000 WTPZ45 KNHC 110839 TCDEP5 TROPICAL STORM LINDA DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152009 200 AM PDT FRI SEP 11 2009 SHORTWAVE INFRARED SATELLITE IMAGERY AND A TRMM OVERPASS AT 0421 UTC INDICATE THAT LINDA HAS SHEARED APART...WITH THE LOW-LEVEL CENTER NOW PARTLY EXPOSED TO THE SOUTH OF THE DECAYING DEEP CONVECTION. QUIKSCAT DATA AT 0228 UTC AND ASCAT DATA AT 0628 UTC SHOWED SEVERAL 40-45 KT WIND VECTORS...AND BASED ON THIS THE INITIAL INTENSITY IS REDUCED TO 45 KT. A COMBINATION OF STRONG SOUTHERLY VERTICAL WIND SHEAR AND SEA SURFACE TEMPERATURES OF LESS THAN 26C SHOULD CAUSE CONTINUED WEAKENING...WITH LINDA EXPECTED TO DECAY TO A TROPICAL DEPRESSION IN ABOUT 24 HR AND A REMNANT LOW BY 48 HR. IF THE CONVECTION DOES NOT MAKE A COMEBACK...THE CYCLONE COULD WEAKEN FASTER THAN CURRENTLY FORECAST. THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 330/5. THE TRACK MODEL GUIDANCE FORECASTS LINDA TO MOVE SLOWLY NORTHWESTWARD FOR THE NEXT 48 HR OR SO ON THE EAST SIDE OF AN UPPER-LEVEL LOW NEAR 22N141W AND ON THE SOUTH SIDE OF A LOW-LEVEL RIDGE. THE GUIDANCE DIVERGES AS LINDA WEAKENS TO A REMNANT LOW...WITH THE GFS-BASED MODELS CALLING FOR A NORTHWARD MOTION AND THE REMAINDER OF THE GUIDANCE CALLING FOR A WESTWARD TO WEST-SOUTHWESTWARD MOTION. THE TRACK FORECAST COMPROMISES BETWEEN THESE EXTREMES WITH A WESTWARD DRIFT AFTER 72 HR. THE WIND RADII HAVE BEEN REVISED BASED ON THE SCATTEROMETER DATA. FORECAST POSITIONS AND MAX WINDS INITIAL 11/0900Z 20.0N 130.8W 45 KT 12HR VT 11/1800Z 20.6N 131.3W 40 KT 24HR VT 12/0600Z 21.3N 132.1W 30 KT 36HR VT 12/1800Z 21.7N 132.5W 25 KT 48HR VT 13/0600Z 22.0N 132.9W 20 KT...REMNANT LOW 72HR VT 14/0600Z 22.5N 133.5W 20 KT...REMNANT LOW 96HR VT 15/0600Z 22.5N 134.0W 20 KT...REMNANT LOW 120HR VT 16/0600Z...DISSIPATED $$ FORECASTER BEVEN