Tropical Depression FIFTEEN-E
ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION FIFTEEN-E DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152006 200 AM PDT MON OCT 09 2006 A SMALL MASS OF DEEP CONVECTION HAS PERSISTED NEAR AND MOSTLY TO THE SOUTH OF THE LOW-LEVEL CENTER FOR THE PAST SEVERAL HOURS...AND UNTIL VERY RECENTLY THE COLDEST TOPS WERE LESS THAN -80 DEGREES CELSIUS. DVORAK INTENSITY ESTIMATES AT 06 UTC WERE 30-35 KT. SINCE THE CONVECTIVE TOPS HAVE BEEN ON A SLIGHT WARMING TREND...THE ADVISORY INTENSITY REMAINS 30 KT. UNFORTUNATELY...THE DEPRESSION FELL SQUARELY WITHIN THE GAP BETWEEN QUIKSCAT SWATHS AT ABOUT 01 UTC AND 03 UTC...SO THERE IS NO WIND DATA FROM ANYWHERE NEAR THE CENTER OF THE DEPRESSION. THE TROPICAL CYCLONE APPEARS TO HAVE A FAIRLY SHORT WINDOW OF OPPORTUNITY IN WHICH TO STRENGTHEN. SOUTHWESTERLY WIND SHEAR SHOULD INCREASE SUBSTANTIALLY DURING THE NEXT COUPLE OF DAYS...AND THE UNDERLYING SEA SURFACE TEMPERATURE ALONG THE FORECAST TRACK WILL DECREASE FROM THE CURRENT 28C TO ABOUT 26C DURING THAT SAME PERIOD. THE NEW OFFICIAL INTENSITY FORECAST IS ADJUSTED SLIGHTLY DOWNWARD AND SHOWS A PEAK AT 40 KT...CLOSE TO A BLEND OF THE SHIPS AND GFDL GUIDANCE. THE CYCLONE IS FORECAST TO WEAKEN SUBSTANTIALLY BEFORE NEARING THE BAJA CALIFORNIA PENINSULA IN A FEW DAYS. THE INITIAL MOTION IS ABOUT THE SAME AS BEFORE...335/8. THE DEPRESSION IS MOVING NORTH-NORTHWESTWARD AROUND THE WESTERN EDGE OF A RATHER WEAK MID-LEVEL RIDGE CENTERED OVER SOUTHERN MEXICO. THE CYCLONE SHOULD TURN NORTHEASTWARD IN 24-36 HOURS AS IT ROUNDS THE RIDGE AND BECOMES EMBEDDED IN A DEEP SOUTHWESTERLY STEERING CURRENT TO THE SOUTH OF A LARGE CUTOFF LOW OVER SOUTHERN CALIFORNIA. HOWEVER...SINCE THE TROPICAL CYCLONE IS EXPECTED TO WEAKEN AND EVENTUALLY BECOME A SHALLOW SYSTEM AFTER IT TURNS NORTHEASTWARD... IT WILL PROBABLY NOT MOVE TOO QUICKLY. IN FACT...THE NEW OFFICIAL TRACK FORECAST IS SLOWER THAN THE PREVIOUS ADVISORY TO BE IN BETTER AGREEMENT WITH MOST OF THE MODEL GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 09/0900Z 15.3N 117.6W 30 KT 12HR VT 09/1800Z 16.3N 118.1W 35 KT 24HR VT 10/0600Z 17.6N 118.2W 40 KT 36HR VT 10/1800Z 18.7N 117.8W 40 KT 48HR VT 11/0600Z 19.6N 117.2W 35 KT 72HR VT 12/0600Z 21.0N 115.5W 30 KT 96HR VT 13/0600Z 22.5N 113.5W 25 KT...REMNANT LOW 120HR VT 14/0600Z 24.0N 111.5W 20 KT...REMNANT LOW $$ FORECASTER KNABB NNNN