000 WTPZ43 KNHC 012042 TCDEP3 TROPICAL STORM OLAF DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP182009 200 PM PDT THU OCT 01 2009 THE CYCLONE HAS BECOME A LITTLE BETTER ORGANIZED SINCE THIS MORNING WITH SEVERAL BANDS OF CONVECTION NOTED IN VISIBLE SATELLITE IMAGERY. A 1702 UTC ASCAT PASS DETECTED AN AREA OF 30-35 KT WINDS TO THE SOUTHEAST OF THE CENTER AND BASED ON THESE DATA THE SYSTEM IS UPGRADED TO A TROPICAL STORM...THE FIFTEENTH OF THE 2009 EASTERN PACIFIC SEASON. OLAF IS CURRENTLY OVER 27-28 DEGREE CELSIUS SSTS...BUT WATER TEMPERATURES GRADUALLY DECREASE ALONG THE FORECAST TRACK. ALSO...AS OLAF MOVES TOWARDS SLIGHTLY HIGHER LATITUDES...IT IS EXPECTED TO ENCOUNTER INCREASING SOUTH- SOUTHWESTERLY UPPER-LEVEL WINDS. GIVEN THESE NEGATIVE ENVIRONMENTAL FACTORS...ONLY A LITTLE ADDITIONAL STRENGTHENING IS SHOWN IN THE OFFICIAL FORECAST. THE NEW FORECAST IS IN GOOD AGREEMENT WITH THE CONSENSUS OF THE INTENSITY GUIDANCE. OLAF IS EXPECTED TO WEAKEN TO A REMNANT LOW IN ABOUT 48 HOURS. LATEST VISIBLE AND MICROWAVE SATELLITE IMAGERY SUGGEST THAT THE CENTER IS A LITTLE NORTHEAST OF THE EARLIER ESTIMATES. THE HIGHLY UNCERTAIN INITIAL MOTION ESTIMATE IS 300/5. THE TRACK GUIDANCE AND FORECAST REASONING HAS NOT CHANGED MUCH FROM THIS MORNING. OLAF IS EXPECTED TO TURN NORTHWARD AS A TROUGH ALONG THE WEST COAST OF THE UNITED STATES WEAKENS THE RIDGE CURRENTLY TO THE NORTH OF THE CYCLONE. THERE REMAINS A LARGE SPREAD IN THE GUIDANCE AS TO WHEN AND WHERE OLAF MAY TURN NORTHEASTWARD. THE MODELS THAT MAINTAIN A STRONGER...MORE VERTICALLY DEEP SYSTEM CONTINUE TO ACCELERATE OLAF TOWARDS BAJA CALIFORNIA IN A COUPLE OF DAYS. THE OFFICIAL FORECAST CONTINUES TO LEAN TOWARD THE SOLUTION THAT OLAF WILL WEAKEN AND BECOME A SHALLOWER SYSTEM. THIS WOULD RESULT IN LESS INFLUENCE FROM THE WEST COAST TROUGH...AND THEREFORE ONLY A SLOW NORTHEASTWARD MOTION IS SHOWN IN THE LATTER PART OF THE FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 01/2100Z 19.4N 117.8W 35 KT 12HR VT 02/0600Z 19.9N 118.8W 40 KT 24HR VT 02/1800Z 20.4N 119.6W 35 KT 36HR VT 03/0600Z 21.0N 120.0W 30 KT 48HR VT 03/1800Z 22.0N 120.0W 25 KT...REMNANT LOW 72HR VT 04/1800Z 23.5N 118.0W 20 KT...REMNANT LOW 96HR VT 05/1800Z...DISSIPATED $$ FORECASTER BROWN