000 WTPZ41 KNHC 301436 TCDEP1 TROPICAL DEPRESSION ALVIN DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP012007 800 AM PDT WED MAY 30 2007 CONVECTION HAS FLARED NEAR ALVIN THIS MORNING...WITH THE CENTER ON THE NORTHEASTERN PORTION OF A BAND. SATELLITE CLASSIFICATIONS ARE ABOUT THE SAME AS EARLIER...AND THE INITIAL INTENSITY WILL BE HELD AT 30 KT. NO SIGNIFICANT CHANGE IN STRENGTH IS EXPECTED FOR THE NEAR TERM. THIS IS BASICALLY A PERSISTENCE FORECAST SINCE ALVIN HAS BEEN PRETTY WEAK ITS ENTIRE LIFETIME IN ABOUT THE SAME ENVIRONMENT. HOWEVER THE GFS INDICATES THAT UPPER DIVERGENCE WILL DECREASE NEAR THE DEPRESSION BY ABOUT TWENTY-FOUR HOURS...WHICH COULD LIMIT THESE PERIODIC BURSTS OF CONVECTION THAT ALVIN HAS BEEN PRODUCING FOR DAYS. THUS THE INTENSITY FORECAST WILL BE REDUCED FROM THE PREVIOUS FORECAST...BUT IS STILL A LITTLE HIGHER THAN THE GFDL/SHIPS GUIDANCE. UPPER CONDITIONS LOOK EVEN LESS FAVORABLE FOR DEVELOPMENT IN THE LONG TERM...AND ALVIN SHOULD BECOME A REMNANT LOW IN FOUR DAYS OR SO...IF NOT SOONER. A PAIR OF MICROWAVE PASSES NEAR 0900 UTC SUGGEST THAT ALVIN HAS BEEN MOVING A LITTLE SLOWER AND TO RIGHT OF ITS PREVIOUS TRACK...GIVING A LONG-TERM MOTION OF 300/3. RIDGING IS FORECAST TO BUILD TO THE NORTH OF THE DEPRESSION...WHICH SHOULD FORCE A WESTWARD MOTION IN A DAY OR SO. THEREAFTER...RIDGING IN THE LOW TO MID-LEVELS IS ORIENTED FROM EAST-NORTHEAST TO WEST-SOUTHWEST. ALL GLOBAL MODELS RESPOND BY SENDING THE CYCLONE ON A WEST-SOUTHWEST OR SOUTHWEST TRACK. THE OFFICIAL FORECAST IS A LITTLE NORTH OF THE PREVIOUS ADVISORY INITIALLY AND A LITTLE SLOWER THAN THE DYNAMICAL MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 30/1500Z 13.4N 114.6W 30 KT 12HR VT 31/0000Z 13.6N 115.1W 30 KT 24HR VT 31/1200Z 13.7N 116.1W 25 KT 36HR VT 01/0000Z 13.7N 117.1W 25 KT 48HR VT 01/1200Z 13.4N 118.1W 25 KT 72HR VT 02/1200Z 12.8N 119.4W 25 KT 96HR VT 03/1200Z 12.0N 120.7W 20 KT...REMNANT LOW 120HR VT 04/1200Z 11.0N 122.3W 20 KT...REMNANT LOW $$ FORECASTER BLAKE