Invest now to improve tornado warnings; an early start to hurricane season?

The Atlantic hurricane season officially begin on Wednesday, June 1, and recent computer model runs predict that we may have some early-season action in the Central Caribbean Sea to coincide with the start of this year's season. The GFS, NOGAPS, and ECMWF models have all indicated in some of their recent runs that a tropical disturbance may form between Jamaica and Central America sometime in the May 31 - June 2 time frame, as a lobe of the Eastern Pacific Intertropical Convergence Zone (ITCZ) pushes across Central America into the Caribbean. Up until now, wind shear has been too high to allow tropical storm formation in the Caribbean, due to the presence of the Subtropical Jet Stream. However, this jet is expected to push northwards over Cuba over the coming week, allowing a region of low wind shear to develop over most of the Caribbean. Water temperatures in the Central Caribbean are about 1°C above average, 29°C, which is plenty warm enough to support development of a tropical storm. The main impediment to development will probably be lack of spin, as we don't have any African tropical waves that are expected to enter the Caribbean Sea next week, to help get things spinning. Stay tuned.


Figure 1. Satellite image of Typhoon Songda.

Typhoon Songda heads for Okinawa and Japan
Typhoon Songda brushed the Philippines yesterday, bringing heavy rains that killed at least two people. Fortunately, the brunt of this year's first Category 5 storm missed the islands, and Songda has weakened slightly to a Category 4 storm with 145 mph winds. Songda is turning northwards and will threaten the island of Okinawa on Saturday. Sea surface temperatures decline rapidly north of the Philippines, and Songda is expected to weaken significantly before reaching Okinawa, where sea surface temperatures are approximately 26°C. Wind shear will also increase to high levels by Saturday, and Songda should be at most a Category 2 typhoon by the time it reaches Okinawa. On Sunday,

Invest now for better tornado warnings
National Weather Service forecasters issued a tornado warning 24 minutes in advance of the Joplin, Missouri tornado this.week, which is now being blamed for at least 132 deaths--the deadliest U.S. tornado since at least 1947. However, we can do better, and the National Weather Service Employees Organization (NWSEO) put out a press release on May 23, arguing that investments in weather service forecasting technology are needed to reduce loss of life in future violent tornadoes:

"The 24-minute lead time is a great improvement over the average lead time of 13 minutes for tornado warnings. The meteorologists in the Springfield Weather Forecast Office are commended for their lifesaving work," said Dan Sobien, NWSEO President. "But in our age of advanced technology and communication, when new radars and modeling opportunities exist that can provide more lead time to get people out of the path of a storm, hundreds of people do not have to die because of a tornado event."

Sobien says the Joplin and Tuscaloosa tornadoes are examples of how the government's neglect to invest in NWS related infrastructure over the last 10 to 15 years has failed to provide the tools necessary to protect lives and property. He says that the tools forecasters use to issue tornado warnings are woefully inadequate and that the technology exists to provide lead times so far in advance of the storm that it would make the need for tornado warnings as we know them obsolete. "The much touted Doppler Weather Radar, also known as the Weather Service Radar or WSR-88D, was developed in 1988. Since that time, technological advances, including phased array radars developed by the Department of Defense, have been shown to increase the current lead time on tornado warnings by almost 50 percent."

"The much touted Warn on Forecast process utilizes Meso-scale modeling and has the potential to let forecasters know hours in advance where a thunderstorm would form and if it is likely to contain strong winds, hail, or even a tornado. With adequate staffing, local National Weather Service forecasters who understand local terrain and the model output, could be embedded with emergency managers and decision makers. In the event of a storm, the forecaster could provide emergency managers with the tornado track with some margin of error and people in the way of the storm could be evacuated hours before the tornado hits. This technology is being developed and tested right now, however without funding it will never be available."

"The art and science of severe weather warnings made considerable progress during the 1980s and 90s, going from almost zero lead time to average of about 13 minutes for tornado warnings. However, in recent years, that progress has stalled, even while the technological advancements have accelerated. If the country made the type of investment in the National Weather Service that it did in the 1980s, scenes like the ones in Missouri this week and in Alabama and Mississippi last month could be a thing of the past."

"I am very proud of my co-workers at the National Weather Service this tornado season. They saved many lives and having been there myself, I can assure you, they feel personally about every lost life," said Sobien. "I know that budgets are tight and there are many priorities, but if you put investing in the National Weather Service up to a vote today in tornado alley, I think the approval would be a landslide."

I wholeheartedly agree with this view--investments in better tornado forecasts and tornado observing technology will potentially give us a huge return in lives saved. Have a great holiday weekend, everyone, and I'll be back Monday or Tuesday with a new post.


Jeff Masters