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Expert Knowledge on Tropical Storms

Hurricane expert joins Millersville’s meteorology faculty.

Millersville University has a new expert on campus who knows all about tropical storms and we recently sat down with Dr. Ellie Casas to ask her about the current news surrounding the weather throughout the oceans.

Tell us about yourself
I am Dr. Ellie Casas, and I am the newest meteorology faculty member here at Millersville University in the Department of Earth Sciences. This is my first year here and I am thrilled to be here! I teach Tropical Meteorology plus a variety of other meteorology courses and hurricanes are my primary area of expertise.

What is your experience before MU?
Before being here at Millersville, I studied several aspects of how hurricanes intensify during my graduate studies at Colorado State University. After graduating, I became a postdoctoral researcher at the Naval Postgraduate School in Monterey, California, where I worked with a team of meteorologists and computer scientists to develop advanced machine-learning tools that may eventually be able to help improve our ability to “see” where the heaviest rain in hurricanes are when they are over the ocean and away from radars. This is important because being able to see the “organization” of rain in a hurricane is important for forecasting how the hurricane will intensify.

What notable storms have occurred in the Atlantic and East Pacific basin and which states were affected?
The Atlantic and East Pacific saw some major hurricanes in 2023. In the Atlantic Basin, there were 19 named storms, and two additional unnamed storms. Surprisingly, one of the unnamed Atlantic storms occurred in January! This storm had a hurricane-like structure with high wind speeds circling around an eye-like feature, but it was classified as a “subtropical cyclone,” which means that it originated from outside of the tropics.

Out of the named storms in the Atlantic, seven reached at least hurricane status, and three out of those seven hurricanes reached “major” hurricane status of at least Category 3 on the Saffir-Simpson scale.

In the Atlantic/Gulf coast, the states directly affected were Texas, Florida, Georgia, South Carolina, North Carolina, and Virginia.

In the East Pacific, there have been 16 named storms and an additional three unnamed storms. Of the named storms, 10 reached hurricane status, and 8 of those hurricanes reached “major” hurricane status.

The National Hurricane Center issued its first-ever tropical storm warning for Southern California as Hurricane Hilary approached on Aug. 20. Why are hurricanes so rare in California?
In the ocean, there are very large circulations called “gyres” that span the entire ocean basin in each hemisphere. In the Northern Hemisphere, these gyres spin clockwise because of the direction in which the Earth spins. In the North Atlantic, the ocean gyre brings up warm, tropical ocean water along the U.S. Atlantic coast, and it is concentrated in the Gulf Stream. This warm water is generally warm enough to sustain hurricane intensification in the summer and fall.

On the U.S. Pacific coast, the ocean gyres bring down cold, arctic water from Alaska. This cold water makes it very difficult for hurricanes to maintain their intensity, and hurricanes typically dissipate and are very weak if they reach California.

What makes Hurricane Hilary so unusual is that it was able to move northward very quickly after it made landfall in Baja California, Mexico. Although Hurricane Hilary was in the process of weakening from the cold water, drier mid-level air, and increasing vertical wind shear, Hilary was still producing much more rain than Southern California typically receives when it arrived. Since Southern California has complex and fragile topography, flooding and landslides were of major concern.

Will the Climavision radar on the MU water tower help with hurricane predictions in our area?
With respect to hurricanes, the new MU radar will be most helpful for identifying imminent severe weather risks associated with storms (including decaying hurricanes) that track within the radar’s line-of-sight, which covers the general Lancaster/Millersville/York region. The radar will also be helpful for our ability to conduct local weather research, such as increasing our understanding of rainfall characteristics of landfalling hurricanes that impact the Millersville area. The new radar will be a huge benefit for the entire region, and we are very fortunate and grateful to begin this partnership with Climavision.

What is the hurricane outlook?
The Southern Hemisphere hurricane season is starting to ramp up. Typically in the Southern Hemisphere, Northern Australia, Madagascar, and many smaller island nations like Fiji are particularly impacted by hurricanes from approximately December to April. Interestingly, South America is very rarely impacted by hurricanes; the environment is generally not conducive to hurricane intensification.

Any additional thoughts?
Hurricanes can actually impact Millersville! While the winds of a hurricane typically weaken before tropical cyclones reach Millersville, we can get rain, flooding, and sometimes even tornado impacts from the remnants of hurricanes. Some notable examples include Hurricanes Irene (2011), Sandy (2012), and Ida (2021). As I have gotten to know our wonderful meteorology students here at MU, I have learned that these specific storms were formative experiences that have led many of our Millersville meteorology students toward discovering their vocations. Many of our students are dedicated to saving lives by improving our meteorological understanding, forecast accuracy, and communication of extreme weather phenomena like hurricanes.

Ultimately, it only takes one hurricane landfall to make it an active season for all who are impacted. Here at Millersville, it is a good idea to keep a reserve of water, nonperishable food, and a first aid kit on hand in the summer and fall when hurricanes are most likely, and for the best hurricane forecasts, I always recommend listening to the friendly experts at the National Hurricane Center when they issue a watch or warning. They have devoted their lives to being the best hurricane forecasters they can be, and they are constantly monitoring the tropics for potential hurricane risks, even while I’m teaching!

 

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