This is storm NANCY that was active in 1961 in the W. Pacific region with maximum winds of 359 km/h.

What was the maximum intensity of the storm?

Max Wind: 359 km/h. Min Pressure: hPa.

storm NANCY (1961) - Track and intensity details

Name: storm NANCY
Start: 1961-09-06
End: 1961-09-20
Location: W. Pacific

NANCY (1961)

Storm Code: 1961250N07173 | Region: W. Pacific
Active from 06/09/1961 to 20/09/1961 (14 days)

343 km/h

1-min Wind (JTWC)

Level 17

359 km/h

10-min Wind (CMA)

Level 17

885 hPa

Min Pressure

11,395 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
WMO (International) (coordinates_only)	~	890	54	11,212	~	~	Undefined
JMA (Japan) (coordinates_only)	~	890	109	11,395	~	~	Undefined
CMA (China)	359	888	91	9,417	290.58	903.14	Level 17 - Super Typhoon
HKO (Hong Kong)	306	885	81	8,020	209.22	530.72	Level 17 - Super Typhoon
JTWC	343	~	81	8,470	265.17	756.60	Level 17 - Super Typhoon
DS824	343	~	81	8,470	265.17	756.60	Level 17 - Super Typhoon
TD9636	343	~	73	6,454	263.14	761.36	Level 17 - Super Typhoon
TD9635	343	885	75	7,082	263.24	757.68	Level 17 - Super Typhoon

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)

WMO (International)
(coordinates_only)

890

11,212

Undefined

JMA (Japan)
(coordinates_only)

890

109

11,395

Undefined

CMA (China)

359

888

9,417

290.58

903.14

Level 17 - Super Typhoon

HKO (Hong Kong)

306

885

8,020

209.22

530.72

Level 17 - Super Typhoon

JTWC

343

8,470

265.17

756.60

Level 17 - Super Typhoon

DS824

343

8,470

265.17

756.60

Level 17 - Super Typhoon

TD9636

343

6,454

263.14

761.36

Level 17 - Super Typhoon

TD9635

343

885

7,082

263.24

757.68

Level 17 - Super Typhoon

Advanced Meteorological Indices by Agency Automatically calculated from raw data

WMO (International) RI

Pressure Variation
Max Pressure Drop/Step	-20 hPa
Max Pressure Drop/24h	-35 hPa	RI
Max Pressure Rise/Step (weakening)	+26 hPa
Movement & Duration
Avg Movement Speed	35.3
Tracking Time	318h (13.3 days)
Peak Intensity & Range
Latitude	7.1°N – 60.5°N (53.4°)
Longitude	128.8°E – 179°E (50.2°)

JMA (Japan) RI

Pressure Variation
Max Pressure Drop/Step	-10 hPa
Max Pressure Drop/24h	-35 hPa	RI
Max Pressure Rise/Step (weakening)	+13 hPa
Movement & Duration
Avg Movement Speed	35.2
Tracking Time	324h (13.5 days)
Peak Intensity & Range
Latitude	7.1°N – 61.3°N (54.2°)
Longitude	-179.6°E – 181.6°E (361.2°)

CMA (China) RI

Energy
ACE (10⁴ (km/h)²)	290.58	Very High
PDI (10⁶ (km/h)³)	903.14
Intensification / Weakening
Max Wind Gain/Step	+28 km/h
Max Wind Gain/24h	+163 km/h	RI
Max Wind Loss/Step	-19 km/h
Pressure Variation
Max Pressure Drop/Step	-10 hPa
Max Pressure Drop/24h	-38 hPa	RI
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	34.9 km/h
Tracking Time	270h (11.3 days)
Time as TD+ (≥34kt)	222h (9.3d)
Time as Storm+ (≥64kt)	201h (8.4d)
Peak Intensity & Range
Peak Intensity	14:00 10/09/1961 11.1°N, 146.7°E
Latitude	7.1°N – 54.6°N (47.5°)
Longitude	128.5°E – 173°E (44.5°)

HKO (Hong Kong) RI

Energy
ACE (10⁴ (km/h)²)	209.22	Very High
PDI (10⁶ (km/h)³)	530.72
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+120 km/h	RI
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-13 hPa
Max Pressure Drop/24h	-56 hPa	RI
Max Pressure Rise/Step (weakening)	+10 hPa
Movement & Duration
Avg Movement Speed	33.4 km/h
Tracking Time	240h (10 days)
Time as TD+ (≥34kt)	237h (9.9d)
Time as Storm+ (≥64kt)	213h (8.9d)
Peak Intensity & Range
Peak Intensity	20:00 11/09/1961 14°N, 140°E
Latitude	8.3°N – 51°N (42.7°)
Longitude	128.8°E – 165.5°E (36.7°)

JTWC RI

Energy
ACE (10⁴ (km/h)²)	265.17	Very High
PDI (10⁶ (km/h)³)	756.60
Intensification / Weakening
Max Wind Gain/Step	+28 km/h
Max Wind Gain/24h	+120 km/h	RI
Max Wind Loss/Step	-19 km/h
Movement & Duration
Avg Movement Speed	35.3 km/h
Tracking Time	240h (10 days)
Time as TD+ (≥34kt)	243h (10.1d)
Time as Storm+ (≥64kt)	216h (9d)
Peak Intensity & Range
Peak Intensity	08:00 12/09/1961 15.5°N, 137.5°E
Latitude	8.8°N – 55°N (46.2°)
Longitude	128.9°E – 164.3°E (35.4°)

DS824 RI

Energy
ACE (10⁴ (km/h)²)	265.17	Very High
PDI (10⁶ (km/h)³)	756.60
Intensification / Weakening
Max Wind Gain/Step	+28 km/h
Max Wind Gain/24h	+120 km/h	RI
Max Wind Loss/Step	-19 km/h
Movement & Duration
Avg Movement Speed	35.3 km/h
Tracking Time	240h (10 days)
Time as TD+ (≥34kt)	243h (10.1d)
Time as Storm+ (≥64kt)	216h (9d)
Peak Intensity & Range
Peak Intensity	08:00 12/09/1961 15.5°N, 137.5°E
Latitude	8.8°N – 55°N (46.2°)
Longitude	128.9°E – 164.3°E (35.4°)

TD9636 RI

Energy
ACE (10⁴ (km/h)²)	263.14	Very High
PDI (10⁶ (km/h)³)	761.36
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+120 km/h	RI
Max Wind Loss/Step	-13 km/h
Movement & Duration
Avg Movement Speed	29.9 km/h
Tracking Time	216h (9 days)
Time as TD+ (≥34kt)	219h (9.1d)
Time as Storm+ (≥64kt)	213h (8.9d)
Peak Intensity & Range
Peak Intensity	08:00 12/09/1961 15.5°N, 137.5°E
Latitude	8.8°N – 39.3°N (30.5°)
Longitude	128.9°E – 164.3°E (35.4°)

TD9635 RI

Energy
ACE (10⁴ (km/h)²)	263.24	Very High
PDI (10⁶ (km/h)³)	757.68
Intensification / Weakening
Max Wind Gain/Step	+24 km/h
Max Wind Gain/24h	+120 km/h	RI
Max Wind Loss/Step	-19 km/h
Pressure Variation
Max Pressure Drop/Step	-11 hPa
Max Pressure Drop/24h	-44 hPa	RI
Max Pressure Rise/Step (weakening)	+5 hPa
Movement & Duration
Avg Movement Speed	31.9 km/h
Tracking Time	222h (9.3 days)
Time as TD+ (≥34kt)	225h (9.4d)
Time as Storm+ (≥64kt)	216h (9d)
Peak Intensity & Range
Peak Intensity	08:00 12/09/1961 15.5°N, 137.5°E
Latitude	8.8°N – 44.6°N (35.8°)
Longitude	128.9°E – 164.3°E (35.4°)

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

🇯🇵 Japan

WMO

28.10°, 129.26° 1961-09-14 23:22:45

JMA

34.65°, 135.21° 1961-09-16 04:06:27

CMA 174 km/h Level 15

34.65°, 135.18° 1961-09-16 04:02:25

HKO 144 km/h Level 13

34.66°, 135.34° 1961-09-16 04:06:38

JTWC 232 km/h Level 17

28.18°, 129.30° 1961-09-14 23:54:12

DS824 232 km/h Level 17

28.18°, 129.30° 1961-09-14 23:54:12

TD9636 233 km/h Level 17

28.10°, 129.26° 1961-09-14 23:22:34

TD9635 232 km/h Level 17

28.18°, 129.30° 1961-09-14 23:54:12

🏳️ Russia

WMO

55.65°, 155.62° 1961-09-18 02:32:56

JMA

55.72°, 155.63° 1961-09-18 03:12:19

CMA 102 km/h Level 10

46.00°, 141.97° 1961-09-16 19:46:21

JTWC 117 km/h Level 11

46.60°, 142.98° 1961-09-16 20:43:29

DS824 117 km/h Level 11

46.60°, 142.98° 1961-09-16 20:43:29

Values are interpolated at landfall time and may differ from actual data.

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

NANCY (1961)

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Advanced Meteorological Indices by Agency Automatically calculated from raw data

Advanced Indices Legend

Countries with Direct Landfall

NANCY

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NANCY (1961)

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Comparison Storms 0

Weather Agencies (8 sources)

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Quick Stats

Agency Data Comparison

Indices Legend

Advanced Meteorological Indices by Agency Automatically calculated from raw data

Advanced Indices Legend

Countries with Direct Landfall

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