1. TROPICAL CYCLONE 18P (JOSIE) WARNING NR 005
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
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WARNING POSITION:
011200Z --- NEAR 20.0S 177.3E
MOVEMENT PAST SIX HOURS - 135 DEGREES AT 03 KTS
POSITION ACCURATE TO WITHIN 040 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
REPEAT POSIT: 20.0S 177.3E
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FORECASTS:
12 HRS, VALID AT:
020000Z --- 20.8S 178.0E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
100 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 150 DEG/ 07 KTS
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24 HRS, VALID AT:
021200Z --- 22.0S 178.8E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 150 DEG/ 09 KTS
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36 HRS, VALID AT:
030000Z --- 23.5S 179.7E
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
140 NM SOUTHEAST QUADRANT
090 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 150 DEG/ 07 KTS
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EXTENDED OUTLOOK:
48 HRS, VALID AT:
031200Z --- 24.7S 179.6W
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
190 NM SOUTHEAST QUADRANT
130 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 140 DEG/ 07 KTS
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72 HRS, VALID AT:
041200Z --- 26.7S 177.7W
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
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REMARKS:
011500Z POSITION NEAR 20.2S 177.5E.
TROPICAL CYCLONE 18P (JOSIE), LOCATED APPROXIMATELY 130 NM SOUTH-
SOUTHWEST OF SUVA, FIJI, HAS TRACKED SOUTHEASTWARD AT 03 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) IMAGERY
DEPICTS AN INCREASINGLY ASYMMETRIC CENTRAL DENSE OVERCAST
OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC). A 011321Z GPM 36
GHZ IMAGE REVEALS CURVED BANDING FEATURES WITH DEEP CONVECTION
CONSTRAINED TO THE EAST AND SOUTH OF THE LLCC. THE INITIAL POSITION
IS BASED ON A DEFINED CENTER IN THE AFOREMENTIONED GPM IMAGE WITH
HIGH CONFIDENCE. THE INITIAL INTENSITY IS HELD AT 40 KNOTS, WHICH IS
AN AVERAGE OF AGENCY DVORAK CURRENT INTENSITIES OF 30-45 KNOTS, WITH
AUTOMATED ADVANCED DVORAK TECHNIQUE YIELDING 40 KNOTS. UNFORTUNATELY
BOTH ASCAT AND OSCAT PASSES MISSED THE CIRCULATION. ENVIRONMENTAL
ANALYSIS INDICATES A SHORTWAVE TROUGH OVERHEAD IS IMPINGING ON THE
WESTWARD OUTFLOW AND PROVIDING HIGH (30 KNOT) VERTICAL WIND SHEAR
(VWS), HOWEVER, ROBUST OUTFLOW TO THE EAST IS PARTIALLY
COMPENSATING. SEA SURFACE TEMPERATURES ARE A FAVORABLE 28 DEGREES
CELSIUS. JOSIE IS TRACKING SOUTHEASTWARD UNDER THE STEERING
INFLUENCE OF A SUB-TROPICAL RIDGE TO THE NORTHEAST. SHIPS ANALYSIS
INDICATES VWS SHOULD CONTINUE TO INCREASE THROUGHOUT THE FORECAST.
FORECAST INTENSITIES REFLECT A SLOW WEAKENING TREND AS OUTFLOW
PARTIALLY OFFSETS THE EFFECTS OF THE VWS. GLOBAL MODELS INDICATE 18P
WILL BEGIN TRANSITIONING TO A SUB-TROPICAL CYCLONE AFTER TAU 48 AS
THERMAL ADVECTION BECOMES MORE PRONOUNCED. THE FORECAST CALLS FOR
INCREASING VWS TO FINALLY RESULT IN DISSIPATION BY TAU 72, WHICH
IS APPROXIMATELY THE SAME TIME THE SUB-TROPICAL TRANSITION IS
EXPECTED TO COMPLETE. THE FORECAST CALLS FOR DISSIPATION OVER WATER,
HOWEVER, SOME MODELS INDICATE RE-STRENGTHENING AFTER THE SUB-
TROPICAL TRANSITION. DUE TO UNCERTAINTY IN THE EXACT TIMING OF
DISSIPATION, IT IS POSSIBLE THAT THE SUB-TROPICAL TRANSITION
SCENARIO MAY PREVAIL. DUE TO LOW SPREAD IN THE MULTI-MODEL
CONSENSUS, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 011200Z IS 15 FEET. NEXT WARNINGS
AT 020300Z AND 021500Z.
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