From launching weather balloons out of a beat-up Subaru to outperforming European weather models by 37% 📈 Read about how we built WindBorne into the future of weather prediction (spoiler: AI really good balloons) nytimes.com/2025/07/13/busin… @nytimes @NOAA @TimFernholz

The balloon constellation will not stop growing. WindBorne now collects more balloon-based weather data than the rest of humanity combined.

Have weather forecasts seemed less accurate lately? There's a major contributing factor: nearly half the morning weather balloons in the Lower 48 are "missing." This is an ongoing crisis that is degrading critical severe weather forecasts that we all rely on. It's having real, tangible impacts on degrading forecast quality. If you work in transportation, agriculture or commerce, this should matter to you. Regardless of the causes, this negatively affects people of ALL political backgrounds. Weather affects everyone. And it's impacting ALL of us negatively. We can't look at weather balloon data that doesn't exist. We can't pump nonexistent data into models. We can't rely as heavily on models that don't "know" what's happening above our heads. This is especially concerning for severe weather forecasts. We can't go 18 hours without ascertaining how the atmosphere is layered, how much storm fuel has built up and if severe thunderstorms are going to erupt. The Storm Prediction Center has even acknowledged forecasting frustrations in at least one public bulletin. As an atmospheric scientist myself, I can say firsthand – the forecasts I'm able to offer you are less accurate than they would otherwise be. I'm not able to predict severe weather with the confidence I normally would. That is extremely concerning. The United States is "supposed" to launch balloons at 0Z and 12Z ideally – a.k.a. around 7 a.m. and 7 p.m. Eastern time. That's not happening. Many sites, due to staffing issues stemming from broader political and organizational issues, have pushed to 18Z, or early afternoon. That's not helpful for morning severe weather forecasts. In other words, you get less lead time. Less advanced notice. Quicker ramp-ups and ramp-downs to the forecast. We're not able to get jet stream, temperature, moisture or wind profiles of the atmosphere each morning like we otherwise would. Moreover, the World Meteorological Organization encourages 12Z soundings; that data is shared via the Global Observing System (GOS) under the World Weather Watch (WWW). That's not happening.

It's been a few weeks since @WindBorneWx released WeatherMesh-6. I hope you read the blog, but there's a pile of results and verifications that didn't make the cut, and I'm still looking for excuses to brag. So here we go 🧵

Glad to see small startups like Ant finally catch up to @WindBorneWx's github.com/windborne/zulipmc…

What happens when you f(ly) around and find out? Here’s a video of the four balloons that contributed to our new achievement of 600 balloons concurrently aloft!

We launched a balloon nearly a year ago and it’s still aloft btw

Today one of our launch operators in South Korea launched their 1000th WindBorne balloon. Cumulative flight time of these balloons is well over a decade, more data collected from a single human's launches than any other person on earth

In doing evaluations for @WindBorneWx’s new WeatherMesh-6 model, I’ve been impressed with the ensemble forecast skill overall and for individual high-impact events. Take this example of an improved medium-range signal via the ensemble mean *and spread* for the February blizzard:

These RMSE improvements vs the IFS and AIFS gold standard are pretty crazy. 3 months ago, I would not have predicted these results. A few major breakthroughs in pre-trianing are what lead to this. Incredible work from the @WindBorneWx AI team.

We are releasing WeatherMesh-6 today, a huge step forward in weather forecasting. Its a fully end-to-end AI-based weather model. Observations in, weather forecasts out.

It's hard to wrap my head around the scale of the WindBorne constellation. Every dot is a balloon. A team of less than 100 people with a single manufacturing facility in Redwood Shores operates a planetary-scale piece of infrastructure.

It's fun flying hundreds of balloons around the southern hemisphere

@WindBorneWx will be in this same position soon with number of balloon flight hours

@WindBorneWx Systems flies 335 weather balloons across 16 countries. Their old finance setup couldn't keep up. Since switching to Brex: 200 hours saved annually on expense reporting Wire approvals down from 20 minutes to instant 40 hours recovered from daily reconciliation fixes

You've probably heard about the historic March heat wave unfolding in the West Coast (unless you live under a rock, which would serve as a cool shelter from the heat). The forecast temps alone are impressive w/ many locations expected to break their all-time March heat records!

Public-private partnerships should complement government operations, not replace them. We recently worked alongside @CW3E_Scripps and the AR Recon program as a massive atmospheric river barreled toward the West Coast. Read more about it on our blog: windbornesystems.com/blog/ar…

Just finished setting up our first launch site in New Zealand! So excited to see all the great southern hemisphere data our balloons will start collecting! 🇳🇿

Forgot to book dinner for tomorrow? Tell your partner you love them with a WindBorne valentine's day card:

It’s a busy time at the @WindBorneWx booth in the #AMS2026 exhibition hall, featuring a snapshot of our model simulating a potential major East Coast snowstorm next weekend

(4/4) How does our forecast compare to other AI models and physics-based models? WM-5c is farther north than the AIFS, IFS and GFS models (from most recently available 12z cycles). Stay tuned over the coming days!