2017 Hurricane Season Comes To An End; One For The Record Books

The 2017 Atlantic Hurricane Season has finally come to an end. We finish with 17 named storms – ten of which became hurricanes, and six of those ten reached category 3 strength or higher. Names like Harvey, Irma, and Maria are ones we won’t soon forget.

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The season got started early. Tropical Storm Arlene formed on April 20th in North Atlantic. It was the second earliest tropical cyclone to form in the Atlantic since the satellite era began (1966). Then came Tropical Storm Bret two months later. It was a weak storm just north of South America that only lasted about 24 hours. One day later, Tropical Storm Cindy formed in the Gulf of Mexico. It brought heavy rain to the central Gulf Coast, with nearly 19″ falling in Ocean Springs, MS. It was the first of what would end up being 6 named storms to strike the U.S. and its territories this season.

After a few quiet weeks, two more tropical storms formed in late July. Don was short-lived and brushed the Windward Islands. Tropical Storm Emily formed on the tail end of a cold front about 75 miles west of Tampa Bay. It made landfall on Anna Maria Island with 45 mph winds. In a typical season we see only one storm form before August 1st. With five already in the books, 2017 was off to hot start.

Below: Tropical Storm Emily makes landfall on July 31st.

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Thanks to weak vertical wind shear, weaker trade winds, more conducive wind patterns coming off of Africa, and a stronger west African monsoon it was always forecast to be an above average year in terms tropical activity. The National Oceanic and Atmospheric Administration’s (NOAA) original outlook for the 2017 season, issued in May, had a 45% chance of an above-normal season and a 35% chance for near-normal activity. When the updated outlook was released in early August, the chance of an above-normal season had increased to 60%. Weak La Niña conditions were expected to persist through the fall and there was very little, if any doubt, that the second half of the season was going to be extremely active.

The very same day the updated outlook was released, Hurricane Franklin formed in the Bay of Campeche. It was our first hurricane of the season and the first of ten straight hurricanes that ended up forming this season. Franklin was a minimal category 1 storm, but it still brought extremely heavy rainfall and a storm surge of 4-6 feet to eastern Mexico. It was just five days later when our second hurricane of the season, Gert, formed over the Gulf Stream about halfway between Bermuda and the United States. It ultimately didn’t have any direct impact on land, but both Franklin and Gert were precursors of what was to come.

Harvey: Harvey formed from a tropical wave just east of the Lesser Antilles on August 17th. After bringing wind and rain to the tiny islands it made its way into the Caribbean Sea. Upon encountering an area of strong wind shear, Harvey weakened dramatically and it seemed as if its days were numbered. However, after crossing the Yucatan Peninsula and emerging into the southwestern Gulf, rapid intensification began. It would strengthen from a tropical storm to a category 4 hurricane in less than 36 hours before making landfall near Rockport, TX with 130 mph winds. It was the first major hurricane of the season and first major hurricane to hit the U.S. since Wilma in 2005.

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After devastating southeast Texas, a complicated upper-level pattern led to a slow-moving heavy rainmaker for the rest of coastal Texas and Louisiana. The Houston area was hit particularly hard. As much 60″ inches of rain fell in spots over a 5 day period. This led to unimaginable flooding across large swaths of the city. It would lead to one of the largest rescue efforts in U.S. history. Harvey will be remembered as the wettest tropical cyclone of all time and one of the costliest hurricanes on record to ever strike the U.S..

Irma: Like Harvey, Irma formed from a tropical wave that rolled off the coast of Africa. It formed much further east though, near the Cabo Verde Islands. It became a tropical storm on August 30th and proceeded to make its way across the Atlantic over the next 11 days. It strengthened into a category 5 storm on September 5th and remained at that intensity for 3 consecutive days. During that stretch, Irma went directly over parts of the Leeward Islands, including Barbuba and St. Maarten. It was the strongest storm to ever impact this part of the Caribbean.

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In the coming days, Irma would inch closer to U.S., clipping tiny islands along the way. Tensions were high all across the southeastern U.S. as models worked out a solution for the storm’s eventual path. Irma ultimately held a more westerly track, taking it along the northern coast of Cuba before making a northward turn and heading up through the state of Florida. On September 10th, Irma made landfall as a category 4 storm in the Florida Keys, near Cudjoe Key, with 130 mph winds. A storm surge of over 10 feet was recorded in parts of the Keys. A second landfall then took place a few hours later on Marco Island as a category 3 storm with 115 mph winds.

For Tampa Bay, there was a high level of concern leading up to Irma. The area hadn’t been hit by a major hurricane since 1921 and is incredibly vulnerable to storm surge. The fear was that Irma would stay a little further west bringing the core of the strongest winds up the coastline while also presenting a higher storm surge threat. In the end, the storm held its northerly track after hitting Marco Island. This brought the most destructive winds (100+ mph) up through Hardee, Highlands, Desoto, and Polk county. Areas like Tampa and St. Petersburg still saw wind gusts to category 1 strength. Tampa Bay ended up with an offshore wind for most of the event, leading to a negative storm surge. This actually lowered water levels in coastal areas by several feet. Meanwhile, storm surge on the east coast of the state, as well up through the Carolinas, was much more significant due to an onshore wind. Irma was a massive storm, and tropical storm force winds made it as far north as Tennessee.

Below: Residents walk on the dry seabed of Tampa Bay along Bayshore Blvd

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Irma was the first storm in what would end up being the most active most September on record in many respects. The day before Irma made landfall in Florida, Hurricane Jose was at peak intensity – category 4 with 155 mph – as it brushed the Leeward Islands; the same area hit hard by Irma less than a week before.

Below: GOES-16 captures Hurricane Irma (left) and Hurricane Jose (right) over the Atlantic on Sep 7th – courtesy NOAA.

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Around the same time, Hurricane Katia formed and made landfall in eastern Mexico. At one point, Irma, Jose, and Katia were all at category 2 strength or higher. According to Dr. Klotzbach at Colorado State University, the last time we had three category 2+ storms at the same time in the Atlantic Basin was 1893. About a week later, Tropical Storm Lee formed near the coast of Africa. It was never destined to impact any land, but the tiny storm managed to linger in central Atlantic for two weeks, peaking as a category 3 hurricane. It was the 7th straight hurricane, and 4th major hurricane, to form in the Atlantic this season.

Maria: On September 17th, Tropical Storm Maria became a hurricane. It ended up being the 3rd major hurricane in a two week period to impact the Leeward Islands. Maria wasn’t done yet though. It headed straight for Puerto Rico, making landfall on the southeastern coast of the island on September 20th as a strong category 4 storm with winds of 155 mph.

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Maria was the strongest hurricane to make landfall in Puerto Rico since before the Great Depression. It decimated the infrastructure of the island to the point that it will likely take years for them to make a full recovery.

Below: Before and after satellite images of Puerto Rico – courtesy NOAA. You’ll notice the loss of power (top) and loss of vegetation (bottom).

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When October began, all eyes turned to the western Caribbean – a common formation area at that point in the season. Sure enough, Tropical Storm Nate formed in this area on October 5th and became a hurricane a day and a half later. It headed due north, where it first made landfall near the mouth of the Mississippi River as a category 1 hurricane, then again near Biloxi, MS. All things considered the outcome could have been a lot worse. Fortunately, this would be the last U.S. landfall of the season.

Not long after Nate, Hurricane Ophelia formed in the Central Atlantic. It was the 10th consecutive hurricane to form. It ultimately became a major hurricane – the farthest east on record. It lost tropical characteristics, but still brought hurricane-force winds to Ireland and the United Kingdom. Later in October, a weak Tropical Storm Philippe formed in the western Caribbean and moved northeast across Cuba and the Bahamas. Parts of South Florida did see heavy rain and a few tornadoes, but impacts were minimal. In early November, the last storm of the season, Tropical Storm Rina, formed in the central Atlantic. It lost tropical characteristics a few days later in the north Atlantic.

2017 Atlantic Hurricane Season Stats & Records

– 3rd consecutive year a storm formed in the Atlantic before June 1st

– Most named storms since 2012

– Most expensive U.S. hurricane season on record – $202.6 Billion

– Most consecutive hurricanes in a single season (10) – tied with 1878, 1886, 1893 according to Dr. Klotzbach (CSU)

– 5th most active season in terms of Accumulated Cyclone Energy (ACE) – behind 1893, 1926, 1933, and 2005.

– September: Highest ACE ever recorded in a single month

– Irma: Longest period of 185+ mph winds for a single storm (37 hours)

– Irma: 2nd strongest Atlantic hurricane on record based on wind speed (185 mph)

2017 Named Storms

Arlene          April 19-21         Max Winds: 50 mph

Bret             June 19-20         Max Winds: 45 mph

Cindy           June 20-23         Max Winds: 60 mph

Don              July 17-18          Max Winds: 50 mph

Emily         July 31 – Aug 1      Max Winds: 45 mph

Franklin          Aug 6-10          Max Winds: 85 mph

Gert             Aug 13-17           Max Winds: 105 mph

Harvey       Aug 17 – Sep 1     Max Winds: 130 mph

Irma          Aug 30 – Sep 12    Max Winds: 185 mph

Jose             Sep 5-22            Max Winds: 155 mph

Katia             Sep 5-9              Max Winds: 105 mph

Lee              Sep 15-30           Max Winds: 115 mph

Maria           Sep 16-30           Max Winds: 175 mph

Nate              Oct 4-9              Max Winds: 90 mph

Ophelia         Oct 9-15            Max Winds: 115 mph

Philippe        Oct 28-29           Max Winds: 60 mph

Rina               Nov 6-9             Max Winds: 60 mph

Blog produced by Meteorologist Tyler Eliasen & Meteorologist Lindsay Milbourne

 

 

 

 

2017 Atlantic Season Winds Down

With ten days left in the 2017 Atlantic hurricane season, there is no sign of any tropical development on the horizon. Wind shear is incredibly high in the Gulf of Mexico with a deepening trough nearby. Upper level winds are also unfavorable for tropical or subtropical organization in the Atlantic and Caribbean. Not to mention, water temperatures are cooling too. At this pace, with no areas of interest, the hyperactive 2017 Atlantic season will wrap up with 17 named storms, 10 hurricanes and 6 major hurricanes. It is the busiest Atlantic season since 2012, in terms of named storms.  When we analyze the total energy output of all tropical systems during the entire hurricane season, or ACE, the number is incredibly high in 2017. According the Dr. Klotzbach and meteorologists at Colorado State University the ACE in 2017 is 226. In an average season, the ACE is 111.  This makes 2017 the 5th busiest season on record in terms of ACE, according to NOAA.

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A series of disturbances bring several opportunities for rain this work week to Florida. A weak surface low will swing across the Sunshine State Thursday and Friday. No tropical development is expected with this feature. Below is the GFS forecast Thursday evening.

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Invest 96L Meanders Near The Azores

Invest 96L is still a non tropical low near The Azores Tuesday afternoon. Upper level winds are favorable for some subtropical development through mid-work week. By late Thursday and Friday wind shear increases and subtropical development is less likely. Regardless, some squalls are expected in the central and south Azores over the next few days.

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There are about 2 weeks left in the 2017 Atlantic season. Mid to late November named storms are less common as water temperatures are cooling and wind shear is elevated with active frontal boundaries. Only 38 named storms have forms in the Caribbean, and Atlantic from November 11th through November 30th since 1851. The graphic below is courtesy Google Earth.

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Subtropical Development is Possible Near The Azores This Work Week

An area of low pressure in the northeast Atlantic could gain some tropical characteristics in the days ahead. As of Monday afternoon there is a medium chance a tropical depression or Subtropical Storm Sean forms over the next 5 days. Invest 96L could impact the central or southeast Azores mid work week as it meanders in the vicinity.

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Elsewhere the tropical Atlantic season winds down. Water temperatures are still in the low to mid 80s in the southwest Caribbean. The GFS keeps pressure in this region generally low over the next 5-7 days+. This is worth keeping an eye on next week.

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Rina to Lose Tropical Characteristics Soon; No Threat as Lifts North in the Atlantic

Tropical Storm Rina continues its track northward over the open northern Atlantic Wednesday. As of 11 AM AST max sustained winds are at 60 mph as it races northward at 21 mph. The 17th named storm of the season has likely maxed out in intensity as it starts to transition to an extra-tropical low. Convection will decrease over even cooler waters Thursday. Rina will merge with a frontal boundary and lose tropical characteristics during this time.

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Elsewhere, there are no areas of interest over the next 5 days. The biggest culprit for lack of tropical features is strong wind shear.  On Wednesday high shear covers the Gulf, southwest Caribbean and much of the Atlantic. There is a small pocket of marginally favorable upper level winds in the northwest Caribbean. The image below is courtesy the University of Wisconsin.

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November named storms are less common as the month progresses. Water temperatures are cooling and upper level winds are less conducive for tropical development with fronts on the move.  74 named storms have formed in November since 1850. Here’s a look at the named storm origin points from November 1-30th. The graphic below is courtesy Google Earth.

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Tropical Storm Rina Races Towards Cooler Waters

Rina became the 17th named storm of the active 2017 Atlantic season Monday night. Rina is still a minimal tropical storm at 10 AM AST with 40 mph winds. Despite hostile upper level winds, convection increases on the northeast side of Rina. If this continues, Rina may increase a bit in intensity over the next 24 hours. The disorganized tropical storm will transition to an extra-tropical system by Thursday morning over the cooler north Atlantic. It is no threat to land.

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RIna sits over luke warm Atlantic waters Tuesday. It moves into an even cooler environment over the next 48 hours. During this time it will lose tropical characteristics. Beyond Rina, there are no areas of interest for the next 5-7 days+.

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Tropical Depression 19 Forms in the North Central Atlantic; No Threat to Land

Tropical Depression 19 forms over the open north central Atlantic Monday morning. As of 5 PM AST max sustained winds are at 35 mph as it slowly moves north-northeast well east of Bermuda. The depression is disorganized as it battles some nearby dry air in the mid levels of the atmosphere. Westerly wind shear exposes the center of circulation. Tropical Depression 19 will likely become the 17th named storm of the 2017 Atlantic season, Rina, by early Tuesday morning. While gradual strengthening is expected, it will transition to an extra-tropical system over the cooler north Atlantic by Thursday afternoon. It is no threat to land, but the remnants of future Rina could bring squalls to Ireland/the United Kingdom by Friday or Saturday.

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30 Days Left In The Atlantic Hurricane Season

16 named storms, 10 hurricanes, 6 major hurricanes… It’s been a historic season in so many ways, and thankfully we’re starting to see the light at the end of the tunnel. Here’s a look at the storms we’ve seen through October.

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Just 30 days remain in the 2017 Atlantic Hurricane Season and this is the time of year when activity starts to diminish rapidly. In fact, only 5% of named storms since 1950 have formed during the month of November. There are only 3 hurricane landfalls in the continental U.S. on record during the month of November. The most recent being Hurricane Kate (Cat. 2) that hit the Florida Panhandle on November 21, 1985.

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In November, tropical systems usually form either in the WSW Caribbean or in the western Atlantic northeast of Cuba. In these areas, water temperatures are still warm enough for storms to thrive and wind shear is low. Closer to the United States there is some level of protection thanks to 1) rapidly cooling Gulf of Mexico waters and 2) more wind shear being present over the Gulf due to frequent cold fronts dropping south. Most November storms end up being more of a problem for places like Cuba, the Bahamas, and Bermuda.

Graphic below courtesy Philip Klotzbach at Colorado State University.

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All is quiet across the Atlantic right now, lets hope it stays that way for the next few weeks.

Philippe Races Away From Florida; Remnants May Pass Close to New England

Philippe, the 16th named storm of the 2017 season, drenched South Florida Saturday and Saturday night. As of 8 AM Sunday it taps energy from a nearby cold front. While the tropical low is disorganized structurally, winds increase up to 50 mph as it races northeast at 32 mph. Tropical Storm wind gusts were felt in the Northwest Bahamas early Sunday morning. Philippe transitions to an extratropical low as it merges with a frontal boundary over the Western Atlantic over the next 24 hours. It strengthens further during this time.

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The remnants of Philippe could clip or pass over coastal New England late Sunday into Monday. Winds could gust to high-end tropical storm force or even hurricane force during this time.

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Tropical Depression 18 Forms-Set to Become Philippe; A Rainmaker for South Florida

Hurricane Hunters found a closed low Saturday morning. Potential Tropical Cyclone 18 is upgraded to Tropical Depression 18 with 35 mph  at 11 AM. Squalls drench western Cuba and a wet late Saturday and early Sunday is in the cards for South Florida and the Northwest and Central Bahamas. As of 11 AM the National Hurricane Center anticipates strengthening to Tropical Storm Philippe by Saturday evening. This will pass close to extreme Southeast Florida overnight Saturday into Sunday with winds of 45 mph. A Tropical Storm Watch is in effect for the upper Florida Keys and Southeast Florida. Wind shear will keep future Philippe a weak tropical storm. It merges with a cold front and transitions to an extra-tropical system by early Monday over the western Atlantic. A stronger area of low pressure in conjunction with that same front drenches New England late Sunday and Monday. Winds could gust up to near hurricane force near the coast.

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Future Philippe brings the threat of flooding to South Florida and the Keys through early Sunday. While widespread 2-4″ of rainfall is likely, isolated areas could pick up 6-7″ of rain. Below is the RPM rainfall accumulation forecast through Sunday.

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Wind  gusts near tropical storm force are possible in the Florida Keys and in South Florida Saturday evening and overnight Saturday into Sunday. Below is the GFS wind gust forecast at 10 PM Saturday. Wind gusts are stronger in a severe summertime thunderstorm.

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