This is storm MAC that was active in 1979 in the W. Pacific region with maximum winds of 130 km/h.

What was the maximum intensity of the storm?

Max Wind: 130 km/h. Min Pressure: hPa.

storm MAC (1979) - Track and intensity details

Name: storm MAC
Start: 1979-09-11
End: 1979-09-25
Location: W. Pacific

MAC (1979)

Storm Code: 1979254N10140 | Region: W. Pacific
Active from 11/09/1979 to 25/09/1979 (15 days)

130 km/h

1-min Wind (JTWC)

Level 12

111 km/h

10-min Wind (HKO)

Level 11

983 hPa

Min Pressure

4,064 km

Distance

Forecast Agencies

Agency	Max Intensity	Trajectory	Energy	highest_classification
TD9636	130	~	105	3,670	21.61	20.33	Level 12 - Violent Storm
CMA (China)	107	983	109	4,064	15.91	14.80	Level 11 - Severe Storm
WMO (International)	102	985	51	3,557	14.54	13.02	Level 10 - Severe Storm
JMA (Japan)	102	985	101	3,491	14.54	13.02	Level 10 - Severe Storm
JTWC	130	~	89	3,422	21.54	20.39	Level 12 - Violent Storm
DS824	130	~	89	3,422	21.54	20.39	Level 12 - Violent Storm
HKO (Hong Kong)	111	990	67	2,341	11.70	9.97	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)

TD9636

130

105

3,670

21.61

20.33

Level 12 - Violent Storm

CMA (China)

107

983

109

4,064

15.91

14.80

Level 11 - Severe Storm

WMO (International)

102

985

3,557

14.54

13.02

Level 10 - Severe Storm

JMA (Japan)

102

985

101

3,491

14.54

13.02

Level 10 - Severe Storm

JTWC

130

3,422

21.54

20.39

Level 12 - Violent Storm

DS824

130

3,422

21.54

20.39

Level 12 - Violent Storm

HKO (Hong Kong)

111

990

2,341

11.70

9.97

Level 11 - Severe Storm

Advanced Meteorological Indices by Agency Automatically calculated from raw data

TD9636 RI

Energy
ACE (10⁴ (km/h)²)	21.61	High
PDI (10⁶ (km/h)³)	20.33
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+74 km/h	RI
Max Wind Loss/Step	-7 km/h
Movement & Duration
Avg Movement Speed	11.8 km/h
Tracking Time	312h (13 days)
Time as TD+ (≥34kt)	174h (7.3d)
Time as Storm+ (≥64kt)	21h (0.9d)
Peak Intensity & Range
Peak Intensity	07:00 17/09/1979 13.7°N, 126.2°E
Latitude	10.1°N – 22.5°N (12.4°)
Longitude	112.8°E – 140.3°E (27.5°)

CMA (China) RI

Energy
ACE (10⁴ (km/h)²)	15.91	Medium
PDI (10⁶ (km/h)³)	14.80
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+57 km/h	RI
Max Wind Loss/Step	-19 km/h
Pressure Variation
Max Pressure Drop/Step	-3 hPa
Max Pressure Drop/24h	-16 hPa
Max Pressure Rise/Step (weakening)	+3 hPa
Movement & Duration
Avg Movement Speed	12.5 km/h
Tracking Time	324h (13.5 days)
Time as TD+ (≥34kt)	126h (5.3d)
Peak Intensity & Range
Peak Intensity	13:00 17/09/1979 13.6°N, 125.6°E
Latitude	11.5°N – 22.7°N (11.2°)
Longitude	112.6°E – 141.7°E (29.1°)

WMO (International)

Energy
ACE (10⁴ (km/h)²)	14.54	Medium
PDI (10⁶ (km/h)³)	13.02
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+19 km/h
Max Wind Loss/Step	-19 km/h
Pressure Variation
Max Pressure Drop/Step	-7 hPa
Max Pressure Drop/24h	-10 hPa
Max Pressure Rise/Step (weakening)	+8 hPa
Movement & Duration
Avg Movement Speed	11.9 km/h
Tracking Time	300h (12.5 days)
Time as TD+ (≥34kt)	120h (5d)
Peak Intensity & Range
Peak Intensity	07:00 17/09/1979 13.8°N, 126.2°E
Latitude	11.7°N – 22.3°N (10.6°)
Longitude	112.8°E – 140.5°E (27.7°)

JMA (Japan)

Energy
ACE (10⁴ (km/h)²)	14.54	Medium
PDI (10⁶ (km/h)³)	13.02
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	-4 hPa
Max Pressure Drop/24h	-10 hPa
Max Pressure Rise/Step (weakening)	+4 hPa
Movement & Duration
Avg Movement Speed	11.6 km/h
Tracking Time	300h (12.5 days)
Time as TD+ (≥34kt)	114h (4.8d)
Peak Intensity & Range
Peak Intensity	07:00 17/09/1979 13.8°N, 126.4°E
Latitude	12°N – 22.6°N (10.6°)
Longitude	112.9°E – 140°E (27.1°)

JTWC RI

Energy
ACE (10⁴ (km/h)²)	21.54	High
PDI (10⁶ (km/h)³)	20.39
Intensification / Weakening
Max Wind Gain/Step	+15 km/h
Max Wind Gain/24h	+74 km/h	RI
Max Wind Loss/Step	-9 km/h
Movement & Duration
Avg Movement Speed	13 km/h
Tracking Time	264h (11 days)
Time as TD+ (≥34kt)	171h (7.1d)
Time as Storm+ (≥64kt)	21h (0.9d)
Peak Intensity & Range
Peak Intensity	07:00 17/09/1979 13.7°N, 126.2°E
Latitude	11.8°N – 22.5°N (10.7°)
Longitude	112.9°E – 139°E (26.1°)

DS824 RI

Energy
ACE (10⁴ (km/h)²)	21.54	High
PDI (10⁶ (km/h)³)	20.39
Intensification / Weakening
Max Wind Gain/Step	+15 km/h
Max Wind Gain/24h	+74 km/h	RI
Max Wind Loss/Step	-9 km/h
Movement & Duration
Avg Movement Speed	13 km/h
Tracking Time	264h (11 days)
Time as TD+ (≥34kt)	171h (7.1d)
Time as Storm+ (≥64kt)	21h (0.9d)
Peak Intensity & Range
Peak Intensity	07:00 17/09/1979 13.7°N, 126.2°E
Latitude	11.8°N – 22.5°N (10.7°)
Longitude	112.9°E – 139°E (26.1°)

HKO (Hong Kong) RI

Energy
ACE (10⁴ (km/h)²)	11.70	Medium
PDI (10⁶ (km/h)³)	9.97
Intensification / Weakening
Max Wind Gain/Step	+28 km/h
Max Wind Gain/24h	+56 km/h	RI
Max Wind Loss/Step	-15 km/h
Pressure Variation
Max Pressure Drop/Step	-5 hPa
Max Pressure Drop/24h	-14 hPa
Max Pressure Rise/Step (weakening)	+4 hPa
Movement & Duration
Avg Movement Speed	11.8 km/h
Tracking Time	198h (8.3 days)
Time as TD+ (≥34kt)	102h (4.3d)
Peak Intensity & Range
Peak Intensity	07:00 23/09/1979 21.4°N, 114.4°E
Latitude	13.4°N – 22.4°N (9°)
Longitude	112.5°E – 129.3°E (16.8°)

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

🇵🇭 Philippines

WMO 102 km/h Level 10

13.80°, 124.40° 1979-09-17 17:12:53

TD9636 104 km/h Level 11

13.80°, 124.40° 1979-09-17 19:27:53

CMA 107 km/h Level 11

13.59°, 123.58° 1979-09-18 00:20:02

JMA 102 km/h Level 10

13.80°, 124.40° 1979-09-17 18:57:07

JTWC 100 km/h Level 10

13.80°, 124.40° 1979-09-17 18:57:07

DS824 100 km/h Level 10

13.80°, 124.40° 1979-09-17 18:57:07

HKO 83 km/h Level 9

13.80°, 124.40° 1979-09-17 14:58:14

🇨🇳 China

WMO 35 km/h Level 5

22.16°, 113.35° 1979-09-23 15:06:40

TD9636 65 km/h Level 8

22.01°, 112.99° 1979-09-23 12:12:39

CMA 31 km/h Level 5

22.59°, 113.85° 1979-09-24 17:12:11

JMA

22.27°, 113.57° 1979-09-23 17:01:27

JTWC 63 km/h Level 8

22.13°, 113.13° 1979-09-23 13:53:22

DS824 63 km/h Level 8

22.13°, 113.13° 1979-09-23 13:53:22

🇲🇴 China

CMA 72 km/h Level 8

22.20°, 113.50° 1979-09-23 15:02:06

HKO 72 km/h Level 8

22.20°, 113.50° 1979-09-23 16:31:13

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

MAC (1979)

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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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Weather Agencies (7 sources)

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Quick Stats

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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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