716 
 WTPZ42 KNHC 220251
 TCDEP2
 TROPICAL STORM ANDRES DISCUSSION NUMBER   2
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022009
 800 PM PDT SUN JUN 21 2009
  
 VISIBLE AND INFRARED SATELLITE IMAGERY INDICATES THAT THE CYCLONE
 HAS CONTINUED TO ORGANIZE DURING THE LAST 6 HOURS...WITH BANDING
 FEATURES INCREASING AND A RECENT BURST OF CONVECTION OVER THE
 CENTER IN WHAT APPEARS TO BE A DEVELOPING CENTRAL DENSE OVERCAST.
 DVORAK T-NUMBERS AT 0000 UTC WERE 2.0 AND 2.5 FROM TAFB AND SAB.
 THE INITIAL INTENSITY IS SET AT THE HIGHER ESTIMATE GIVEN THE
 IMPROVEMENT IN THE SATELLITE PRESENTATION OF THE SYSTEM. THIS MARKS
 THE LATEST FORMATION OF THE FIRST NAMED STORM IN THE EASTERN NORTH
 PACIFIC BASIN SINCE 1971.
  
 RECENT FIXES INDICATE AN INITIAL MOTION OF 275/05...WHICH IS TO THE
 LEFT OF MOST OF THE GUIDANCE. THE MOST RECENT GFDL AND HWRF RUNS
 IMMEDIATELY TAKE ANDRES ON A MORE NORTHERLY COURSE VERY CLOSE TO
 THE SOUTHWESTERN COAST OF MEXICO DURING THE NEXT 24 TO 48 HOURS.
 THESE TWO SOLUTIONS ARE WELL TO THE RIGHT OF THE REST OF THE MODEL
 GUIDANCE...AND IT IS NOT CLEAR FROM MODEL FIELDS WHAT IS CAUSING
 THIS MOTION. THE FORECAST WAS ADJUSTED ONLY SLIGHTLY TO THE RIGHT
 OF THE PREVIOUS TRACK THROUGH 72 HOURS...BUT REMAINS LEFT OF THE
 MODEL CONSENSUS. BY 72 HOURS...THE MODELS ARE IN BETTER AGREEMENT
 THAT THE SUBTROPICAL RIDGE SHOULD GUIDE ANDRES ON A MORE
 WEST-NORTHWESTERLY TRACK AWAY FROM THE COAST. ULTIMATELY...AS
 ANDRES WEAKENS LATE IN THE PERIOD...THE CYCLONE WILL BE STEERED
 WESTWARD WITH THE LOW-LEVEL FLOW.
  
 SEA SURFACE TEMPERATURES REMAIN WARM ALONG THE FORECAST TRACK
 THROUGH ABOUT 48-72 HOURS...WITH A FAIRLY RAPID DROP OFF IN OCEANIC
 HEAT CONTENT THEREAFTER. HOWEVER...THE SHIPS MODEL INDICATES THAT
 NORTHEASTERLY TO EASTERLY SHEAR WILL DEVELOP OVER THE CYCLONE DURING
 THE NEXT COUPLE OF DAYS...AND NONE OF THE GUIDANCE SHOWS ANDRES
 REACHING HURRICANE INTENSITY. THE OFFICIAL FORECAST HAS ANDRES
 PEAKING IN INTENSITY IN A COUPLE OF DAYS...WITH A STEADY DECREASE
 IN STRENGTH BEYOND 72 HOURS AS THE CYCLONE ENCOUNTERS INCREASINGLY
 COOLER WATERS AND A MORE STABLE AIRMASS.
  
 GIVEN THE FORECAST TRACK AND WIND RADII OF ANDRES...THE GOVERNMENT
 OF MEXICO HAS ISSUED A TROPICAL STORM WATCH FOR A PORTION OF THE
 SOUTHWESTERN COAST OF MEXICO.
 
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      22/0300Z 14.8N 101.9W    35 KT
  12HR VT     22/1200Z 15.1N 102.4W    40 KT
  24HR VT     23/0000Z 15.8N 103.2W    50 KT
  36HR VT     23/1200Z 16.6N 103.8W    55 KT
  48HR VT     24/0000Z 17.8N 104.8W    60 KT
  72HR VT     25/0000Z 20.5N 108.5W    50 KT
  96HR VT     26/0000Z 21.5N 113.0W    40 KT
 120HR VT     27/0000Z 21.5N 117.5W    30 KT
  
 $$
 FORECASTER KIMBERLAIN