iiinova — where your digital self keeps evolving

Reposted by Brian McNoldy

🚨 PolarWx Model Viewer Alert 🚨 At some point between Thursday 10/15 & Friday 10/23, the PolarWx model page will be partly or mostly shut down for a 1-2 week period as underlying work is done to transition to a brand new interface. I apologize in advance for any inconvenience.

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Brian McNoldy @bmcnoldy.bsky.social · 20h

As I mentioned in the original post, "It's too late in the season to recover anywhere close to average." So my hunch is no.

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Reposted by Brian McNoldy

Michael Lowry @michaelrlowry.bsky.social · 13/10/2026

When does the mainland U.S. usually see its last hurricane landfall? In today's newsletter I look at what the historical record tells us and why the next few weeks are especially meaningful for folks living in the hurricane zone. ⬇️

michaelrlowry.substack.com

When Do We Usually See the Last U.S. Hurricane Landfall?

90% of Atlantic hurricane seasons see their last hurricane landfall by October 18th

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Brian McNoldy @bmcnoldy.bsky.social · 13/10/2026

This is done by monthly triads (OND, NDJ, etc), relative to the peak of each El Niño: bsky.app/profile/bmcn...

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Brian McNoldy @bmcnoldy.bsky.social · 13/10/2026

NMME forecasts: nmme.earth.miami.edu Historical RONI: bmcnoldy.earth.miami.edu/tropics/roni/

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Brian McNoldy @bmcnoldy.bsky.social · 13/10/2026

The October run of the NMME (North American Multi-Model Ensemble) continues to predict a record-strong El Niño for the Sep-Oct-Nov timeframe, and then strengthening some more beyond that to a peak at the Oct-Nov-Dec value. The forecast peak is 0.42°C above the previous record in DJF 1982-83! 🤯

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Brian McNoldy @bmcnoldy.bsky.social · 12/10/2026

Good question... it certainly could reinforce the usual "cool" relationship. The "wet" part of the relationship comes about through the location of the subtropical jet stream.

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Brian McNoldy @bmcnoldy.bsky.social · 12/10/2026

The detached anticyclonic warm eddy that had been present for months northwest of the Loop Current is still there, but a zombie of what it was a week ago since Isaias passed over it. It's too late in the season to recover anywhere close to average.

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Brian McNoldy @bmcnoldy.bsky.social · 12/10/2026

The ocean heat content averaged over the Gulf of Mexico has been below average since June, but Isaias really zapped it and the values are plummeting...

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Brian McNoldy @bmcnoldy.bsky.social · 12/10/2026

Based on the operational size & intensity estimates of Hurricane #Isaias, here is my swath of sustained wind speed at the surface. This takes land use and roughness into account (which the NHC's wind swath product does not). The wind speed contours are simply categorized by the Saffir-Simpson scale.

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Brian McNoldy @bmcnoldy.bsky.social · 11/10/2026

OFCL: National Hurricane Center GDMI: Google Deepmind ensemble mean HCCA: HFIP Corrected Consensus Approach TVCN: Track Variable Consensus

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Brian McNoldy @bmcnoldy.bsky.social · 11/10/2026

Here's a beautiful huge sample size (thanks El Nino) of track and intensity verification stats for the East and Central Pacific hurricane seasons so far this year. Again, these are preliminary and some storms are still in progress, so this is as of Sunday afternoon. Some key acronyms:

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Brian McNoldy @bmcnoldy.bsky.social · 11/10/2026

What I didn't have the characters for was to explain the model acronyms. The Google Deepmind model is GDMI on there, and the National Hurricane Center is OFCL on there.

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Brian McNoldy @bmcnoldy.bsky.social · 10/10/2026

Hurricane Isaias' eventual landfall location was inside of all 13 track forecast cones issued by the National Hurricane Center from formation through landfall. 🧐

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Brian McNoldy @bmcnoldy.bsky.social · 10/10/2026

Preliminary track verification statistics for #Isaias show that the Google Deepmind model dominated the model guidance by a huge margin. The National Hurricane Center closely and wisely followed it. Details at bmcnoldy.blogspot.com/2026/10/isai...

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Brian McNoldy @bmcnoldy.bsky.social · 10/10/2026

From Thursday morning through Friday morning, #Isaias rapidly intensified and became the first major hurricane of the season. Then just as it was approaching the coastline on Friday night, it weakened slightly to a 90-knot Category 2 hurricane.

bmcnoldy.blogspot.com

Isaias makes landfall after quick shot up to major hurricane

Updates and summaries on tropical Atlantic activity... including easterly waves, tropical storms, subtropical storms, and hurricanes.

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Brian McNoldy @bmcnoldy.bsky.social · 09/10/2026

Don't forget about the HTI graphics for #Isaias... bmcnoldy.blogspot.com/2026/10/inte...

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Brian McNoldy @bmcnoldy.bsky.social · 09/10/2026

Another update to this figure... showing all 11 track forecast cones for #Isaias as of Friday morning. There's a very focused 75-mile stretch of coastline that has been inside every cone so far. Landfall will be very near Pensacola FL around midnight tonight.

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

Through the first eight advisories for #Isaias, the length of coastline contained within all eight track forecast cones is 120 miles. The forecasts have been very steady. Landfall is Friday evening.

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

1980 is widely considered to be the start of reliable tropical cyclone data worldwide. ACE is not trending upward even with a good period of record.

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

Oh, you're referring to interannually! Sort of, but it's not *entirely* due to activity, it's partly due to better observations!

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

There's occasionally talk of moving the start date of the Atlantic hurricane season earlier. If anything, the date of the first hurricane formation is trending later!

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

Ten hours of Hurricane #Isaias intensifying in the central Gulf of Mexico overnight. See my previous post related to some "first hurricane" stats.

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Brian McNoldy @bmcnoldy.bsky.social · 08/10/2026

Indeed, we have our first hurricane on October 8. #Isaias

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

Ten hours of an intensifying Tropical Storm #Isaias on October 7, from sunrise to sunset.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

Yes, I agree exactly... March 1.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

From the Wednesday afternoon cycle of the 1000-member Google Deepmind ensemble, nearly the entire ensemble is east of the NHC track forecast, and 74% of the members reach Category 3+ intensity now. The most likely intensity at landfall is Category 1 hurricane. #Isaias

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

Yes, there have been a handful. I'd count Alex in that list (Jan 14, 2016), then Epsilon (Dec 2, 2005), then Lili (Dec 20, 1984), then Alice (Dec 31, 1954), and three other unnamed hurricanes prior to that.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

I am not counting Alex on January 10, 2016 because I firmly stand by that being a meteorological late-comer to the 2015 hurricane season rather than an early addition to the 2016 season.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

During these 61 years, the record earliest first hurricane was Alma on May 20, 1970. That was the only one to form prior to the official beginning of hurricane season on June 1.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

It's all but certain that the first hurricane of the 2026 Atlantic hurricane season will go in the books on October 8. During the satellite era (I'm using 1966), that is BY FAR the latest... by 27 days! It's an incredible 63 days after the median date.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

As you've probably noticed over the years, I've been a big fan and proponent of the Hurricane Threats and Impacts graphics that the NWS has produced for every tropical cyclone near the U.S. since 2015. Here is the suite of graphics from Wednesday afternoon for #Isaias. These will evolve of course.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

#Isaias will pass over a deep reservoir of warm water on Friday morning... very high ocean heat content. That should offer an interesting battle against the increasing wind shear.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

Some important differences between the conventional physics-based models (European and American ensembles are 1st and 2nd panels) and the AI models (Google Deepmind operational and experimental ensembles are 3rd and 4th panels). The differences in both track and intensity are obvious. #Isaias

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

In terms of intensity, 99% of members indicate it reaching hurricane intensity, and 64% of members indicate it reaching at least Category 3 intensity. The most likely intensity at landfall is a Category 1 hurricane.

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

The Wednesday morning update from the 1000-member Google Deepmind ensemble shows a tight clustering of tracks at the Gulf coast, though notably almost all east of the official NHC forecast. That is because the conventional physics-based models are generally further west, so NHC splits the difference

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

Remember that the intensity forecast also contains uncertainty, just like the track does. Here's my take on the intensity forecast cone, as of Wednesday morning's Advisory #3. The cone is based on NHC's intensity forecast errors over the previous five seasons. bmcnoldy.blogspot.com/2026/10/trop...

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Brian McNoldy @bmcnoldy.bsky.social · 07/10/2026

The official forecast from early Wednesday morning brings #Isaias up to a borderline Category 2-3 hurricane in the central Gulf, then shows some weakening prior to landfall overnight on Friday, likely between New Orleans LA and Panama City FL.

bmcnoldy.blogspot.com

Tropical Storm Isaias likely to become first hurricane of the season

Updates and summaries on tropical Atlantic activity... including easterly waves, tropical storms, subtropical storms, and hurricanes.

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Brian McNoldy @bmcnoldy.bsky.social · 06/10/2026

The timing of landfall on the north-central Gulf coast is Friday afternoon through Saturday morning, most likely as a tropical storm.

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Brian McNoldy @bmcnoldy.bsky.social · 06/10/2026

Tuesday morning's run of the 1000-member Google Deepmind ensemble shows a virtually 100% chance of Invest #92L becoming Tropical Storm #Isaias by Thursday morning. Then, it indicates a 93% chance of it becoming the season's 1st hurricane, and a 43% chance of it reaching Category 3+ intensity.

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Brian McNoldy @bmcnoldy.bsky.social · 06/10/2026

The area I highlighted six days ago is coming together... it's currently tagged as Invest 92L but is close to becoming the season's 9th named storm, Isaias. As of Tuesday morning, it's located in the far western Gulf and has had a significant flare-up of strong thunderstorm activity over the center.

bmcnoldy.blogspot.com

Eyes still on southern Gulf of Mexico for next potential storm

Updates and summaries on tropical Atlantic activity... including easterly waves, tropical storms, subtropical storms, and hurricanes.

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Brian McNoldy @bmcnoldy.bsky.social · 06/10/2026

10 years ago today, the center of Category 4 Hurricane Matthew passed just 95 miles from Miami. That was a close call!!

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Brian McNoldy @bmcnoldy.bsky.social · 05/10/2026

One is daily and one is a 3-month mean. One uses OISSTv2 and one uses ERSSTv6. So, different averaging periods AND even a different data source. But the averaging periods are the primary reason for the difference. RONI isn't really used on a weekly basis... historical values are 3-month means.

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Brian McNoldy @bmcnoldy.bsky.social · 05/10/2026

The latest Relative Oceanic Niño Index (RONI) value is up to +1.70 °C, which is in the "strong #ElNiño" category. It is still increasing and is fully expected to reach the highest category (a "very strong El Niño") later this Fall, when the RONI crosses the +2.0 °C threshold.

bmcnoldy.earth.miami.edu

Relative Oceanic Nino Index

Time series of the Relative Oceanic Niño Index from 1850 to present.

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Brian McNoldy @bmcnoldy.bsky.social · 03/10/2026

As always, a great time seeing @garyallanmusic.bsky.social in concert. 30 years of listening to his music and it's still special to hear it live.

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