2020/21 North Atlantic Hurricane Force Wind Events
Highlighting the hurricane force (HF) wind event season from June 1, 2020, through May 31, 2021.
INTRODUCTION
An ever present danger to all mariners is the possibility of encountering extreme winds created by powerful mid-latitude cyclones. These violent winds quickly build dangerous seas, posing life-threatening hazards to vessels on the open ocean.
Cargo ship in violent storm to hurricane force conditions. Video credit Alexey Fadeev.
Hurricane force (HF) wind warnings are issued by the Ocean Prediction Center (OPC) when non-tropical sustained winds of 64 kt (74 mph) or greater are being observed, or are forecast to occur within 48 hours. These warnings represent the highest wind warning category issued by OPC and the National Weather Service.
Accurate and reliable weather forecasts are critical to provide mariners adequate time to plan safe, economically sound routes days in advance, thereby minimizing exposure to the strongest winds and roughest seas, ultimately keeping the crew, vessel, and cargo as safe as possible. The Ocean Prediction Center, as part of the National Weather Service, helps fulfill the NOAA mission of providing weather, water, and climate data, forecasts and warnings for the protection of life and property and enhancement of the national economy.
The following story map takes a deeper dive into the season, with some historical context.
THE 2020/2021 SEASON
From June 1, 2020, to May 31, 2021, OPC forecasters analyzed 42 separate hurricane force wind events across the North Atlantic Ocean, either created by low pressure systems or driven by synoptic scale forcing.
Each of the 129 circles on the left side of the interactive map represents a low pressure or the location of hurricane force winds, and are color coded by pressure; the warmer the colors, the deeper the pressure. Clicking on the circle will provide more information, including the position, pressure, date, and storm id number (for local, in-house tracking purposes only). Some HF wind events only lasted for one analysis period, and others spanned multiple days. For synoptic scale events -- barrier and tip jet events where no discernible surface low pressure was analyzed -- a zero pressure and white color coding was assigned.
The right side of the swipe is a heat map, highlighting the most concentrated areas of hurricane force (HF) wind events of the season. Drag the slider left and right for an immersive look at the 2020-2021 season.
swipe map showing individual hurricane force wind events (left), with heat map density display (right)
HISTORICAL CONTEXT
The seasonal 42 hurricane force wind events were slightly lower than the previous 15 year average of 45. The following section should help to put the latest season into some recent historical context.
The accumulation graph highlights the fast start to the season (red line), with 14 hurricane force wind events during the September, October, and November months, compared to the typical 9 hurricane force wind events on average during the previous 15 seasons (blue line).
A tranquil period from December 23 through January 20 slowed the pace, putting the season below the ongoing 15 year average. A typical February, followed by a slightly above average March, helped pull the final number (42) closer toward the mean (45).
A look at the June 2020 to May 2021 monthly totals compared to seasonal averages highlights the active early and late periods, with an abnormally quiet stretch in December and January. The quilt below (click to enlarge), is another way to visualize hurricane force winds events and trends by month. Keep in mind OPC separates seasons from June 1 through May 31 of the following year.
Another look at the most recent 2020 - 2021 hurricane force wind event season total, and how that fits into the variability and trends of the previous 15 seasons.
This animation highlights all hurricane force winds events analyzed, by date, since June 1, 2005. Notice the slow but steady increase in hurricane force wind events through the Fall and Winter, peaking around February 14th, followed by a quick decline into the quieter spring and summer months.
ALL 42 EVENTS
This next and final section of the story map highlights all 42 of the hurricane force wind events in the June 2020 to May 2021 season, in chronological order, with selected surface analysis charts, satellite imagery, and other remotely sensed data. Click the charts to enlarge, and use the right and left arrows to view accompanying satellite imagery and data. You can also skip ahead by clicking on a number on the map.
01 / 42
1
#1 September 15, 2020
The 1st hurricane force wind event of the OPC 20/21 season was generated by a strong occluded front pinching against the SW Greenland Coast.
2
#2 September 16-17, 2020
The next HF wind event occurred the following day as Hurricane Paulette transitioned into an intense Post-Tropical Cyclone across the central Atlantic.
3
#3 September 23-25, 2020
Hurricane Teddy transitioned into a powerful Post-Tropical cyclone south of Nova Scotia, then produced a second round of hurricane force winds Sep 24 in the barrier jet between the approaching occluded front and the SW Greenland coast. The last image highlights the lack of vessels in the area (taken from marinetraffic.com), a positive sign that mariners heeded warnings to avoid the strongest winds and roughest seas.
4
#4 October 1, 2020
The 4th hurricane force wind event of the season occurred in the occlusion pinch along the SW Greenland coast.
5
#5 October 24, 2020
Low pressure rapidly intensified west of Ireland and the U.K., producing the next round of hurricane force winds on October 24.
6
#6 October 26-28, 2020
The 6th hurricane force wind event was a deep, sprawling extratropical cyclone that saw incredible deepening rates during the intensification phase. This low absorbed the remnants of Post-Tropical cyclone Epsilon. The Advanced Scatterometer (ASCAT) returned wind retrievals to 75 kt (wind speed legend top right of the loop), and altimeter instruments detected 59 ft (18 m) significant wave heights.
7
#7 November 1, 2020
The 7th hurricane force wind event was a strong low pressure that passed just west of Ireland and the U.K., likely with some embedded remnant energy from Post-Tropical cyclone Zeta.
8
#8 November 3, 2020
The 8th hurricane force wind event was generated by a deep low pressure in the Labrador Sea; the first instance of HF winds was in the occlusion pinch along coast of Greenland, followed by the more typical southwest quadrant of the low pressure.
9
#9 November 4-5, 2020
The next hurricane force wind event took place as a strong low pressure passed to the south of Greenland.
10
#10 November 12, 2020
The 10th hurricane force wind event of the season was a strong low pressure churning across the northeastern Atlantic.
11
#11 November 18, 2020
This hurricane force wind event occurred as a strong occluded front pressed against the southwest coast of Greenland.
12
#12 November 20, 2020
The next hurricane force wind event was a classic low track as a mid-latitude cyclone deepened across the central ocean, then passed south and east of Iceland.
13
#13 November 25-26, 2020
The next hurricane force wind event occurred as a deep low pressure tracked across southern Greenland, then continued northeast through the Denmark Strait. Prolonged hurricane force winds continued even as the low gained latitude.
14
#14 November 30 - December 1, 2020
A strong low pressure tracked south of Greenland, then northeast through the Denmark Strait marking the 14th hurricane force wind event of the season.
15
#15 December 9, 2020
The next hurricane force wind event was generated by a strong low pressure passing south of Nova Scotia and Newfoundland, likely aided by the northeast extension of the Gulf Stream current and anomalously warm sea surface temperatures.
16
#16 December 16, 2020
This low pressure explosively deepened 55 mb in just 24 hours, and by December 16, was producing hurricane force winds northeast of Newfoundland. The low bottomed into the 930's millibars, which ranks among some of the lowest pressures across the mid-latitudes.
17
#17 December 16-17, 2020
Another round of hurricane force winds developed near the southern tip of Greenland as a stationary front pressed against the coast along the northern, broad circulation of a deep central ocean low. This was messaged as a separate hurricane force wind warning from the previous low in the official high seas text bulletin (METAREA IV).
18
#18 December 23, 2020
The 18th hurricane force wind event of the season occurred as a strong occluded front pinched along the southwest coast of Greenland.
19
#19 January 21, 2021
After a remarkable 28 day span without hurricane force winds across the north Atlantic basin, the 1st hurricane force wind event of 2021 -- and the 19th of the season -- occurred across the Western Atlantic atop the Gulf Stream.
20
#20 January 25, 2021
The next hurricane force wind event of the season occurred as a deep low pressure tracked across the central Atlantic.
21
#21 January 26-28, 2021
The next and prolonged hurricane force wind event took place as a barrier jet developed between a quasi-stationary front and the east coast of Greenland.
22
#22 January 28-29, 2021
The next hurricane force wind took place across the central Atlantic -- a relatively low latitude, intense system.
23
#23 January 28-31, 2021
The 23rd hurricane force wind event occurred as a low pressure rapidly intensified across the Gulf Stream, then continued to produce hurricane force winds for the next 54 hours as it tracked across the Atlantic basin.
24
#24 January 30-31, 2020
The next instance of hurricane force winds occurred southeast of Greenland in the barrier jet between a stationary front and the coast.
25
#25 February 7-9, 2021
Another prolonged tip jet along the south and southeast coasts of Greenland marked the 25th hurricane force wind event of the season.
26
#26 February 8-9, 2021
The next hurricane force event was generated as low pressure rapidly intensified into the central Atlantic, passing just south of Nova Scotia and Newfoundland.
27
#27 February 11-13, 2021
Another long duration barrier and tip jet event produced hurricane force winds off the southern tip of Greenland.
28
#28 February 11-12, 2021
The next hurricane force wind event occurred as low pressure rapidly intensified across the central Atlantic.
29
#29 February 14, 2021
A strong low pressure passed northwest of Ireland and the U.K., with the ASCAT instrument returning hurricane force wind retrievals, marking the 29th event of the season. If you recall from the historical section above, since 2005, the highest single date of hurricane force wind warnings is February 14th.
30
#30 February 22-23, 2021
The next hurricane force low rapidly intensified across the central Atlantic.
31
#31 February 24 2021
The 31st instance of hurricane force winds occurred as low pressure intensified into the northern portion of the basin.
32
#32 February 26, 2021
The next hurricane force wind event occurred in the occluded front pinch along the eastern coast of Greenland.
33
#33 March 3, 2021
Another strengthening barrier jet between a westward drifting stationary front and the eastern coast of Greenland produced the next round of hurricane force winds.
34
#34 March 4, 2021
The next hurricane force wind event was generated in the strong easterly flow poleward of an occluded front.
35
#35 March 9-10, 2021
The 35th hurricane force wind event of the season was a rapidly intensifying low tracking across the central Atlantic.
36
#36 March 17, 2021
The next hurricane force low was across the northern and central portion of the Atlantic basin, well south of Greenland.
37
#37 March 24, 2021
The next low that produced hurricane force winds was centered to the north of the OPC North Atlantic surface area. ASCAT wind retrievals returned hurricane force winds northeast of the Faroe Islands.
38
#38 March 27-28, 2021
Another deep low pressure across the southern portions of the Denmark Strait generated hurricane force winds in the barrier jet against the eastern coast of Greenland.
39
#39 March 30, 2021
The next low to produce hurricane force winds developed across the Labrador Sea, with strongest winds between the occluded front and the southwest coast of Greenland.
40
#40 April 16, 2021
A deep low pressure developed across the Denmark Strait, producing hurricane force winds east of the occluded front and just west of Iceland.
41
#41 April 16-17, 2021
The next hurricane force wind event was generated off the southern tip of Greenland as another deep low pressure re-developed across the southern portions of the Denmark Strait.
42
#42 May 2-3, 2021
The final and 42nd hurricane force wind event of the 2020-2021 season occurred as a low pressure deepened into the southern Labrador Sea. The hurricane force winds were generated in the E-SE flow poleward of the occluded front as the boundary pinched against the southern coast of Greenland.
