This is storm FRAN that was active in 1964 in the W. Pacific region with maximum winds of 93 km/h.

What was the maximum intensity of the storm?

Max Wind: 93 km/h. Min Pressure: hPa.

storm FRAN (1964) - Track and intensity details

Name: storm FRAN
Start: 1964-10-13
End: 1964-10-23
Location: W. Pacific

FRAN (1964)

Storm Code: 1964287N13165 | Region: W. Pacific
Active from 13/10/1964 to 23/10/1964 (10 days)

93 km/h

1-min Wind (JTWC)

Level 10

89 km/h

10-min Wind (CMA)

Level 10

996 hPa

Min Pressure

5,182 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
WMO (International) (coordinates_only)	~	996	40	4,595	~	~	Undefined
JMA (Japan) (coordinates_only)	~	996	81	4,680	~	~	Undefined
CMA (China)	89	996	79	5,182	28.78	25.47	Level 10 - Severe Storm
HKO (Hong Kong)	83	998	21	921	4.18	3.24	Level 9 - Storm
JTWC	93	~	19	866	10.53	8.00	Level 10 - Severe Storm
DS824	93	~	19	866	10.53	8.00	Level 10 - Severe Storm
TD9635	93	1000	19	866	10.53	8.00	Level 10 - Severe Storm
TD9636	93	~	17	776	9.36	7.05	Level 10 - 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)

WMO (International)
(coordinates_only)

996

4,595

Undefined

JMA (Japan)
(coordinates_only)

996

4,680

Undefined

CMA (China)

996

5,182

28.78

25.47

Level 10 - Severe Storm

HKO (Hong Kong)

998

921

4.18

3.24

Level 9 - Storm

JTWC

866

10.53

8.00

Level 10 - Severe Storm

DS824

866

10.53

8.00

Level 10 - Severe Storm

TD9635

1000

866

10.53

8.00

Level 10 - Severe Storm

TD9636

776

9.36

7.05

Level 10 - Severe Storm

Advanced Meteorological Indices by Agency Automatically calculated from raw data

WMO (International)

Pressure Variation
Max Pressure Drop/Step	-4 hPa
Max Pressure Drop/24h	-6 hPa
Movement & Duration
Avg Movement Speed	19.6
Tracking Time	234h (9.8 days)
Peak Intensity & Range
Latitude	13°N – 34.4°N (21.4°)
Longitude	156.4°E – 179.9°E (23.5°)

JMA (Japan)

Pressure Variation
Max Pressure Drop/Step	-2 hPa
Max Pressure Drop/24h	-6 hPa
Max Pressure Rise/Step (weakening)	+2 hPa
Movement & Duration
Avg Movement Speed	19.5
Tracking Time	240h (10 days)
Peak Intensity & Range
Latitude	13°N – 34.6°N (21.6°)
Longitude	-179.4°E – 181.3°E (360.7°)

CMA (China)

Energy
ACE (10⁴ (km/h)²)	28.78	High
PDI (10⁶ (km/h)³)	25.47
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+35 km/h
Pressure Variation
Max Pressure Drop/Step	-2 hPa
Max Pressure Drop/24h	-4 hPa
Movement & Duration
Avg Movement Speed	22.1 km/h
Tracking Time	234h (9.8 days)
Time as TD+ (≥34kt)	228h (9.5d)
Peak Intensity & Range
Peak Intensity	08:00 17/10/1964 19.8°N, 159.3°E
Latitude	13°N – 34.4°N (21.4°)
Longitude	156.4°E – 179.9°E (23.5°)

HKO (Hong Kong)

Energy
ACE (10⁴ (km/h)²)	4.18	Low
PDI (10⁶ (km/h)³)	3.24
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+19 km/h
Pressure Variation
Max Pressure Drop/Step	-2 hPa
Max Pressure Drop/24h	-6 hPa
Movement & Duration
Avg Movement Speed	15.4 km/h
Tracking Time	60h (2.5 days)
Time as TD+ (≥34kt)	42h (1.8d)
Peak Intensity & Range
Peak Intensity	14:00 17/10/1964 20.7°N, 159.7°E
Latitude	16°N – 21.6°N (5.6°)
Longitude	158.9°E – 163°E (4.1°)

JTWC

Energy
ACE (10⁴ (km/h)²)	10.53	Medium
PDI (10⁶ (km/h)³)	8.00
Intensification / Weakening
Max Wind Gain/Step	+15 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-15 km/h
Movement & Duration
Avg Movement Speed	16 km/h
Tracking Time	54h (2.3 days)
Time as TD+ (≥34kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	08:00 17/10/1964 19.8°N, 159.3°E
Latitude	16.2°N – 21.5°N (5.3°)
Longitude	158.9°E – 162.7°E (3.8°)

DS824

Energy
ACE (10⁴ (km/h)²)	10.53	Medium
PDI (10⁶ (km/h)³)	8.00
Intensification / Weakening
Max Wind Gain/Step	+15 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-15 km/h
Movement & Duration
Avg Movement Speed	16 km/h
Tracking Time	54h (2.3 days)
Time as TD+ (≥34kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	08:00 17/10/1964 19.8°N, 159.3°E
Latitude	16.2°N – 21.5°N (5.3°)
Longitude	158.9°E – 162.7°E (3.8°)

TD9635

Energy
ACE (10⁴ (km/h)²)	10.53	Medium
PDI (10⁶ (km/h)³)	8.00
Intensification / Weakening
Max Wind Gain/Step	+15 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-15 km/h
Pressure Variation
Max Pressure Drop/Step	-2 hPa
Max Pressure Drop/24h	-6 hPa
Max Pressure Rise/Step (weakening)	+1 hPa
Movement & Duration
Avg Movement Speed	16 km/h
Tracking Time	54h (2.3 days)
Time as TD+ (≥34kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	08:00 17/10/1964 19.8°N, 159.3°E
Latitude	16.2°N – 21.5°N (5.3°)
Longitude	158.9°E – 162.7°E (3.8°)

TD9636

Energy
ACE (10⁴ (km/h)²)	9.36	Medium
PDI (10⁶ (km/h)³)	7.05
Intensification / Weakening
Max Wind Gain/Step	+7 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-7 km/h
Movement & Duration
Avg Movement Speed	16.2 km/h
Tracking Time	48h (2 days)
Time as TD+ (≥34kt)	102h (4.3d)
Peak Intensity & Range
Peak Intensity	08:00 17/10/1964 19.8°N, 159.3°E
Latitude	16.3°N – 21.5°N (5.2°)
Longitude	159.1°E – 161.9°E (2.8°)

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

Storm did not make landfall

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

FRAN (1964)

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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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FRAN (1964)

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Weather Agencies (8 sources)

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Quick Stats

Agency Data Comparison

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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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