WTPS31 PGTW 070300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 23P (NIRAN) WARNING NR 025// RMKS/ 1. TROPICAL CYCLONE 23P (NIRAN) WARNING NR 025 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 070000Z --- NEAR 27.3S 175.7E MOVEMENT PAST SIX HOURS - 110 DEGREES AT 20 KTS POSITION ACCURATE TO WITHIN 050 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 115 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT REPEAT POSIT: 27.3S 175.7E --- FORECASTS: 12 HRS, VALID AT: 071200Z --- 29.5S 177.8W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT --- REMARKS: 070300Z POSITION NEAR 27.9S 177.3E. 07MAR21. TROPICAL CYCLONE 23P (NIRAN), LOCATED APPROXIMATELY 572 NM SOUTH-SOUTHWEST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 20 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS BECOME ELONGATED AND THE LOW LEVEL CIRCULATION CENTER IS NOW FULLY EXPOSED. THE INITIAL POSITION WAS PLACED WITH FAIR CONFIDENCE USING THE AFOREMENTIONED MSI. THE INITIAL INTENSITY OF 50KTS IS HEDGED SLIGHTLY HIGHER THAN PGTW ESTIMATE OF ST3.0/45KTS AND SLIGHTLY LOWER THAN THE ADVANCED DVORAK TECHNIQUE (ADT) WITH A CURRENT INTENSITY ESTIMATE OF T3.4/53KTS AND EXTRAPOLATED USING A PARTIAL PASS FROM A 062212Z METOP-B ASCAT IMAGE. UPPER LEVEL ANALYSIS INDICATES STRONG POLEWARD OUTFLOW BEING OFFSET BY VERY STRONG (30-40KTS) VERTICAL WIND SHEAR AND SEA SURFACE TEMPERATURES (SST) 24-25C. THE CYCLONE IS MOVING ALONG THE SOUTHWEST PERIPHERY OF THE DEEP LAYERED SUBTROPICAL RIDGE TO THE EAST. THE HARSH UPPER LEVEL DYNAMICS, ALONG WITH THE DECREASED SSTS, HAS DECREASED THE SYSTEM INTENSITY OVER THE PAST SIX HOURS AS THE SYSTEM IS UNDERGOING SUBTROPICAL TRANSITION AND IS EXPECTED TO COMPLETE SUBTROPICAL TRANSITION WITHIN THE NEXT 12 HOURS. NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH TAU 12 WITH ONLY A 70NM SPREAD. THERE IS HIGH CONFIDENCE IN THE FIRST 12 HOURS OF THE FORECAST TRACK AND LOW CONFIDENCE THEREAFTER DUE TO THE INCREASING SPREAD IN MODEL SOLUTIONS. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070000Z IS 27 FEET.// NNNN