000 WTPZ44 KNHC 150247 TCDEP4 HURRICANE CARLOS DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042009 800 PM PDT TUE JUL 14 2009 THE EYE OF CARLOS HAS BECOME LESS DEFINED IN VISIBLE IMAGERY THIS EVENING...BUT REMAINS VERY DISTINCT IN INFRARED IMAGES. THE EYE HAS COOLED A LITTLE DURING THE PAST SIX HOURS...BUT SO HAS THE SURROUNDING RING OF COLD CLOUD TOPS. DVORAK INTENSITY ESTIMATES FROM BOTH AGENCIES SUPPORT INCREASING THE INITIAL INTENSITY TO 90 KT. WATER VAPOR IMAGERY IMAGERY SUGGESTS THAT CARLOS IS APPROACHING AN AREA OF WESTERLY FLOW ALOFT...AND THE GLOBAL MODELS SHOW A GRADUAL INCREASE IN WESTERLY UPPER-LEVEL WINDS BETWEEN 130W AND 140W DURING THE NEXT COUPLE OF DAYS. THE ECMWF SHOWS SIGNIFICANTLY STRONGER 200 MB FLOW IN THAT AREA THAN DOES THE GFS MODEL...WHICH THE SHIPS GUIDANCE USES FOR ITS SHEAR COMPUTATION. THE OFFICIAL FORECAST WILL LEAN TOWARD THE GFS/SHIPS SOLUTION AND FORECAST ONLY A SLIGHT DECREASE IN INTENSITY DURING THE NEXT DAY OR TWO. LATER IN THE PERIOD NORTHWESTERLY SHEAR IS PREDICTED TO INCREASE...WHICH SHOULD PRODUCE ADDITIONAL WEAKENING. THE INTENSITY FORECASTS FOR TINY CARLOS HAVE PROVEN TO BE VERY CHALLENGING SO FAR. IF THE SHEAR TURNS OUT TO BE STRONGER THAN EXPECTED...THE SMALL HURRICANE WOULD ALMOST CERTAINLY WEAKEN FASTER THAN SHOWN BELOW. THE INITIAL MOTION IS 275/6. THE TRACK GUIDANCE GENERALLY KEEPS THE HURRICANE ON A WEST TO WEST-NORTHWESTWARD HEADING THROUGHOUT THE 5 DAY FORECAST PERIOD. THE MODELS CONTINUE TO HAVE SIGNIFICANT DIFFERENCES IN THE FORWARD SPEED OF THE HURRICANE...WITH MOST OF THE GUIDANCE HAVING EXHIBITED A SIGNIFICANT WESTWARD BIAS THUS FAR. THE OFFICIAL FORECAST ASSUMES THAT CARLOS WILL BE ABLE TO REMAIN A DEEP SYSTEM FOR THE NEXT DAY OR TWO...AND IF THIS OCCURS IT WILL LIKELY CONTINUE TO MOVE MORE SLOWLY THAN THE GUIDANCE INDICATES. SOME ACCELERATION WOULD BE EXPECTED WHENEVER CARLOS WEAKENS AND IS INCREASINGLY STEERED BY THE FASTER LOW- TO MID-LEVEL FLOW. FORECAST POSITIONS AND MAX WINDS INITIAL 15/0300Z 10.0N 128.6W 90 KT 12HR VT 15/1200Z 10.3N 129.8W 85 KT 24HR VT 16/0000Z 10.7N 131.4W 80 KT 36HR VT 16/1200Z 11.1N 133.3W 75 KT 48HR VT 17/0000Z 11.6N 135.6W 70 KT 72HR VT 18/0000Z 12.0N 140.5W 60 KT 96HR VT 19/0000Z 12.0N 146.5W 55 KT 120HR VT 20/0000Z 12.0N 153.0W 50 KT $$ FORECASTER BROWN