000 WTPZ42 KNHC 012100 TCDEP2 TROPICAL STORM BORIS DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022008 200 PM PDT TUE JUL 01 2008 BORIS HAS FAILED TO DISPLAY AN EYE IN VISIBLE OR INFRARED GOES IMAGERY DURING THE PAST SEVERAL HOURS...BUT DVORAK INTENSITY ESTIMATES REMAIN 65 KT. A QUIKSCAT OVERPASS AT 1425 UTC INCLUDED MAXIMUM WINDS OF ABOUT 55 KT IN THE 25-KM-RESOLUTION RETRIEVALS. BORIS MIGHT STILL HAVE BEEN A HURRICANE AT THAT TIME...AS SUGGESTED BY A LONE 65-KT RETRIEVAL IN THE 12.5-KM QUIKSCAT RETRIEVALS...BUT THE GRADUAL DETERIORATION OF THE CONVECTIVE PATTERN SINCE THEN SUGGESTS THAT THE CYCLONE HAS PROBABLY WEAKENED. THE ADVISORY INTENSITY IS REDUCED SLIGHTLY TO 60 KT. SEA-SURFACE TEMPERATURES ALONG THE FORECAST TRACK WILL CONTINUE TO SLOWLY COOL DURING THE NEXT 24-36 HOURS OR SO...THEN DECREASE FASTER WHILE FALLING TO 25C OR LESS THEREAFTER. THE OFFICIAL INTENSITY FORECAST CALLS FOR CONTINUED GRADUAL WEAKENING THROUGH 48 HOURS...FOLLOWED BY A MORE RAPID DECLINE AND EVENTUAL DEGENERATION TO A REMNANT LOW IN THE 3 TO 5 DAY TIME FRAME. THE NEW INTENSITY FORECAST IS CHANGED LITTLE FROM THE PREVIOUS ADVISORY AND IS CLOSEST TO THE SHIPS AND LGEM GUIDANCE. BORIS CONTINUES TO SLOW DOWN...A LITTLE SOONER THAN PREVIOUSLY ANTICIPATED...AND THE INITIAL MOTION ESTIMATE IS NOW 280/7. THE STORM IS HEADED INTO A WEAKNESS IN THE SUBTROPICAL RIDGE TO ITS NORTH THAT IS ASSOCIATED WITH AN EASTWARD-MOVING MID- TO UPPER-LEVEL TROUGH CURRENTLY ALONG 140W AND NORTH OF 25N. A GENERAL WEST-NORTHWESTWARD MOTION OF BORIS WILL PROBABLY PREVAIL FOR THE NEXT COUPLE OF DAYS...UNTIL THAT TROUGH LIFTS OUT AND RIDGING BUILDS BACK IN. BY THAT TIME...THE CYCLONE SHOULD BE WEAKENING OVER COOLER WATERS AND IS EXPECTED TO TURN TOWARD THE WEST OR EVEN SOUTH OF WEST IN THE LOWER-LEVEL FLOW. THE NEW TRACK FORECAST IS ADJUSTED SLIGHTLY NORTH OF THE PREVIOUS ADVISORY...BUT IS OTHERWISE VERY SIMILAR...INCLUDING THAT THE TRACK REMAINS GENERALLY ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE...IN BEST AGREEMENT WITH THE GFS AND UKMET. FORECAST POSITIONS AND MAX WINDS INITIAL 01/2100Z 15.0N 125.3W 60 KT 12HR VT 02/0600Z 15.2N 126.4W 55 KT 24HR VT 02/1800Z 15.6N 127.8W 50 KT 36HR VT 03/0600Z 16.0N 129.2W 45 KT 48HR VT 03/1800Z 16.2N 130.4W 40 KT 72HR VT 04/1800Z 16.0N 133.0W 30 KT 96HR VT 05/1800Z 15.5N 135.5W 25 KT...REMNANT LOW 120HR VT 06/1800Z 15.0N 138.0W 25 KT...REMNANT LOW $$ FORECASTER KNABB