Tropical Storm Laura (2008)

Infobox Hurricane
Name=Tropical Storm Laura
Type=Tropical Storm
Year=2008
Basin=Atl
Image location=Pre-laura low, 2008, non-trop.jpg


Formed=September 29, 2008
Dissipated=October 1, 2008
1-min winds=50
Pressure=994
Da

Fatalities=None
Areas=Netherlands, British Isles, Norway (when post-tropical)
Hurricane season=2008 Atlantic hurricane season

Tropical Storm Laura was the twelfth named storm of the 2008 Atlantic hurricane season. Laura formed out of a large non-tropical low pressure area located 1015 miles (1635 km) west of the western islands of the Azores on September 29. Laura slowly developed tropical characteristics throughout the day as it moved over warmer waters. On the afternoon of September 30, Laura had acquired enough tropical characteristics to be designated a Tropical Storm. Shortly after being declared tropical, Laura began to undergo an extratropical transition, which did not fully take place until the morning of October 1. Laura degenerated into a post-tropical cyclone later that morning, and the final advisory by the National Hurricane Center was issued.

Meteorological History

In late September, a large non-tropical system located over the north-central Atlantic slowly moved westward away from the Azores. The low produced hurricane-force winds, but did not exhibit the characteristics of a tropical cyclone. The storm steadily weakened over the following days, [cite web|author=NHC|title=12L 2008 Trackfile|year=2008|publisher=National Hurricane Center|accessdate=2008-09-29|url=ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/invest_al122008.invest] but developed tropical characteristics as it moved over slightly warmer waters. By September 29, the low had developed sufficient convection and was declared Subtropical Storm Laura. [cite web|author=Stewart|title=Subtropical Storm Laura Public Advisory One|year=2008|publisher=National Hurricane Center|accessdate=2008-09-29|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.public.001.shtml?] Upon being upgraded, cold cloud tops began to wrap around the center of Laura and consolidate near the center of circulation. The convection organized around the center quickly and a satellite pass over the storm revealed that it could be intensifying. [cite web|author=Stewart|title=Subtropical Storm Laura Discussion One|year=2008|publisher=National Hurricane Center|accessdate=2008-09-29|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.001.shtml?] A later satellite pass disregarded the possibility of intensification as the intensity was confirmed to be at 60 mph (95 km/h). The overall structure of Laura remained subtropical but there were indications that it was acquiring tropical characteristics. [cite web|author=Berg/Pasch|title=Subtropical Storm Laura Discussion Two|year=2008|publisher=National Hurricane Center|accessdate=2008-09-29|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.002.shtml?]

During the afternoon, satellites revealed that Laura had developed a deep warm core, a characteristic of a tropical cyclone, but the wind field remained subtropical in nature. [cite web|author=Berg/Franklin|title=Subtropical Storm Laura Discussion Three|year=2008|publisher=National Hurricane Center|accessdate=2008-09-30|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.003.shtml?] By the nighttime hours, the radius of the strongest winds contracted to 80 mi (130 km), much smaller than what is typical of a subtropical cyclone. However, Laura was still under the influence of an upper-level low and cloud tops remained shallow. [cite web|author=Franklin|title=Subtropical Storm Laura Discussion Four|year=2008|publisher=National Hurricane Center|accessdate=2008-09-30|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.004.shtml?] However, the cloud tops became colder overnight and Laura was on the verge of becoming a tropical cyclone by the morning of September 30, but strong interaction with the upper-level low meant it was still subtropical. [cite web|author=Beven|title=Subtropical Storm Laura Discussion Five|year=2008|publisher=National Hurricane Center|accessdate=2008-09-30|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.005.shtml?] Despite moving over colder waters, a water vapor satellite image determined that Laura had separated itself from the upper-level low, signifying it had developed into a tropical cyclone. Laura was upgraded to a tropical storm at a relatively high latitude, 41.2°N. [cite web|author=Berg/Pasch|title=Tropical Storm Laura Discussion Six|year=2008|publisher=National Hurricane Center|accessdate=2008-09-30|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.006.shtml?] Not long after being declared tropical, early signs of an extratropical transition appeared. Cold air began to enter the storm on the west side and forecast models showed Laura becoming extratropical the next morning and non-tropical later the next day. [cite web|author=Berg/Pasch|title=Tropical Storm Laura Discussion Seven|year=2008|publisher=National Hurricane Center|accessdate=2008-10-01|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.007.shtml?]

Overnight, convection associated with Laura began to diminish and lose tropical characteristics, but still retained its status. [cite web|author=Avila|title=Tropical Storm Laura Discussion Eight|year=2008|publisher=National Hurricane Center|accessdate=2008-10-01|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.008.shtml?] Early on October 1, the extratropical transition was fully apparent. Laura remained tropical but the cloud pattern was becoming frontal and there was little convection around the center of the system. [cite web|author=Beven|title=Tropical Storm Laura Discussion Nine|year=2008|publisher=National Hurricane Center|accessdate=2008-10-01|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.006.shtml?] Laura later degenerated into a post-tropical cyclone, a term that had been previously used by the Canadian Hurricane Centre to describe a storm that has lost tropical characteristics, but is not subtropical or extratropical. The transition was forecasted to be complete by the end of the day. [cite web|author=Franklin|title=Post-Tropical Cyclone Laura Discussion Ten|year=2008|publisher=National Hurricane Center|accessdate=2008-10-01|url=http://www.nhc.noaa.gov/archive/2008/al12/al122008.discus.010.shtml?]

Impact

As a tropical cyclone, Laura never approached land, and no effects, damages, or fatalities occurred. However, the storm's remnants were caught in an upper-level jet stream, and steered towards Europe. [Cite web|author=Paul Simons|title=Weather: torrential rain expected as strong winds hit Wales and the South West|year=2008|publisher="The Times"|accessdate=2008-10-05|url=http://www.timesonline.co.uk/tol/news/weather/uk_and_roi/article4877139.ece] Heavy rain fell across portions of Britain, causing localized accumulation of flood waters. As a result, Glebe Road near Windermere, England was closed in both directions, and along the A65 road between Old Hutton and Kirkby Lonsdale, previously saturated soil, combined with overwhelmed storm drains resulted in localized flooding. Traffic on the M6 Motorway was slowed due to poor driving conditions. [cite web|author=Staff Writer|title=Tropical storm brings floods|year=2008|publisher="The Westmorland Gazette"|accessdate=2008-10-05|url=http://www.thewestmorlandgazette.co.uk/news/3728628.Tropical_storm_brings_floods/]

After the remnants of now extratropical Laura made final landfall on the southern coast of the Netherlands, it's rain bands started interacting with a cold front associated with a well-developed low west of Norway [Cite web|author=Rob Sluijter|title=5 oktober 2008: Wateroverlast in het noordwesten.|year=2008|publisher="KNMI"|accessdate=2008-10-08|url=http://www.knmi.nl/klimatologie/nieuws/wateroverlast_051008.html] , dropping up to 113 mm [Cite web|author=Meteo Consult|title=De Noord-Hollandse 'zondvloed' nader bekeken.|year=2008|publisher="Meteo Consult"|accessdate=2008-10-08|url=http://www.weer.nl/nl/home/weer/weer_in_het_nieuws/weernieuws/archive/2008/october/ch/f2d584b038/article/de_noord_hollandse_zondvloed_nader_bekeken.html] (4.5 in) of precipitation in the Northwestern Netherlands, flooding streets and homes in the village of Hippolytushoef. More than 10,000 people lost electricity in southern Norway because of damage to the electrical system caused by the remnants of the storm. [ [http://www.nrk.no/nyheter/1.6247956 NRK.no: Kraftig uvær på Østlandet] ]

ee also

*2008 Atlantic hurricane season

References

External links

*The NHC's [http://www.nhc.noaa.gov/archive/2008/refresh/LAURA+shtml/144402.shtml? Archive on Laura]