Tropical Depression NINETEEN-E
ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION NINETEEN-E DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP192006 100 PM PST WED NOV 08 2006 AFTER BEING VERY CLOSE TO TROPICAL STORM STRENGTH EARLIER TODAY... THE DEPRESSION'S CONVECTIVE PATTERN HAS FALLEN APART DURING THE DAY. VERTICAL WIND SHEAR HAS DISPLACED MOST OF THE DEEP CONVECTION TO THE EASTERN SEMICIRCLE OF THE CYCLONE. IN ADDITION THE LOW-LEVEL STRUCTURE OF THE DEPRESSION LOOKS SOMEWHAT DISORGANIZED WITH OUTFLOW BOUNDARIES SHOOTING OUTWARD TO THE NORTH AND WEST. SATELLITE CLASSIFICATIONS ARE UNCHANGED FROM EARLIER AND THE INITIAL INTENSITY WILL REMAIN 30 KT. IT APPEARS THAT THE SYSTEM HAS A NARROW WINDOW OF 12 TO 24 HOURS TO INTENSIFY BEFORE VERTICAL WIND SHEAR BECOMES PROHIBITIVE FOR DEVELOPMENT. BASED ON THE CURRENT POOR ORGANIZATION OF THE SYSTEM...THE OFFICIAL INTENSITY FORECAST IS BELOW THE SHIPS AND GFDL WHICH CONTINUE TO SHOW SOME STRENGTHENING DESPITE 30 KT OF FORECAST WESTERLY WIND SHEAR. IT SHOULD BE NOTED THAT THE SYSTEM MAY NOT SURVIVE SUCH STRONG SHEAR...AND IT COULD DISSIPATE SOONER THAN SHOWN HERE. AN EARLIER TRMM PASS HELPED TO FORM AN INITIAL MOTION ESTIMATE OF 335/6. MOST OF THE GLOBAL MODELS KEEP THE SYSTEM MOVING IN GENERALLY NORTHWARD DIRECTION... RESPONDING TO A MIDDLE TO UPPER LEVEL TROUGH NORTHWEST OF THE DEPRESSION. HOWEVER THESE MODELS ALSO SUGGEST THAT THE DEPRESSION WILL STAY A VERTICALLY-COHERENT SYSTEM DESPITE STRONG SHEAR. SINCE THE TROPICAL CYCLONE IS LIKELY TO BEGIN DECOUPLING LATER IN THE PERIOD DUE TO THE SHEAR...I HAVE OPTED TO STAY ON THE FAR LEFT SIDE OF THE GUIDANCE ENVELOPE... CLOSER TO THE ECMWF...GFS... AND BAM SHALLOW MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 08/2100Z 14.3N 104.3W 30 KT 12HR VT 09/0600Z 15.1N 104.8W 35 KT 24HR VT 09/1800Z 15.9N 105.3W 35 KT 36HR VT 10/0600Z 16.4N 105.7W 35 KT 48HR VT 10/1800Z 16.6N 106.1W 30 KT 72HR VT 11/1800Z 16.8N 106.5W 30 KT 96HR VT 12/1800Z 17.0N 107.0W 25 KT...DISSIPATING 120HR VT 13/1800Z 17.0N 107.5W 20 KT...REMNANT LOW $$ FORECASTER BLAKE NNNN