WTPA41 PHFO 110859 TCDCP1 TROPICAL STORM PALI DISCUSSION NUMBER 16 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP012016 1100 PM HST SUN JAN 10 2016 WARM SPOTS CONTINUE TO SHOW UP IN INFRARED SATELLITE IMAGERY AS THIS ADVISORY FOR PALI IS BEING PREPARED. BASED ON A 0513Z AMSU AND A 0541Z SSMIS PASS OVER THE SYSTEM...THESE WARM SPOTS SEEM TO COINCIDE WITH THE ESTIMATED CENTER OF PALI. THE OVERALL SATELLITE PRESENTATION OF THE CYCLONE...INCLUDING THE OUTFLOW STRUCTURE...ALSO CONTINUES TO IMPROVE THIS EVENING. THE LATEST ESTIMATES OF ENVIRONMENTAL VERTICAL WIND SHEAR IN THE VICINITY OF PALI WERE 4 TO 10 KT FROM THE SOUTH ACCORDING TO THE LATEST SHIPS AND UW/CIMSS GUIDANCE. THE MOST RECENT SUBJECTIVE SATELLITE DVORAK INTENSITY ESTIMATES WERE 3.0/45 KT FROM HFO AND SAB AND 2.5/35 KT FROM JTWC. THE LATEST UW/CIMSS ADT ESTIMATE WAS 3.9/63 KT. BASED ON THE OVERALL IMPROVING SATELLITE PRESENTATION OF PALI...WE HAVE INCREASED THE INITIAL INTENSITY TO 55 KT. THE INITIAL MOTION FOR THIS ADVISORY REMAINS A VERY SLOW 065/03 KT. PALI IS A RATHER SMALL CYCLONE AT A RELATIVELY LOW LATITUDE...SO BETA DRIFT IS A MINIMAL STEERING MECHANISM. THERE ARE ALSO NO LARGE SCALE SYNOPTIC FORCING SYSTEMS THAT MIGHT CAUSE PALI TO BEGIN ACCELERATING AWAY FROM ITS CURRENT LOCATION. THE SYSTEM REMAINS IN THE VICINITY OF AN EAST-NORTHEAST TO WEST-SOUTHWEST ORIENTED TROUGH BETWEEN THE SUBTROPICAL RIDGE TO THE NORTH NEAR LATITUDE 23N...AND WESTERLY FLOW TO THE SOUTH NEAR THE EQUATOR. AS NOTED IN THE PREVIOUS DISCUSSION...TROPICAL CYCLONES NEAR TROUGHS LIKE THIS... WHICH ARE SIMILAR TO MONSOON TROUGHS...OFTEN MEANDER AND MAKE MULTIPLE LOOPS WITHIN THE TROUGH. THE LATEST RELIABLE TRACK GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT SHOWING PALI CONTINUING TO MOVE EAST SLOWLY OVER THE NEXT 24 HOURS...THEN CURVING TOWARD THE SOUTHEAST AND THEN THE SOUTH THROUGH 48 HOURS. AFTER THAT...THE CYCLONE IS FORECAST TO MOVE TOWARD THE SOUTHWEST...WITH A SLIGHT INCREASE IN FORWARD SPEED. THE LATEST OFFICIAL FORECAST TRACK HAS BEEN NUDGED A BIT TO THE EAST OF THE PREVIOUS TRACK THROUGH 48 HOURS. THE NEW TRACK THEN IS NEAR THE OLD ONE BY DAY 3...BUT IT HAS PALI MOVING MORE TOWARD THE WEST-SOUTHWEST ON DAYS 4 AND 5. NOTE THAT THIS FORECAST CONTINUES TO KEEP PALI WELL EAST OF THE INTERNATIONAL DATE LINE THROUGH DAY 5. SINCE THERE IS SOME UNCERTAINTY IN THE INITIAL INTENSITY OF PALI... CONFIDENCE REMAINS LOW IN THE LATEST INTENSITY FORECAST. MODEL GUIDANCE CONTINUES TO SHOW WARM SEA SURFACE TEMPERATURES...HIGH OCEAN HEAT CONTENT AND RELATIVELY LOW VERTICAL WIND SHEAR ALONG THE FORECAST TRACK. THE LATEST INTENSITY FORECAST IS GIVING A NOD TOWARD THE APPARENT IMPROVEMENT OF THE STRUCTURE OF THE SYSTEM IN MICROWAVE AND INFRARED SATELLITE IMAGERY. ASSUMING THIS TREND CONTINUES...SOME ADDITIONAL SLOW INTENSIFICATION SEEMS REASONABLE. THE CURRENT FORECAST DOES NOT EXPLICITLY INTENSIFY PALI TO A HURRICANE BEFORE IT BEGINS MOVING SOUTHWARD BEYOND 36 HOURS. HOWEVER...IT WOULD NOT BE SURPRISING TO SEE IT BRIEFLY BECOME A MINIMAL HURRICANE. NOTE ALSO THAT THE LATEST INTENSITY FORECAST IS SLIGHTLY HIGHER ON DAYS 4 AND 5 SINCE PALI IS NOW FORECAST TO REMAIN A BIT FARTHER NORTH OF THE EQUATOR. FORECAST POSITIONS AND MAX WINDS INIT 11/0900Z 7.9N 173.3W 55 KT 65 MPH 12H 11/1800Z 8.1N 172.9W 60 KT 70 MPH 24H 12/0600Z 8.0N 172.3W 60 KT 70 MPH 36H 12/1800Z 7.3N 171.8W 60 KT 70 MPH 48H 13/0600Z 6.4N 171.8W 55 KT 65 MPH 72H 14/0600Z 4.4N 172.4W 45 KT 50 MPH 96H 15/0600Z 3.5N 174.0W 40 KT 45 MPH 120H 16/0600Z 3.0N 176.0W 35 KT 40 MPH $$ FORECASTER HOUSTON