This is storm CHANTHU that was active in 2004 in the W. Pacific region with maximum winds of 139 km/h.

What was the maximum intensity of the storm?

Max Wind: 139 km/h. Min Pressure: hPa.

storm CHANTHU (2004) - Track and intensity details

Name: storm CHANTHU
Start: 2004-06-05
End: 2004-06-15
Location: W. Pacific

CHANTHU (2004)

Storm Code: 2004158N07142 | Region: W. Pacific
Active from 05/06/2004 to 15/06/2004 (10 days)

139 km/h

1-min Wind (JTWC)

Level 13

111 km/h

10-min Wind (JMA)

Level 11

967 hPa

Min Pressure

4,063 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
JTWC	139	967	61	4,063	29.22	29.47	Level 13 - Violent Storm
WMO (International)	111	975	32	3,592	6.79	6.03	Level 11 - Severe Storm
JMA (Japan)	111	975	63	3,586	13.17	11.69	Level 11 - Severe Storm
CMA (China)	107	980	47	3,161	11.87	10.61	Level 11 - Severe Storm
HKO (Hong Kong)	111	975	25	1,598	15.26	13.91	Level 11 - Severe Storm

Agency

Max Intensity

Trajectory

Energy

highest_classification

Max Wind (km/h)

Min Pressure (hPa)

Number of points

Distance (km)

ACE (10⁴ (km/h)²)

PDI (10⁶ (km/h)³)

JTWC

139

967

4,063

29.22

29.47

Level 13 - Violent Storm

WMO (International)

111

975

3,592

6.79

6.03

Level 11 - Severe Storm

JMA (Japan)

111

975

3,586

13.17

11.69

Level 11 - Severe Storm

CMA (China)

107

980

3,161

11.87

10.61

Level 11 - Severe Storm

HKO (Hong Kong)

111

975

1,598

15.26

13.91

Level 11 - Severe Storm

Advanced Meteorological Indices by Agency Automatically calculated from raw data

JTWC

Energy
ACE (10⁴ (km/h)²)	29.22	High
PDI (10⁶ (km/h)³)	29.47
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-15 km/h
Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-13 hPa
Max Pressure Rise/Step (weakening)	+6 hPa
Movement & Duration
Avg Movement Speed	22.6 km/h
Tracking Time	180h (7.5 days)
Time as TD+ (≥34kt)	198h (8.3d)
Time as Storm+ (≥64kt)	30h (1.3d)
Peak Intensity & Range
Peak Intensity	13:00 12/06/2004 14°N, 110.2°E
Latitude	6.4°N – 14°N (7.6°)
Longitude	106.1°E – 141.7°E (35.6°)

WMO (International)

Energy
ACE (10⁴ (km/h)²)	6.79	Low
PDI (10⁶ (km/h)³)	6.03
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+46 km/h	Fast
Max Wind Loss/Step	-19 km/h
Pressure Variation
Max Pressure Drop/Step	-10 hPa
Max Pressure Drop/24h	-21 hPa	Strong
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	19.3 km/h
Tracking Time	186h (7.8 days)
Time as TD+ (≥34kt)	60h (2.5d)
Peak Intensity & Range
Peak Intensity	13:00 12/06/2004 14°N, 110.1°E
Latitude	8.5°N – 18.2°N (9.7°)
Longitude	102.1°E – 132.3°E (30.2°)

JMA (Japan)

Energy
ACE (10⁴ (km/h)²)	13.17	Medium
PDI (10⁶ (km/h)³)	11.69
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-15 hPa
Max Pressure Rise/Step (weakening)	+5 hPa
Movement & Duration
Avg Movement Speed	19.3 km/h
Tracking Time	186h (7.8 days)
Time as TD+ (≥34kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	13:00 12/06/2004 13.8°N, 109.8°E
Latitude	8.6°N – 18.2°N (9.6°)
Longitude	102.1°E – 132.2°E (30.1°)

CMA (China)

Energy
ACE (10⁴ (km/h)²)	11.87	Medium
PDI (10⁶ (km/h)³)	10.61
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+30 km/h
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-4 hPa
Max Pressure Drop/24h	-13 hPa
Max Pressure Rise/Step (weakening)	+4 hPa
Movement & Duration
Avg Movement Speed	22.9 km/h
Tracking Time	138h (5.8 days)
Time as TD+ (≥34kt)	120h (5d)
Peak Intensity & Range
Peak Intensity	13:00 12/06/2004 14°N, 110.2°E
Latitude	8.6°N – 15.3°N (6.7°)
Longitude	104.5°E – 132.2°E (27.7°)

HKO (Hong Kong)

Energy
ACE (10⁴ (km/h)²)	15.26	Medium
PDI (10⁶ (km/h)³)	13.91
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+19 km/h
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-3 hPa
Max Pressure Drop/24h	-9 hPa
Max Pressure Rise/Step (weakening)	+4 hPa
Movement & Duration
Avg Movement Speed	22.2 km/h
Tracking Time	72h (3 days)
Time as TD+ (≥34kt)	120h (5d)
Peak Intensity & Range
Peak Intensity	13:00 12/06/2004 14°N, 110.3°E
Latitude	11.6°N – 14.7°N (3.1°)
Longitude	105°E – 119.1°E (14.1°)

Advanced Indices Legend

ACE: Accumulated Cyclone Energy - measures total storm activity

PDI: Power Dissipation Index - measures potential destructiveness

RI: Rapid Intensification - when wind increases >=30 kt/24h or pressure drops >=30 hPa/24h

Countries with Direct Landfall

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Index	Meaning	Formula / Condition	Classification
ACE Accumulated Cyclone Energy	Accumulated Cyclone Energy. Measures the total energy generated by the storm during its lifetime. Only counts reports with wind ≥ 35 kt (TS level or higher).	`ACE = Σ(V_max²) / 10&sup4;` Unit: 10⁴ kt²	< 2: Low 2-6: Medium 6-15: High ≥ 15: Very High
PDI Power Dissipation Index	Power Dissipation Index. More sensitive than ACE to extremely strong storms due to using cubic power. Reflects potential destructive power.	`PDI = Σ(V_max&sup³;) / 10&sup6;` Unit: 10⁶ kt³	Higher value = greater cumulative destructive power
RI Rapid Intensification	Rapid Intensification - storm strengthens suddenly in a short time. Very dangerous as it is difficult to forecast and causes surprise for prevention efforts.	Wind increase ≥ 30 kt/24h or Pressure drop ≥ 30 hPa/24h	Has RI or Fast increase (≥20kt)
Max wind gain/step	Maximum wind increase between 2 consecutive reports (usually 6 hours apart). Shows the fastest local intensification rate.	`max(V_i+1 - V_i)` Unit: kt (km/h)	Positive value = storm strengthening
Max wind gain/24h	Maximum wind increase in a 24-hour window. Main criterion for determining Rapid Intensification (RI).	`max(V_t+24h - V_t)` RI if ≥ 30 kt/24h	≥ 30kt: RI ≥ 20kt: Fast
Max wind loss/step	Maximum wind weakening between 2 consecutive reports. Shows at which stage the storm weakened fastest.	`max(V_i - V_i+1)` Unit: kt (km/h)	Positive value = storm weakening
Max pressure drop/step	Maximum pressure drop between 2 consecutive reports. Pressure decrease = storm center strengthening. Reflects local deepening rate.	`max(P_i - P_i+1)` Unit: hPa	Higher value = faster strengthening
Max pressure drop/24h	Maximum pressure drop in a 24-hour window. Important index for evaluating explosive deepening / explosive intensification.	`max(P_t - P_t+24h)` Explosive if ≥ 30 hPa	≥ 30hPa: RI ≥ 20hPa: Strong
Max pressure rise/step	Maximum pressure rise between 2 consecutive reports. Pressure increase = storm weakening. Large value indicates rapid weakening (due to terrain interaction, landfall, etc.).	`max(P_i+1 - P_i)` Unit: hPa	Higher value = faster weakening
Average moving speed	Average moving speed of the storm center during the entire monitoring period by that agency.	`V_avg = S_total / T_total` Unit: kt (km/h)	Slow-moving storms (<15 km/h) usually cause prolonged heavy rain
Monitoring duration	Total time from first report to last report of that agency.	`T = t_end - t_start` Unit: hours (days)	Different agencies may monitor for different durations
TS+ Duration	Total hours with average wind ≥ 34 kt (Tropical Storm level or higher). Reflects how long the storm maintained significant intensity.	Average wind ≥ 34 kt	Longer storm = greater total damage
TY+ Duration	Total hours with average wind ≥ 64 kt (Typhoon level or higher). Storms maintaining this level longer have much greater destructive power.	Average wind ≥ 64 kt	Longer time at Typhoon level = more dangerous
Peak Intensity	Time and location (lat, lon) when the storm reached maximum wind according to each agency. Helps identify where the storm was strongest.	V_max = max(V_i)	Peak location helps assess danger for nearby areas
Latitude / Longitude	Spatial range of activity by latitude and longitude. Shows whether the storm affected area is wide or narrow.	min-max(lat), min-max(lon)	Large range = long trajectory, wide impact

Index

Meaning

Formula / Condition

Classification

ACE
Accumulated Cyclone Energy

Accumulated Cyclone Energy. Measures the total energy generated by the storm during its lifetime. Only counts reports with wind ≥ 35 kt (TS level or higher).

ACE = Σ(V_max²) / 10&sup4;
Unit: 10⁴ kt²

< 2: Low
2-6: Medium
6-15: High
≥ 15: Very High

PDI
Power Dissipation Index

Power Dissipation Index. More sensitive than ACE to extremely strong storms due to using cubic power. Reflects potential destructive power.

PDI = Σ(V_max&sup³;) / 10&sup6;
Unit: 10⁶ kt³

Higher value = greater cumulative destructive power

RI
Rapid Intensification

Rapid Intensification - storm strengthens suddenly in a short time. Very dangerous as it is difficult to forecast and causes surprise for prevention efforts.

Wind increase ≥ 30 kt/24h or Pressure drop ≥ 30 hPa/24h

Has RI or
Fast increase (≥20kt)

Max wind gain/step

Maximum wind increase between 2 consecutive reports (usually 6 hours apart). Shows the fastest local intensification rate.

max(V_i+1 - V_i)
Unit: kt (km/h)

Positive value = storm strengthening

Max wind gain/24h

Maximum wind increase in a 24-hour window. Main criterion for determining Rapid Intensification (RI).

max(V_t+24h - V_t)
RI if ≥ 30 kt/24h

≥ 30kt: RI
≥ 20kt: Fast

Max wind loss/step

Maximum wind weakening between 2 consecutive reports. Shows at which stage the storm weakened fastest.

max(V_i - V_i+1)
Unit: kt (km/h)

Positive value = storm weakening

Max pressure drop/step

Maximum pressure drop between 2 consecutive reports. Pressure decrease = storm center strengthening. Reflects local deepening rate.

max(P_i - P_i+1)
Unit: hPa

Higher value = faster strengthening

Max pressure drop/24h

Maximum pressure drop in a 24-hour window. Important index for evaluating explosive deepening / explosive intensification.

max(P_t - P_t+24h)
Explosive if ≥ 30 hPa

≥ 30hPa: RI
≥ 20hPa: Strong

Max pressure rise/step

Maximum pressure rise between 2 consecutive reports. Pressure increase = storm weakening. Large value indicates rapid weakening (due to terrain interaction, landfall, etc.).

max(P_i+1 - P_i)
Unit: hPa

Higher value = faster weakening

Average moving speed

Average moving speed of the storm center during the entire monitoring period by that agency.

V_avg = S_total / T_total
Unit: kt (km/h)

Slow-moving storms (<15 km/h) usually cause prolonged heavy rain

Monitoring duration

Total time from first report to last report of that agency.

T = t_end - t_start
Unit: hours (days)

Different agencies may monitor for different durations

TS+ Duration

Total hours with average wind ≥ 34 kt (Tropical Storm level or higher). Reflects how long the storm maintained significant intensity.

Average wind ≥ 34 kt

Longer storm = greater total damage

TY+ Duration

Total hours with average wind ≥ 64 kt (Typhoon level or higher). Storms maintaining this level longer have much greater destructive power.

Average wind ≥ 64 kt

Longer time at Typhoon level = more dangerous

Peak Intensity

Time and location (lat, lon) when the storm reached maximum wind according to each agency. Helps identify where the storm was strongest.

V_max = max(V_i)

Peak location helps assess danger for nearby areas

Latitude / Longitude

Spatial range of activity by latitude and longitude. Shows whether the storm affected area is wide or narrow.

min-max(lat), min-max(lon)

Large range = long trajectory, wide impact

CHANTHU (2004)

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Advanced Meteorological Indices by Agency Automatically calculated from raw data

Advanced Indices Legend

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CHANTHU

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CHANTHU (2004)

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Advanced Meteorological Indices by Agency Automatically calculated from raw data

Advanced Indices Legend

Countries with Direct Landfall

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