ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM ERICK DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052013 200 AM PDT SAT JUL 06 2013 ERICK CONTINUES TO GENERATE A LARGE AREA OF CONVECTION WITH TOPS COLDER THAN -80C NEAR ITS CENTER...AND THERE HAVE BEEN OCCASIONAL ATTEMPTS TO FORM AN EYE. HOWEVER...ANALYSIS OF MICROWAVE DATA DURING THE PAST 12-18 HOURS SHOW THAT THE CYCLONE IS HAVING TROUBLE BECOMING VERTICALLY ALIGNED...WITH THE MID-LEVEL EYE CONSISTENTLY TO THE WEST OR SOUTHWEST OF THE LOW-LEVEL CENTER. SATELLITE INTENSITY ESTIMATES ARE 65 KT FROM TAFB AND 55 KT FROM SAB. BASED ON THIS AND THE OBSERVED STRUCTURE IN MICROWAVE DATA...THE INITIAL INTENSITY REMAINS 60 KT. THE INITIAL POSITION HAS BEEN SHIFTED A LITTLE TO THE EAST BASED ON THE MICROWAVE DATA...AND THE INITIAL MOTION IS NOW 315/7. A WEAK MID-LEVEL RIDGE OVER MEXICO IS EXPECTED TO STEER ERICK GENERALLY TOWARD THE NORTHWEST DURING THE NEXT 48 HOURS...WITH THE MOTION BECOMING MORE WESTWARD AS THE CYCLONE ENCOUNTERS A STRONGER RIDGE OVER NORTHWESTERN MEXICO AND THE SOUTHWESTERN UNITED STATES. WHILE THE TRACK GUIDANCE GENERALLY AGREES WITH THIS SCENARIO...THERE IS A FAIR AMOUNT OF SPREAD AND SOME SIGNIFICANT OUTLIER MODELS. THE GFS MOVES THE STORM ONSHORE SOUTH OF CABO CORRIENTES...WHILE THE UKMET AND GFDL MODELS BRING THE CENTER CLOSE TO SOUTHERN BAJA CALIFORNIA. THE NEW FORECAST TRACK IS ADJUSTED A LITTLE TO THE NORTH AND EAST OF THE PREVIOUS TRACK...BASED IN THE SHORT-TERM ON THE INITIAL POSITION AND IN THE LONGER TERM BY A NORTHWARD SHIFT IN THE GUIDANCE. WHILE IT KEEPS THE CENTER OFFSHORE...ANY DEVIATION TO THE RIGHT OF THE TRACK COULD BRING THE CENTER ON TO THE MEXICAN COAST SIMILAR TO THE GFS FORECAST. IF THE CYCLONE DOES NOT HIT THE MEXICAN COAST...IT SHOULD STRENGTHEN TO A HURRICANE DURING THE NEXT 24 HOURS. AFTER THAT...ERICK SHOULD MOVE OVER DECREASING SEA SURFACE TEMPERATURES...WHICH COULD BE AS COLD AS 20-21C BY THE 96 HOUR POINT. THIS SHOULD CAUSE RAPID WEAKENING...WITH THE CYCLONE EXPECTED TO DEGENERATE TO A REMNANT LOW AROUND 96 HOURS. THE NEW INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS FORECAST. SINCE THE NEW FORECAST TRACK IS CLOSER TO THE COAST OF MEXICO...THE GOVERNMENT OF MEXICO HAS ISSUED A HURRICANE WATCH FROM PUNTA SAN TELMO TO CABO CORRIENTES. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 17.3N 103.6W 60 KT 70 MPH 12H 06/1800Z 18.0N 104.3W 70 KT 80 MPH 24H 07/0600Z 19.0N 105.5W 70 KT 80 MPH 36H 07/1800Z 20.3N 107.0W 65 KT 75 MPH 48H 08/0600Z 21.5N 108.8W 55 KT 65 MPH 72H 09/0600Z 23.0N 112.5W 30 KT 35 MPH 96H 10/0600Z 24.0N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 11/0600Z 24.0N 120.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ FORECASTER BEVEN NNNN