WPAC: CHAN-HOM - Post-Tropical

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TXPQ24 KNES 080902
TCSWNP

A. 16W (CHAN-HOM)

B. 08/0830Z

C. 29.2N

D. 133.4E

E. ONE/HIMAWARI-8

F. T4.5/4.5

G. IR/EIR/SWIR

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR DATA. A
WMG EYE THAT IS SURROUNDED BY MEDIUM GREY AND EMBEDDED IN MEDIUM GREY
MAKES THE DT EQUAL TO 4.5 WITH NO EYE ADJUSTMENT MADE TO THE DT VALUE. THE
MET AND PT AGREE AND ARE ALSO EQUAL TO 4.5 BASED ON A STEADY INTENSITY
TREND OVER THE PAST 24 HOURS. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...SAMBUCCI

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TPPN10 PGTW 080922

A. TYPHOON 16W (CHAN-HOM)

B. 08/0900Z

C. 29.14N

D. 133.30E

E. FIVE/HMWRI8

F. T4.0/4.5/S0.0/24HRS STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 34A/PBO LARGE EYE/ANMTN. WMG EYE SURROUNDED BY MG
YIELDS AN E# AND DT (NO EYE ADJUSTMENT) OF 4.5. MET AND PT
YIELD 4.0. DBO PT.

I. ADDITIONAL POSITIONS:
08/0407Z 28.47N 132.80E ATMS
08/0457Z 28.58N 132.82E MMHS


HEINS

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CURRENT ESTIMATE
Date (mmddhhmm): 10080119
SATCON: MSLP = 957 hPa MSW = 86 knots
SATCON Member Consensus: 85.0 knots
Pressure -> Wind Using SATCON MSLP: 89 knots
Distance to Outer Closed Isobar Used is 200 nm
Eye Size Correction Used is 0 knots Source: NA

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Chan-Hom is beautiful. It looks like one entire system from India to Alaska.

[NotoSans]

Have to agree it’s underestimated by Dvorak. Remote sensing technique (SMAP, AMSU, etc) supports low-end category 2.

But the comparison between Chan-hom and Delta is unnecessary. The former exhibits a larger core while the latter is a pinhole system, so the latter is more likely to be underestimated if only satellite estimates are used.

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WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (CHAN-HOM)
WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 16W (CHAN-HOM), LOCATED APPROXIMATELY 413 NM
SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT
07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS SPIRAL BANDS OF DEEP CONVECTION WRAPPING INTO
AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL
POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE BANDING IN THE
MSI LOOP AS WELL AS THE LOW LEVEL FEATURES PRESENT IN A 090438Z ATMS
88.2GHZ IMAGE. THE INITIAL INTENSITY OF 70 KTS IS PLACED WITH HIGH
CONFIDENCE AND IS HEDGED BETWEEN MULTI-AGENCY DVORAK CURRENT
INTENSITY ESTIMATES OF T4.0 (65 KTS, PGTW), T4.5 (77 KTS, RJTD) AND
A 090437Z CIMSS SATCON INTENSITY ESTIMATE OF 65 KTS. TY CHAN-HOM
IS TRACKING ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST AND THROUGH AN OVERALL UNFAVORABLE ENVIRONMENT
WITH MODERATE TO HIGH (25 KTS) VERTICAL WIND SHEAR (VWS) OFFSET BY
WARM (27-28 CELSIUS) SEA SURFACE TEMPERATURES (SST) AND ROBUST
POLEWARD OUTFLOW ALOFT, ENHANCED BY THE JET POSITIONED TO THE NORTH
OVER JAPAN.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY CHAN-HOM WILL TRACK GENERALLY EAST-NORTHEASTWARD OVER THE
NEXT 24 HOURS. DURING THIS TIME, THE SYSTEM WILL GRADUALLY
WEAKEN TO 55 KNOTS BY TAU 24, LARGELY DUE TO INCREASING VWS WHICH
IS EXPECTED EXCEED 30 KTS BY TAU 24. AFTER THIS TIME, THE TRACK WILL
BECOME GENERALLY EAST-NORTHEASTWARD TO EASTWARD AS THE SYSTEM TRACKS
ALONG THE NORTHERN PERIPHERY OF THE STEERING STR AND APPROACHES THE
BAROCLINIC ZONE. BY TAU 36, CONTINUED HIGH VWS WILL LEAD TO FURTHER
WEAKENING TO 50 KTS AS THE SYSTEM BEGINS EXTRATROPICAL TRANSITION.
BY TAU 72, THE SYSTEM WILL BECOME FULLY EMBEDDED IN THE
AFOREMENTIONED WESTERLY FLOW ALOFT AND WILL COMPLETE ETT, BECOMING A
COLD CORE LOW. NUMERICAL MODEL SOLUTIONS HAVE CONTINUED TO STRUGGLE
WITH THE LATER PORTION OF THE TRACK FOR TY 16W, HOWEVER THEY ARE
BEGINNING TO CONVERGE ON A SOLUTION WHICH BRINGS THE CYCLONE CENTER
ON A SOUTHEASTWARD TRACK AFTER TAU 36 DUE TO A REPOSITIONING OF THE
STEERING RIDGE AFTER THIS TIME. SPECIFICALLY, THERE IS A 160 NM
SPREAD IN ACROSS TRACK SOLUTIONS AT TAU 36 THAT INCREASES TO 585 NM
BY TAU 72. DUE TO THE THE LARGE SPREAD IN MODEL SOLUTIONS THERE IS
OVERALL POOR CONFIDENCE IN THE JTWC FORECAST, WHICH IS PLACED CLOSE
TO THE JTWC MULTI-MODEL CONSENSUS.//
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WDPN31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (CHAN-HOM) WARNING
NR 021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 16W (CHAN-HOM), LOCATED APPROXIMATELY 343 NM
SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 07
KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
(EIR) SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED LOW LEVEL
CIRCULATION CENTER WITH ASSOCIATED CONVECTION SHEARED TO THE
NORTHEAST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE FULLY-EXPOSED NATURE OF THE LLCC AND LOW LEVEL FEATURES
EVIDENT IN A 091629Z AMSR2 89 GHZ MICROWAVE IMAGE. THE INITIAL
INTENSITY IS SET AT 50 KTS AND IS SUPPORTED BY MULTI-AGENCY DVORAK
INTENSITY ESTIMATES RANGING FROM T2.5-3.5 (35-55 KTS) AND A 091740Z
ADVANCED DVORAK TECHNIQUE ESTIMATE OF T2.8 (43 KTS). A 091627Z AMSR2
WINDSPEED PRODUCT REVEALS SWATHS OF 50 KT WINDS AROUND THE LLCC,
LENDING GOOD CONFIDENCE TO THE INITIAL INTENSITY. UPPER LEVEL
ANALYSIS REVEALS A ROBUST POLEWARD OUTFLOW CHANNEL ASSOCIATED WITH
THE JET POSITIONED OVER JAPAN BEING OFFSET BY HIGH (>30 KT) VERTICAL
WIND SHEAR (VWS) VALUES. SEA SURFACE TEMPERATURES (SST) REMAIN
CONDUCIVE AT 26-27 CELSIUS. OVERALL, TS 16W IS TRACKING THROUGH AN
UNFAVORABLE ENVIRONMENT FOR DEVELOPMENT ALONG THE NORTHERN PERIPHERY
OF A SUBTROPICAL RIDGE. THE SYSTEM IS TRACKING ALONG THE EDGE OF THE
BAROCLINIC ZONE AND HAS BEGUN SUBTROPICAL TRANSITION (STT) AS IT
BEGINS TO EXHIBIT A COMBINATION OF TROPICAL AND EXTRATROPICAL
CHARACTERISTICS.
3. FORECAST REASONING.
A. THE FORECAST PHILOSOPHY HAS SHIFTED FROM AN EXTRATROPICAL
TRANSITION TO A DISSIPATION SCENARIO IN THIS PROGNOSTIC REASONING
BASED ON MODEL GUIDANCE.
B. TS 16W WILL CONTINUE TO TRACK EAST-NORTHEASTWARD THEN EASTWARD
THROUGH TAU 24 AS IT CONTINUES STT, INTERACTING WITH THE BAROCLINIC
ZONE TO THE NORTH. PERSISTENTLY HIGH VWS WILL LEAD TO STEADY
WEAKENING TO 40 KTS BY TAU 24. AFTER THIS, THE SYSTEM WILL TURN TO A
SOUTHEASTWARD TRACK AS A BREAK APPEARS WITHIN THE STR. ALONG THIS
TRACK, THE SYSTEM WILL RAPIDLY WEAKEN DUE TO HIGH VWS VALUES AND DRY
AIR ENTRAINMENT. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 24. AFTERWARDS, ALL MODEL SOLUTIONS BEGIN TO TURN THE
SYSTEM TO THE SOUTHEAST WITH SPREAD INCREASING TO 202 NM BY TAU 48.
THIS DIVERGENCE IN TRACK GUIDANCE PLACES OVERALL POOR CONFIDENCE IN
THE JTWC FORECAST TRACK, WHICH IS PLACED NEAR THE MULTI-MODEL
CONSENSUS AND THE ECMWF TRACK SOLUTION.//
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WDPN31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (CHAN-HOM) WARNING
NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 16W (CHAN-HOM), LOCATED APPROXIMATELY 227
NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED EAST-
SOUTHEASTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY REVEALS AN EXPOSED, DEFINED LOW
LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION DISPLACED TO
THE NORTHEAST. AN 110701Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS
SHALLOW BANDING WRAPPING TIGHTLY INTO THE DEFINED LLCC WITH
DISORGANIZED DEEP CONVECTION OVER THE EASTERN SEMICIRCLE. THE
INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON DVORAK CURRENT
INTENSITY ESTIMATES RANGING FROM 2.5-3.0 (35-45 KNOTS). TS 16W IS
LOCATED WITHIN A MARGINAL ENVIRONMENT AND IS TRACKING EQUATORWARD
UNDER THE BACK EDGE OF AN UPPER-LEVEL SHORTWAVE TROUGH WITH STRONG
(30-35 KNOTS) VERTICAL WIND SHEAR (VWS). ADDITIONALLY, THERE IS
SIGNIFICANT DRY AIR ENTRAINING INTO THE SYSTEM. TS 16W APPEARS TO BE
A HYBRID/SUBTROPICAL SYSTEM WITH AN ASYMMETRIC APPEARANCE IN THE
TOTAL PRECIPITABLE WATER IMAGERY AND MODERATE BAROCLINICITY. THE
SYSTEM IS TRACKING ALONG THE NORTHEASTERN PERIPHERY OF A LOW-LEVEL
SUBTROPICAL RIDGE POSITIONED TO THE SOUTHWEST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 16W IS EXPECTED TO TURN SOUTH-SOUTHEASTWARD AS IT TRACKS
ALONG THE EASTERN PERIPHERY OF THE LOW-LEVEL STR THROUGH THE
FORECAST PERIOD. TS 16W WILL WEAKEN STEADILY DUE TO STRONG (>30 KT)
VWS AND CONTINUED DRY AIR ENTRAINMENT WITH DISSIPATION ANTICIPATED
BY TAU 36. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU
36 BUT DIVERGES AFTER TAU 36. OVERALL, THERE IS FAIR CONFIDENCE IN
THE JTWC FORECAST TRACK. AFTER TAU 72, AS THE SYSTEM TRACKS OVER
WARM SST (28-29C) AND UNDER DECREASING VWS (<20 KNOTS), THERE IS
SOME POTENTIAL FOR IT TO SLOWLY REGENERATE AS A WARM-CORE TROPICAL
SYSTEM.//
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Final Warning

WTPN31 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL DEPRESSION 16W (CHAN-HOM) WARNING NR 031//
RMKS/
1. TROPICAL DEPRESSION 16W (CHAN-HOM) WARNING NR 031
02 ACTIVE TROPICAL CYCLONES IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
120600Z --- NEAR 29.4N 142.4E
MOVEMENT PAST SIX HOURS - 180 DEGREES AT 08 KTS
POSITION ACCURATE TO WITHIN 020 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
REPEAT POSIT: 29.4N 142.4E
---
FORECASTS:
12 HRS, VALID AT:
121800Z --- 28.7N 142.9E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 135 DEG/ 04 KTS
---
24 HRS, VALID AT:
130600Z --- 28.2N 143.5E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
120900Z POSITION NEAR 29.2N 142.5E.
12OCT20. TROPICAL DEPRESSION (TD) 16W (CHAN-HOM), LOCATED
APPROXIMATELY 138 NM NORTH OF CHICHI JIMA, HAS TRACKED SOUTHWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED SYSTEM WITH LOW-LEVEL
CLOUD LINES WRAPPING INTO A DEFINED CENTER, WHICH SUPPORTS THE
INITIAL POSITION WITH GOOD CONFIDENCE. A 120648Z SSMIS 91GHZ IMAGE
REVEALS SHALLOW BANDING WRAPPING INTO A DEFINED LOW-LEVEL
CIRCULATION CENTER WITH NO DEEP CONVECTION. THE INITIAL INTENSITY IS
ASSESSED AT 25 KNOTS BASED ON RECENT ASCAT DATA. ENVIRONMENTAL
ANALYSIS INDICATES UNFAVORABLE CONDITIONS WITH MODERATE (20-25
KNOTS) VERTICAL WIND SHEAR, CONVERGENCE ALOFT AND SIGNIFICANT DRY
AIR ENTRAINMENT. TD 16W IS FORECAST TO TRACK SOUTHEASTWARD ALONG THE
NORTHEAST PERIPHERY OF THE LOW-LEVEL SUBTROPICAL RIDGE AND IS
FORECAST TO DISSIPATE BY TAU 12. 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 120600Z IS 10 FEET. REFER TO TROPICAL STORM 18W
(NANGKA) WARNINGS (WTPN33 PGTW) FOR SIX-HOURLY UPDATES.//

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[doomhaMwx]

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