I was quoted in a recent press release [PDF] from AccuWeather.com regarding our new Model Spread maps. I want to expound on that a bit here. I was quoted as saying:

That quote was formulated by our Marketing department (of course) but I'm glad they mentioned my name because I really was the project manager for these updates (shout out to Dave & Dennis in IT for getting it done). You can see these new Model Spread tracking graphics whenever there are named storms on the AccuWeather.com Hurricane Center (and of course on Premium and Pro as well - Pro has them before the storm is named too). Below, I will show previous examples of the different types of maps we've added, and explain what these new maps do.

What's A Model Spread?

Years ago for the "JessePedia" I defined what a "model spread" entails:

You can get a list of all of the models on the JessePedia page. So what's so special about these new maps?

1. STORM-STRENGTH MODEL SPREADS

The first new map is called "Storm Strength" and this is the one that I'm most excited about. Here, instead of showing just the tracks of the models with time, we color the tracks with the storms strength (based on converting the sustained wind speeds to the Saffir-Simpson scale [WikiPedia] classification. Now, you not only know where the models are taking the storm, but how strong they think it will be (which Marketing Jesse said above). In the example below, one model says it will be a Category 3 hurricane; most say a Cat 1 Hurricane or Tropical Storm. NOTE: Of the 181 models, only a handful predict strength, so you should use this in concert with the more plentiful Short/Medium/Long-Range graphics.

NOTE: All maps shown here are examples from the 2008 hurricane season. For live maps see Hurricane.AccuWeather.com

2. SHORT, MEDIUM, AND LONG-RANGE MODEL SPREADS

First of all, when we first started making these ATCF maps, we found out a peculiarity. The mapping system determines the extent of the map based on the extents of the tracks, so if you have one fast-moving model, especially at longer time frames, you get a map of North America and you can't see where they storm is going in the short-range. So, initially we "solved" this by simply cutting off the data at 92 hours - but then we missed the fun of the GFS running a hurricane through the Canadian Plains or Europe. So, the solution we came up with was to show a short-range map that would stay really zoomed in, then the Medium range we had before, and the Long range which can go all the way out to 15 days. Here's what it looks like:

3. THE ACCUPICKS

There are a handful of models that AccuWeather meteorologists settled on as being "the best of the best" when it comes to finding the gems in this 181-model array. They are shown on a map by themselves, and they are: The HWRF, GFDL, CGUN & EGRI.

4. NHC CONSENSUS MODELS

The NHC [JessePedia] runs their own "consensus" model runs where they show one track based on a consensus average amongst models. These consensus models fall into three categories: Fixed, Variable, Continued and (rarely) Forecaster. The latter, I presume, are model picks from the NHC forecasters (not sure if they are set, or dynamic per storm). You can read more about these models in this PDF from the NHC.

5. NHC "CLASSIC" MODELS

Before the ATCF's 181 models, the NHC had 4 computer models that they relied on for hurricane forecasting: The LBAR, BAMM, BAMD, and BAMS (you can read more about these models in a previous blog entry). We still carry these models on a map by themselves, but we do something that no one else is doing: we combine all the tracks together to come up with an Average Track. This may be a good indicator of where things will eventually go.

6. MAJOR MODELS

When you're a meteorologist, there are several "major" computer forecast models - those that regularly predict weather around North America or the World, and are preferred when it comes to general forecasting. These models may not have particular skill in the hurricane world, but they are more likely to see "the big picture" so it's important to look at them by themselves. These include: the NMM (NAM/ETA), GFS, NOGAPS, ECMWF, and the UKMET.

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