Tropical Storm Danny (2009)
Encyclopedia
Tropical Storm Danny was a weak and disorganized tropical cyclone
that formed in August 2009. The fourth tropical system and third named storm of the 2009 Atlantic hurricane season
, Danny developed on August 26 from the interaction between a westward-moving tropical wave
and an upper-level trough
while situated east of the Bahamas. The storm never fully matured, and resembled a subtropical cyclone
. It meandered generally northwestward before being absorbed into another weather system on August 29.
Danny had only minor effects on land. However, it triggered high surf and rip currents from Florida
through the Mid-Atlantic states
, leading to the death of a 12-year-old boy in North Carolina
. The cyclone's remnants contributed to widespread rainfall in the northeast United States. At one point, some weather forecasts predicted Danny to rapidly strengthen, and hit Nantucket as a Category 1 Hurricane, although this never occurred. Localized flooding was reported, particularly in Pennsylvania
. It later caused heavy precipitation and power outages in Atlantic Canada
.
that exited the west coast of Africa
on August 18 and entered the Atlantic Ocean
. Convective activity
associated with the system briefly showed signs of organization on August 22; however, wind shear
stunted further development. On August 24, shower activity once again increased as the disturbance interacted with an upper-level trough
. On the afternoon of August 25, the National Hurricane Center
assessed a high chance of tropical cyclone formation within 48 hours. That same day, a Hurricane Hunters
mission into the system revealed a broad area of tropical-storm force winds, but no closed circulation center. However, around 0900 UTC on August 26, satellite imagery and QuikSCAT
information indicated that a closed circulation had formed. While situated about 430 mi (692 km) to the east of Nassau, Bahamas
, the feature was declared a tropical storm—skipping the tropical depression stage.
Due to the interaction of the initial wave and the upper-level trough, Danny maintained a "non-classical" structure resembling that of a subtropical cyclone
. Even after its designation as a tropical storm, the storm was highly disorganized. Little or no deep thunderstorm activity surrounded the center, and the highest winds in relation to the cyclone were confined to a rainband
in the northern semicircle. The storm moved erratically northwestward throughout the day, strengthening slightly. Danny's center reformed several times, making it difficult to determine its exact forward motion.
By early on August 27, the tropical storm became slightly better organized, although the most intense winds were still removed from the center. Danny peaked with maximum sustained winds of 60 mph (95 km/h) and a minimum pressure of 1006 mbar (hPa; 29.71 inHg). It held this strength for about 12 hours before wind shear
caused the storm to gradually weaken as it meandered northward. By August 28, Danny further deteriorated, and reconnaissance aircraft found that it was barely a tropical storm. After stalling during the afternoon, the center resumed a north or north-northwestward drift.
A strong upper-level trough moving through the southeastern United States forced Danny northeastward, and also triggered the formation of another low pressure system near the coast of North Carolina
early on August 29. Although this low formed within Danny's cyclonic envelope, satellite imagery indicates that it did not have the characteristics of a tropical cyclone. Therefore, it is not considered to be a continuation of Danny. The new low caused the tropical storm to degenerate into a trough about 275 mi (445 km) southeast of Wilmington, North Carolina
, and Danny's remnants were absorbed into a developing frontal zone
shortly thereafter.
from Cape Lookout to Duck at 2100 UTC on August 27. It was discontinued on August 29.
Since the storm remained offshore for the most part, its effects were limited. However, it generated strong rip currents and rough waves on the U.S. East Coast which may have resulted in the death of a 12-year-old boy who went was missing while body-boarding near Corolla, North Carolina
on August 28. On September 1, the Currituck County
Sheriff's Office reported that the boy's body was found on the beach about 1 mi (1.6 km) north of where he went missing. Further to the south, Danny created waves 6 to 7 ft (1.8 to 2.1 m) in height along Florida
's coast. High surf and rip currents also affected Delaware
and New Jersey
, prompting officials to issue bathing restrictions. A surfer in Monmouth County
broke his leg in the rough conditions.
The remnants of the storm interacted with a frontal boundary
, triggering widespread rainfall in numerous states which led to localized flooding. In Delaware County
, torrential rainfall produced flash flooding that trapped one family in their basement. A creek near Philadelphia overflowed its banks and caused minor flooding. Several roads in Lehigh County
, including one lane of U.S. Route 222, were closed due to flood waters. Flooding also took place in New Jersey; numerous basements were submerged and water rescues from vehicles were performed in Camden County
. Isolated reports of 7 in (177.8 mm) of precipitation were received in Maryland
.
Once extratropical, the system impacted New England
with high winds and heavy rainfall. At least 2 in (50.8 mm) of rain fell in Massachusetts
and Rhode Island
. Some roads throughout the region became impassable due to standing water. A site in the Nantucket Sound
recorded a wind gust to 61 mph (98.2 km/h). The former tropical cyclone produced wind gusts of 60 mph (96.6 km/h) in Maine
, toppling trees and ripping boats from their moorings at a harbor in Eastport
. The system also brought heavy rainfall to the area.
Danny's remnants later caused heavy rain across Atlantic Canada
. At Saint John, New Brunswick
, 100 mm (3.9 in) of rain fell, and at least 50 basements were flooded. The Meteorological Service of Canada
declared several weather advisories for New Brunswick
, Newfoundland
, Prince Edward Island
and Nova Scotia
. In Nova Scotia, during the storm's worst, over 16,000 residences lost power.
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
that formed in August 2009. The fourth tropical system and third named storm of the 2009 Atlantic hurricane season
2009 Atlantic hurricane season
The 2009 Atlantic hurricane season was a below-average year, unlike the 2009 Pacific hurricane season, which was above average, both due to a moderate El Niño. During this year, nine tropical storms formed, the fewest since the 1997 season.An average season has ten tropical storms, six hurricanes...
, Danny developed on August 26 from the interaction between a westward-moving tropical wave
Tropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
and an upper-level trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
while situated east of the Bahamas. The storm never fully matured, and resembled a subtropical cyclone
Subtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
. It meandered generally northwestward before being absorbed into another weather system on August 29.
Danny had only minor effects on land. However, it triggered high surf and rip currents from Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
through the Mid-Atlantic states
Mid-Atlantic States
The Mid-Atlantic states, also called middle Atlantic states or simply the mid Atlantic, form a region of the United States generally located between New England and the South...
, leading to the death of a 12-year-old boy in North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
. The cyclone's remnants contributed to widespread rainfall in the northeast United States. At one point, some weather forecasts predicted Danny to rapidly strengthen, and hit Nantucket as a Category 1 Hurricane, although this never occurred. Localized flooding was reported, particularly in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
. It later caused heavy precipitation and power outages in Atlantic Canada
Atlantic Canada
Atlantic Canada is the region of Canada comprising the four provinces located on the Atlantic coast, excluding Quebec: the three Maritime provinces – New Brunswick, Prince Edward Island, and Nova Scotia – and Newfoundland and Labrador...
.
Meteorological history
Danny originated in a tropical waveTropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
that exited the west coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
on August 18 and entered the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. Convective activity
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
associated with the system briefly showed signs of organization on August 22; however, wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
stunted further development. On August 24, shower activity once again increased as the disturbance interacted with an upper-level trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
. On the afternoon of August 25, the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
assessed a high chance of tropical cyclone formation within 48 hours. That same day, a Hurricane Hunters
Hurricane Hunters
The Hurricane Hunters are aircraft that fly into tropical cyclones in the North Atlantic Ocean and Northeastern Pacific Ocean for the specific purpose of directly measuring weather data in and around those storms. In the United States, the Air Force, Navy, and NOAA units have all participated in...
mission into the system revealed a broad area of tropical-storm force winds, but no closed circulation center. However, around 0900 UTC on August 26, satellite imagery and QuikSCAT
QuikSCAT
The QuikSCAT is an earth-observing satellite that provided estimates of wind speed and direction over the oceans to National Oceanic and Atmospheric Administration and others. This "quick recovery" mission intended to replace the NASA Scatterometer , which failed in June 1997...
information indicated that a closed circulation had formed. While situated about 430 mi (692 km) to the east of Nassau, Bahamas
Nassau, Bahamas
Nassau is the capital, largest city, and commercial centre of the Commonwealth of the Bahamas. The city has a population of 248,948 , 70 percent of the entire population of The Bahamas...
, the feature was declared a tropical storm—skipping the tropical depression stage.
Due to the interaction of the initial wave and the upper-level trough, Danny maintained a "non-classical" structure resembling that of a subtropical cyclone
Subtropical cyclone
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones. They were officially recognized by the National...
. Even after its designation as a tropical storm, the storm was highly disorganized. Little or no deep thunderstorm activity surrounded the center, and the highest winds in relation to the cyclone were confined to a rainband
Rainband
A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as...
in the northern semicircle. The storm moved erratically northwestward throughout the day, strengthening slightly. Danny's center reformed several times, making it difficult to determine its exact forward motion.
By early on August 27, the tropical storm became slightly better organized, although the most intense winds were still removed from the center. Danny peaked with maximum sustained winds of 60 mph (95 km/h) and a minimum pressure of 1006 mbar (hPa; 29.71 inHg). It held this strength for about 12 hours before wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
caused the storm to gradually weaken as it meandered northward. By August 28, Danny further deteriorated, and reconnaissance aircraft found that it was barely a tropical storm. After stalling during the afternoon, the center resumed a north or north-northwestward drift.
A strong upper-level trough moving through the southeastern United States forced Danny northeastward, and also triggered the formation of another low pressure system near the coast of North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
early on August 29. Although this low formed within Danny's cyclonic envelope, satellite imagery indicates that it did not have the characteristics of a tropical cyclone. Therefore, it is not considered to be a continuation of Danny. The new low caused the tropical storm to degenerate into a trough about 275 mi (445 km) southeast of Wilmington, North Carolina
Wilmington, North Carolina
Wilmington is a port city in and is the county seat of New Hanover County, North Carolina, United States. The population is 106,476 according to the 2010 Census, making it the eighth most populous city in the state of North Carolina...
, and Danny's remnants were absorbed into a developing frontal zone
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...
shortly thereafter.
Impact
In advance of the cyclone, a tropical storm watch was posted for North CarolinaNorth Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
from Cape Lookout to Duck at 2100 UTC on August 27. It was discontinued on August 29.
Since the storm remained offshore for the most part, its effects were limited. However, it generated strong rip currents and rough waves on the U.S. East Coast which may have resulted in the death of a 12-year-old boy who went was missing while body-boarding near Corolla, North Carolina
Corolla, North Carolina
Corolla is an unincorporated community located in Poplar Branch township, Currituck County, North Carolina along the northern Outer Banks. It has a permanent population of approximately 500 people; during the summer vacation season, the population surges into the thousands...
on August 28. On September 1, the Currituck County
Currituck County, North Carolina
-National protected areas:*Currituck National Wildlife Refuge*Mackay Island National Wildlife Refuge -Demographics:As of the census of 2010, there were 23,547 people, 6,902 households, and 5,204 families residing in the county. The population density was 70 people per square mile . There were...
Sheriff's Office reported that the boy's body was found on the beach about 1 mi (1.6 km) north of where he went missing. Further to the south, Danny created waves 6 to 7 ft (1.8 to 2.1 m) in height along Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
's coast. High surf and rip currents also affected Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...
and New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
, prompting officials to issue bathing restrictions. A surfer in Monmouth County
Monmouth County, New Jersey
Monmouth County is a county located in the U.S. state of New Jersey, within the New York metropolitan area. As of the 2010 Census, the population was 630,380, up from 615,301 at the 2000 census. Its county seat is Freehold Borough. The most populous municipality is Middletown Township with...
broke his leg in the rough conditions.
The remnants of the storm interacted with a frontal boundary
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...
, triggering widespread rainfall in numerous states which led to localized flooding. In Delaware County
Delaware County, Pennsylvania
Delaware County is a county located in the U.S. state of Pennsylvania. As of 2010, the population was 558,979, making it Pennsylvania's fifth most populous county, behind Philadelphia, Allegheny, Montgomery, and Bucks counties....
, torrential rainfall produced flash flooding that trapped one family in their basement. A creek near Philadelphia overflowed its banks and caused minor flooding. Several roads in Lehigh County
Lehigh County, Pennsylvania
-Climate:Most of the county's climate is considered to fall in the humid continental climate zone. Summers are typically hot and muggy, fall and spring are generally mild, and winter is cold. Precipitation is almost uniformly distributed throughout the year....
, including one lane of U.S. Route 222, were closed due to flood waters. Flooding also took place in New Jersey; numerous basements were submerged and water rescues from vehicles were performed in Camden County
Camden County, New Jersey
-Demographics:As of the 2010 Census the population of Camden County was 60.28% Non-Hispanic white, 18.45% Non-Hispanic black, 1.12% Hispanic blacks, 0.17% Non-Hispanic Native American, 0.15% Hispanic Native Americans, 5.07% Non-Hispanic Asian, and 0.14% non-Hispanics reporting some other race...
. Isolated reports of 7 in (177.8 mm) of precipitation were received in Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
.
Once extratropical, the system impacted New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
with high winds and heavy rainfall. At least 2 in (50.8 mm) of rain fell in Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
and Rhode Island
Rhode Island
The state of Rhode Island and Providence Plantations, more commonly referred to as Rhode Island , is a state in the New England region of the United States. It is the smallest U.S. state by area...
. Some roads throughout the region became impassable due to standing water. A site in the Nantucket Sound
Nantucket Sound
Nantucket Sound is a roughly triangular area of the Atlantic Ocean offshore from the U.S. state of Massachusetts. It is long and wide, and is enclosed by Cape Cod on the north, Nantucket on the south, and Martha's Vineyard on the west. Between Cape Cod and Martha's Vineyard it is connected to the...
recorded a wind gust to 61 mph (98.2 km/h). The former tropical cyclone produced wind gusts of 60 mph (96.6 km/h) in Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
, toppling trees and ripping boats from their moorings at a harbor in Eastport
Eastport, Maine
Eastport is a small city in Washington County, Maine, United States. The population was 1,640 at the 2000 census. The principal island is Moose Island, which is connected to the mainland by causeway...
. The system also brought heavy rainfall to the area.
Danny's remnants later caused heavy rain across Atlantic Canada
Atlantic Canada
Atlantic Canada is the region of Canada comprising the four provinces located on the Atlantic coast, excluding Quebec: the three Maritime provinces – New Brunswick, Prince Edward Island, and Nova Scotia – and Newfoundland and Labrador...
. At Saint John, New Brunswick
Saint John, New Brunswick
City of Saint John , or commonly Saint John, is the largest city in the province of New Brunswick, and the first incorporated city in Canada. The city is situated along the north shore of the Bay of Fundy at the mouth of the Saint John River. In 2006 the city proper had a population of 74,043...
, 100 mm (3.9 in) of rain fell, and at least 50 basements were flooded. The Meteorological Service of Canada
Meteorological Service of Canada
The Meteorological Service of Canada , also known as "The Canadian Weather Service", is a division of Environment Canada, which primarily provides public meteorological information and weather forecasts and warnings of severe weather and other environmental hazards...
declared several weather advisories for New Brunswick
New Brunswick
New Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...
, Newfoundland
Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
, Prince Edward Island
Prince Edward Island
Prince Edward Island is a Canadian province consisting of an island of the same name, as well as other islands. The maritime province is the smallest in the nation in both land area and population...
and Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
. In Nova Scotia, during the storm's worst, over 16,000 residences lost power.
See also
- Timeline of the 2009 Atlantic hurricane seasonTimeline of the 2009 Atlantic hurricane seasonThe 2009 Atlantic hurricane season was a below-average year in which nine tropical storms formed, the fewest since 1997.An average season has eleven tropical storms, six hurricanes and two major hurricanes. Although Tropical Depression One formed on May 28, 2009, the season officially began on...
- List of North Carolina hurricanes (1980–present)
- List of New England hurricanes
- List of Canada hurricanes
- Other storms of the same name
External links
- Advisory archive for Tropical Storm Danny
- List of bulletins from the Canadian Hurricane Centre