The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland
On 22 September 1982, an intense windstorm caused considerable damage in northern Finland. Local forecasters noted that this windstorm potentially was related to Hurricane Debby, a category 4 hurricane that occurred just 5 days earlier. Due to the unique nature of the event and lack of prior researc...
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/313867 2024-01-07T09:45:27+01:00 The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland Laurila, Terhi Sinclair, Victoria Gregow, Hilppa Institute for Atmospheric and Earth System Research (INAR) 2020-04-02T13:26:02Z 25 application/pdf http://hdl.handle.net/10138/313867 eng eng American Meteorological Society 10.1175/MWR-D-19-0035.1 Laurila , T , Sinclair , V & Gregow , H 2020 , ' The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland ' , Monthly weather review , vol. 148 , no. 1 , pp. 377-401 . https://doi.org/10.1175/MWR-D-19-0035.1 ORCID: /0000-0002-2125-4726/work/71511512 7929d67a-4c40-4921-b4f1-c6082cda6ff1 http://hdl.handle.net/10138/313867 000504712300001 unspecified openAccess info:eu-repo/semantics/openAccess ATLANTIC DIABATIC ROSSBY VORTEX DOWNSTREAM Extratropical cyclones Extreme events IMPACT LIFE-CYCLE MODEL Numerical analysis REINTENSIFICATION TROPICAL CYCLONE TROUGH Tropical cyclones WIND Wind gusts modeling 1171 Geosciences Article publishedVersion 2020 ftunivhelsihelda 2023-12-14T00:12:55Z On 22 September 1982, an intense windstorm caused considerable damage in northern Finland. Local forecasters noted that this windstorm potentially was related to Hurricane Debby, a category 4 hurricane that occurred just 5 days earlier. Due to the unique nature of the event and lack of prior research, our aim is to document the synoptic sequence of events related to this storm using ERA-Interim reanalysis data, best track data, and output from OpenIFS simulations. During extratropical transition, the outflow from Debby resulted in a ridge building and an acceleration of the jet. Debby did not reintensify immediately in the midlatitudes despite the presence of an upper-level trough. Instead, ex-Debby propagated rapidly across the Atlantic as a diabatic Rossby wave-like feature. Simultaneously, an upper-level trough approached from the northeast and once ex-Debby moved ahead of this feature near the United Kingdom, rapid reintensification began. All OpenIFS forecasts diverged from reanalysis after only 2 days indicating intrinsic low predictability and strong sensitivities. Phasing between Hurricane Debby and the weak trough, and phasing of the upper- and lower-level potential vorticity anomalies near the United Kingdom was important in the evolution of ex-Debby. In the only OpenIFS simulation to correctly capture the phasing over the United Kingdom, stronger wind gusts were simulated over northern Finland than in any other simulation. Turbulent mixing behind the cold front, and convectively driven downdrafts in the warm sector, enhanced the wind gusts over Finland. To further improve understanding of this case, we suggest conducting research using an ensemble approach. Peer reviewed Article in Journal/Newspaper Northern Finland HELDA – University of Helsinki Open Repository Monthly Weather Review 148 1 377 401 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
ATLANTIC DIABATIC ROSSBY VORTEX DOWNSTREAM Extratropical cyclones Extreme events IMPACT LIFE-CYCLE MODEL Numerical analysis REINTENSIFICATION TROPICAL CYCLONE TROUGH Tropical cyclones WIND Wind gusts modeling 1171 Geosciences |
spellingShingle |
ATLANTIC DIABATIC ROSSBY VORTEX DOWNSTREAM Extratropical cyclones Extreme events IMPACT LIFE-CYCLE MODEL Numerical analysis REINTENSIFICATION TROPICAL CYCLONE TROUGH Tropical cyclones WIND Wind gusts modeling 1171 Geosciences Laurila, Terhi Sinclair, Victoria Gregow, Hilppa The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
topic_facet |
ATLANTIC DIABATIC ROSSBY VORTEX DOWNSTREAM Extratropical cyclones Extreme events IMPACT LIFE-CYCLE MODEL Numerical analysis REINTENSIFICATION TROPICAL CYCLONE TROUGH Tropical cyclones WIND Wind gusts modeling 1171 Geosciences |
description |
On 22 September 1982, an intense windstorm caused considerable damage in northern Finland. Local forecasters noted that this windstorm potentially was related to Hurricane Debby, a category 4 hurricane that occurred just 5 days earlier. Due to the unique nature of the event and lack of prior research, our aim is to document the synoptic sequence of events related to this storm using ERA-Interim reanalysis data, best track data, and output from OpenIFS simulations. During extratropical transition, the outflow from Debby resulted in a ridge building and an acceleration of the jet. Debby did not reintensify immediately in the midlatitudes despite the presence of an upper-level trough. Instead, ex-Debby propagated rapidly across the Atlantic as a diabatic Rossby wave-like feature. Simultaneously, an upper-level trough approached from the northeast and once ex-Debby moved ahead of this feature near the United Kingdom, rapid reintensification began. All OpenIFS forecasts diverged from reanalysis after only 2 days indicating intrinsic low predictability and strong sensitivities. Phasing between Hurricane Debby and the weak trough, and phasing of the upper- and lower-level potential vorticity anomalies near the United Kingdom was important in the evolution of ex-Debby. In the only OpenIFS simulation to correctly capture the phasing over the United Kingdom, stronger wind gusts were simulated over northern Finland than in any other simulation. Turbulent mixing behind the cold front, and convectively driven downdrafts in the warm sector, enhanced the wind gusts over Finland. To further improve understanding of this case, we suggest conducting research using an ensemble approach. Peer reviewed |
author2 |
Institute for Atmospheric and Earth System Research (INAR) |
format |
Article in Journal/Newspaper |
author |
Laurila, Terhi Sinclair, Victoria Gregow, Hilppa |
author_facet |
Laurila, Terhi Sinclair, Victoria Gregow, Hilppa |
author_sort |
Laurila, Terhi |
title |
The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
title_short |
The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
title_full |
The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
title_fullStr |
The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
title_full_unstemmed |
The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland |
title_sort |
extratropical transition of hurricane debby (1982) and the subsequent development of an intense windstorm over finland |
publisher |
American Meteorological Society |
publishDate |
2020 |
url |
http://hdl.handle.net/10138/313867 |
genre |
Northern Finland |
genre_facet |
Northern Finland |
op_relation |
10.1175/MWR-D-19-0035.1 Laurila , T , Sinclair , V & Gregow , H 2020 , ' The Extratropical Transition of Hurricane Debby (1982) and the Subsequent Development of an Intense Windstorm over Finland ' , Monthly weather review , vol. 148 , no. 1 , pp. 377-401 . https://doi.org/10.1175/MWR-D-19-0035.1 ORCID: /0000-0002-2125-4726/work/71511512 7929d67a-4c40-4921-b4f1-c6082cda6ff1 http://hdl.handle.net/10138/313867 000504712300001 |
op_rights |
unspecified openAccess info:eu-repo/semantics/openAccess |
container_title |
Monthly Weather Review |
container_volume |
148 |
container_issue |
1 |
container_start_page |
377 |
op_container_end_page |
401 |
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1787426987684397056 |