000
WTPZ41 KNHC 180232
TCDEP1
 
TROPICAL DEPRESSION ALETTA DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP012012
800 PM PDT THU MAY 17 2012
 
DEEP CONVECTION INCREASED OVER AND AROUND THE CENTER OF ALETTA A FEW
HOURS AGO...BUT NOW APPEARS TO BE ON THE WANE.  THE SYSTEM
CONTINUES TO LACK BANDING FEATURES...AND DVORAK CLASSIFICATIONS
FROM BOTH TAFB AND SAB GIVE AN INTENSITY ESTIMATE OF 30 KT.  THE
CYCLONE SHOULD CONTINUE TO BE UNDER THE INFLUENCE OF STRONG
SOUTHERLY SHEAR FOR THE NEXT DAY OR TWO...AND VERY DRY AIR LIES
JUST TO THE NORTHWEST OF THE DEPRESSION.  AS THIS AIR BECOMES MORE
ENTRAINED INTO THE CIRCULATION OF ALETTA...CONVECTION SHOULD
DIMINISH ENOUGH TO CAUSE THE SYSTEM TO DEGENERATE INTO A REMNANT
LOW IN A DAY OR SO.  THE OFFICIAL WIND SPEED FORECAST FOLLOWS THE
LGEM GUIDANCE AND IS THE SAME AS THE PREVIOUS NHC INTENSITY
FORECAST.  THE CYCLONE SHOULD LOSE ITS IDENTITY IN 3-4 DAYS OR
SOONER AS IT BECOMES ABSORBED INTO A DEVELOPING CIRCULATION TO ITS
EAST.

THE HEADING OF THE DEPRESSION HAS CONTINUED TO VEER TO THE RIGHT...
WITH THE INITIAL MOTION ESTIMATE NOW ABOUT 020/5.  STEERING
CURRENTS ARE WEAK AND THE TRACK MODEL GUIDANCE IS FAIRLY DIVERGENT. 
HOWEVER...THERE IS GENERAL AGREEMENT AMONG THE MODELS THAT ALETTA
OR ITS REMNANT WILL TURN EASTWARD DUE TO LOW-LEVEL WESTERLY FLOW
AND THEN BEGIN TO MOVE SOUTHEASTWARD AS IT INTERACTS WITH A LARGER
CYCLONIC CIRCULATION TO ITS EAST IN 2-3 DAYS.  THE OFFICIAL TRACK
FORECAST IS SIMILAR TO THE PREVIOUS ONE AND IS CLOSE TO THE MODEL
CONSENSUS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0300Z 13.6N 114.3W   30 KT  35 MPH
 12H  18/1200Z 13.9N 114.2W   25 KT  30 MPH
 24H  19/0000Z 14.1N 113.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  19/1200Z 14.1N 113.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  20/0000Z 13.7N 112.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  21/0000Z 12.8N 112.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  22/0000Z...DISSIPATED
 
$$
FORECASTER PASCH