Atlantic-Carib-Gulf MexTropical Depression SIXTEEN...TROPICAL DEPRESSION FORMS EAST-NORTHEAST OF THE CENTRAL BAHAMAS... 11:00 AM EDT Thu Oct 11Location: 25.4°N 72.6°WMoving: S at 1 mphMin pressure: 1009 mbMax sustained: 35 mph
000WTNT41 KNHC 112035TCDAT1TROPICAL STORM PATTY DISCUSSION NUMBER 2NWS NATIONAL HURRICANE CENTER MIAMI FL AL162012500 PM EDT THU OCT 11 2012SATELLITE IMAGES INDICATE THAT WHILE THE CYCLONE REMAINSSHEARED...CONVECTION IS A LITTLE CLOSER TO THE CENTER THAN EARLIERTODAY. SUBJECTIVE DVORAK ESTIMATES FROM TAFB AND SAB ARE 45KT...WHILE THE CIMSS ADT IS AT 35 KT. WHILE THE SUBJECTIVE VALUESLOOK A BIT HIGH...GIVEN THE STEADY CONVECTION TODAY...IT SEEMSLIKELY THAT THE SYSTEM HAS INTENSIFIED SINCE THE 30-KT ASCAT PASSFROM LAST NIGHT. THUS THE INITIAL WIND SPEED IS CONSERVATIVELY SETTO 35 KT...MAKING PATTY THE SIXTEENTH NAMED STORM OF THE SEASON. THE TROPICAL STORM APPEARS TO BE ON BORROWED TIME AS THERE ARE ACOUPLE OF FACTORS COMING TOGETHER THAT SHOULD WEAKEN THE CYCLONE. FIRST...SOUTHWESTERLY SHEAR SHOULD INCREASE DURING THE NEXT DAY ORSO DUE TO A BUILDING LOW-LEVEL RIDGE OVER THE WESTERN ATLANTIC ANDPERSISTENT UPPER-LEVEL SOUTHWESTERLY FLOW. SECOND...A COLD FRONTIS LOCATED IN THE WESTERN PORTION OF THE CIRCULATION...AND SOME OFTHAT DRIER AND MORE STABLE AIR WILL LIKELY ENTRAIN INTO THE CENTER. THESE ENVIRONMENTAL CONDITIONS SHOULD CAUSE THE CYCLONE TO WEAKENBY TOMORROW...AND WILL LIKELY CAUSE PATTY TO SHEAR APART INTO ATROUGH. THIS SCENARIO IS IN GOOD AGREEMENT WITH THE GLOBAL MODELFORECASTS...AND NO SUBSTANTIAL CHANGE IS MADE TO THE PREVIOUSFORECAST AFTER ACCOUNTING FOR THE SLIGHTLY HIGHER INITIAL WINDS. THE CYCLONE HAS NOT MOVED MUCH TODAY...PROBABLY DUE TO THE CENTERMAINTAINING VERTICAL COHERENCE IN SPITE OF THE SHEAR. GLOBALMODELS STRONGLY SUGGEST THAT PATTY WILL MOVE TO THE SOUTHWEST BYTOMORROW AS HIGH PRESSURE BUILDS INTO THE WESTERN ATLANTIC OCEAN. THE OFFICIAL FORECAST IS LITTLE SLOWER THAN THE PREVIOUS FORECASTINITIALLY...THEN IS BLENDED NEAR THE LATEST CONSENSUS AT 24H. GIVEN THE STRONG SOUTHWESTERLY UPPER-LEVEL WINDS...IT IS UNLIKELYTHAT PATTY COULD REACH THE BAHAMAS AS A TROPICAL STORM...ANDTHEREFORE NO WATCHES OR WARNINGS ARE IN EFFECT FOR THOSE ISLANDS. FORECAST POSITIONS AND MAX WINDSINIT 11/2100Z 25.8N 72.5W 35 KT 40 MPH 12H 12/0600Z 25.4N 72.9W 35 KT 40 MPH 24H 12/1800Z 24.9N 73.4W 30 KT 35 MPH 36H 13/0600Z...DISSIPATED$$FORECASTER BLAKE