Melissa Becomes a Tropical Storm
Subtropical Storm Melissa, the 13th named storm of the 2013 Atlantic hurricane season, has transitioned into a full-fledged tropical storm, the U.S. National Hurricane Center announced this morning (Nov. 20).
A subtropical cyclone has characteristics of both tropical and extratropical storms. Tropical cyclones feature closed circulations around a clear center (the iconic "eye" of the storm) and don't feature any weather fronts, like those that cause regular thunderstorms; they are driven by the warm ocean waters that fuel convection. Extratropical cyclones, in contrast, are driven by the temperature difference between warm and cold air masses and have associated fronts.
Melissa's shift to a tropical storm was expected, and was observed today on satellite images that showed the storm had deep convection near its center and cloud patterns consistent with a tropical energy source.
Melissa's time as a tropical storm is expected to be brief, though, as it moves over colder waters in the North Atlantic and transitions to an extratropical storm. The storm doesn't pose a threat to land, but is creating rough surf in Bermuda, the Leeward Islands, Puerto Rico, Hispaniola and the southeastern Bahamas.
Melissa formed after a 25-day lull in Atlantic storm activity. The season has been a relatively tame one compared to recent years, with only two hurricanes, and only one of those reaching major status (Category 3 or higher on the Saffir-Simpson scale). The official end to the hurricane season is Nov. 30, though storms have been known to form after this time.
Tropical Storm Jerry Forms, 10th of the Season
After a September lull in tropical cyclones over the Atlantic Ocean that lasted nearly two weeks, the season looks to be off and running again with the formation of Tropical Storm Jerry.
Jerry strengthened from a tropical depression into a tropical storm this morning (Sept. 30), becoming the 10th named storm of the 2013 Atlantic hurricane season, a season that has been far less active than initially forecast.
The 2013 season was initially predicted to have 13 to 20 named storms (later revised down to 13 to 19), of which seven to 11 would become hurricanes, three to six of them major (or Category 3, 4 or 5). Of the 10 named storms that have formed in 2013, only two have strengthened into hurricanes, and none have reached major hurricane status. [Image Gallery: Hurricane Season 2013]
Meteorologist Brian McNoldy, of the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, discusses the factors behind the sluggish season at the Washington Post's Capital Weather Gang blog. Prior to the start of the season on June 1, McNoldy writes, there were several factors in place that pointed to lots of storm activity, such as warm sea surface temperatures (which fuel a storm's convection engine) and the lack of an El Nino, which affects atmospheric wind patterns in a way that tends to dampen hurricane formation.
But other factors that couldn’t be predicted ahead of time have cropped up to tamp down storm activity, namely extremely dry air.
The storms that have formed have also tended to stay well out in the Atlantic, or have formed in the Caribbean and impacted Mexico, Central America and Caribbean nations, making the impact to the United States fairly minimal. But it only takes one storm to change that, as Hurricane Sandy showed. While Jerry is not expected to impact the United States and is likely to stay out at sea, any later-forming storms this season could potentially impact the country.
The season has passed its September peak, but it is far from over (it doesn't officially end until Nov. 30), and serious storms can happen any time during the season (Sandy was a late-October storm) — but right now, the 2013 season forecast looks as if it could be a bust. But forecasters can take what they learn about this season to help better inform forecasts of future seasons, McNoldy writes.
Two Quiet Ocean Basins
After a burst of activity in early September, and storms that hit Mexico on both its coasts, the Pacific and Atlantic Ocean basins have gone quiet.
There are no tropical storms or hurricanes over either ocean right now, and the U.S. National Hurricane Center is not watching any systems for development into a cyclone (the generic term for hurricanes, tropical storms and typhoons).
September is generally the most active month of the Atlantic hurricane season, with the average peak in activity occurring on Sept. 10. So far, there have been 10 named storms in the Atlantic, with just two of those reaching hurricane status. The season is expected to see 13 to 19 named storms (which include tropical storms and hurricanes) and six to nine hurricanes. [Image Gallery: Hurricane Season 2013]
More storms could still develop in the season, which officially lasts until Nov. 30. Tropical storms and hurricanes can cause major damage, no matter when they occur, as Hurricane Sandy showed when it struck the U.S. Northeast in late October 2012.
Ingrid Drenches Mexico, Humberto Returns
Over the weekend, Tropical Storm Ingrid strengthened into Hurricane Ingrid over the Gulf of Mexico as it barreled toward a landfall on Mexico's gulf coast. Ingrid weakened into a tropical storm again as it made landfall over La Pesca around 8 a.m. EDT.
As it hit the coast and has moved inland, Ingrid has dumped considerable amounts of rain, which the U.S. National Hurricane Center predicted could reach between 10 and 15 inches in the affected area. Some places could see as much as 25 inches from the storm, the NHC said. The large amounts of rain and mountainous terrain could combine to create "life-threatening flash floods and mud slides," the NHC said. [Image Gallery: Hurricane Season 2013]
Ingrid hit Mexico just one day after Tropical Storm Manuel hit the country on its opposite coast, also bringing substantial rains.
While Ingrid slammed into Mexico, Tropical Storm Humberto re-formed out over the Atlantic Ocean. Humberto, which at one point last week reached hurricane status — the first storm of the 2013 season to do so — currently has maximum sustained winds of 40 mph (65 km/h) and is expected to strengthen somewhat as it moves to the north-northwest. Humberto was declared a post-tropical cyclone on Saturday (Sept. 14), which means it no longer exhibited tropical characteristics, but had been expected to re-form in the coming days.
Humberto is not currently a threat to land, and isn't expected to be one through Saturday, according to NHC projections.
Tropical Storm Ingrid Forms Over Gulf of Mexico
September is earning its reputation as the busiest time of the Atlantic hurricane season: In addition Humberto and Gabrielle, a new tropical storm, named Ingrid, has formed in the Gulf of Mexico.
Ingrid strengthened from a tropical depression into a tropical storm this morning (Sept. 13); it currently has maximum sustained winds of 45 mph (75 km/h) and is situated 60 miles (95 kilometers) east-northeast of Veracruz, Mexico. The storm is moving slowly westward, and is expected to make a turn to the north-northwest tonight or tomorrow, making landfall over Mexico sometime in the Sunday-Monday timeframe.
Ingrid's location just off the coat of Mexico is expected to mean torrential rains for the area — 10 to 15 inches (25 to 38 centimeters) are expected across large parts of the eastern coast, and some areas could even see up to 25 inches (63 cm). Such rains are expected to cause "life-threatening flash floods and mud slides," according to the U.S. National Hurricane Center.
Ingrid is the ninth named storm of the 2013 Atlantic hurricane season, which is expected to see 13 to 19 named storms (which includes tropical storms and hurricanes) and six to nine hurricanes. So far only one hurricane, Humberto, has formed this season. [Image Gallery: Hurricane Season 2013]
Gabrielle Returns as Humberto Headed to Hurricane Status
It's the climatological peak of the Atlantic hurricane season, and, sure enough, things are heating up in the basin.
Not only is Tropical Storm Humberto forecasted to become a hurricane later today (Sept. 10), but Tropical Storm Gabrielle has reorganized south of Bermuda and is expected to impact the island later today and tomorrow. [Image Gallery: Hurricane Season 2013]
Gabrielle currently has maximum sustained winds of 40 mph (65 km/h), and could bring storm surge of 2 to 3 feet (about 0.5 to 1 meter) to Bermuda, along with 3 to 5 inches (7.6 to 12.7 centimeters) of rain. After it passes the island, the storm is expected to continue north, roughly parallel to the U.S. East Coast, according to projections from the National Hurricane Center.
Meanwhile, Tropical Storm Humberto is expected to become a hurricane later today or tonight. If it does, it will keep intact the record held by 2002's Hurricane Gustav for the latest-forming hurricane in the modern record (extending back to 1944). Gustav formed on Sept. 11 of that year.
Tropical Storm Humberto Forms, Could be First Hurricane
The Atlantic Ocean basin could finally see its first hurricane of the season as newly formed Tropical Storm Humberto continues to gain steam near the Cape Verde Islands off the west coast of Africa.
Humberto began as a tropical depression on Sunday evening (Sept. 8), then strengthened into the eighth named storm of the 2013 season early Monday morning. It brought rains and tropical storm-force winds to the southern Cape Verde Islands.
The U.S. National Hurricane Center expects the storm to become a hurricane over the next day or two. If the storm strengthens before 8:00 a.m. EDT (1200 UTC) on Sept. 11, it will just miss out being the latest forming hurricane in the era of airplane reconnaissance and satellite coverage (stretching back to 1944), Brian McNoldy, a researcher at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, wrote on his blog. Hurricane Gustav formed at that time in 2002 and holds that record.
Dry air and wind shear (a change of wind direction with height in the atmosphere) has stymied the development of storms so far this season, but conditions are shifting as the season reaches its traditional September peak. [Image Gallery: Hurricane Season 2013]
The hurricane season is still expected to see 13 to 19 named storms (which includes tropical storms and hurricanes) and six to nine hurricanes.
Updated 2013 Hurricane Season Forecast Issued
As we come to the peak of the 2013 Atlantic hurricane season (usually from mid-August into October), the National Oceanic and Atmospheric Administration has issued its updated forecast for the entire season, which runs from June 1 to Nov. 30. The updated outlook calls for a 70 percent chance of an above-average season, with the following breakdown of storms:
- 13 to 19 named storms (top winds of 39 mph or higher; includes tropical storms and hurricanes)
- 6 to 9 hurricanes (top winds of 74 mph or higher)
- 3 to 5 major hurricanes (Category 3 or higher on the Saffir-Simpson scale)
The original forecast issued before the beginning of the season called for 13-20 named storms, 7-11 hurricanes and 3-6 major hurricanes, so the possibilities for extremes have been tempered somewhat. The 30-year average for hurricane season is 12 named storms, six hurricanes and three major hurricanes.
The above-average season is expected because of atmospheric and oceanic conditions that have been in place during previous busy seasons, according to a NOAA release, including above-average sea surface temperatures in the Atlantic (warm waters help fuel storms) and an active rainy season in West Africa. A stormy environment in West Africa produces wind patterns that encourage the growth of tropical cyclones, the general name for tropical storms, hurricanes and typhoons.
The outlook was tempered from the pre-season forecast because of other situations that have or haven't developed. La Niña, which reduces wind shear (the change in wind direction with height, which can cut of storm development), doesn't look likely to develop. There also hasn't been much storm activity in July, NOAA noted.
But, "our confidence for an above-normal season is still high because the predicted atmospheric and oceanic conditions that are favorable for storm development have materialized," said Gerry Bell, lead seasonal hurricane forecaster at NOAA's National Climate Prediction Center.
Tropical Storm Flossie Takes Aim at Hawaii
While the Atlantic basin is in a storm lull, the Pacific has Tropical Storm Flossie headed right for the Hawaiian Islands.
Flossie first formed as a tropical depression last Wednesday (July 24), then strengthened into a tropical storm less than 24 hours later, making it the sixth named storm in the eastern Pacific so far this season. (Tropical storms and hurricanes in the eastern Pacific are counted and named separately than those in the Atlantic; the eastern Pacific hurricane season also starts earlier than the Atlantic season, on May 15 instead of June 1.) [50 Amazing Hurricane Facts]
As of the latest update from the Central Pacific Hurricane Center (which takes over forecasting duties from the National Hurricane Center when storms cross 140 degrees west longitude), Flossie was 165 miles (320 kilometers) east of Hilo and had maximum sustained winds of 50 mph (85 km/h). Flossie has been weakening over the last day or so and is expected to continue to weaken as it moves toward landfall.
Areas on the main island of Hawaii were expected to begin seeing tropical storm conditions this morning (July 29), followed by Maui in the late morning and Oahu tonight, according to the CPHC. The center forecasts rains between 6 to 10 inches (15 to 25 centimeters) on Hawaii and Maui, with isolated spots seeing up to 15 inches (38 cm). Oahu could see between 4 to 8 inches (10 to 20 cm), with isolated spots of 12 inches (30 cm).
Hurricane Season Rolls Along With Tropical Storm Dorian
The fourth named storm of the 2013 Atlantic hurricane season, Tropical Storm Dorian, has formed over the tropical Eastern Atlantic, though it doesn’t currently pose a threat to anyone on land.
Dorian formed first as a tropical depression on Wednesday (July 24) and strengthened into a tropical storm a few hours later. (A tropical depression has maximum sustained winds of 38 mph [62 km/h] and a tropical storm has winds above that threshold, but below 73 mph [118 km/h].)
Dorian currently has maximum sustained winds of 60 mph (95 km/h), and is expected to maintain about the same level of intensity over the next few days as it heads west-northwestward, according to the latest update from the National Hurricane Center. It's too early to tell if the storm will pose any kind of threat to the mainland United States next week, but it remains a possibility.
Dorian was unusual for forming so early in the hurricane season, which officially runs from June 1 to Nov. 30, though storms have been known to form before and after those dates. On average, the fourth named storm of any hurricane season wouldn't form until about Aug. 23, according to University of Miami hurricane researcher Brian McNoldy, writing at the Washington Post's Capital Weather Gang blog. August and September are typically the most active months of the hurricane season.
See the full list of 2013's hurricane names.
Tropical Storm Barry Forms, Second of the Season
After looking like it would be too weak from its sojourn over Central America, Tropical Depression Two emerged over the Bay of Campeche on Wednesday (June 19) and strengthened enough that it was declared a tropical storm later in the day. The second tropical storm of the season, it has been named Barry.
Hurricane hunters flew through Tropical Storm Barry today to take wind speed measurements in the heart of the storm. The data from their flight, coupled with satellite views of the tempest, indicated that the storm had strengthened to just above the tropical storm threshold. A depression becomes a tropical storm when its winds reach a sustained 39 mph (63 km/h). Tropical Storm Barry's winds are currently estimated at 40 mph (65 km/h).
A tropical storm warning is in effect for parts of Mexico along the Gulf coast. Barry could bring heavy rains to parts of southern Mexico.
Tropical Depression Two Drenches Central America
After forming early in the morning of June 17 over the Caribbean Sea, Tropical Depression Two made landfall over Belize and has been drenching several countries in Central America. Areas have seen 3 to 5 inches (8 to 13 centimeters) of rain, and there is potential for some spots to see up to 10 inches (25 cm).
There is the possibility that the low pressure system will emerge over the Bay of Campeche later on Wednesday (June 19). If it does so, it could strengthen slightly, but it is not expected to become a tropical storm. The next tropical storm will be the second of the 2013 Atlantic hurricane season and will be named Barry.
First Named Storm of the Season, Andrea, Forms
The first named storm of the 2013 Atlantic hurricane season, Tropical Storm Andrea, has formed in the Gulf of Mexico, and looks to bring significant rains to Florida and along the East Coast in the coming days.
Andrea became a tropical storm yesterday (June 5) around 6 p.m. EDT, as a low pressure system became more developed. Tropical storm warnings are in effect for parts of the Florida peninsula. Rains from the storms could cause issues with flash flooding in affected areas.
The National Oceanic and Atmospheric Administration has forecast 13 to 20 named storms for the 2013 season, well above the average of 12. Seven to 11 of those are expected to become hurricanes. Tropical Storm Andrea is not expected to strengthen into a hurricane.
See the rest of the 2013 hurricane name list.
Hurricane Season Begins
It's June 1 — the official start to the Atlantic basin hurricane season.
Currently, the basin (which includes the North Atlantic, Gulf of Mexico and Caribbean Sea) are relatively quiet. The remnants of Hurricane Barbara, which formed in the East Pacific, are moving over Mexico into the Bay of Campeche, but forecasters aren't giving it much of a chance of redeveloping into the first named storm for the Atlantic. That first storm will be named Andrea. (See the 2013 hurricane name list.)
Hurricane activity typically doesn't ramp up until August, when ocean surface temperatures will be at their warmest. These warm waters provide the fuel that drives tropical storms and hurricanes.
Hurricane season officially ends on Nov. 30, but storms have formed both before and after the official season dates. The dates were picked by hurricane forecasters because they mark the time period when most tropical storms and hurricanes form in the region.
NHC holds Hurricane Preparedness Tweet Chat
Have questions about how to prepare for hurricane season (which starts on June 1)? Ask the experts at the National Hurricane Center in a tweet chat today at 2 p.m. EDT.
Just tweet your questions to @NOAALive using the hashtag #HurriChat.
Hurricane Season Forecast Released
The National Oceanic and Atmospheric Administration (NOAA) has released their forecast for the 2013 Atlantic hurricane season, which could see seven to 11 hurricanes, three to six of which could become major storms (Category 3 or higher). Read more about the hurricane season forecast.