I think everyone was surprised to the naming of  Tropical Storm (TS) Julia overland last night at 10 PM EDT. My jaw basically dropped when my iPhone alerted me that the National Hurricane Center (NHC) upgraded investigation area 93L to named storm Julia.
This was a huge surprise for many other meteorologists as well and likely even caught the NHC off guard: Just nine hours earlier they had only given the system 40% chance (image below) and 12 hours prior only a 20% chance of development over the next 48 hours. In fact, the NHC didn’t even classify the system as a depression – the system went straight to a named storm. So clearly, the system developed rapidly by feeding off the very warm waters off the Florida coast.

nhcprob

A look at yesterday 2 pm EDT NHC 5 Day probability of tropical cyclone formation. At 11 PM EDT they upgraded the storm to Tropical Storm Julia

The other surprising fact is that Julia was overland most of yesterday, and it’s really rare for a storm to be named overland. In fact, The Weather Channel’s Michael Lowry reported that only 2% of all tropical cyclones in the Atlantic have formed over land. But according to Philip Klotzbach at Colorado State University, none of the 2% actually formed over Florida, and Julia will go into the record books as being the first named storm to form over Florida and not make landfall.

The other interesting fact is that the NHC barely acknowledged the overland tropical system that will likely have an economic impact above $10 Billons in Louisiana. So the NHC seems to be making up for this mistake by forecasting that Julia will likely also have large flooding impact across the Southeast U.S. and it should have a name like the Louisiana system should have had a name.  It’s possible, but I have been clear that the NHC plays name games with systems, and the storm name (or lack thereof) is less important than the storm impact.

TS Julia will remain overland, quickly weaken today to a Tropical Depression, and park itself over Southern Georgia where it will cause flooding rain (which is likely to be the main insurance impact).

juliarainfallforecast

Tropical Storm Julia Rainfall Forecast showing 2 – 8″ of rain over the next 72 hours over the southeast coast of the U.S.

Tropical Depression 12 just formed near Cape Verde and will struggle to move generally west over the next several days. At this time, is not a threat to the insurance industry. Named storm Karl should be expected later today.

Peak Season

September 10 marked the statistical peak of the Atlantic hurricane season. Based on data gathered since 1851, it’s more likely for a named storm to be active on this date than on any other date in the entire season — from June 1 to November 30. However, this year brought no named storm on September 10. This absence has only occurred in 12 of the past 50 years.
Although Julia’s progression highlights issues with the inconsistency of naming named storm, this year’s count is above normal so far this year. The average date for 11th Atlantic named storm is Nov. 23 and Karl is expected to be named later today. In terms of Accumulated Cyclone Energy (ACE), the basin as a whole is 75% below normal with Hurricane Gaston generating more than 59% of the total ACE this season.

aceasof9_14_2016

As I predicted at the start of the season, storms have struggled to develop in the Main Development Region (MDR) of in the Atlantic Ocean and have developed closer to the U.S. This is due to the large amount of dry dusty air in the atmosphere in this area of the Atlantic basin. This should result in storm having a better chance to form closer to the U.S.

For the Remainder of the Season

The insurance industry should expect more of the same. With warm water, less shear and dry air near the U.S. coastline, conditions are ripe for storm development. The ECMWF ensemble % chance of tropical cyclone development guidance might be the best way to sum up the current and future activity of tropical cyclone activity over the Atlantic Basin over the next two weeks.  As overall I expect less activity over the basin next week as an large scale area of sinking air moves over much of the basin next week.  As of right now besides Julia I don’t expect any U.S. insurance industry concerns over the next two weeks.

wsi_ecmwf_prob