This is storm JULIAN that was active in 2021 in the N. Atlantic region with maximum winds of 93 km/h.

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

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Storm Detail 2021

JULIAN (2021)

Name: storm JULIAN
Start: 2021-08-28
End: 2021-08-31
Location: N. Atlantic

Storm Code: 2021241N32308 | Region: N. Atlantic
Active from 28/08/2021 to 31/08/2021 (3 days)

93 km/h

As measured · 1-min avg

Peak wind · 1-min (JTWC)

Converted ≈ 81 km/h · 10-min avg

Level 9

93 km/h

As measured · 10-min avg

Peak wind · 10-min (WMO)

Converted ≈ 81 km/h · 10-min avg

Level 9

993 hPa

Min Pressure

2,764 km

Distance

Forecast Agencies

Beaufort scale: all winds converted to the 10-min avg standard (WMO). Each agency's original value is shown alongside.

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Storm Lifecycle Timeline

Source: JTWC

Key milestones: formation → peak → landfall → dissipation

Formation

19:00 28/08/2021

First recorded point of the system Level 6

Wind Speed: 46 km/h

Pressure: 1010 hPa

32.1°N, 51.7°W

Peak Intensity

13:00 30/08/2021

Moment of strongest winds Level 9

Wind Speed: 93 km/h

Pressure: 993 hPa

38.9°N, 40.0°W

No landfall

Storm stayed over water without direct landfall

Dissipation

19:00 31/08/2021

Last recorded point Level 8

Wind Speed: 83 km/h

Pressure: 1000 hPa

50.5°N, 35.5°W

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Weather Agencies (2 sources)

WMO (International) 93 km/h

JTWC 93 km/h

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Storm Structure

JULIAN

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JULIAN

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Track List (0 points)

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

Wind Intensity Chart

JTWC

No data

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Quick Stats

93 km/h

Max Wind

993 hPa

Min Pressure

72h

Activity Duration

Forecast Agencies

Agency Data Comparison

WMO (International) 1-min avg

81 km/h Max Wind Orig.: 93 km/h

993 hPa Min Pressure

13 Measurements

JTWC 1-min avg

81 km/h Max Wind Orig.: 93 km/h

993 hPa Min Pressure

25 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)	81 Orig.: 93	993	13	2,757	7.34	6.35	Level 9 - Storm
JTWC	81 Orig.: 93	993	25	2,764	7.34	6.35	Level 9 - 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)	7.34	Medium
PDI (10⁶ (km/h)³)	6.35
Intensification / Weakening
Max Wind Gain/Step	+19 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-9 km/h
Pressure Variation
Max Pressure Drop/Step	-6 hPa
Max Pressure Drop/24h	-13 hPa
Max Pressure Rise/Step (weakening)	+2 hPa
Movement & Duration
Avg Movement Speed	38.3 km/h
Tracking Time	72h (3 days)
Time as TD+ (≥34kt)	60h (2.5d)
Peak Intensity & Range
Peak Intensity	01:00 30/08/2021 35.9°N, -45.7°E
Latitude	32.1°N – 50.5°N (18.4°)
Longitude	-51.7°E – -34.5°E (17.2°)

JTWC

Energy
ACE (10⁴ (km/h)²)	7.34	Medium
PDI (10⁶ (km/h)³)	6.35
Intensification / Weakening
Max Wind Gain/Step	+9 km/h
Max Wind Gain/24h	+37 km/h	Fast
Max Wind Loss/Step	-6 km/h
Pressure Variation
Max Pressure Drop/Step	-3 hPa
Max Pressure Drop/24h	-13 hPa
Max Pressure Rise/Step (weakening)	+1 hPa
Movement & Duration
Avg Movement Speed	38.4 km/h
Tracking Time	72h (3 days)
Time as TD+ (≥34kt)	57h (2.4d)
Peak Intensity & Range
Peak Intensity	01:00 30/08/2021 35.9°N, -45.7°E
Latitude	32.1°N – 50.5°N (18.4°)
Longitude	-51.7°E – -34.5°E (17.2°)

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

JULIAN (2021)

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Storm Structure

Storm Lifecycle Timeline

Comparison Storms 0

Weather Agencies (2 sources)

Export GIF/Video

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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JULIAN

Storm Structure