000 WTNT45 KNHC 250859 TCDAT5 TROPICAL DEPRESSION TEN DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102011 500 AM EDT THU AUG 25 2011 THE AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE SEVERAL HUNDRED MILES WEST-SOUTHWEST OF THE SOUTHERN CAPE VERDE ISLANDS HAS ACQUIRED SUFFICIENT ORGANIZATION TO BE DECLARED A TROPICAL DEPRESSION. THE CENTER APPEARS TO BE LOCATED NEAR THE NORTHEAST TIP OF A CURVED BAND WRAPPING AROUND THE WESTERN SEMICIRCLE. SATELLITE INTENSITY ESTIMATES ARE AT T2.5 FROM TAFB AND SAB WHICH SUGGEST THAT THE DEPRESSION COULD BE NEAR TROPICAL STORM STRENGTH. HOWEVER...GIVEN THE UNCERTAINTY REGARDING THE CENTER LOCATION AND THE RECENT WARMING OF CONVECTIVE TOPS NEAR THE ESTIMATED CENTER...A MORE CONSERVATIVE ASSESSMENT OF THE INTENSITY SEEMS MOST PRUDENT. THE INITIAL INTENSITY IS SET AT 30 KT. SINCE THE CENTER HAS NOT BEEN WELL FORMED...THE INITIAL MOTION ESTIMATE IS A FAIRLY UNCERTAIN 280/10. THE DEPRESSION SHOULD DECELERATE ON A WEST-NORTHWESTWARD AND THEN NORTHWESTWARD COURSE DURING THE NEXT DAY OR TWO AS IT NEARS THE WESTERN EDGE OF A LOW- TO MID-LEVEL RIDGE OVER THE FAR EASTERN ATLANTIC. GLOBAL MODELS SHOW A WEAKNESS IN THE RIDGE ALONG 35W IN 2-3 DAYS WHICH SHOULD BECOME MORE PRONOUNCED AS A MID- TO UPPER-LEVEL TROUGH BEGINS TO DIG SOUTHWARD OVER THE NORTHEAST ATLANTIC. THIS SHOULD CAUSE THE TRACK OF THE CYCLONE TO TURN TOWARD THE NORTH-NORTHWEST AND POSSIBLY THE NORTH LATER IN THE FORECAST PERIOD. THE TRACK AROUND 96-120 HOURS IS HIGHLY DEPENDENT ON THE VERTICAL INTEGRITY OF THE CYCLONE...WITH A WEAKER/SHALLOWER SYSTEM LIKELY LYING WEST OF THE FORECAST TRACK. THE OFFICIAL NHC TRACK IS CLOSE TO THE MULTI-MODEL CONSENSUS TVCN. EVEN THOUGH THE DEPRESSION SHOULD TRACK OVER WARM ENOUGH WATERS DURING THE NEXT COUPLE OF DAYS...ANALYSES FROM UW-CIMSS CURRENTLY SHOW 15-20 KT OF NORTHEASTERLY SHEAR OVER THE DEPRESSION WHICH IS FORECAST BY THE SHIPS MODEL TO CONTINUE. ALTHOUGH A TEMPORARY REDUCTION OF THE SHEAR COULD OCCUR IN ABOUT 48 HOURS...THE ABRUPT TURN OF THE CYCLONE TOWARD THE NORTH-NORTHWEST BEYOND THIS TIME WILL BRING IT OVER 25C-26C WATERS AND LATER IN A REGION OF INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH THE SOUTHWARD EXTENSION OF AN UPPER-LEVEL TROUGH OVER THE NORTHEAST ATLANTIC. THE OFFICIAL NHC INTENSITY FORECAST IS IN GOOD AGREEMENT WITH THE MULTI-MODEL CONSENSUS THROUGH 48 HOURS...SHOWING SLOW STRENGTHENING. WEAKENING IS INDICATED AFTER THAT TIME IN LIGHT OF THE NEGATIVE ENVIRONMENTAL FACTORS THE CYCLONE IS FORECAST TO ENCOUNTER AND IS BELOW MOST THE GUIDANCE. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 12.4N 30.4W 30 KT 35 MPH 12H 25/1800Z 12.8N 31.8W 35 KT 40 MPH 24H 26/0600Z 13.5N 33.4W 40 KT 45 MPH 36H 26/1800Z 14.5N 34.3W 45 KT 50 MPH 48H 27/0600Z 15.5N 35.1W 50 KT 60 MPH 72H 28/0600Z 17.7N 36.1W 45 KT 50 MPH 96H 29/0600Z 20.0N 37.0W 35 KT 40 MPH 120H 30/0600Z 22.5N 38.5W 30 KT 35 MPH $$ FORECASTER KIMBERLAIN