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| #376344 (Received by flhurricane at: 10:58 PM 15.Sep.2010) TCDAT2 HURRICANE JULIA DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL122010 1100 PM AST WED SEP 15 2010 JULIA IS COMING UNDER INCREASING INFLUENCE OF SOUTHERLY SHEAR...AND RECENT MICROWAVE IMAGES INDICATE THAT THE LOW-LEVEL CENTER AND THE MID-LEVEL EYE ARE DISPLACED FROM ONE ANOTHER. SATELLITE INTENSITY ESTIMATES ARE NOW T5.0/5.5 FROM TAFB...T4.0/5.0 FROM SAB...AND T5.3/5.7 FROM THE UW-CIMSS ADT. THE INITIAL INTENSITY IS LOWERED TO 100 KT FOR THIS ADVISORY...BUT IT IS POSSIBLE THAT JULIA COULD BE WEAKER THAN THAT. JULIA IS LOCATED VERY NEAR A DEVELOPING CLOSED UPPER-LEVEL LOW...AND STRONG SHEAR IS EXPECTED TO CONTINUE OVER THE HURRICANE DURING THE FORECAST PERIOD. THE OFFICIAL FORECAST INDICATES GRADUAL WEAKENING DURING THE NEXT 48-72 HOURS AND IS IN LINE WITH THE INTENSITY CONSENSUS. JULIA SHOULD WEAKEN TO A TROPICAL STORM BY DAYS 4 AND 5...BUT THE FORECAST IS A LITTLE ABOVE THE INTENSITY CONSENSUS AT THAT TIME SINCE THE SHIPS MODEL...FOR SOME UNKNOWN REASON...SHOWS THE SYSTEM DISSIPATED BY DAY 5. THIS SEEMS UNREASONABLE SINCE THE GFS STILL SHOWS AN INTACT AREA OF LOW PRESSURE. THE HURRICANE IS STARTING TO ACCELERATE AND IS NOW MOVING AT 315/14. ADDITIONAL ACCELERATION IS EXPECTED OVER THE NEXT 24 HOURS AS JULIA IS STEERED BETWEEN A MID-LEVEL HIGH TO ITS NORTHEAST AND THE UPPER-LEVEL LOW TO ITS SOUTHWEST...ALMOST LIKE A SLING-SHOT AFFECT. JULIA WILL THEN BE STEERED NORTH-NORTHWEST AND THEN NORTH FROM 48-72 HOURS AS IT REACHES THE WESTERN SIDE OF THE RIDGE AND THE EASTERN SIDE OF THE LARGE CIRCULATION ASSOCIATED WITH IGOR. THE RECURVATURE TO THE NORTHEAST IS ANTICIPATED BY DAY 5 AS JULIA GETS EMBEDDED WITHIN THE MID-LATITUDE WESTERLY FLOW. THE OFFICIAL TRACK FORECAST IS VERY CLOSE TO THE PREVIOUS FORECAST...AND LIES JUST TO THE WEST OF THE MODEL CONSENSUS. JUST LIKE IN THE CASE WITH IGOR...THE ECMWF MODEL LIES AT THE WESTERN SIDE OF THE GUIDANCE ENVELOPE AND CANNOT BE IGNORED. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 20.2N 34.6W 100 KT 12HR VT 16/1200Z 21.7N 36.9W 90 KT 24HR VT 17/0000Z 23.6N 40.4W 85 KT 36HR VT 17/1200Z 25.3N 43.8W 80 KT 48HR VT 18/0000Z 27.0N 46.5W 75 KT 72HR VT 19/0000Z 31.5N 49.5W 65 KT 96HR VT 20/0000Z 35.0N 48.0W 50 KT 120HR VT 21/0000Z 36.5N 43.5W 40 KT $$ FORECASTER BERG |
