000 WTPZ43 KNHC 090858 TCDEP3 TROPICAL STORM LOWELL DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132008 200 AM PDT TUE SEP 09 2008 THE CLOUD PATTERN OF LOWELL REMAINS THAT OF A SHEARED TROPICAL CYCLONE. A SERIES OF MICROWAVE IMAGES BETWEEN 0100 AND 0600 UTC CONFIRMS THAT THE CENTER OF LOWELL IS ALONG THE EASTERN EDGE OF THE CONVECTION. A QUIKSCAT PASS FROM 0120 UTC REVEALED A COUPLE OF BELIEVABLE 40-45 KT WIND VECTORS. BASED ON THE QUIKSCAT DATA AND DVORAK INTENSITY ESTIMATES OF T3.0...THE INITIAL INTENSITY IS LOWERED TO 45 KT. THIS COULD BE A LITTLE GENEROUS SINCE THE CLOUD TOPS HAVE WARMED AND THE OVERALL CLOUD PATTERN HAS DEGRADED SINCE THE CLASSIFICATIONS WERE PERFORMED. THE MICROWAVE IMAGERY SHOWS THAT LOWELL CONTINUES MOVING NORTHWESTWARD...BUT AT A LITTLE SLOWER FORWARD SPEED. A MID- TO UPPER-LEVEL TROUGH SEEN IN WATER VAPOR IMAGERY APPROACHING THE WEST COAST OF THE UNITED STATES IS FORECAST TO TURN LOWELL TO THE NORTH...THEN NORTHEAST DURING THE NEXT COUPLE OF DAYS. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION. HOWEVER...THE MAIN QUESTION IS HOW DEEP OF A TROPICAL CYCLONE LOWELL WILL REMAIN DURING THIS TIME. THE DYNAMICAL MODELS ALL KEEP LOWELL A DEEP ENOUGH SYSTEM THAT IT ACCELERATES NORTHEASTWARD ACROSS THE BAJA PENINSULA AND INTO NORTHWEST MEXICO IN 2-3 DAYS. HOWEVER...IT IS POSSIBLE THAT LOWELL WILL WEAKEN MORE QUICKLY...AND NOT FEEL AS MUCH INFLUENCE FROM THE TROUGH. FOR NOW THE OFFICIAL FORECAST IS SOMEWHAT BETWEEN THESE SOLUTIONS. THE NEW NHC FORECAST IS A LITTLE FASTER THAN THE PREVIOUS ADVISORY...BUT REMAINS SLOWER THAN THE MODEL CONSENSUS AT 48 HOURS AND BEYOND. THE NEW INTENSITY FORECAST SHOWS GRADUALLY WEAKENING OF LOWELL DURING THE NEXT FEW DAYS. THE FORECAST IS IN EXCELLENT AGREEMENT WITH THE INTENSITY GUIDANCE WHICH PREDICTS THE CYCLONE TO WEAKEN AS THE RESULT OF CONTINUED SHEAR...A MORE STABLE ENVIRONMENT...AND SLIGHTLY COOLER SSTS ALONG THE PATH OF THE STORM. FORECAST POSITIONS AND MAX WINDS INITIAL 09/0900Z 20.7N 112.9W 45 KT 12HR VT 09/1800Z 21.4N 113.3W 45 KT 24HR VT 10/0600Z 22.4N 113.3W 40 KT 36HR VT 10/1800Z 23.3N 112.8W 40 KT 48HR VT 11/0600Z 24.4N 112.1W 35 KT 72HR VT 12/0600Z 26.5N 111.0W 25 KT 96HR VT 13/0600Z 28.5N 110.0W 20 KT...INLAND 120HR VT 14/0600Z...DISSIPATED $$ FORECASTER BROWN