Hurricane Bertha (2008)

Infobox Hurricane
Name=Hurricane Bertha
Type=hurricane
Year=2008
Basin=Atl
Image location=Bertha 07 july 2008 1630Z.jpg


Formed=July 3, 2008
Dissipated=July 20, 2008
1-min winds=105
Pressure=948
Da

Fatalities=0 direct, 3 indirect
Areas=Bermuda, New Jersey, and Iceland
Hurricane season=2008 Atlantic hurricane season

Hurricane Bertha was a rare early season Cape Verde-type hurricane. It is both the longest-lived July Atlantic tropical cyclone on record, [http://www.nhc.noaa.gov/archive/2008/tws/MIATWSAT_jul.shtml Tropical Weather Summary ] ] and the easternmost forming July tropical storm on record. Cite web|author=Jeff Masters|title=Tropical Storm Bertha forms--and sets a record|year=2008|publisher=Wunderground|accessdate=2008-07-06|url=http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=973&tstamp=200807] The second named storm of the 2008 Atlantic hurricane season, Bertha developed from a tropical wave that emerged off the coast of Africa on July 1. Tropical Depression Two formed about 250 miles (405 km) south of Cape Verde. The system quickly strengthened into Tropical Storm Bertha on July 3. Bertha moved westward over the next few days as a weak tropical storm. Late on July 6, Bertha began to strengthen well to the east of the Northern Leeward Islands. Bertha continued to strengthen and became the first hurricane of the season on July 7, as well as the first major hurricane, later that day. The hurricane weakened during the day on July 8, due to a nearby upper level low to its northeast. Thereafter, it drifted north-northwest towards Bermuda before slowly looping to its southeast on July 12 and July 13. The system moved within convert|40|mi|km of Bermuda on July 14 before moving northeast away from the island. On July 16, Bertha curved back to the southeast due to the influence of a deep cyclone to its east, and then turned northeast, reaching hurricane strength before becoming extratropical on July 20.

Meteorological history

Early on July 1, a strong and large tropical wave emerged off the coast of Africa. [cite web|author=Blake|title=July 1 6z Tropical Weather Outlook|year=2008|publisher=National Hurricane Center|accessdate=2008-07-04|url=http://www.nhc.noaa.gov/archive/text/TWOAT/TWOAT.200807010541.txt] By early the next day, a surface low developed and the wave became better organized. [cite web|author=Cangialosi|title=July 2 2:05a EDT Tropical Weather Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-04|url=http://www.nhc.noaa.gov/archive/text/TWDAT/TWDAT.200807020558.txt] The National Hurricane Center upgraded the system to Tropical Depression Two in the morning hours of July 3 after the system was able to maintain convection over its center for at least 12 hours.cite web|author=Blake|title=Tropical Depression Two Advisory 1 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-04|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.001.shtml?] The depression organized further and developed two distinct bands of convection. Six hours after becoming a depression, it was upgraded to Tropical Storm Bertha, the second named storm of the season. [cite web|author=Brown|title=Tropical Depression Two Advisory 2 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-04|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.002.shtml?] The National Hurricane Center noted that this tropical cyclone was remarkably forecasted up to a week in advance by many global computer models.

Bertha continued on a westward motion as the storm moved under a ridge of high pressure.cite web|author=Knabb|title=Tropical Storm Bertha Advisory 5 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-07|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.005.shtml?] Despite low wind shear, Bertha remained a weak tropical storm due to cool sea surface temperatures. Over the next few days, the system started to move over warmer waters again, while moving west at over 25 mph (40 km/h). cite web|author=Knabb|title=Tropical Storm Bertha Advisory 13 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-07|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.013.shtml?] Bertha began to strengthen on July 6 as microwave images showed a developing eye-like feature.cite web|author=Avila|title=Tropical Storm Bertha Advisory 16 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-07|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.016.shtml?] Intensification continued into the morning of July 7 when Tropical Storm Bertha strengthened into a hurricane, the first of the season.cite web|author=Avila|title=Tropical Storm Bertha Advisory 17 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-07|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.017.shtml?] The deepening later became more rapid, and Bertha strengthened into a Category 3 hurricane late that afternoon.cite web|author=Rhome|title=Tropical Storm Bertha Advisory 18 Discussion|year=2008|publisher=National Hurricane Center|accessdate=2008-07-07|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.discus.018.shtml?] Later in the evening, the National Hurricane Center said that Bertha may have been stronger than 115 mph (185 km/h) between 3 p.m. EDT (1900 UTC) and 5 p.m. EDT (2300 UTC) that evening as objective intensity estimates were at about 135 mph (215 km/h).

On July 8 Bertha began to quickly weaken under increasing wind shear and was downgraded to a Category 2 hurricane later in the morning. Bertha continued to weaken that afternoon and was downgraded to a Category 1 hurricane in the late afternoon, but re-intensified to Category 2 the next day. However, on July 10 Bertha was again downgraded to a Category 1 hurricane as an eyewall replacement cycle had begun. Movement slowed as steering currents collapsed, and by July 12, Bertha was stationary south-southeast of Bermuda. After barely moving for a full day, Bertha caused an upwelling of cold water which significantly cooled the sea surface temperature beneath it. This cooler water then weakened the hurricane down to strong tropical storm strength. [ [http://www.nhc.noaa.gov/text/refresh/MIATCDAT2+shtml/122037.shtml Tropical Storm BERTHA Forecast Discussion ] ] On July 14 Bertha passed within about convert|40|mi|km of Bermuda. [ [http://www.nhc.noaa.gov/archive/2008/al02/al022008.public_a.046.shtml Tropical Storm BERTHA ] ] After moving off to Bermuda's northeast, a deep cyclone east of Bertha forced the tropical cyclone on a southeasterly track on July 16. On July 18, Bertha strengthened up to Category 1 hurricane strength on the SSHS scale. [cite web|author=Blake|title=Hurricane Bertha Public Advisory 63|year=2008|publisher=National Hurricane Center|accessdate=2008-07-09|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.public.063.shtml?] On July 20, Bertha became extratropical, and the final advisory (Advisory 70), was written at 11 a.m. EST that day. Bertha lasted as a tropical system for 17 days, the longest lasting storm since Hurricane Ivan in 2004.

Preparations

On July 7, Bermuda residents began purchasing lamps, tarpaulins and flashlights in anticipation of Hurricane Bertha. In the sudden rush, some stores sold out of batteries.citation|author=Staff Writer|publisher=Bermuda Sun|title=No Title|page=A1|date=2008-07-09] Bermuda Public Safety Minister Senator David Burch called a meeting of the island's Emergency Measures Organisation for the night of July 9. He also urged residents to prepare "emergency supply kits" of flashlights and batteries, a first aid kit, nonperishable foods, water and disposable utensils.cite web|author=Tim Smith|publisher=The Royal Gazette|accessdate=2008-07-09|date=2008-07-09|url=http://www.royalgazette.com/siftology.royalgazette/Article/article.jsp?articleId=7d874af30030001&sectionId=60|title=EMO meets today to discuss Hurricane Bertha] On July 10 the Department of Parks placed high surf warning signs along the South Shore beaches as Bertha sent strong waves ahead of its path. [cite web|author=Staff Writer|publisher=The Royal Gazette|title=Bertha back to Category One|url=http://www.royalgazette.com/siftology.royalgazette/Article/article.jsp?articleId=7d875af30030000&sectionId=48|accessdate=2007-07-11|date=July 11, 2008] On July 11 at 11 a.m. AST the Bermuda Weather Service issued a tropical storm watch for the island, [ [http://www.nhc.noaa.gov/archive/2008/al02/al022008.fstadv.034.shtml Hurricane BERTHA ] ] and 24 hours later this was raised to a tropical storm warning. [ [http://www.nhc.noaa.gov/archive/2008/al02/al022008.fstadv.038.shtml Hurricane BERTHA ] ] On July 13 barricades were erected at all of the island's beaches, which were closed to swimming and watersports.

Impact

As a tropical storm, Bertha dropped rainfall over the southern Cape Verde islands. No damages or deaths were reported. [cite web|author=Rhome|title=Tropical Storm Bertha Public Advisory #4|year=2008|publisher=National Hurricane Center|accessdate=2008-07-21|url=http://www.nhc.noaa.gov/archive/2008/al02/al022008.public.004.shtml?]

All flights into and out of Bermuda were disrupted on July 14 as the storm made its final approach to the island. JetBlue and Delta Air Lines canceled their flights while American Airlines flew its Miami and New York flights a day early, escaping before the tropical storm arrived. British Airways delayed its flight to the afternoon, hoping that the storm would have passed by the time its plane arrives.cite web|author=Amanda Dale|Publisher=The Royal Gazette|title=Bertha loses strength|accessdate=2008-07-14|date=2008-07-14|url=http://www.theroyalgazette.com/siftology.royalgazette/Article/article.jsp?articleId=7d8772b30030003&sectionId=48] cite web|author=Don Burgess|publisher=The Bermuda Sun|title=Flights cancelled as storm buffets Bermuda|accessdate=2008-08-14|date=2008-08-14|url=http://www.bermudasun.bm/main.asp?SectionID=24&SubSectionID=270&ArticleID=38261] Ferry service to St. Georges was canceled for the whole day, and all other routes outside of Hamilton Harbour were canceled after their morning runs.cite web|author=Tim Hall|publisher=Bermuda Sun|accessdate=2008-07-14|date=2008-07-14|title=Causeway expected to remain open; buses to keep running|url=http://www.bermudasun.bm/main.asp?FromHome=1&TypeID=1&ArticleID=38262&SectionID=24&SubSectionID=270] Some roads flooded, and tree branches were broken around the island. The wind downed power lines, causing scattered power outages, but engineers from the Bermuda Electric Light Company were reattaching cables immediately, even during the height of the storm.

Even as Bertha was passing to the east of the island and delivering tropical storm force winds, worries that it might re-strengthen to a hurricane before clearing the island prompted the government of Bermuda to issue a hurricane watch. [ [http://www.nhc.noaa.gov/archive/2008/al02/al022008.update.07141855.shtml Tropical Storm BERTHA ] ] A total of convert|4.69|in|mm of rainfall fell at their international airport. [David M. Roth [http://www.hpc.ncep.noaa.gov/tropical/rain/tcmaxima.html Tropical Cyclone Point Maxima.] Retrieved on 2008-07-14.]

The hurricane produced strong waves and rip currents along the East Coast of the United States, which caused three deaths along the coastline of New Jersey. [cite news|work=The Reporter|date=2008-07-14|title=Three Swimmers Drown at Jersey Shore over the Weekend|accessdate=2008-07-15|url=http://www.thereporteronline.com/site/news.cfm?newsid=19849163&BRD=2275&PAG=461&dept_id=466404&rfi=6]

Records

Hurricane Bertha holds the records for the longest-lived July Atlantic tropical cyclone at 17 days, the easternmost forming tropical storm, at 24.7°W, easternmost-forming hurricane at 50.2°W, and easternmost-forming pre-August major hurricane at 52.1°W (records all previously held by 1996's Bertha). Bertha is also the sixth strongest pre-August Atlantic tropical cyclone on record and was the third strongest July storm on record, behind Dennis and Emily of 2005.Cite web|author=Jeff Masters|title=Hurricane Bertha: 6th strongest early season hurricane on record|year=2008|publisher=Wunderground|accessdate=2008-07-08|url=http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=978&tstamp=200807] Bertha became the longest-lived July Atlantic tropical cyclone on record, and is also the longest-lived tropical cyclone in the Atlantic Basin since Ivan in 2004. [National Hurricane Center. [http://www.nhc.noaa.gov/tracks1851to2007_atl_reanal.txt Atlantic Hurricane Database.] Retrieved on 2008-07-13.] It was also the first "B" storm to reach hurricane strength since Hurricane Bret in 1999. Bertha was also the 7th wettest storm in Bermuda's history since record keeping began, dumping almost 5 inches of rainfall there.

ee also

*List of Atlantic hurricanes
*List of wettest tropical cyclones in Bermuda

References