Nav: Home

Tropical Cyclone Haleh weakening in NASA-NOAA satellite imagery  

March 07, 2019

Tropical Cyclone Haleh continues to weaken while being battered by outside winds. NASA-NOAA's Suomi NPP satellite passed over the Southern Indian Ocean and captured an image the elongated storm.

Wind shear and cooler waters continue to weaken Haleh is it moves on a southerly course. The storm has fallen below the hurricane threshold and is now a tropical storm. On March 7, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard the Suomi NPP satellite showed Haleh appeared elongated from the outside winds.   

In general, wind shear is a measure of how the speed and direction of winds change with altitude. In order to understand how it affects a tropical cyclone or hurricane, think of a tropical cyclone as a vertical rotating cylinder. The different levels of rotating winds in the center of tropical cyclones need to be stacked on top each other for the storm to strengthen. If there are outside winds pushing against the cylinder near the top, it affects the balance of the entire cylinder and that's what happens when vertical wind shear pushes against a storm. It pushes the center and weakens (or wobbles) the rotation of the entire cylinder (storm) and stretches the storm out.

The Joint Typhoon Warning Center or JTWC reported "animated multispectral satellite imagery depicts a 130 nautical-mile cirrus cloud [high clouds] shield [layer] with isolated deep convection [strong storms] that is obscuring the low level circulation center. Low level rain bands are visible beyond the cirrus shield in all quadrants."

At 10 a.m. EDT (1500 UTC) on March 7, JTWC noted that the center of Tropical Cyclone Haleh was located near latitude 27.7 degrees north and longitude 67.0 degrees east. That's about 691 miles northeast of Port Louis, Mauritius. Maximum sustained winds have decreased to 69 mph (60 knots/111 kph).

The storm is forecast to become extra-tropical by March 8. When a storm becomes extra-tropical, it means that a tropical cyclone has lost its "tropical" characteristics. NOAA's National Hurricane Center defines "extra-tropical" as a transition that implies both poleward displacement (meaning it moves toward the north or south pole) of the cyclone and the conversion of the cyclone's primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force.
-end-
By Rob Gutro
NASA's Goddard Space Flight Center

NASA/Goddard Space Flight Center

Related Hurricane Articles:

Hurricane resilience in the Bahamas
A new Stanford-led study provides information on how to invest in natural coastal ecosystems that the Bahamian government, community leaders and development banks are applying in post-disaster recovery and future storm preparation in the Bahamas.
NASA finds a weaker hurricane Juliette
Hurricane Juliette has been weakening and NASA-NOAA's Suomi NPP satellite provided a look at the strength of storms within.
NASA sees Dorian become a hurricane
NASA's Terra satellite passed over the northwestern Atlantic Ocean as Dorian reached hurricane status during the afternoon of August 28, 2019.
Landslides triggered by Hurricane Maria
Hurricane Maria hit the island of Puerto Rico on 20 September 2017 and triggered more than 40,000 landslides in at least three-fourths of Puerto Rico's 78 municipalities.
NASA sees Atlantic's Leslie become a hurricane
NASA's Aqua satellite captured an infrared image of Hurricane Leslie that revealed strong storms circled the center.
NASA sees Walaka becoming a powerful Hurricane
The Global Precipitation Measurement mission or GPM core satellite passed over the Central Pacific Hurricane Center and analyzed Walaka's rainfall and cloud structure as it was strengthening into a hurricane.
NASA finds a weaker Hurricane Olivia
Infrared data from NASA's Terra satellite revealed that the area of coldest cloud topped thunderstorms has dropped from the previous day, indicating weaker uplift and less-strong storms
NASA looks at heavy rainmaker in Hurricane Lane
Cloud top temperatures provide scientists with an understanding of the power of a tropical cyclone.
Hector weakens but remains Category 4 Hurricane
Hurricane Hector has weakened slightly but still remains a robust Category Four storm at present.
UA forecast: Below-average hurricane activity
The UA hurricane forecasting model, which has proved to be extremely accurate over the years, is calling for fewer hurricanes in the Atlantic this year on the heels of a devastating 2017.
More Hurricane News and Hurricane Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Processing The Pandemic
Between the pandemic and America's reckoning with racism and police brutality, many of us are anxious, angry, and depressed. This hour, TED Fellow and writer Laurel Braitman helps us process it all.
Now Playing: Science for the People

#568 Poker Face Psychology
Anyone who's seen pop culture depictions of poker might think statistics and math is the only way to get ahead. But no, there's psychology too. Author Maria Konnikova took her Ph.D. in psychology to the poker table, and turned out to be good. So good, she went pro in poker, and learned all about her own biases on the way. We're talking about her new book "The Biggest Bluff: How I Learned to Pay Attention, Master Myself, and Win".
Now Playing: Radiolab

Invisible Allies
As scientists have been scrambling to find new and better ways to treat covid-19, they've come across some unexpected allies. Invisible and primordial, these protectors have been with us all along. And they just might help us to better weather this viral storm. To kick things off, we travel through time from a homeless shelter to a military hospital, pondering the pandemic-fighting power of the sun. And then, we dive deep into the periodic table to look at how a simple element might actually be a microbe's biggest foe. This episode was reported by Simon Adler and Molly Webster, and produced by Annie McEwen and Pat Walters. Support Radiolab today at Radiolab.org/donate.