109 
 WTNT41 KNHC 192042
 TCDAT1
  
 TROPICAL STORM ALBERTO DISCUSSION NUMBER   1
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012012
 500 PM EDT SAT MAY 19 2012
  
 SATELLITE...RADAR...AND SURFACE DATA INDICATE THAT THE SMALL SURFACE
 LOW LOCATED OFF THE COAST OF SOUTH CAROLINA HAS ACQUIRED THE
 CHARACTERISTICS OF A TROPICAL CYCLONE.  ORGANIZED DEEP CONVECTION
 HAS BEEN PERSISTENT OVER THE CENTER FOR MORE THAN 18 HOURS...AND
 THE CIRCULATION CENTER HAS BEEN MOVING SOUTH AWAY FROM AN AIRMASS
 BOUNDARY THAT EXTENDS ROUGHLY ALONG 33N.  BASED ON AN ASCAT PASS
 FROM AROUND 1530 UTC...THE INITIAL INTENSITY IS SET AT 40 KT.
 ALBERTO IS SITUATED IN A MARGINAL THERMODYNAMIC ENVIRONMENT FOR
 STRENGTHENING...WITH A MARKEDLY DRY CONTINENTAL AIRMASS TO ITS NORTH
 AND WEST OVER THE EASTERN CAROLINAS.  GIVEN THIS...ONLY MODEST
 INTENSIFICATION IS EXPECTED DESPITE THE CYCLONE BEING OVER
 THE RELATIVELY WARM GULF STREAM.  ALBERTO IS EXPECTED TO BECOME
 EXTRATROPICAL BY 96 HOURS...AND SHOULD DISSIPATE BY DAY 5.  THE NHC
 INTENSITY FORECAST IS A BLEND OF THE MORE AGGRESSIVE STATISTICAL
 GUIDANCE AND THE WEAKER DYNAMICAL MODELS.
  
 THE LOW-LEVEL CIRCULATION IS A BIT TO THE EAST OF THE COLDEST CLOUD
 TOPS AND THE CIRCULATION CENTER SEEN ON RADAR...AND THE INITIAL
 MOTION ESTIMATE IS 220/03. THE SYNOPTIC ENVIRONMENT IS COMPLEX...AS
 ALBERTO IS IN A REGION OF WEAK STEERING FLOW WITHIN A BROAD
 MID/UPPER-LEVEL TROUGH. THE NHC FORECAST SHOWS A SLOW SOUTHWESTWARD
 MOTION OVER THE NEXT DAY OR SO DUE TO THE STRONG NORTHEASTERLY FLOW
 BETWEEN A SURFACE RIDGE EAST OF THE APPALACHIANS AND A LARGER
 EXTRATROPICAL LOW CENTERED NEAR 36N/72W. AS THAT LOW MOVES WESTWARD
 AND WEAKENS BY SUNDAY NIGHT...ALBERTO IS EXPECTED TO TURN NORTHWARD
 AND THEN ACCELERATE NORTHEASTWARD AFTER 48 HOURS AS A SHORTWAVE
 TROUGH MOVES INTO THE EASTERN UNITED STATES AND THE STEERING FLOW
 BECOMES SOUTHWESTERLY. GIVEN THE SMALL SIZE OF ALBERTO AND THE
 COMPLEX STEERING PATTERN...IT IS NOT SURPRISING THAT THE TRACK
 MODEL GUIDANCE SHOWS A LARGE AMOUNT OF SPREAD...BOTH IN TERMS OF
 HOW FAR SOUTH AND WEST ALBERTO WILL MOVE...AND HOW SHARP THE TURN
 TOWARD THE NORTHEAST WILL BE. THE NHC TRACK FORECAST IS GENERALLY
 CLOSE TO THE TVCA MULTI-MODEL CONSENSUS...AND IS OF VERY LOW
 CONFIDENCE.
 
 A TROPICAL STORM WATCH COULD BE REQUIRED FOR A PORTION OF THE COAST
 OF THE CAROLINAS THIS EVENING.
 
 ALBERTO IS EARLIEST-FORMING TROPICAL STORM IN THE ATLANTIC BASIN
 SINCE ANA IN 2003.  THIS IS ALSO THE FIRST TIME THAT A TROPICAL
 STORM HAS FORMED BEFORE THE OFFICIAL START OF THE HURRICANE SEASON
 IN BOTH THE ATLANTIC AND EAST PACIFIC BASINS.
  
 
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  19/2100Z 32.2N  77.7W   40 KT  45 MPH
  12H  20/0600Z 31.9N  78.1W   45 KT  50 MPH
  24H  20/1800Z 31.7N  78.5W   45 KT  50 MPH
  36H  21/0600Z 31.9N  78.9W   45 KT  50 MPH
  48H  21/1800Z 32.7N  78.5W   45 KT  50 MPH
  72H  22/1800Z 34.5N  75.5W   45 KT  50 MPH
  96H  23/1800Z 37.5N  72.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 120H  24/1800Z...DISSIPATED
  
 $$
 FORECASTER BRENNAN