Tag Archive for: CSU

Average But Unusual 2025 Hurricane Season Ends Today

11/30/2025 – Today marks the end of the 2025 hurricane season. It was average in terms of the number of storms, but unusual in terms of where they tracked. These three screen captures from the National Hurricane Center tell the story.

2025 Named-Storm Tracks. Only one named storm hit the mainland U.S. – Chantal in early July. And none hit the US Gulf Coast.

This table shows the strength and timing of each.

And this table compares the 2025 season to a 30-year average (1991-2020).

So, the Atlantic basin had one less named storm, two fewer hurricanes, and one more major hurricane than in an average year. But for the most part, they stayed away from the U.S.

Actual Vs. Predicted

For those keeping track, in April, Colorado State University researchers predicted an above-average season with

  • 17 named storms
  • 9 hurricanes
  • 4 major hurricanes (Category 3 or higher).

Then in May, NOAA also predicted an above-average season with:

  • 13 – 19 named storms
  • 6 – 10 hurricanes
  • 3 – 5 major hurricanes

CSU also predicted the probability of where storms would make landfall. Texas residents, they said, had a 19% chance of being within 50 miles of a major hurricane landfall this season. Those chances increased to 44% for a hurricane and 70% for a named storm. Oops.

All in, I’d say NOAA’s National Hurricane Center predictions came closer to the actual numbers, though neither was very far off.

Actual Vs. Averages

But how did the 2025 season compare to the long-term averages?

So, the Gulf had far less activity than in an average year. However, basin wide, we came close to the average.

How Unusual Was Gulf This Year?

How unusual is it for the Gulf to have no hurricanes? Over the long term, the probability is about 20%. So it’s unusual, but far from unprecedented. There are multiple historical examples of No-Gulf-Hurricane seasons.

The longest recorded “Gulf hurricane drought” on record lasted 1,080 days (≈ 3 years), from September 2013 until September 2016 — during that period, no hurricanes entered or developed in the Gulf, according to The Weather Channel.

Why does that happen occasionally? It usually reflects unfavorable conditions for storm formation or strengthening in our sub-basin (e.g., upper-level wind shear, atmospheric stability, unfavorable steering currents). But as the map above shows, that does not mean the overall Atlantic or Caribbean is quiet. Storms may still form and even become major hurricanes, but track elsewhere, as Melissa did.

Plan for Worst, Hope for Best

The variability — including periods of many storms — argues for resilience and planning, even if some seasons are quiet. The recent cyclones that struck Sri Lanka and Indonesia make good cases in point.

Deadly floods and landslides in Sri Lanka left at least 153 people dead with hundreds more still missing at this point. According to Reuters, more than 78,000 people have been displaced.

Another cyclone struck Indonesia and killed 435 people. It destroyed tens of thousands of homes and displaced more than 200,000 people. And the cascading effects are just starting. Flooding and landslides disrupt not only homes, but agriculture, transport, and supply chains — with ripple effects on food security, local economies, and displacement.

Posted by Bob Rehak on 11/30/25

3015 Days since Hurricane Harvey

CSU Predicts Above Average 2025 Hurricane Season

4/3/2025 – Colorado State University (CSU) researchers issued their forecast for the 2025 hurricane season today for the Atlantic basin. Forecasters expect the season to be above average, with 17 named storms, 9 hurricanes, and 4 major hurricanes (Category 3 or higher).

The 30-year average is for 14.4 for named storms, 7.2 for hurricanes, and 3.2 for major hurricanes. 

Landfall Location Probabilities and Other Predictions

Researchers at CSU also predicted the probabilities of major hurricanes making landfall:

  • Anywhere along the U.S. coastline
  • Along the East Coast, including the Florida Panhandle
  • Anywhere along the Gulf Coast from the Florida Panhandle to Brownsville, Tx.

They predict a:

  • 51% chance for any coast (up from a 140-year average of 43%)
  • 26% chance for the East Coast (up from a 140-year average of 21%)
  • 33% chance for the Gulf Coast (up from a 140 year average of 27%)

They also believe Atlantic basin Accumulated Cyclone Energy (ACE) and Net Tropical Cyclone (NTC) activity in 2025 will be approximately 125 percent of their long-term averages. 

Value of Long-Range Forecasts

People frequently ask CSU researchers what the value is of such long-range forecasts? Aside from people’s curiosity, they point out that it is possible to make seasonal forecasts with greater accuracy than climatology.

From CSU Extended-Range Forecast for 2025 Atlantic Hurricane Season

Accuracy of Long-Range Predictions

The models CSU uses sometimes fail, but their “hindcasts” show that their predictions correlate highly with actual storm activity. In the last 10 years, using “correlation” as a skill metric, CSU’s April forecasts have a .59 coefficient of correlation.

correlation coefficient of 0.59 indicates a moderate to strong positive relationship between two variables.

In general, statisticians consider:

  • 0.1 to 0.3: Weak
  • 0.3 to 0.5: Moderate
  • 0.5 to 0.7: Moderate to strong
  • 0.7 to 1.0: Strong

CSU’s June forecasts have a .69 coefficient of correlation and their August forecasts rate a .84.

So, statistically speaking, they are very successful. And that’s why they are so well respected in the industry.

Chances of Texans Getting Hit

By the way, they believe that Texas residents have a 19% chance of being within 50 miles of a major hurricane landfall this season. Those chances increase to 44% for a hurricane and 70% for a named storm.

CSU looks at multiple models as well as many analog factors, such as sea surface temperatures, global winds, La Niña, El Niño, and more. Budding meteorologists can review their thinking by reading the full 41-page report here.

It’s never too early to start preparing for hurricane season. A friend contacted me today about portable electrical power packs he just purchased. He’s also buying solar panels to recharge them. The memory of power outages during Beryl still has him smarting.

To help get ready for hurricane season, see the Preparedness Tab on my Links Page.

Posted by Bob Rehak on 4/3/2025

2774 Days since Hurricane Harvey