Just after sunrise on April 27th, the SPC elevated the thunderstorm forecast for southeastern Missouri to a moderate risk. A deep upper level trough was generating a strong area of low pressure in the Plains that was feasting on the chaos of colliding air masses. Cold and Canadian with tropical and maritime. The helicity in the atmosphere meant tornadoes were likely.

There were indeed several tornadoes from Missouri to Indiana, with a great deal of damage wrought by straight line winds. The tornadoes were embedded within a line, and at some point, it becomes a bit academic as to whether damage is caused by winds or tornadoes.

The changes to the SPC and the deeper set of information within the convective outlook are new features to the thunderstorm season. I wanted to take this specific example to look at what the SPC released, and see what factors best correlate to the outlook that is provided. First, here is the outlook, issued in the early hours on Monday.

As a bit of background, the change that was recently made to the storm hazard maps added a storm intensity rubric to go along with the probability guidelines that had been a part of those maps before. Take a look at the wind and hail maps to get the idea.

So, you can see there was a high probability of strong wind, and a lower probability of hail, but the hail in the forecast was expected to be larger. We can also see that neither the high probability of severe wind, or the expectation of large hail defined the moderate outlook boundaries. That’s not particularly surprising. That the significant hail in central Texas didn’t lead to a higher outlook than a marginal risk in central Texas surprised me, though.

Moderate and high risk events generally need a threat of tornadoes, so let’s look at the tornado outlook issued at the same time as the full outlook.

The threat for strong tornadoes is only designated on the charts as 1, 2 or 3, and the probability of a tornado within 25 miles of a spot is more well defined. Perhaps it is no surprise, then, that the moderate hugs the 15% chance of a tornado risk. I’m sure it didn’t hurt the case that the forecast was a level 2 on the intensity scale, either.

For what it’s worth, here is the break down of severe reports.

March was not a busy month here at Victoria-Weather, at least on the forecast side. We had plenty of updates and weather discussions, but the forecasting was light. Therefore, it is tough to split the difference between our two top options for Forecaster of the Month: The Weather Channel and Clime.

Outlet	Forecast Wins (year)
The Weather Channel	3
Accuweather	1
WeatherNation	1
National Weather Service	1.5
Clime	0.5
Victoria-Weather
Weatherbug

12:05AM: A full week into April now, and we are definitely in severe season. If it were a busier pattern. Instead, the concern is going to be fire in the Plains.

6:23PM: The concern for fire in the Plains is shifting a bit further north. Here is the outlook from NWS North Platte.

11:32PM: Today is the beginning of April. Broadly, what are we thinking? Well, warm, too be sure, but less than oppressive. The CPC has the outlook:

Precipitation shows a threat for above average rain particularly in the mid-Mississippi Valley.

Take a look at the hail forecast from the SPC, issued for Monday. There is a swath of the Great Lakes that will see a threat for hail tomorrow.

There are two things to call out, design wise. First, perhaps most obviously, the color scale has changed to a creamier tone. The scale is distinctive, and particularly well defined on the general severe weather outlook. It’s easier on the eyes.

The other addition is in the bottom right corner. The individual hazards have always had a probability scale, but now, there is also an intensity scale for for every type of severe weather. There is no intense hail coming tomorrow, and in fact, it is just a marginal risk for severe weather overall. Better believe I’ll feature an outlook later this summer with forecasts for intense severe weather. You can look ahead though, these new maps are live already.

9:16AM: Good morning! We have some changes to our weather pattern. They may not be significant, but it will be for residents of the West Coast. The hot weather will continue nearly everywhere, but the Pacific Coast is going to get a reprieve, and will enjoy temperatures a little closer to normal through the beginning of April.

8:37PM: Just a look at the forecast map from the WPC, showing that “average” in late March can still mean “wintry”

11:28PM: I know, based on previous updates today, you might be led to believe that this is snow, but it’s rain, and it is along a cold front that will give way to chilly weather tomorrow, and eventually severe storms in the Great Lakes this week.

Spring officially kicked off yesterday. Spring is a season of transition, and because of that, is a season of big weather stories. Indeed, this week started with a snowstorm in the Great Lakes, and a couple of severe weather days in the Eastern US, and now the unseasonable heat is the story for everyone.

Well…. Maybe not EVERYONE. Yes, those are winter weather advisories in New England, where snow is falling, and the heat wave has not made it’s way in. That is quite the contrast. The 300mb jet seems to suggest a particular bone to pick with Maine.

While it does seem a little bit cruel to keep just one corner of the country out of the fun, it does serve as a reminder that this little breach in the jet is allowing snow making conditions into a country that is otherwise experiencing record breaking heat.

This isn’t summer time yet. Cold air is just across the border. This is why we will probably see a few more big weather days before spring gives way.

10:19PM: The heat is on, with record breaking warmth across the west. The NWS has a discussion covering this heat wave that is valid through the weekend.

11:48PM. Spring!

One thing that comes up every year, it seems, and one thing that I write about every single year, is the amount of variability that a single forecast can hold. If you live in the Great Lakes, it feels like there was a particularly significant tornado event, though the SPC had a Marginal Outlook that day. And it was a marginal event. There was one storm that had one track. Terribly, it tracked through three towns and caused damage and heart break and loss of life along the way.

In Minneapolis, there was a significant snow storm over the weekend. There were forecasts that called for nearly two feet of snow as a possibility in the metro and throughout western Wisconsin. There were accumulations of that high degree, but they were about 30 miles southeast of Minneapolis. It was a slog, to be sure, but not the one that had been feared originally.

This time, though, I want to tie it back to a couple of other trending headlines. Artificial Intelligence and the current administration. Artificial Intelligence has been around for a while. The big change is a revolution in computational power. Meteorologists have used numerical models for decades, now, and they have been aided by computers since that time. They work by reducing the time it takes to navigate the numbers ingested into the models. Increasing compute abilities makes the models run faster, and without the same server load.

The increased ability to compute these models has allowed private enterprise, and increasingly, private citizens to develop their own models, based on smaller territories, or focused on specific metrics derived from the model guidance. There are any number of WRF models for specific locations out there now. It takes a lot less to crank one of these models out, for the same reason that AI is exploding nowadays: Faster computers.

But the problem with models is the same as it has always been. They are only as good as the data that is ingested to generate them. More or less ,this is the problem with AI and the large language models that are so popular. Real time data is collected hourly from airports and other sensor sites. Upper air data is collected in the weather balloons sent from WFO office, of which there aren’t really THAT many. And they are sent up fewer times a day. And now, actually, even fewer than before thanks to government cutbacks.

There is a larger point that could be made about AI and it’s future impact (that it’s only as good as the user and data ingested), but instead, I’ll make a point that I make annually. The forecast will always get you close to what will transpire perfectly, however there is always going to be some inaccuracy, related to the resolution of the models. It then is on us, the consumer to monitor weather that is ongoing, and to know your local geography.

Man, if I write this every year, maybe I should just ChatGPT it next year?

There have been plenty of, and will continue to be plenty of, storms for the spring. This weekend will be highlighted by snow and severe weather. Behind that? Historic warmth.

A double round of hot weather is coming for the western US, and will end ski season and all the good vibes of a healthy winter of moisture. We aren’t just talking a little warm, either. By the middle of next week, places like St. George, Utah could see triple digits. On St. Patrick’s Day!

A strong, standing ridge will arc over the western Continental US. Despite a good system in the Gulf of Alaska, the hot high pressure is going to be stuck in. The jet will eventually weaken, but not necessarily move. The heat may wear off as March wears on, but it will not ever fully go away, not for a while, anyhow.

The real hazard will ultimately come from the strength of the surface ridge, and whether or not Santa Ana winds compound things in Southern California.

And yes, between the last two posts here, it’s been a real roller coaster.