(WAFB) - 1. Southeast Louisiana was quite fortunate
Saturday morning we woke up to an intensifying Hurricane Nate that was racing toward an expected landfall in southeast Louisiana. By 10 a.m., maximum winds had increased to 90 mph and for the first time, the National Hurricane Center (NHC) was forecasting Nate to reach our coast as Category 2 hurricane with winds of 105 mph.
Instead, wind shear and dry air chewed away at Nate's western side, sparing most of southeast Louisiana from any significant rain or wind impacts. Yes, storm surge was still an issue, but even that could have been worse.
Nine hours after Nate was forecast to reach our coast as a Category 2 hurricane with winds of 105 mph, it actually made landfall as a Category 1 with winds of 85 mph and that may even prove to be generous.
2. NHC track forecasts are really good (most of the time)
Nate was upgraded to a tropical depression on Wednesday morning and the first few forecast cycles from the NHC had Nate's track pointed toward the Florida Panhandle. However, a big shift in the forecast was made by early Thursday morning and shifted the threat toward southeast Louisiana. From there until the time of landfall, NHC remained pretty steadfast in their tracks even as model guidance continued to bounce around. On Friday and even Saturday, I speculated that NHC might be a tad too far east with their track, but ultimately they were proven correct.
Check out the error trends in NHC forecast tracks since 1989 in the graphic below. Significant reductions in errors have occurred at all forecast lead times, with 72-hour forecasts now matching the accuracy of 24-hour forecasts about 20 years ago. That is a remarkable improvement in a relatively short amount of time.
View the full sequence of forecast tracks for Nate here.
3. NHC intensity forecasts are still a weakness
The NHC actually did quite well with intensity forecasts for most of Nate's life cycle. NHC consistently forecast a storm that was on the "strong" side of available guidance tools and for the most part they ended up being right.
However, as noted in Point #1 above, the official forecast issued just nine hours before landfall called for Nate to make landfall as a Category 2 hurricane. Instead, the hurricane actually weakened slightly during that stretch and had maximum winds 20 mph below that earlier forecast.
A look at intensity forecast trends since 1990 shows some improvement but not nearly at the same rate as track improvements. Meteorologists are quite aware of this weakness and are working hard to solve the problem, but it remains among the biggest challenges in tropical weather forecasting.
4. Three Louisiana landfalls in one season is pretty rare
It seems hard to believe, but do you realize we've had three separate named tropical systems make landfall in Louisiana so far this hurricane season? In addition to Hurricane Nate, we've also had Tropical Storms Cindy and Hurricane Harvey making landfall in Cameron Parish.
Cindy made landfall on June 22 as a minimal tropical storm and its primary impact was limited to some modest storm surge in southwest Louisiana, and after devastating Texas, Harvey made a second landfall also in Cameron Parish in late August. It did produce some significant flooding near and west of Lake Charles, but even Harvey lacked the widespread impacts that we often see from a landfalling tropical system.
A check of the record books shows that Louisiana has only had three other years since 1851 when three tropical storms and/or hurricanes made landfall – 1860, 2002, and 2005.