WTPS31 PGTW 062100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (DONNA) WARNING NR 013// RMKS/ 1. TROPICAL CYCLONE 18P (DONNA) WARNING NR 013 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 061800Z --- NEAR 13.4S 164.1E MOVEMENT PAST SIX HOURS - 180 DEGREES AT 02 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 055 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 165 NM SOUTHWEST QUADRANT 125 NM NORTHWEST QUADRANT REPEAT POSIT: 13.4S 164.1E --- FORECASTS: 12 HRS, VALID AT: 070600Z --- 14.3S 164.1E MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 060 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 165 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 170 DEG/ 06 KTS --- 24 HRS, VALID AT: 071800Z --- 15.5S 164.3E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 060 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 095 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 185 NM NORTHEAST QUADRANT 205 NM SOUTHEAST QUADRANT 170 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 170 DEG/ 07 KTS --- 36 HRS, VALID AT: 080600Z --- 16.9S 164.6E MAX SUSTAINED WINDS - 105 KT, GUSTS 130 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 205 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 155 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 081800Z --- 18.5S 165.4E MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 075 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 155 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 145 DEG/ 09 KTS --- 72 HRS, VALID AT: 091800Z --- 21.2S 167.6E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 005 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 005 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 155 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 135 DEG/ 11 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 101800Z --- 24.1S 170.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY EXTRATROPICAL RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 175 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT --- REMARKS: 062100Z POSITION NEAR 13.6S 164.1E. TROPICAL CYCLONE 18P (DONNA), LOCATED APPROXIMATELY 354 NM NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED SOUTHWARD AT 02 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES 18P IS ENTERING ANOTHER RELATIVE CONVECTIVE LULL IN ITS CONTINUED PATTERN OF PULSATING DEEP CONVECTION OBSERVED OVER THE PAST SEVERAL DAYS. BANDING REMAINS TIGHTLY WRAPPED INTO AN ILL-DEFINED LOW LEVEL CIRCULATION CENTER, AND A LARGE CONVECTIVE ASYMMETRY HAS FORMED TO THE SOUTHEAST. A 061624Z SSMIS 91 GHZ IMAGE REVEALS THE INTENSE CONVECTION ASSOCIATED WITH THE CENTRAL BANDING, AND THE 37 GHZ CHANNEL PRESENTS A WELL DEFINED MICROWAVE EYE. THE INITIAL POSITION IS EXTRAPOLATED FROM THE AFOREMENTIONED MICROWAVE EYE. A RE-ANALYSIS OF RECENT MICROWAVE IMAGERY, INCLUDING A 061114Z BYU ASCAT PRODUCT AND ASSOCIATED NORMALIZED RADAR CROSS SECTION INDICATES DONNA HAS REMAINED ALMOST QUASI-STATIONARY (QS) FOR NEARLY 18 HOURS. THE CURRENT INTENSITY IS ASSESSED AT 90 KNOTS BASED ON DVORAK ESTIMATES OF T5.0 FROM PGTW AND KNES. TC 18P IS CURRENTLY LOCATED WITHIN A COMPETING STEERING ENVIRONMENT BETWEEN A WEAK SUBTROPICAL RIDGE (STR) OVER NORTHEAST AUSTRALIA AND A STRONG STR TO THE EAST. GLOBAL MODEL ANALYSES ARE STARTING TO SUGGEST THE WESTERN STR IS FINALLY STARTING TO ERODE, WITH THE EASTERN STR EXPECTED TO BECOME THE DOMINANT STEERING INFLUENCE OVER THE NEXT DAY RESULTING IN A MORE PRONOUNCED SOUTHWARD MOTION. UPWELLING DURING THIS QS PERIOD HAS LIKELY TEMPERED THE POTENTIAL FOR INTENSIFICATION. ADDITIONALLY, ALTHOUGH VERTICAL WIND SHEAR (VWS) IS RELATIVELY LIGHT, THE BROAD AND DIFFUSE UPPER LEVEL WINDS OVER THE CENTER HAVE NEGATIVELY IMPACTED THE ORGANIZATION OF THE CENTRAL CORE. AS TC DONNA BEGINS TO MOVE TO THE SOUTH OVER WARMER WATERS, CONTINUED ROBUST OUTFLOW MAY ALLOW SOME ADDITIONAL INTENSIFICATION, WITH THE UPPER END OF THE GUIDANCE AROUND 105 KNOTS. THE SYSTEM WILL ACCELERATE AND TURN SOUTHEASTWARD AROUND TAU 48. EXTRA-TROPICAL TRANSITION WILL BEGIN AROUND TAU 72 AS TC DONNA MOVES OVER COOLER WATERS AND BEGINS TO INTERACT WITH THE BAROCLINIC ZONE. A SIGNIFICANT INCREASE IN VWS AT THAT TIME WILL INITIATE RAPID WEAKENING. DONNA IS EXPECTED TO COMPLETE EXTRA-TROPICAL TRANSITION AND BE FULLY EMBEDDED WITHIN THE MID-LATITUDE WESTERLIES BY TAU 96. DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 061800Z IS 27 FEET. NEXT WARNINGS AT 070300Z, 070900Z, 071500Z, AND 072100Z. //