The path of Hurricane Irma. (Darla Cameron/The Washington Post)

The founder of the popular weather website Weather Underground is congratulating the National Hurricane Center this week for its “excellent forecasts.”

Jeff Masters, a PhD meteorologist and former Hurricane Hunter flight scientist, said the forecasts were excellent “at a time when they were short-staffed and under tremendous stress due to the impacts of the hurricane on Miami,” where the National Hurricane Center is located. In fact, the building lost power, and the entire staff lived at work for the duration of the storm.

In an email to tropical weather researchers and forecasters, Masters did a quick analysis of the margin of error on the track, and found that Irma’s forecast was around 30 percent better than the average error over the past five years.

Official NHC 5-year average forecast errors (2012 — 2016), all tropical cyclones, for 12hr, 24hr, 48hr, 72hr, and 120hr forecasts, in miles:

29, 46, 81, 118, 171, 225 miles

Approximate NHC track errors for all 12hr, 24hr, 48hr, 72hr, and 120hr forecasts made in Irma, in miles, eyeballed from Brian Tang’s website:

19, 31, 59, 87, 118, 155 miles

As we keep pointing out here at the Capital Weather Gang — Florida itself is only 100 miles wide, at best. From a global perspective — which is where weather models are coming from — 100 miles is a drop in the bucket. It’s a mere step to the left or right.


Euro ensemble forecasts four days out and one day out for Hurricane Irma. (Gabriel Florit/The Washington Post)

If a storm is expected to move from south to north over the state, predicting which coast will be hardest hit is not in the realm of scientific possibility more than two days out.

“Given that the average error in two-day and three-day NHC forecasts has been 81 miles and 118 miles, we cannot expect the kind of forecast precision being demanded,” Masters wrote,“particularly in a meteorological situation where the hurricane is undergoing a change in steering regimes.”

Masters also dropped some real talk for anyone — particularly members of Congress — who are disappointed in the forecast.

“If we wanted that kind of precision, we should have listened to the National Science Board in 2007, when they put out a report calling for the formation of a National Hurricane Research Initiative,” he suggested.

The accompanying legislation, which was introduced by Florida’s senators, would have increased hurricane research funding from around $20 million per year to $320 million per year. It wasn’t passed. If it had been, there’s a good chance our current hurricane forecast error could have been significantly reduced for Irma.

“This year is a good time to remind people that if we want to be less hurricane-vulnerable, we have to make the investments needed to make that happen,” Masters wrote.

In other words, it’s time to put our money where our mouth is.