Tropical Storm Barry
Tropical Storm Barry (Photo Credit: National Oceanic Atmospheric Association)
Invest 92L, now known as Tropical Storm Barry, has been absolutely fascinating to watch develop over the last week. Barry formed very similarly to the way hurricanes in the Atlantic form – from a cluster of thunderstorms. In Africa, storms will move from east to west due to the tropical trade winds that blow near the equator. As the storms move off the coast of Africa, the systems maintain their unstable nature over the warm waters of the tropics and, as long as conditions are right, the storms will develop into a tropical depression, storm, and eventually hurricane. Barry formed in a similar fashion – a cluster of rotating thunderstorms that projected south into the steaming waters of the Gulf of Mexico and has since thrived and could potentially landfall as a Category 1. This case is much more interesting because not many areas of thunderstorms develop into hurricanes off of the United States, especially a hurricane that is not considered an “extra tropical cyclone” because it is forming in the mid-latitudes.
Will Barry pack a punch? It’s expected for flooding to be the main threat, as National Hurricane Center has discussed if it does become a Cat 1, it will be on the lower end of the category with winds averaging below 100 mph. Their track currently has Barry making landfall on the Louisiana coastline, which has already seen their fair share of flooding from storm systems that came through earlier in the week. Currently, there is a State of Emergency listed, but there will be no mandatory evacuations issued since the storm is below a Category 3. However, with the levees already facing their limits as it comes to the incredible flooding issues that Louisiana and much of the Southeast has experienced so far this year, the storm surge from Barry has a very good possibility of breaking those levees. Evacuation is stressed in low-lying areas. Barry is expected to move slow (averaging between 3-5 mph over the last 24 hours) as it comes inland leaving rainfall amounts of 15-20 inches at the area of landfall. Barry is quite a unique storm, however, just because it is only a Tropical Storm, with Category 1 at best, it is still strengthening (and expected to continue so as it makes landfall). The shear that it is propagating through to its north is not affecting it whatsoever, which is not a good sign.
Tropical Storm Barry may not sound scary, but with the area that it is projected to affect through the weekend and into early next week, the future is not looking promising. The Mississippi River is already at record flood stages, with many towns in the Delta still underwater and many farmers whose cropland is now a lake due to all the rain that was received in the early part of the year. The last disaster these communities need to experience is more flooding and that is an unfortunate reality as areas as far north as northwest Mississippi and Tennessee are expected to see 6-8 inches of rainfall over the next few days. Hopefully in the upcoming days, people along the coastline of Louisiana will take the warnings and evacuate and it won’t rain as much as models are projecting to help save some of the communities from being underwater any longer. However, this is something that will have to be closely watched as this progresses.
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©2019 Meteorologist Ashley Lennard
An Update on the Pacific Tropical Systems (Credit: NHC, Central Pacific Hurricane Center)
Discussion: Hurricane Erick is currently located approximately centered 510 miles southeast of Hilo, HI. As of 11am HST on July 31, 2019, the Central Pacific Hurricane Center’s latest advisory has Erick moving to the west-northwest at 14 mph. Erick’s maximum sustained winds are 115mph which is indicative of a category three hurricane on the Saffir-Simpson scale. The Saffir-Simpson scale measures a hurricane’s maximum sustained winds. Forecasters predict that Hurricane Erick will slowly weaken over the next 48 hours. Looking at Hurricane Erick’s forecast cone, it will pass south of the Hawaiian Islands. There are still some hazards to land that will be associated with Erick. Swells that are generated by this storm will arrive to the islands within the next few days. These swells could cause dangerous surf conditions along the western shorelines. Rainfall is another hazard, as moisture from this storm makes its way over the islands. Rainfall is expected to be heaviest over the eastern and southeastern slopes of the Big Island of Hawaii. The National Weather Service in Honolulu has issued a flash flood watch as heavy rainfall that could cause flooding is expected.
According to the National Hurricane Center, satellite imagery shows that Tropical Storm Flossie is weakening. It currently has maximum sustained winds of 70mph. It is moving towards the west-northwest over open water and isn’t expected to be a threat to land. Flossie’s current structure and the wind shear in the area where Flossie is present have been contributing to its weakening. A tropical system needs low wind shear and warm sea surface temperatures in order to help it thrive. As we head through the late summer into the fall, check the National Hurricane Center and Central Pacific Hurricane Center for the latest on any developing tropical disturbances. If you live in a hurricane prone area, it is important to be prepared!
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© 2019 Meteorologist Shannon Scully
Hurricane Alvin is first storm of 2019 Eastern Pacific Hurricane Season (Photo Credit: National Hurricane Center)
DISCUSSION: On June 25, the National Hurricane Center (NHC) issued the first advisory of the 2019 Eastern Pacific Hurricane season when an area of low pressure and thunderstorms officially strengthened into a Tropical Depression. The Eastern Pacific hurricane season starts on June 1, the same date as the Atlantic Hurricane season also begins. The tropical depression which at the time was called One-E is the first tropical storm of the season in the Pacific Ocean. One-E began as a low-pressure system off the southwestern coast of Mexico when the NHC first took notice of it on June 19. One-E began to move out toward open ocean westward and on the 25th developed a defined center of circulation with sustained winds at 30 nautical miles per hour (knots) or 35 miles per hour.
One-E officially became Alvin as it strengthened into a Tropical Storm on the 26th at the sustained windspeed of 35 knots. Alvin, according to the NHC, is the third latest date of the development of the first storm in the Pacific Ocean basin since 1966. Alvin made a westerly track as it increased in intensity with maximum sustained winds at about 55 knots. Alvin was the strongest during the afternoon of the 27th before weakening gradually as it moved westward into some of the more colder waters of the Pacific and was not be able to sustain energy for development and dissipate. Tropical storms generally weaken if the sea-surface temperature is at 80 degrees Fahrenheit or below, as there is less energy available for usage as temperature decreases. 80 degrees Fahrenheit is vital for tropical cyclogenesis (the creation and evolution of tropical cyclones) as warmer water is able to evaporate quickly and the water vapor rises up and cools down which releases the latent heat (the heat needed to convert liquid to gas or vapor) which is the main engine of the storm as it condenses. In addition, 80 degrees Fahrenheit is vital for this process as deep convection is not as possible at lower temperatures which is vital as deep convection is when the temperature of an imaginary parcel of air is warmer than the surrounding up to and above 500 millibars. Deep convection is usually affiliated especially with tropical cyclones due to the fact that the amount of energy that is released and absorbed in the storms is crucial in the thunderstorms and evaporation needed to sustain the cyclone.
Alvin officially became dissipated on the morning of 29th as it became a remnant low. A remnant low is a low pressure system which involves the remains of the tropical storms and hurricanes. Alvin was never a concern to hit land due to the westward track it was taking. However, we at the Global Weather and Climate Center would like to remind you to be prepared this hurricane season by listening to warnings issued by the National Weather Service as well as to have emergency food and water for about fourteen days, blankets, batteries, flashlights, sandbags and boards for windows ready if a hurricane or tropical storm is expected to hit your area and you cannot evacuate.
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©2019 Meteorologist JP Kalb