELD A
   FORWARD PROPAGATING MCS...WITH EMBEDDED BOWS THAT POSE AN RISK FOR
   MORE WIDESPREAD DMGG WIND OVER THE FL PANHANDLE...N FL...AND
   SRN/CNTRL GA DURING THE AFTN.
   
   FARTHER E/NE...DIURNALLY ENHANCED TSTMS ALSO MAY FOCUS ALONG SLOWLY
   MOVING FRONT FROM TN ESE INTO SC.  ALTHOUGH FORCING FOR ASCENT...MID
   LVL COOLING...AND SHEAR WILL BE SOMEWHAT WEAKER UNTIL LATER IN THE
   DAY RELATIVE TO POINTS W...SUFFICIENT DESTABILIZATION AND LOW LVL
   CONFLUENCE SHOULD EXIST FOR STORM DEVELOPMENT BY EARLY AFTN.  ONCE
   INITIATED...COMBINATION OF INCREASING DEEP SHEAR AND MODEST SWLY LOW
   LVL FLOW SUGGEST THAT THE STORMS ALSO WILL BE CAPABLE OF BOTH LARGE
   HAIL AND DMGG WIND. SOME OF THE STORMS MAY EVOLVE INTO A CLUSTER
   OVER THE SRN APPALACHIANS THIS EVENING THAT IS UNDERCUT BY THE
   CONTINUED SWD MOVEMENT OF THE FRONT.
   
   LATE TNGT AND EARLY FRI YET ANOTHER ROUND OF STRONG TO SVR STORMS
   MAY ARISE OVER CNTRL AND SRN FL AS CONTINUED ESE MOVEMENT OF THE AR
   UPR LOW ENHANCES LOW LVL CONVERGENCE ALONG PRE-FRONTAL TROUGH OVER
   THE ERN GULF OF MEXICO AND CNTRL FL.  WITH A MOIST...WEAKLY CAPPED
   BOUNDARY LAYER AIR MASS IN PLACE...AND WITH MID LVL WNWLY FLOW
   INCREASING TO AOA 50S KTS...SUPERCELLS AND/OR BOWING SEGMENTS WILL
   BE POSSIBLE...WITH AN ATTENDANT RISK FOR DMGG WIND...HAIL...AND
   POSSIBLY A TORNADO.
   
   ..CORFIDI/COHEN.. 04/05/2012
   
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