000 WTNT41 KNHC 290253 TCDAT1 TROPICAL STORM ARLENE DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012011 1000 PM CDT TUE JUN 28 2011 WHILE THE DEEP CONVECTION NEAR AND TO THE NORTHEAST OF THE CENTER OF ARLENE HAS CONTINUED TO INCREASE DURING THE LAST FEW HOURS...THERE HAS BEEN NO FURTHER INCREASE IN ITS ORGANIZATION. DVORAK SATELLITE INTENSITY ESTIMATES REMAIN UNCHANGED SINCE 0000 UTC...AND THE INITIAL INTENSITY IS HELD AT 35 KT. SATELLITE IMAGERY SUGGESTS THAT UPPER-LEVEL WESTERLY WINDS CONTINUE TO IMPINGE ON THE CYCLONE...AND UW CIMSS SHEAR ANALYSES INDICATE ABOUT 20 KT OF WESTERLY SHEAR AFFECTING ARLENE. THE DYNAMICAL MODEL AND SHIPS GUIDANCE SUGGEST THAT THE SHEAR WILL DECREASE DURING THE NEXT 24 HOURS WHICH SHOULD ALLOW AN OPPORTUNITY FOR GRADUAL STRENGTHENING. HOWEVER...THE LARGE CIRCULATION OF THE TROPICAL CYCLONE AND THE POSSIBILITY OF A SLOWER REDUCTION OF THE WESTERLY SHEAR COULD LIMIT ITS POTENTIAL FOR SIGNIFICANT INTENSIFICATION PRIOR TO LANDFALL. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND CLOSE TO CONSENSUS OF THE INTENSITY GUIDANCE. ARLENE CONTINUES MOVING SLOWLY WEST-NORTHWESTWARD OR 295/6. THE STORM IS FORECAST TO TURN TOWARD THE WEST ON WEDNESDAY AS A MID- TO UPPER-LEVEL RIDGE OVER THE CENTRAL UNITED STATES BUILDS EASTWARD. SEVERAL OF THE DYNAMICAL MODELS INDICATE THAT ARLENE COULD TURN WEST-SOUTHWESTWARD AS IT APPROACHES THE COAST OF MEXICO DUE TO THE STRENGTHENING RIDGE. THE OFFICIAL TRACK FORECAST SUGGESTS THIS POSSIBILITY AND LIES BETWEEN THE GFS AND ECMWF MODEL SOLUTIONS. GIVEN THE LARGE SIZE OF THE CIRCULATION OF ARLENE...ONE SHOULD NOT FOCUS ON THE EXACT FORECAST TRACK...AS IMPACTS COULD BE FELT OVER A LARGE PORTION OF NORTHEASTERN MEXICO WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 21.4N 94.1W 35 KT 40 MPH 12H 29/1200Z 21.8N 95.1W 40 KT 45 MPH 24H 30/0000Z 22.0N 96.3W 45 KT 50 MPH 36H 30/1200Z 21.9N 97.4W 50 KT 60 MPH 48H 01/0000Z 21.7N 98.6W 35 KT 40 MPH...INLAND 72H 02/0000Z 21.3N 100.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 03/0000Z...DISSIPATED $$ FORECASTER BROWN/KIMBERLAIN 000 WTNT41 KNHC 290253 TCDAT1 TROPICAL STORM ARLENE DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012011 1000 PM CDT TUE JUN 28 2011 WHILE THE DEEP CONVECTION NEAR AND TO THE NORTHEAST OF THE CENTER OF ARLENE HAS CONTINUED TO INCREASE DURING THE LAST FEW HOURS...THERE HAS BEEN NO FURTHER INCREASE IN ITS ORGANIZATION. DVORAK SATELLITE INTENSITY ESTIMATES REMAIN UNCHANGED SINCE 0000 UTC...AND THE INITIAL INTENSITY IS HELD AT 35 KT. SATELLITE IMAGERY SUGGESTS THAT UPPER-LEVEL WESTERLY WINDS CONTINUE TO IMPINGE ON THE CYCLONE...AND UW CIMSS SHEAR ANALYSES INDICATE ABOUT 20 KT OF WESTERLY SHEAR AFFECTING ARLENE. THE DYNAMICAL MODEL AND SHIPS GUIDANCE SUGGEST THAT THE SHEAR WILL DECREASE DURING THE NEXT 24 HOURS WHICH SHOULD ALLOW AN OPPORTUNITY FOR GRADUAL STRENGTHENING. HOWEVER...THE LARGE CIRCULATION OF THE TROPICAL CYCLONE AND THE POSSIBILITY OF A SLOWER REDUCTION OF THE WESTERLY SHEAR COULD LIMIT ITS POTENTIAL FOR SIGNIFICANT INTENSIFICATION PRIOR TO LANDFALL. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND CLOSE TO CONSENSUS OF THE INTENSITY GUIDANCE. ARLENE CONTINUES MOVING SLOWLY WEST-NORTHWESTWARD OR 295/6. THE STORM IS FORECAST TO TURN TOWARD THE WEST ON WEDNESDAY AS A MID- TO UPPER-LEVEL RIDGE OVER THE CENTRAL UNITED STATES BUILDS EASTWARD. SEVERAL OF THE DYNAMICAL MODELS INDICATE THAT ARLENE COULD TURN WEST-SOUTHWESTWARD AS IT APPROACHES THE COAST OF MEXICO DUE TO THE STRENGTHENING RIDGE. THE OFFICIAL TRACK FORECAST SUGGESTS THIS POSSIBILITY AND LIES BETWEEN THE GFS AND ECMWF MODEL SOLUTIONS. GIVEN THE LARGE SIZE OF THE CIRCULATION OF ARLENE...ONE SHOULD NOT FOCUS ON THE EXACT FORECAST TRACK...AS IMPACTS COULD BE FELT OVER A LARGE PORTION OF NORTHEASTERN MEXICO WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 21.4N 94.1W 35 KT 40 MPH 12H 29/1200Z 21.8N 95.1W 40 KT 45 MPH 24H 30/0000Z 22.0N 96.3W 45 KT 50 MPH 36H 30/1200Z 21.9N 97.4W 50 KT 60 MPH 48H 01/0000Z 21.7N 98.6W 35 KT 40 MPH...INLAND 72H 02/0000Z 21.3N 100.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 03/0000Z...DISSIPATED $$ FORECASTER BROWN/KIMBERLAIN