[JTWC] Summary: TROPICAL CYCLONE (TC) 06P (ULA), LOCATED APPROXIMATELY 301 NM SOUTHWEST OF PAGO PAGO, HAS TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS AN EMBEDDED CENTER FEATURE THAT HAS EVOLVED INTO A WEAK EYE FEATURE. THE CURRENT POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON TIGHTLY CURVED BANDING SEEN IN A 011718Z SSMIS 91GHZ MICROWAVE IMAGE. THE CURRENT INTENSITY HAS DROPPED TO 75 KNOTS BASED ON CURRENT INTENSITY ESTIMATES OF T4.5 (77 KNOTS) FROM PGTW AND KNES. THE UPPER LEVEL ENVIRONMENT REMAINS MOSTLY FAVORABLE WITH LOW VERTICAL WIND SHEAR (VWS) AND STRONG DIVERGENCE; HOWEVER, THE SYSTEM IS STRUGGLING AS SIGNIFICANT DRY AIR TO THE SOUTH IS APPLYING PRESSURE AGAINST THE SYSTEM AND ELONGATING THE MOISTURE FIELD. THIS IS EVIDENT IN THE TOTAL PRECIPITABLE WATER LOOP. TC ULA CONTINUES TO TRACK ALONG THE NORTHERN PERIPHERY OF THE DEEP-LAYERED SUB-TROPICAL RIDGE TO THE SOUTH. VWS WILL QUICKLY BEGIN TO INCREASE AND THE SYSTEM WILL TURN POLEWARD INTO COLDER WATER. THESE FACTORS WILL START A WEAKENING TREND AND LEAD TO FULL DISSIPATION BY THE END OF THE FORECAST PERIOD. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT ON THE AFOREMENTIONED TRACK SCENARIO WHICH LEADS TO HIGH CONFIDENCE IN THE JTWC FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 011800Z IS 25 FEET. NEXT WARNINGS AT 020900Z AND 022100Z.