ZCZC MIATCDAT5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM EARL DISCUSSION NUMBER 7 NATIONAL WEATHER SERVICE MIAMI FL 5 AM EDT WED SEP 02 1998 AIR FORCE RECON REPORTS MULTIPLE CENTERS AT FLIGHT LEVEL 1500 FT AND TRACKING A LOW-LEVEL CIRCULATION CENTER IS MOST DIFFICULT. TAFB AND SAB SATELLITE FIXES ARE 110 NMI APART. THE PAST 24 HOUR MOTION IS 030/10. THE PAST 6 HOUR MOTION IS STATIONARY. I HAVE NO IDEA WHICH IS CLOSER TO BEING RIGHT. THE 00Z AVIATION MODEL AND THE ETA SHOW VERY SLOW NORTHEAST AND THEN NORTHWESTWARD MOTION FOR 48 HOURS...CUT OFF FROM THE WESTERLIES. THE NOGAPS AND UKMET ALSO SHOW VERY SLOW MOTION FOR 72 HOURS. IN CONTRAST...THE 00Z GFDL AND LBAR ACCELERATES THE STORM NORTHEASTWARD...UNDER 10 KNOTS FOR 24 HOURS THEN NEAR 20 KNOTS BY 48 HOURS...INDICATING EARL GETTING PICKED UP BY WESTERLIES...BUT NOT REAL FAST. THE OFFICIAL INITIAL MOTION FOR 09Z IS 045/08...A COMPROMISE AVERAGE OF THE RANGE OF POSSIBILITES. THE FORECAST TRACK CONTINUES THIS FORWARD SPEED FOR 24 HOURS...OUT OF RESPECT FOR THE GFDL AND THE PREVIOUS ADVISORY. AFTER 24 HOURS THE FORECAST IS A SLOW NORTHWARD DRIFT...RESPECTING THE OTHER GUIDANCE. GPS DROPS FROM THE GULFSTREAM AIRCRAFT EARLIER SHOWED A 500 MB TROUGH IN THE WESTERLIES WITH A POSSIBLE LOW JUST SOUTH OF EASTERN LOUISIANA. THE LOW LEVEL CENTER IS SOUTHWEST OF THE 500 MB LOW. THIS SYSTEM DOES NOT APPEAR TO BE STRICTLY TROPICAL. THE DEEPEST CONVECTION IS IN TWO AREAS...ONE CDO TYPE NEAR THE CENTER AND THE OTHER ELONGATED EAST OF THE CENTER. THE MAXIMUM RECON WIND WAS 51 KNOTS AT 1500 FT AND BUOYS AND RIGS ALL SHOW THAT EARLY IS A 45 KNOT STORM. IT IS STILL WARM CORE AT 1500 FT HOWEVER AND...FOR ALL I KNOW...INTENSIFICATION IS STILL POSSIBLE. I AM RELUCTANT TO CHANGE THE PREVIOUS FORECAST TO REACH 65 KNOTS BEFORE LANDFALL EVEN THOUGH IT MAY NOT BE THE MOST LIKELY POSSIBILITY. WARNINGS ARE SHIFTED A LITTLE EASTWARD AS IS THE OFFICIAL FORECAST TRACK. LAWRENCE FORECAST POSITIONS AND MAX WINDS INITIAL 02/0900Z 27.8N 90.5W 50 KTS 12HR VT 02/1800Z 28.7N 89.6W 55 KTS 24HR VT 03/0600Z 30.0N 88.5W 65 KTS 36HR VT 03/1800Z 31.0N 88.5W 40 KTS...INLAND 48HR VT 04/0600Z 32.0N 88.5W 30 KTS...INLAND 72HR VT 05/0600Z 33.0N 88.5W 25 KTS...INLAND NNNN