****0000002978****
WTXS31 PGTW 010900

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//

SUBJ/TROPICAL CYCLONE 27S (COURTNEY) WARNING NR 020//

RMKS/

1. TROPICAL CYCLONE 27S (COURTNEY) WARNING NR 020

   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO

   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE

   WIND RADII VALID OVER OPEN WATER ONLY

    ---

   WARNING POSITION:

   010600Z --- NEAR 25.0S 88.4E

     MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS

     POSITION ACCURATE TO WITHIN 030 NM

     POSITION BASED ON CENTER LOCATED BY SATELLITE

   PRESENT WIND DISTRIBUTION:

   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT

   WIND RADII VALID OVER OPEN WATER ONLY

   BECOMING SUBTROPICAL

   RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT

                            140 NM SOUTHEAST QUADRANT

                            110 NM SOUTHWEST QUADRANT

                            060 NM NORTHWEST QUADRANT

   REPEAT POSIT: 25.0S 88.4E

    ---

   FORECASTS:

   12 HRS, VALID AT:

   011800Z --- 25.2S 87.9E

   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT

   WIND RADII VALID OVER OPEN WATER ONLY

   SUBTROPICAL

   RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT

                            110 NM SOUTHEAST QUADRANT

                            080 NM SOUTHWEST QUADRANT

                            040 NM NORTHWEST QUADRANT

    ---

REMARKS:

010900Z POSITION NEAR 25.1S 88.3E.

01APR25. TROPICAL CYCLONE 27S (COURTNEY), LOCATED APPROXIMATELY

907 NM SOUTH-SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED WEST-

SOUTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED

MULTI-SPECTRAL SATELLITE IMAGERY DEPICTS A COMPLETELY EXPOSED,

ELONGATED, LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION

HEAVILY SHEARED OFF TO THE SOUTHEAST. A 010232Z METOP-B ASCAT IMAGE

REVEALED THE ASYMMETRIC WIND FIELD WITH 40-45 KTS CONFINED TO THE

SOUTHERN SEMICIRCLE. ENVIRONMENTAL ANALYSIS INDICATES THAT TC 27S IS

PLACED WITHIN A HIGHLY UNFAVORABLE ENVIRONMENT CHARACTERIZED BY

VERY HIGH (OVER 50 KTS) NORTHWESTERLY VERTICAL WIND SHEAR,

SIGNIFICANT DRY AIR ENTRAINMENT, AND COOL (24-25 C) SEA SURFACE

TEMPERATURES. TC 27S IS EXPECTED TO TRACK FURTHER WESTWARD OVER THE

NEXT COUPLE DAYS, ALONG THE NORTHERN PERIPHERY OF A SHALLOW

SUBTROPICAL RIDGE POSITIONED TO THE SOUTH OF THE SYSTEM. INTENSITY

IS FORECAST TO CONTINUE DROPPING IN RESPONSE TO THE INCREASINGLY

HOSTILE ENVIRONMENT. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT

REGARDING BOTH THE WESTWARD TRACK AND THE CONTINUED WEAKENING TREND.

SUBTROPICAL TRANSITION IS FORECAST TO COMPLETE WITHIN THE NEXT 12

HOURS AS THE VORTEX FURTHER SHALLOWS AND BECOMES COMPLETELY TAKEN

OVER BY DRY AIR. 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. MINIMUM CENTRAL PRESSURE AT

010600Z IS 993 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010600Z IS 20

FEET.//

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