WTXS31 PGTW 152100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 26S (JERUTO) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 26S (JERUTO) WARNING NR 003
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
151800Z --- NEAR 16.2S 83.1E
MOVEMENT PAST SIX HOURS - 255 DEGREES AT 07 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
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 - 000 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
REPEAT POSIT: 16.2S 83.1E
---
FORECASTS:
12 HRS, VALID AT:
160600Z --- 17.0S 81.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
152100Z POSITION NEAR 16.4S 82.7E.
15APR20. TROPICAL CYCLONE (TC) 26S (JERUTO), LOCATED APPROXIMATELY 828
NM SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) REVEALS A FAINT, FULLY EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) SHEARED 165NM TO THE NORTH WEST OF THE REMAINING
CONVECTION. A 151630Z METOP-B ASCAT PASS DEPICTS AN ELONGATING
CIRCULATION WITH MOSTLY 30 KT WINDS TO THE SOUTH OF THE CIRCULATION,
WITH A FEW ISOLATED 35 KT WIND BARBS. SOME OF THESE HIGHER WINDS ARE
NOT WRAPPING AROUND INTO THE SYSTEM, BUT ARE DUE TO GRADIENT FLOW
BETWEEN THE CIRCULATION AND A SURFACE HIGH PRESSURE SYSTEM TO THE
SOUTH. THE NORTH SIDE OF THE SYSTEM SHOWS 10-15 KT WINDS, WITH AN
ISOLATED AREA OF 20 KTS TO THE EAST SIDE WRAPPING INTO THE LLCC. THE
INITIAL INTENSITY IS BASED ON THE AFOREMENTIONED ASCAT PASS, ABOVE
THE PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS) AND IN
LINE WITH THE FMEE CI OF T2.5 (35 KTS). TC 26S IS LOCATED IN AN AREA
OF MODERATE (15-20 KT) VERTICAL WIND SHEAR (VWS); HOWEVER, THE STORM
MOTION DIRECTLY OPPOSES THE SHEAR VECTOR, SO THE EFFECTIVE SHEAR FELT
BY THE SYSTEM IS MUCH GREATER, AS REFLECTED IN THE DISPLACEMENT
BETWEEN THE LLCC AND CONVECTION. THE EXTREME EFFECTIVE VWS WILL
OVERCOME THE GOOD POLEWARD OUTFLOW AND WARM (26-27 CELSIUS) SEA
SURFACE TEMPERATURES, LEADING TO CONTINUED UNRAVELING AND DISSIPATION
BY TAU 12. FOR THE DURATION OF THE FORECAST, TC 26S WILL TRACK ALONG
THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE TO THE EAST. CONDITIONS
WILL CONTINUE TO BE UNFAVORABLE AND THE SYSTEM WILL DISSIPATE BY TAU
12. NUMERICAL MODEL GUIDANCE DEPICTS A GENERALLY WEST-SOUTHWESTWARD
TRACK THROUGH TAU 24. THEREFORE, THERE IS GOOD CONFIDENCE IN THE JTWC
FORECAST TRACK. 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 151800Z
IS 13 FEET.
//
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WTXS31 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 26S (TWENTYSIX) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/141451APR2020//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 26S (TWENTYSIX) WARNING NR 001
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
141800Z --- NEAR 14.8S 86.2E
MOVEMENT PAST SIX HOURS - 235 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 030 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 - 070 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
REPEAT POSIT: 14.8S 86.2E
---
FORECASTS:
12 HRS, VALID AT:
150600Z --- 15.7S 84.6E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 245 DEG/ 09 KTS
---
24 HRS, VALID AT:
151800Z --- 16.5S 82.9E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
130 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 240 DEG/ 09 KTS
---
36 HRS, VALID AT:
160600Z --- 17.3S 81.3E
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
120 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
000 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 245 DEG/ 07 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
161800Z --- 17.9S 80.0E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
142100Z POSITION NEAR 15.0S 85.8E.
14APR20. TROPICAL CYCLONE 26S (TWENTYSIX), LOCATED APPROXIMATELY
929 NM EAST-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED SOUTHWESTWARD
AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY INDICATES THAT CONVECTION HAS INCREASED AND
CONSOLIDATED DURING THE OVERNIGHT CONVECTIVE MAXIMUM, WITH LOW
LEVEL BANDS SPIRALING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER
(LLCC). THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED
ON AN EXTRAPOLATION OF A 141536Z ASCAT-A AMBIGUITY ANALYSIS,
SUPPORTING A 141731Z GPM 37 GHZ MICROWAVE IMAGE WHICH SHOWED THE
SPIRAL BANDING TO GOOD EFFECT. THE INITIAL INTENSITY IS SET AT 40
KNOTS BASED PRIMARILY ON THE PREVIOUSLY DISCUSSED ASCAT-A PASS,
WHICH SHOWED A BROAD AREA OF 35-40 KNOT WINDS IN THE SOUTHEAST AND
NORTHEAST QUADRANTS OF THE SYSTEM. THIS IS A GOOD DEAL HIGHER THAN
THE DVORAK CURRENT INTENSITY ESTIMATE OF T1.0 FROM PGTW AND
SLIGHTLY HIGHER THAN THE T2.0 FROM FMEE. ENVIRONMENTAL ANALYSIS
REVEALS THE SYSTEM LIES IN A FAVORABLE AREA, WITH LOW TO MODERATE
(15-20 KNOTS) VWS, STRONG POLEWARD AND WEAK EQUATORWARD OUTFLOW
ALOFT AND WARM (28 DEG CELSIUS) SSTS. THIS FAVORABLE ENVIRONMENT IS
EXPECTED TO BE FAIRLY SHORT LIVED HOWEVER, WITH CONDITIONS BECOMING
INCREASINGLY UNFAVORABLE AFTER TAU 24. TC 26S IS CURRENTLY TRACKING
SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF A LOW TO MID-LEVEL
SUBTROPICAL RIDGE AND IS EXPECTED TO CONTINUE THIS MOTION THROUGH
THE FORECAST PERIOD. THE SYSTEM IS FORECAST TO INTENSIFY SLIGHTLY,
PEAKING AT 45 KNOTS BY TAU 12, AS THE UPPER LEVEL SHEAR REMAINS
SUPPORTIVE. AFTER TAU 24 HOWEVER, SHEAR BEGINS TO RAPIDLY INCREASE
IN MAGNITUDE AND WILL DECAPITATE THE SYSTEM BY TAU 36 LEADING TO
RAPID WEAKENING AND DISSIPATION BY TAU 48. NUMERICAL MODEL GUIDANCE
IS MIXED, WITH THE ECMWF BEING THE SOUTHERLY OUTLIER, TAKING THE
SYSTEM SOUTHWEST AND THEN MORE SOUTHERLY AFTER TAU 12. THE
REMAINDER OF THE MODEL PACKAGE ALL AGREE ON THE SOUTHWESTWARD TRACK
THROUGH TAU 48 AND THE JTWC FORECAST TRACK LIES JUST NORTH OF THE
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 141800Z IS 13 FEET. NEXT WARNINGS AT 150900Z AND
152100Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTXS21 PGTW 141500).////
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