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| #43916 (Received by flhurricane at: 11:03 PM 03.Sep.2005) TCDAT4 TROPICAL STORM MARIA DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT SAT SEP 03 2005 MARIA APPEARED TO BE ON THE CUSP OF HURRICANE STATUS EARLIER TODAY... BUT CONVECTION HAS SINCE BECOME SOMEWHAT LESS VIGOROUS. THE OUTFLOW PATTERN REMAINS WELL ESTABLISHED... ALTHOUGH MAYBE NOW A LITTLE MORE ELONGATED NORTHWEST TO SOUTHEAST. DVORAK INTENSITY ESTIMATES ARE 65 KT FROM TAFB AND 55 KT FROM SAB... AND BOTH AGENCIES HAVE ANALYZED A DATA T NUMBER OF 3.5. THE ADVISORY INTENSITY IS KEPT AT 60 KT. THE CONVECTION SEEMS TO BE TRYING TO MAKE A COMEBACK AROUND THE CENTER DURING THE LAST HOUR OR TWO... SO THE RECENT SPUTTERING MIGHT ONLY BE TEMPORARY. THE ESTIMATED INITIAL MOTION OF 330/12 KT IS JUST A LITTLE SLOWER AND TO THE EAST COMPARED TO THE PREVIOUS ADVISORY. THE STEERING TOWARD THE NORTH-NORTHWEST IS BEING PROVIDED BY A LOW TO MIDDLE LEVEL RIDGE JUST EAST OF MARIA. THIS RIDGE IS FORECAST BY THE DYNAMICAL MODELS TO BUILD NORTHWARD DURING THE NEXT COUPLE OF DAYS... RESULTING IN ONLY A GRADUAL BEND IN THE TRACK TO THE NORTH. THEREAFTER... A MIDDLE LATITUDE TROUGH CURRENTLY OVER THE NORTHEASTERN U.S. IS EXPECTED TO MOVE OUT OVER THE WESTERN ATLANTIC AND ERODE THE RIDGE... AND ACCELERATE MARIA NORTHEASTWARD AND AWAY FROM NORTH AMERICA. THE DYNAMICAL MODELS ARE TIGHTLY CLUSTERED BEFORE THE RECURVATURE... BUT AS USUAL DIFFER IN THE SUBSEQUENT FORWARD SPEED. THE OFFICIAL FORECAST IS A BLEND OF THE GFDL AND NOGAPS MODELS WHICH DEPICT A STRONGER SYSTEM THAN THE FASTER GFS THAT KEEPS THE CIRCULATION OF MARIA SEEMINGLY TOO WEAK. THIS IS JUST A HAIR TO THE EAST OF THE PREVIOUS ADVISORY THROUGH ABOUT 48 HOURS AND IS FASTER AT DAYS 3 THROUGH 5. MARIA HAD BEEN STRENGTHENING TODAY WITHIN A WEAK SHEAR ENVIRONMENT... BENEATH A NORTH-SOUTH ORIENTED UPPER-LEVEL RIDGE THAT IS SANDWICHED IN BETWEEN AN UPPER-LEVEL LOW NEAR BERMUDA AND A LARGE EXTRATROPICAL LOW PRESSURE SYSTEM OVER THE EASTERN ATLANTIC. IT SHOULD REMAIN WITHIN THIS RIDGE FOR THE NEXT 48 HOURS OR SO... AND SINCE THE SSTS WILL REMAIN GREATER THAN 28C DURING THIS PERIOD... SOME FURTHER INTENSIFICATION IS ANTICIPATED... BUT NOT AS MUCH AS BEFORE DUE TO THE RECENT LEVELLING OFF AND LESS BULLISH GUIDANCE. THE OFFICIAL FORECAST PEAKS AT 80 KT... WHICH IS JUST A LITTLE LESS THAN THE SHIPS GUIDANCE THROUGH 48 HOURS AND FAVORS THE GFDL WEAKENING TREND THEREAFTER. AFTER RECURVATURE BEGINS... MARIA IS EXPECTED TO ENCOUNTER STRONG MIDLATITUDE WESTERLIES TO THE NORTH OF THE RIDGE. THE INCREASING WESTERLY SHEAR COMBINED WITH COOLER SEA SURFACE TEMPERATURES SHOULD STEADY WEAKENING. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 04/0300Z 27.1N 54.9W 60 KT 12HR VT 04/1200Z 28.6N 55.8W 65 KT 24HR VT 05/0000Z 30.8N 56.5W 75 KT 36HR VT 05/1200Z 33.0N 57.0W 80 KT 48HR VT 06/0000Z 35.2N 56.7W 80 KT 72HR VT 07/0000Z 38.5N 53.5W 75 KT 96HR VT 08/0000Z 41.0N 50.0W 65 KT 120HR VT 09/0000Z 42.5N 45.0W 55 KT |
