ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM ALEX DISCUSSION NUMBER 13 NATIONAL WEATHER SERVICE MIAMI FL 11 AM EDT THU JUL 30 1998 THERE IS AN AREA OF CONCENTRATED CONVECTION NEAR THE CENTER AND CONSEQUENTLY THE DVORAK T-NUMBERS ARE 3.0 FROM BOTH TAFB AND SAB. THEREFORE...THE WINDS ARE ADJUSTED TO 45 KNOTS. THE OUTFLOW IS PARTIALLY RESTRICTED BUT IS ENOUGH TO MAINTAIN THE SYSTEM. THERE ARE HOSTILE UPPER LEVEL WINDS AHEAD OF THE STORM...HOWEVER ...GLOBAL MODELS SUGGEST THAT THESE WESTERLIES WILL WEAKEN OR RETROGRADE AND THEN SOME SOUTHERLY SHEAR MAY DEVELOP. THE OFFICIAL FORECAST CALLS FOR SOME STRENGTHENING SINCE THE GFDL AND SHIPS MODELS BRING THE TROPICAL CYCLONE TO 65 TO 65 KNOTS BY 72 HOURS. ON THE LONGER RANGE...4-5 DAYS... THE UPPER LEVEL WINDS BECOME A LITTLE MORE FAVORABLE IN THE AREA BETWEEN PUERTO RICO AND BERMUDA. ALEX IS CURRENTLY MOVING AROUND THE PERIPHERY OF A WELL ESTABLISHED DEEP LAYER MEAN RIDGE AT ABOUT 280/13. THIS RIDGE IS FORECAST TO HAVE A WEAKNESS ALONG 60-65 WEST. THIS WOULD INDUCE A TRACK MORE TO THE WEST-NORTHWEST AND NORTHWEST BY THE END OF THE FORECAST PERIOD. ON THIS TRACK...ALEX WOULD SKIRT THE NORTHERN LEEWARD ISLANDS BUT THEY STILL NEED TO MONITOR THIS STORM. THE OFFICIAL FORECAST IS VERY CLOSE TO THE GFDL BUT TO THE SOUTH OF MOST OF THE OTHER GUIDANCE. THE HIGH ALTITUDE NOOA JET IS SCHEDULED TO SAMPLE THE ENVIRONMENT SURROUNDING THE TROPICAL CYCLONE LATE FRIDAY. AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 30/1500Z 14.8N 46.1W 45 KTS 12HR VT 31/0000Z 15.1N 48.1W 50 KTS 24HR VT 31/1200Z 15.8N 50.8W 55 KTS 36HR VT 01/0000Z 16.5N 53.5W 60 KTS 48HR VT 01/1200Z 17.0N 56.0W 60 KTS 72HR VT 02/1200Z 20.0N 60.5W 60 KTS NNNN