342 
 WTPZ42 KNHC 271432
 TCDEP2
 TROPICAL STORM BORIS DISCUSSION NUMBER   2
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022008
 800 AM PDT FRI JUN 27 2008
  
 A CONVECTIVE BAND WITH CLOUD TOP TEMPERATURES TO -80C HAS DEVELOPED
 AROUND THE CENTER OF TROPICAL DEPRESSION TWO-E DURING THE PAST
 SEVERAL HOURS.  SATELLITE INTENSITY ESTIMATES ARE 35 KT FROM BOTH
 SAB AND TAFB...AND RE-EXAMINATION OF EARLIER SCATTEROMETER DATA
 SUGGESTED 35 KT WINDS.  BASED ON THIS...THE DEPRESSION IS UPGRADED
 TO TROPICAL STORM BORIS.  THE INITIAL INTENSITY IS INCREASED TO 35
 KT...AND THIS MAY BE CONSERVATIVE.  THE CIRRUS OUTFLOW IS CURRENTLY
 GOOD IN THE SOUTHWESTERN SEMICIRCLE AND POOR ELSEWHERE.
 
 THE INITIAL MOTION IS 295/8. WATER VAPOR IMAGERY AND LARGE-SCALE
 MODEL ANALYSES SHOW A MID/UPPER-LEVEL TROUGH OVER THE PACIFIC NORTH
 OF 15N BETWEEN 115-135W.  THE MODELS FORECAST THIS TROUGH TO MOVE
 WESTWARD AND WEAKEN...WITH A MID/UPPER-LEVEL RIDGE BUILDING
 WESTWARD FROM MEXICO TO THE NORTH OF BORIS.  THIS EVOLUTION SHOULD
 ALLOW BORIS TO MOVE WEST-NORTHWESTWARD FOR 24 HR OR SO...FOLLOWED
 BY A TURN TOWARD THE WEST AS SHOWN BY THE GFS GFDL AND HWRF.  THE
 FORECAST TRACK FOLLOWS THIS SCENARIO...WITH THE NEW FORECAST BEING
 A LITTLE NORTH OF AND SLOWER THAN THE PREVIOUS FORECAST.  IT IS
 DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE IN BEST AGREEMENT WITH THE
 CORRECTED MODEL CONSENSUS.  THE ECMWF SHOWS AN ALTERNATE
 SCENARIO...WITH BORIS BECOMING STATIONARY OR MOVING EASTWARD AFTER
 96 HR DUE TO THE DEVELOPMENT OF ANOTHER TROPICAL CYCLONE TO THE
 EAST.  WHILE ANOTHER CYCLONE IS A DISTINCT POSSIBILITY...THE ECMWF
 MAY BE MAKING THE SYSTEM TOO POWERFUL AND TOO LARGE.  THUS...ITS
 FORECAST TRACK FOR BORIS APPEARS UNLIKELY AT THIS TIME.
 
 BORIS IS CURRENTLY IN AN ENVIRONMENT OF LIGHT TO MODERATE
 EAST-NORTHEASTERLY VERTICAL WIND SHEAR.  THE LARGE-SCALE MODELS
 FORECAST THIS PATTERN TO PERSIST FOR 24-36 HR.  AFTER THAT...THEY
 FORECAST A PIECE OF AN UPPER-LEVEL TROUGH CURRENTLY OVER THE GULF
 OF MEXICO TO MOVE WESTWARD AND PASS NEAR BORIS...ACCOMPANIED BY
 A SIGNIFICANT INCREASE IN SHEAR.  THIS WOULD LIKELY STOP
 INTENSIFICATION...SO THE INTENSITY FORECAST CALLS FOR BORIS TO
 REACH A PEAK INTENSITY OF 50 KT IN ABOUT 48 HR.  THE SHEAR IS
 FORECAST TO DECREASE AFTER 72 HR...BUT BY THAT TIME BORIS IS
 FORECAST TO MOVE OVER COOLER SEA SURFACE TEMPERATURES.  AN
 ALTERNATIVE SCENARIO BASED ON CURRENT CONVECTIVE TRENDS IS THAT
 BORIS COULD STRENGTHEN FASTER THAN CURRENTLY FORECAST FOR THE FIRST
 36 HR AND REACH A HIGHER PEAK INTENSITY.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      27/1500Z 12.6N 109.3W    35 KT
  12HR VT     28/0000Z 13.0N 110.4W    40 KT
  24HR VT     28/1200Z 13.3N 111.8W    45 KT
  36HR VT     29/0000Z 13.4N 113.5W    50 KT
  48HR VT     29/1200Z 13.5N 115.2W    50 KT
  72HR VT     30/1200Z 13.5N 118.5W    50 KT
  96HR VT     01/1200Z 13.5N 122.0W    40 KT
 120HR VT     02/1200Z 13.5N 125.0W    35 KT
  
 $$
 FORECASTER BEVEN