000 WTNT45 KNHC 020243 TCDAT5 TROPICAL STORM EMILY DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052011 1100 PM AST MON AUG 01 2011 EMILY STILL HAS A RATHER DISHEVELED APPEARANCE IN GEOSTATIONARY IMAGERY...AND THE CLOUD TOPS HAVE WARMED A BIT OVER THE PAST FEW HOURS AND LACK MUCH IN THE WAY OF CURVATURE. BASED ON THE LACK OF IMPROVEMENT IN THE SATELLITE PRESENTATION...THE INITIAL INTENSITY ESTIMATE IS HELD AT 35 KT FOR THIS ADVISORY IN AGREEMENT WITH THE 00Z DVORAK INTENSITY ESTIMATE FROM SAB. THE ATMOSPHERIC ENVIRONMENT NEAR AND AHEAD OF THE THE CYCLONE APPEARS TO BE ONLY MARGINALLY FAVORABLE FOR INTENSIFICATION...AS SEEN BY THE COPIOUS DRY AIR IN THE 00Z SAN JUAN RADIOSONDE AND SATELLITE PRECIPITABLE WATER IMAGERY. THE INTENSITY GUIDANCE SHOWS ONLY MODEST STRENGTHENING IN THE NEXT 48 HOURS...AND IN FACT THE LATEST GFDL MODEL RUN EVEN DISSIPATES THE CYCLONE IN ABOUT TWO DAYS. THE OFFICIAL FORECAST IS CLOSE TO THE IVCN INTENSITY CONSENSUS THROUGH 36 HOURS...AND THEN SHOWS WEAKENING AT 48 AND 72 HOURS AS EMILY IS EXPECTED TO INTERACT WITH HISPANIOLA. ASSUMING THAT EMILY RECOVERS FROM INTERACTION WITH THE ISLAND...GRADUAL STRENGTHENING IS EXPECTED LATE IN THE PERIOD AND THE NHC FORECAST IS CLOSE TO THE LGEM. THE CENTER HAS BEEN A BIT DIFFICULT TO LOCATE SINCE THE AIRCRAFT DEPARTED...SO THE INITIAL POSITION AND INITIAL MOTION OF 275/15 ARE QUITE UNCERTAIN AND BASED LARGELY ON CONTINUITY. OVERALL THE GLOBAL MODELS ARE IN GOOD AGREEMENT WITH THE EVOLUTION OF THE SYNOPTIC PATTERN...AS A MID-LEVEL TROUGH DIGGING INTO THE WESTERN ATLANTIC WILL GRADUALLY ERODE THE RIDGE NORTH OF EMILY OVER THE NEXT 2 OR 3 DAYS. THIS WILL ALLOW EMILY TO TURN TOWARD THE WEST-NORTHWEST AND GRADUALLY SLOW DOWN DURING THIS TIME PERIOD. LATE IN THE PERIOD... THE MODELS SHOW THE TROUGH LIFTING OUT AND SOME RIDGING RE-BUILDING NORTH OF EMILY. HOWEVER...BOTH THE DETAILS OF THE RIDGE AND THE DEPTH OF THE CYCLONE APPEAR TO MAKE ALL THE DIFFERENCE IN THE EVENTUAL TRACK. FOR EXAMPLE...THE LATEST GFS RUN HAS A SLIGHTLY WEAKER RIDGE AND A MUCH DEEPER REPRESENTATION OF EMILY THAT MOVES MORE NORTHWARD. THE HWRF AND GFS ENSEMBLE MEAN ALSO FOLLOW THIS GENERAL SCENARIO. ON THE OTHER HAND...THE ECMWF HAS A MUCH WEAKER REPRESENTATION OF EMILY THAT MOVES MORE WESTWARD LATE IN THE PERIOD UNDERNEATH A STRONGER RIDGE. GIVEN THE LARGE MODEL SPREAD...THERE IS SIGNIFICANT UNCERTAINTY IN THE TRACK FORECAST AT THE END OF THE PERIOD. THE NEW NHC TRACK FORECAST IS LARGELY AN UPDATE OF THE PREVIOUS PACKAGE THROUGH 72 HOURS...AND HAS BEEN ADJUSTED A LITTLE TO THE RIGHT TOWARD THE TVCA MULTI-MODEL CONSENSUS AT DAYS 4 AND 5. FORECAST POSITIONS AND MAX WINDS INIT 02/0300Z 15.5N 62.9W 35 KT 40 MPH 12H 02/1200Z 15.9N 64.9W 40 KT 45 MPH 24H 03/0000Z 16.8N 67.2W 45 KT 50 MPH 36H 03/1200Z 17.8N 69.4W 50 KT 60 MPH 48H 04/0000Z 18.9N 71.4W 45 KT 50 MPH...INLAND 72H 05/0000Z 22.0N 75.0W 40 KT 45 MPH...OVER WATER 96H 06/0000Z 25.0N 78.0W 50 KT 60 MPH 120H 07/0000Z 27.5N 80.0W 65 KT 75 MPH $$ FORECASTER BRENNAN