Closely watching TS Koto for potential additional heavy rainfall. In US, tornadoes impact northwest Houston suburbs.

Nov 25, 2025

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Yesterday, the New York Times published a deep dive article (gift link) about the incredible heavy rainfall and flooding that has been plaguing Vietnam, and particularly central Vietnam, over recent weeks. The article has a few statements I would push back on (particularly I don’t see where Vietnam has been hit by 14 typhoons this year, I am assuming someone gave the reporters numbers including weak tropical systems), but I encourage you to read it for the stories of those impacted by the devastating flooding and residents’ concerns about warnings and infrastructure.

More than 6 feet of rain has fallen in the last week in some parts of Vietnam per the reporting, and that is on top of incredible rainfall leading up to the landfall of Typhoon Kalmaegi in early November. More than 90 people have been killed in the last week by flooding and mudslides, and Gallagher Re Chief Science Officer Steve Bowen posted on BlueSky yesterday that initial damage estimates are up to $500M.

While there is currently a lull in rainfall over the region, Invest 92W that I discussed in yesterday’s newsletter has become Tropical Storm Koto with 45 mph winds in the western Philippines. It is expected to move slowly west over the next few days, and gradually intensify into a strong tropical storm or low end typhoon. Steering currents are forecast to be weak, and as you can see in the Google Deep Mind AI forecast for Saturday, the forecast spread in where Koto will be this weekend becomes rather large. However, there is certainly potential for Koto to eventually produce additional heavy rainfall in parts of Vietnam by early next week, so that will be something to watch given the magnitude of the disastrous flooding currently happening there.

Recapping yesterday’s severe weather, one of the first supercell storms of the day ended up being the most impactful, as a tornadic supercell moved through the northwest suburbs of the Houston metro area during the early afternoon. Based on radar and reports, at least two distinct tornadoes appear to have occurred with this storm. While no injuries were reported, more than 100 homes and businesses were damaged and thousands were left without power.

The storms organized into more linear structures as they moved east across Louisiana, and seem to have intensified a bit as they moved into better low level moisture over Mississippi. At least one confirmed (likely weak) tornado occurred as the line moved across western Mississippi, and a number of incidences of wind damage were reported across central Mississippi and northern Alabama.

A few additional severe storms and tornadoes are possible today across parts of Mississippi and Alabama. Meanwhile, on the northern side of this storm system, heavy snow is anticipated across parts of the upper Midwest, and winter storm warnings are in effect from the eastern Dakotas into the Upper Peninsula of Michigan. Snowfall forecasts have trended up with this system, and widespread 4-8” are expected in the warning area along with significant blowing and drifting snow. Heavier amounts are anticipated in far northern Wisconsin and the UP of Michigan where moisture from Lake Superior will enhance snowfall totals.

For the busiest travel day of the year, the eastern storm system will continue to move east, with rain and scattered thunderstorms possible along the Eastern Seaboard. A light wintry mix is possible from the eastern Great Lakes into northern New England, while heavy lake effect snow is expected downwind of Lake Superior. Rain and mountain snows will continue in the Northwest as a series of weather systems continues to impact this region. Most of the rest of the country will be dry.

Thanksgiving Day will be colder and blustery in the Northeast and Great Lakes with scattered snow showers and heavy lake effect snow in the snowbelt regions downwind of all of the Great Lakes. The Northwest will continue to see periodic rain and mountain snows, but the rest of the country will be relatively quiet.