000
WTNT42 KNHC 060850
TCDAT2
 
HURRICANE LESLIE DISCUSSION NUMBER  28
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 AM AST THU SEP 06 2012
 
THE SATELLITE PRESENTATION OF LESLIE REMAINS RAGGED...WITH MOST OF
THE DEEP CONVECTION DISPLACED EAST OF THE CENTER. THE OUTFLOW
APPEARS RESTRICTED IN THE WESTERN SEMICIRCLE DUE TO WESTERLY SHEAR
FROM AN UPPER-LEVEL ANTICYCLONE LOCATED TO THE SOUTHWEST OF LESLIE.
IN ADDITION...THE LACK OF MOTION IS RESULTING IN SOME COOLING OF THE
SEA SURFACE NEAR THE CYCLONE...AS EVIDENCED BY A 1C SST DECREASE IN
THE LAST 24 HOURS AT NOAA BUOY 41049. THE INITIAL INTENSITY REMAINS
65 KT BASED ON THE LASTEST DVORAK ESTIMATES FROM TAFB AND SAB. 

MODERATE WESTERLY SHEAR...THE POSSIBLE INFLUENCE OF DRY AIR...AND
UPWELLING WILL LIKELY RESULT IN ONLY GRADUAL STRENGTHENING FOR THE
NEXT DAY OR SO. AFTER THAT TIME...THE SHEAR BEGINS TO DECREASE AND
LESLIE SHOULD HAVE AN OPPORTUNITY TO STRENGTHEN AS IT BEGINS TO
MOVE NORTHWARD. THE NHC INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS ONE AND IS CLOSE TO OR A LITTLE ABOVE THE INTENSITY
CONSENSUS THROUGH THE PERIOD.
 
LESLIE HAS HARDLY MOVED OVERNIGHT...WITH AN INITIAL MOTION ESTIMATE
OF 360/01 AS THE CYCLONE IS TRAPPED SOUTH OF A WEAK MID-LEVEL
ANTICYCLONE. THE OVERALL SYNOPTIC PATTERN WILL NOT CHANGE MUCH
DURING THE NEXT 48 HOURS...AND A SLOW NORTHWARD TO NORTH-
NORTHWESTWARD MOTION IS EXPECTED THROUGH THAT TIME. THE NHC
FORECAST IS A LITTLE SLOWER AND RIGHT OF THE PREVIOUS ONE THROUGH
48 HOURS DUE TO THE INITIAL POSITION AND MOTION AND THE TREND OF
THE LATEST TRACK GUIDANCE. LATER IN THE FORECAST PERIOD...MOST OF
THE GUIDANCE HAS TRENDED MUCH SLOWER WITH THE FORWARD SPEED OF THE
CYCLONE. THIS APPEARS TO BE DUE TO THE SLOWER MOTION OF LESLIE
EARLY ON AND A SLIGHTLY SLOWER AND/OR LESS AMPLIFIED TROUGH MOVING
THROUGH THE EASTERN UNITED STATES IN 4 TO 5 DAYS. THE GFS IS ON THE
RIGHT SIDE OF THE RELIABLE MODELS AND SHOWS THE TROUGH MISSING
LESLIE ENTIRELY. AT THE OTHER EXTREME IS THE GFDL...WHICH IS A FAST
OUTLIER THAT SHOWS LESLIE BEING CAPTURED BY THE TROUGH AT END OF
THE PERIOD. THE NEW MULTI-MODEL CONSENSUS IS WELL TO THE RIGHT OF
AND SLOWER THAN THE PREVIOUS OFFICIAL FORECAST AT DAYS 4 AND 5. THE
NHC TRACK HAS BEEN ADJUSTED IN THAT DIRECTION BUT IS STILL FASTER
AND TO THE LEFT OF MOST OF THE GUIDANCE. CONFIDENCE IN THE LONG-
RANGE TRACK FORECAST IS LOW AND FURTHER ADJUSTMENTS MAY BE
NECESSARY LATER TODAY. 
 
THE INITIAL WIND RADII WERE ADJUSTED BASED ON A 0153 UTC ASCAT PASS
AND DATA FROM NOAA BUOY 40149. LESLIE IS A LARGE TROPICAL CYCLONE
THAT IS FORECAST TO GROW IN SIZE OVER THE NEXT SEVERAL DAYS. THE
WIND FIELD OF LESLIE...COMBINED WITH ITS EXPECTED SLOW MOTION...
WILL GENERATE LONG-PERIOD SWELLS THAT WILL PRODUCE LARGE WAVES AND
LIFE-THREATENING RIP CURRENTS ON BERMUDA AND ALONG MUCH OF THE U.S.
EAST COAST FOR THE REMAINDER OF THIS WEEK.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/0900Z 26.3N  62.4W   65 KT  75 MPH
 12H  06/1800Z 26.5N  62.4W   70 KT  80 MPH
 24H  07/0600Z 26.7N  62.5W   75 KT  85 MPH
 36H  07/1800Z 27.1N  62.7W   80 KT  90 MPH
 48H  08/0600Z 27.7N  63.0W   85 KT 100 MPH
 72H  09/0600Z 31.0N  63.0W   90 KT 105 MPH
 96H  10/0600Z 36.5N  61.5W   90 KT 105 MPH
120H  11/0600Z 43.0N  59.0W   80 KT  90 MPH
 
$$
FORECASTER BRENNAN