[86] The majority of residents remained without electricity, as of September16. A woman died when her vehicle crashed into a downed tree near Union. [91], The Cape Fear River crested at 61.4ft (18.7m)about 35ft (11m) above flood stagenear Fayetteville early on September19. [1] The hurricane's eyewall eroded entirely along the south side and convection became disrupted. [53] Early on September15, this band remained situated over Onslow, Carteret, Jones, Lenoir, and Wayne counties. Analyses after the hurricane indicate that warming led to an increase in total rainfall of around 5% and an increase in diameter of around 1.5 miles. Tropical Depression Nine appeared at the same time as Eight but was much quicker to develop. An unexpected bout of rapid intensification ensued on September45, culminating with Florence becoming a Category4 major hurricane on the SaffirSimpson scale (SSHWS), with estimated maximum sustained winds of 130mph (215km/h). [21] The hurricane's core structure and outer banding improved markedly, catching forecasters off-guard and intensifying beyond model outputs. North Atlantic tropical cyclone data was obtained from the International Best Track Archive for Climate Stewardship (IBTrACS). The synoptic scale also includes warm-core cyclones . [83], In Chesterfield County, the Pee Dee River crested at 46.51ft (14.18m) at Cheraw. [1] Throughout the majority of the day intense rainbands persisted over southern North Carolina, with six-hourly accumulations averaging 3 to 6in (76 to 152mm) in two bands extending from Brunswick to Bladen counties and Pender to Sampson counties. Its close proximity to the coastline enabled it to maintain its organization and only slowly degrade. It will be replaced with Francine for the 2024 season.[152]. The first stage of development is known as cyclogenesis. Torrential rains began affecting the state on this day and persisted through September17. In Hampstead, a woman died of a heart attack; downed trees on roads kept first responders from reaching her. Woody White, New Hanover County chairman of the board of commissioners, issued a statement advising all travelers to avoid the Wilmington area. The storm dropped up to 27.2in (690mm) of rain near Kings Grant. Where are exoplanets? [101], Rip currents and rough seas in New Smyrna Beach, Florida, caused 13rescues; one victim died at a hospital and two others had impact injuries. [26] Mariners were advised to remain cautious of large swells around the islands, potentially reaching 9.8 to 16.4ft (3 to 5m). In addition, West Virginia state parks offered reduced rates for rooms, cabins, and campsites until September 18 in order to provide assistance to evacuees. In terms of the life cycle of a tropical cyclone, which on average lasts for nine days, it passes through four phases as well. [100] Virginia suffered a total of $200million in damages. [8] Later, however, pronounced banding features developed around the circulation, prompting the NHC to upgrade the depression to Tropical Storm Florence at 0900Z on September 1. [93] Estimated insurance losses ranged between $2.85billion. In this live Grade 12 Geography show we take a look at Tropical Cyclones. On this Wikipedia the language links are at the top of the page across from the article title. Annually, up to hundred tropical storms form. [28] Eleven military personnel were deployed to Rinco to assist in evacuations and preparations. Flooding persisted along multiple rivers for more than a week after the storm. H urricane Florence made landfall at 7:15 am Friday near Wrightsville Beach, North Carolina. [38] Local officials established overnight curfews for the cities of Aynor, Conway, Dillon, Myrtle Beach, and Surfside Beach to limit the number of people on the roads and enable effective emergency responses. [48] Florence's forward motion slowed throughout the day as the ridge steering it northwest built ahead of the cyclone toward the Appalachian Mountains. [148], After two patients at a mental hospital died when the van carrying them was swept away by floods, the State Law Enforcement Division and Highway Patrol opened an investigation into the incident, and the deputies involved, who were escorting the women and were rescued from the top of the van, were placed on administrative leave. Best answer. [34] The cost of hurricane preparation in Virginia were at US$10.8million. The largest low-pressure systems include extratropical cyclones and polar vortices. [119] The deputies were put on administrative leave. The storm developed as Tropical Depression Eight. The hurricane slowed to a crawl by September13 as it approached North Carolina. [1], Florence weakened below hurricane strength by 00:00UTC on September15. [132] On September 19, the H.F. Lee Energy Complex in Goldsboro flooded to the point where their three ponds were completely underwater and began releasing coal ash into the Neuse River. For other storms of the same name, see, Hurricane Florence near peak intensity south of, Meteorological history of Hurricane Florence, September11, 2018, White House press briefing, University of North Carolina at Wilmington, University of North Carolina at Asheville, University of North Carolina at Chapel Hill, "Major preliminary rainfall totals for Hurricane Florence", "Storm Summary Number 21 for Heavy Rain and Wind Associated with Florence", Potential Tropical Cyclone Six Discussion Number 2, Potential Tropical Cyclone Six Discussion Number 1, Tropical Depression Six Discussion Number 6, Tropical Depression Six Discussion Number 7, Tropical Storm Florence Discussion Number 8, Tropical Storm Florence Advisory Number 38, Tropical Storm Florence Advisory Number 39, Hurricane Florence Tropical Cyclone Update, "After Florence: What's Next in the Atlantic? [26][29] Weather models became increasingly consistent on the storm's future track, leading to greater confidence in a major impact to the Southeastern United States. [1] Heavy rains propagated north along with the circulation center; however, rainbands extended from Virginia to South Carolina through September17 with a narrow band of convection pivoting along the eastern slopes of the Appalachian Mountains. [1], Large swells ahead of the hurricane reached Assateague State Park, Maryland, by September9, prompting the Maryland Department of Natural Resources to close beach access indefinitely. Farther south along the Waccamaw River, homes in a neighborhood in Socastee were flooded with as much as 8ft (2.4m) of water. These images show flooding on January 30, 2021, seven days after Eloise made . This sets a tropical cyclone rainfall record for SC (preliminarily). winds speeds are greater in a hurricane. did mallory and nick get married on family ties . [18][19] Broad-scale conditionsmoderate wind shear, sea surface temperatures below 81F (27C), and low relative humidity valuesdid not favor further intensification. [80][106][108] One man was killed in Kinston by strong winds while checking on his hunting dogs. A new rain band developed closer to the storm's core over New Hanover, Brunswick, Pender, Bladen, and Sampson counties. Answer: Meteorologists have divided the development of a tropical cyclone into four stages: Tropical disturbance, tropical depression, tropical storm, and full-fledged tropical cyclone. [1] Thereafter, increasing wind shear caused the hurricane to rapidly weaken to tropical storm strength by September8. Furthermore, due to the slow motion of the storm, heavy rain fell throughout the Carolinas for several days. In Nichols, flooding damaged about 150 homes which had been rebuilt after Hurricane Matthew. Upper level conditions became hostile soon afterwards, and the depression weakened. With the system remaining close to the coastline it weakened slowly, eventually degrading to a tropical depression on September16. Catastrophic flooding and extensive wind damage ensued, resulting in 22 direct fatalities and 30 indirect deaths across the Carolinas and Virginia. [45] Florence steadily grew in size during this time, with tropical storm-force winds extending 195mi (315km) by the end of September12. The heaviest rains shifted to South Carolina early on September16; estimated rainfall rates reached 2 to 3in (51 to 76mm) per hour in Dillon, Marion, and Marlboro counties. The hurricane's sluggish movement resulted in widespread, catastrophic rainfall throughout North and South Carolina. A tropical cyclone will then continue to strengthen toward its maximum potential intensity. A .gov website belongs to an official government organization in the United States. What are the 5 stages of typhoon development? Intensifying to a tropical storm the following day, Florence embarked on a west-northwest to northwest trajectory over open ocean. Intensifying to a tropical storm the following day, Florence embarked on a west-northwest to northwest trajectory over open ocean. ", NHC Graphical Tropical Weather Outlook Archive, "Subtropial Storm Leslie Discussion Number 1", https://en.wikipedia.org/w/index.php?title=Meteorological_history_of_Hurricane_Florence&oldid=1063134656, Meteorological histories of individual tropical cyclones, Pages using infobox tropical cyclone with unknown parameters, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 1 January 2022, at 12:17. [33] Convective banding blossomed around the storm and a formative eye appeared on satellite imagery. This article is about the Atlantic hurricane of 2018. Tropical Cyclone Classification (Stages of Development) Tropical cyclone "opportunities" One of the conditions needed for a tropical cyclone to develop is a pre-existing near-surface disturbance, low-pressure area or region of convergence. Florence made landfall near Wrightsville Beach on September14 with winds of 90mph (150km/h). [1] However, the remnants of Florence subsequently emerged into the Atlantic, before splitting into two separate storms. Moderate rain with localized areas of heavy precipitation extended into Pennsylvania, New York, and southern New England on September18. What is the stage of development of the tropical cyclone Florence? [37] The system rapidly achieved Category4 intensity by 16:00UTC, with reconnaissance aircraft recording surface winds near 130mph (215km/h) and a pressure of 946mbar (hPa; 27.93inHg). Additionally, Florence contributed to the wettest year in Wilmington history, with annual rainfall totals eclipsing the previous record set in 1877. [52] Rainfall rates within the western eyewall reached an estimated 3in (75mm) per hour while widespread accumulations of 1 to 2in (25 to 50mm) per hour fell within the eastern band. You can specify conditions of storing and accessing cookies in your browser, what is the richest country in the worldplease help i need it ., Give 1 specific circumstance in the Philippines that relate to each item listed In the Importance of DRRM Section, explain the effects of globalization in the philippines. Wilmington was cut off entirely from the rest of the mainland by the flooding. [30], In anticipation of adverse conditions, Norwegian Cruise Lines and Oceania Cruises adjusted itineraries for Norwegian Escape, Norwegian Dawn, and Sirena to avoid crossing the hurricane's path and not dock in Bermuda. [51], In North Carolina, mandatory evacuations were issued on September 11 for Brunswick County, Carteret County, Craven County, Onslow County, Pamlico County, Tyrrell County, North Topsail Beach, Emerald Isle, Ocracoke Island, Atlantic Beach, Indian Beach, Kure Beach, Pine Knoll Shores, and Wrightsville Beach. Calor had also recently been at war with Glaciem, which intended to steal some of Calor's land. Tropical cyclonesvariously defined as hurricanes, typhoons, and cyclonesregularly impact human populations and periodically produce devastating weather-related natural disasters. Tropical Depression Nine strengthened into Humberto -the next name on the list-before Eight became a named storm. A park was flooded after the Gills Creek overflowed. The storm displaced more than 16,000 people, damaged around 17,000 houses, and killed more than a dozen people across a few countries in southeast Africa. Minimal diabatic heating stemming from the hurricane's lack of a thermal gradient kept the threat of tornadic storms low, with the primary driving force being ample atmospheric moisture. A total of 21 homes in Darlington County received severe flood damage, while another home was destroyed. More than 450people required rescue across Wilmington. On August28, 2018, the National Hurricane Center (NHC) began monitoring a tropical wavean elongated area of low air pressureover West Africa for possible tropical cyclogenesis over the subsequent five days as it progressed west. [111] Two other accidents each killed one person: an elderly man died of oxygen loss related to chronic obstructive pulmonary disease during a power outage, and a person collapsed and died in Sampson County while helping an evacuee. [22] The system to the south would eventually become Subtropical Storm Leslie several days later. Biophysical factor Temperature CO2 concentration Temperate vs. tropical impacts. 720 Gracern Road The Waccamaw River in Conway crested at 22.1ft (6.7m) on September 26, exceeding the Hurricane Matthew record of 19.1ft (5.8m). [120], On September17, ten tornadoes of strengths between EF0 and EF2 [100][121] touched down in Virginia, resulting in one death in Chesterfield County, Virginia. [6] Toward the end of August31, the system's convective organization became sufficient for the NHC to upgrade the disturbance to Tropical Depression Six south of Santiago in Cape Verde. This is essential for the continuing development of the cyclone, by providing energy into the storm system. Catastrophic flash flooding from these bands ensued throughout the day, washing out roads and prompting water rescues. [142], The continued flooding closed many major roads for days after the incident. Most of these tornadoes caused little damage other than downed trees, tree limbs, or electrical poles. Projections prior to landfall made the case that the hurricane could be up to 50% larger and 50 miles wider given the effects of anthropogenic warming. [84] The city of Wilmington became entirely isolated, as all roads to the city flooded and were deemed impassable,[85] though one unidentified road was opened briefly on September 17. In a phenomenal re-birth, Ingrid rapidly re-intensified, going from tropical storm strength back to a Category 4 cyclone with maximum sustained winds estimated at 120 knots (138 mph) by the Joint Typhoon Warning Center in the span of just 12 . Originating from a tropical wave over West Africa, Florence quickly organized upon its emergence over the Atlantic Ocean. Environmental conditions became increasingly conducive to reorganization on September8 as NOAA Hurricane Hunters began reconnaissance of the cyclone, with the shear decreasing and warm waters becoming deeper. Also known as typhoons, they cause a lot of damage because of their high speeds of up to 74 miles/ hour and are characterized by heavy rains. [145], President Donald Trump visited North and South Carolina on September 19, and spoke to emergency workers in an airplane hangar at the Marine Corps Air Station Cherry Point. Convective bursts with frequent lightning surrounded the eyewall,[36] giving rise to a well-defined 12mi (19km) wide eye. ", "Even after floods and dead pigs, the reckoning of NC hog lagoons is still elusive", "Rains from Florence cause collapse at NC coal ash landfill", "Duke Energy confirms new coal ash spill in North Carolina", "Video Shows Animals Stranded by Florence Getting Rescued", "Photos: Pet Rescues in the Wake ofHurricane Florence", "East Tennessee animal centers give shelter to dogs, cats displaced by Hurricane Florence", "The animal rescuers of Florence: Dogs saved from submerged crate, pets shuttled away in bus", "Lions, tigers and shelter pets will ride out Hurricane Florence in place", "N.C. At 22.4N / 46.2W, this also makes #Florence the furthest north category 4 hurricane east of 50W ever recorded in the Atlantic", Tropical Storm Florence Discussion Number 31, Tropical Storm Florence Discussion Number 33, "A lot of huge track shifts we've seen the last 3-4 days are also related to the downstream impact of #Jebi's #ET. The overflowing river flooded almost 1,000homes and businesses. [110] An 18-wheeler aquaplaned off Interstate 85 near Kings Mountain and crashed into a tree; the vehicle tore in half, killing the driver. On the 23rd it became a tropical depression before executing an anticyclonic loop. When the wind speed reaches 39 mph (63 km/h), it is called a tropical storm. Initially being inhibited by increased wind shear and dry air, the small cyclone took advantage of a small area of low shear and warm waters. [60] Aided by an anticyclone, this band stretched across 350mi (565km) along the eastern side of Florence. At 11:15UTC (7:15a.m. EDT) on September 14, Florence made landfall just south of Wrightsville Beach, North Carolina as a Category 1 hurricane, with sustained winds of 90mph (150km/h) and a central pressure of 956mbar (28.2inHg). [108] A vehicle lost control along Interstate 20 near Columbia and crashed into a bridge support, killing the driver. Favorable conditions again fostered intensification on September9 and the system regained hurricane status. [94] Hurricane-related flooding damaged an estimated seventy-five thousand structures, many of which had been previously damaged in Hurricane Matthew. [147] South Carolina Governor McMaster applied for $1.2billion in federal funding for recovery, including $165million under the National Flood Insurance Program and $125million for agriculture. Florence weakened to a tropical storm by September 7, but the system regained hurricane strength on September 9 and major hurricane status with winds of 140 mph on September 10. 1 Answer. The storm also spawned two tornadoes in Horry County, both rated EF0. Winds downed about 20trees in the Lancaster area, one of which fell onto a home and others falling onto a road. [20] The compact system unexpectedly rapidly organized within a small area of low wind shear. The first three stages of a developing hurricane are (from first stage to third stage): tropical disturbance, tropical depression, and tropical storm. A number of people evacuated and were still not able to access their homes by October1. [39] Slight weakening ensued thereafter as an eyewall replacement cycle started; convection surrounding the eyewall became ragged and the eye itself filled. [49] On September 10, Virginia Governor Ralph Northam ordered mandatory evacuations for low-lying coastal areas in the Hampton Roads and Eastern Shore regions effective September 11, constituting 245,000 people. Florence was a short-lived tropical storm over the eastern Atlantic Ocean that dissipated east of the northern Leeward Islands. McMaster Orders Entire Coastline to Evacuate", "1 Million People Ordered to Evacuate South Carolina Coast as Hurricane Florence Gathers Strength", "Virginia Governor Orders Mandatory Evacuation for Some of Virginia, Including Parts of the Eastern Shore", "US 'monster' hurricane set to strengthen", "Mandatory evacuations issued ahead of Hurricane Florence", "Evacuations Recommended, County Shelter to Open", "UNC-Wilmington issues mandatory evacuation order beginning Monday", "UNCW issues mandatory evacuation for students", "NC State vs. West Virginia Football Game Will Not Be Played This Weekend", "UNC-UCF, WVU-NC State, ECU-Va. Tech games called off", "App State-Southern Miss Football Game Will Not Be Played Saturday", "South Carolina-Marshall football game canceled", "As Florence approaches, most Greensboro and N.C. colleges will close", "Closings this week at UNC-Greensboro, High Point University", "UNC, NC State, ECU games called off for the weekend; classes canceled", "McMaster orders schools across SC to close Tuesday as Florence approaches", "Charlotte Motor Speedway, Atlanta Motor Speedway open campgrounds to Florence evacuees", "Bristol Motor Speedway opens campground for Hurricane Florence evacuees", "Talladega Superspeedway offers shelter for Hurricane Florence evacuees", "Justice suspends Turnpike work, lowers state park prices as part of Florence response", "Over 2 dozen rip current rescues at Wrightsville Beach this weekend as Hurricane Florence approaches The University of North Carolina Wilmington received over $140 million in damage and have been forced to close The University Apartments, a residential hall on campus", "North Carolina Meteorologists Forced Off-Air During Broadcast By Florence Flooding", "Statement from WCTI General Manager Matt Bowman", "Hurricane Florence Forces WCTI Meteorologists to Evacuate During Broadcast", "Around 150 people in need of rescue in N. Carolina City", "America's 'One-in-1,000-Year' Rainfall Events in 2018 | The Weather Channel", "Hurricane Florence makes landfall in North Carolina, with plenty of destruction and suffering ahead", "Over 100 volunteers unite to prevent flooding in North Carolina community", "Updated preliminary rainfall totals across North and South Carolina from Hurricane Florence received as of 2 p.m. EDT, on Sunday, September 16. On September10 and 11, the states of North Carolina, South Carolina, and Virginia issued mandatory evacuation orders for some of their coastal communities, predicting that emergency personnel would be unable to reach people there once the storm arrived. Florence, U. Martin Persson, Javier Godar, and Thomas Kastner. [136] Many rescuers were looking for local residents in need of assistance or evacuation aid, and discovered some animals in flooding cages, some attempting to seek shelter, and some stranded on porches. [113] In late September, two people were killed in North Carolina while repairing damage from Hurricane Florence to their homes, bringing the death toll in the state to 39. [133], During and after the storm made landfall, local rescuers and nationwide donors and organizations worked to aid the many pets that had been left by their owners, or alongside their owners. [85], Early on September 17, a tornado was confirmed in Elm City, North Carolina. At the same given temperature, dry air is less buoyant than moist air and thus limits ascending . The magnitude of flooding greatly exceeded the levels observed due to Hurricane Matthew in 2016. Crop development Faster development and shorter. NEXRAD radar data from Morehead City indicated rainfall rates of 1 to 2in (25 to 50mm) per hour within these bands. Over the next several days, the hurricane delivered historic amounts of rainfall across North and South Carolina, causing substantial flooding in many communities across, 12201 Sunrise Valley Drive Reston, VA 20192, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands), South Atlantic Water Science Center (SAWSC), Preliminary peak stage and streamflow data for selected U.S. Geological Survey streamgaging stations in North and South Carolina for flooding following Hurricane Florence, September 2018, South Atlantic Water Science Center (SAWSC) News, South Atlantic Water Science Center - Columbia, SC Office. FEMA utilized Transitional Sheltering Assistance Programs to pay for hotel stays for individuals while they look for more permanent solutions, the programs had 342 households and a total of 1,044 people as of October 3. Gravity is a weak force, but has only one sign of charge. Water levels on the Neuse River at Oriental, North Carolina peaked at 9.6 feet above normal. Meteorological history of a 2018 hurricane, Florence as a Category3 hurricane at 16:30UTC on September5 (, Meteorological history of Hurricane Florence. . [70] Employees at ABC affiliate WCTI-TV (which serves the surrounding market that includes Greenville and Jacksonville) were forced to evacuate its New Bern studio facility that evening due to the rising waters, with WCTI switching to a simulcast of Sinclair sister station WPDE's live coverage of the storm until station staff could resume their own broadcasts. It converts the energy available from a warm ocean surface into strong vertical air currents and horizontal wind speeds via the evaporation of warm water from the ocean surface and the subsequent . [1][nb 2] The extent of hurricane-force winds doubled in size and well-defined mesovortices rotated along the inner eyewall. [104], Two people in North Carolina died while trying to evacuate: one in Columbus County and Wayne County. New study provides answers", "EPA descends on Cheraw, begins toxic cleanup", "Hurricane Florence, another 1,000-year event, caused at least $1.2 billion in damage in SC", "Florence regains hurricane force, forecast to hit Southeast coast as a major storm", "Man drowns while swimming in New Smyrna Beach amid rip current warning, officials say", "Hurricane Florence updates: Gas stations run dry in parts of South Carolina", "Florence death toll at 17 after 3-month-old dies in North Carolina mobile home", "Florence death toll rises to 32, including 3 young children, Carolinas officials say", "Five dead from Hurricane Florence, including mother and baby, say officials", "Florence death toll at 14, including 2 from carbon monoxide", "Hurricane Florence updates: 23 dead, including 17 dead in North Carolina", "1-year-old child becomes 19th victim of Florence, officials say", "Man drowns in trailer near Cape Fear River despite mandatory evacuation warning", "NC deaths from Florence up to 32 after tree falls on man", "Hurricane Florence death toll rises to 51", "7 dead in NC as Florence, an 'uninvited brute,' brings heavy flooding and power outages", "17 deaths in the Carolinas linked to Florence flooding, fallen trees and power outages", "2 women drown in back of police van swept away by Florence flooding", "Florence flood kills 2 mental health patients when Horry sheriff van is overcome: report", "Sheriff's deputies transporting 2 mental health patients who drowned in flood waters put on leave, authorities say", "Family outraged after women die in flooded van driven by South Carolina deputies", "Tornado count from Monday increases to ten", "1 dead after tornado destroys Chesterfield building near Hull Street", "Louisa man killed in flash flood; Chesterfield tornado victim died while helping co-workers escape", "More than a month after Hurricane Florence devastated NC, the deaths continue", "The death toll from Hurricane Florence has risen again, four months after the storm", "Florence flooding kills 3.4 million poultry, 5,500 hogs, NC officials say", "A disgusting side effect of Florence: Escaped pig poop. The meteorological history of Hurricane Florence spanned 22 days from its inception on August 28, 2018, to its dissipation on September 18. [63], Atlanta Motor Speedway, Bristol Motor Speedway, Charlotte Motor Speedway and Talladega Superspeedway opened their campgrounds to evacuees of Hurricane Florence free of charge. [129], In total, more than a hundred and thirty hog waste lagoons were compromised, and thirty-three overflowed to the point of discharging their contents into the Cape Fear River watershed. [107] A house fire in Fayetteville killed a husband and wife. Sustained winds rose to 130mph (215km/h) and its pressure fell to 950mbar (hPa; 28.05inHg); this ranked it as a Category4 hurricane on the Saffir-Simpson scale. [103] One child drowned in Green Swamp near Sumter, South Carolina, after water released from the Second Mill Pond flowed into the river. What are the stages of development of a hurricane? Progressing along a steady west-northwest trajectory, the system gradually strengthened, acquiring tropical storm strength on September1. Continuous wet weather (CWW) is a special weather phenomenon that occurs frequently during the late winter and early spring in South China. [138] Other zoos such as the North Carolina Zoo were lightly impacted by the storm and opened on September 18, and offered free admission for evacuees from September 18 to 21. [124], A 69-year-old man in Robeson County, North Carolina whose house was damaged apparently committed suicide. Yet each stage of the process entails a fresh contribution to greenhouse. The sixth named storm, third hurricane, and the first major hurricane of the 2018 Atlantic hurricane season, Florence originated from a strong tropical wave that emerged off the west coast of Africa on August30, 2018. After achieving hurricane strength early on September 4, Florence underwent an unexpected period of rapid deepening through September 5, culminating with it becoming a Category . The storm begins as a tropical disturbance, which typically occurs when loosely organized cumulonimbus clouds in an easterly wave begin to show signs of a weak circulation.