000 WTPZ43 KNHC 080857 TCDEP3 TROPICAL STORM LOWELL DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132008 200 AM PDT MON SEP 08 2008 THE CLOUD PATTERN OF LOWELL CONTINUES TO CONSIST OF A LARGE BURST OF DEEP CONVECTION LOCATED TO THE SOUTH AND SOUTHWEST OF THE CENTER. DVORAK INTENSITY ESTIMATES REMAIN 45 KT FROM BOTH AGENCIES. AN 0146 UTC QUIKSCAT OVERPASS REVEALED SOME BELIEVABLE 45-50 KT WIND VECTORS OVER THE SOUTHWESTERN SEMICIRCLE. THEREFORE...THE INITIAL INTENSITY REMAINS 50 KT. SHEAR ANALYSIS FROM UW-CIMSS SHOWS ABOUT 20-25 KT OF EASTERLY SHEAR CURRENTLY OVER LOWELL. THE GLOBAL MODELS AND SHIPS GUIDANCE PREDICTS THAT THE SHEAR WILL ONLY DECREASE A LITTLE THROUGHOUT THE FORECAST PERIOD...AND SSTS ALONG THE FORECAST TRACK ARE EXPECTED TO DECREASE SLIGHTLY DURING THE NEXT 2-3 DAYS. SINCE BOTH OF THESE FACTORS ARE NEGATIVE...VERY LITTLE ADDITIONAL STRENGTHENING IS EXPECTED. HOWEVER...THE INTENSITY FORECAST IS A LITTLE ABOVE NEARLY ALL OF THE GUIDANCE...EXCEPT FOR THE HWRF. RECENT MICROWAVE IMAGERY AND SCATTEROMETER DATA SHOW THAT LOWELL CONTINUES MOVING WEST-NORTHWESTWARD EARLY THIS MORNING. THE GUIDANCE SUGGESTS THAT LOWELL SHOULD TURN NORTHWESTWARD VERY SOON. THE NEW FORECAST WAS ADJUSTED SLIGHTLY TO THE WEST...DUE TO THE CURRENT MOTION. THEREAFTER...LITTLE CHANGE HAS BEEN MADE TO THE OFFICIAL FORECAST. THE GLOBAL MODELS FORECAST A STRONG TROUGH ALONG THE WEST COAST OF THE UNITED STATES IN A COUPLE OF DAYS...WHICH SHOULD TURN LOWELL TOWARD THE NORTH AND NORTHEAST. THE MODELS THAT MAINTAIN LOWELL AS A STRONGER AND DEEPER SYSTEM MOVE THE STORM MUCH FASTER TO THE NORTHEAST THAN THE MODELS THAT WEAKEN LOWELL. THE OFFICIAL FORECAST LEANS TOWARD THE SOLUTION OF A WEAKER LOWELL AND SHOWS THE STORM SLOWING DOWN AS IT NEARS THE BAJA PENINSULA. FORECAST POSITIONS AND MAX WINDS INITIAL 08/0900Z 18.2N 110.6W 50 KT 12HR VT 08/1800Z 19.0N 111.8W 55 KT 24HR VT 09/0600Z 20.0N 113.0W 55 KT 36HR VT 09/1800Z 20.9N 113.8W 50 KT 48HR VT 10/0600Z 21.9N 114.0W 45 KT 72HR VT 11/0600Z 23.3N 113.2W 40 KT 96HR VT 12/0600Z 24.2N 112.0W 35 KT 120HR VT 13/0600Z 25.0N 110.5W 30 KT $$ FORECASTER BROWN