This is storm AL04 that was active in 2012 in the S. Pacific region with maximum winds of 74 km/h.

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Max Wind: 74 km/h. Min Pressure: hPa.

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Storm Detail 2012

AL04 (2012)

Name: storm AL04
Start: 2012-06-27
End: 2012-07-01
Location: S. Pacific

Storm Code: 2012179S09153 | Region: S. Pacific
Active from 27/06/2012 to 01/07/2012 (4 days)

65 km/h

1-min Wind (JTWC)

Level 8

74 km/h

10-min Wind (BOM)

Level 8

996 hPa

Min Pressure

722 km

Distance

Forecast Agencies

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Weather Agencies (3 sources)

WMO (International) 74 km/h

BOM (Australia) 74 km/h

JTWC 65 km/h

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Storm Structure

AL04

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AL04

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Track List (0 points)

#	Time (GMT+7)	Position	Wind (km/h)	Pressure	Level

Wind Intensity Chart

BOM JTWC

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Quick Stats

74 km/h

Max Wind

996 hPa

Min Pressure

96h

Activity Duration

Forecast Agencies

Agency Data Comparison

WMO (International)

74 km/h Max Wind

996 hPa Min Pressure

17 Measurements

BOM (Australia)

74 km/h Max Wind

996 hPa Min Pressure

33 Measurements

JTWC

65 km/h Max Wind

996 hPa Min Pressure

23 Measurements

Agency	Max Intensity		Trajectory		Energy		highest_classification
Agency	Max Wind (km/h)	Min Pressure (hPa)	Number of points	Distance (km)	ACE (10⁴ (km/h)²)	PDI (10⁶ (km/h)³)	highest_classification
WMO (International)	74	996	17	714	2.37	1.65	Level 8 - Storm
BOM (Australia)	74	996	33	722	3.91	2.73	Level 8 - Storm
JTWC	65	996	23	509	1.27	0.83	Level 8 - Storm

Indices Legend

Max Wind (kt/km/h): Maximum wind speed by agency

Min Pressure: Lowest central pressure

Number of points: Number of observation points in track

Distance: Total track distance traveled

ACE: Accumulated Cyclone Energy

PDI: Power Dissipation Index

Advanced Meteorological Indices by Agency Automatically calculated from raw data

WMO (International)

Energy
ACE (10⁴ (km/h)²)	2.37	Low
PDI (10⁶ (km/h)³)	1.65
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-4 hPa
Max Pressure Drop/24h	-9 hPa
Max Pressure Rise/Step (weakening)	+3 hPa
Movement & Duration
Avg Movement Speed	7.4 km/h
Tracking Time	96h (4 days)
Time as TD+ (≥34kt)	30h (1.3d)
Peak Intensity & Range
Peak Intensity	07:00 29/06/2012 -11.3°N, 154.1°E
Latitude	-11.6°N – -9°N (2.6°)
Longitude	152.6°E – 155°E (2.4°)

BOM (Australia)

Energy
ACE (10⁴ (km/h)²)	3.91	Low
PDI (10⁶ (km/h)³)	2.73
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+28 km/h
Max Wind Loss/Step	-6 km/h
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	7.5 km/h
Tracking Time	96h (4 days)
Time as TD+ (≥34kt)	48h (2d)
Peak Intensity & Range
Peak Intensity	07:00 29/06/2012 -11.2°N, 154°E
Latitude	-11.5°N – -9°N (2.5°)
Longitude	152.6°E – 155°E (2.4°)

JTWC

Energy
ACE (10⁴ (km/h)²)	1.27	Low
PDI (10⁶ (km/h)³)	0.83
Intensification / Weakening
Max Wind Gain/Step	+6 km/h
Max Wind Gain/24h	+9 km/h
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-2 hPa
Max Pressure Drop/24h	-4 hPa
Max Pressure Rise/Step (weakening)	+3 hPa
Movement & Duration
Avg Movement Speed	7.7 km/h
Tracking Time	66h (2.8 days)
Time as TD+ (≥34kt)	18h (0.8d)
Peak Intensity & Range
Peak Intensity	19:00 29/06/2012 -11.7°N, 154.9°E
Latitude	-11.7°N – -10°N (1.7°)
Longitude	152.7°E – 155°E (2.3°)

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

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User Guide

AL04 (2012)

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Storm Structure

Comparison Storms 0

Weather Agencies (3 sources)

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Track List (0 points)

Wind Intensity Chart

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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AL04

Storm Structure