Advanced warnings appear to make a big differenceApril 15th, 2012 at 9:28 pm by David Mazza under Weather
Daily the Storm Prediction Center makes severe weather forecasts or “convective outlooks” for the next few days. Something the SPC did this past week was a bit different though; they issued a High Risk for the day 2 forecast. This is something that has only been done once before. At the time I could understand the reasoning behind issuing the forecast given the weather parameters, even though they typically only issue High Risk areas 1 day out. Looking back on the data, this forecast was not only very accurate, but also saved lives. I think our goals as meteorologists is to make accurate, easy to understand forecasts that prepare people for the weather. This can be your day-to-day, what to wear, bring the sunglasses or raincoat kind of forecast, or it can be the one that may prepare people in a life threatening situation. This weekend was one of those when I think the proper information, given well out in advance helped people to prevent major loss of life. I should note that, sadly, early this morning there were 5 people killed in Oklahoma from a tornado touchdown in Woodward, Oklahoma. There were also a few dozen injuries from that tornado overnight as well.
First, I want to show the graphic of the day 2 forecast, issued around 1am on Friday morning. This forecast graphic shows the risk of severe thunderstorms from 7am Saturday to 7am Sunday.
As new weather data becomes available through the day, additional forecasts are made and the graphics are slightly tweaked as well. So when this day 2 forecast from above was issued for the day of in the morning (Day 1 forecast), the High Risk area was enlarged a bit. The graphic below shows the Day 1 forecast that was issued just before 8am on Saturday, for the next 23 hours. On top of it is a plot of all the storm reports that came in during that forecast time.
When examining this graphic, it’s incredible that every tornado report fell in an area under at least a Slight Risk. The majority of them did fall in the Moderate to High Risk areas. In the caption area on the convective outlooks, it says that this is a forecast within 25 miles of any given point. Based on this, the argument could be made that every tornado fell in a Moderate to High Risk forecast area. Lets go back to what is clear though on this graphic, when the SPC put out a Slight Risk or higher Saturday morning, every tornado that was reported that day fell in that shaded area. So the Outlook was issued around 7:45am, the first tornado report in Kansas was around 12:30 in the afternoon, and the next occurred an hour later. The tornadoes really got going in a time period from around 5pm-12am when there were at 1-2 dozen tornado reports each hour.
These Convective Outlook’s alone gave people at minimum of 4.5 hours of a heads up before any tornadic activity occurred yesterday, and I think really could have played a major role in people being prepared for yesterday’s weather. We constantly stress that being prepared is so important during severe weather, and yesterday is a great example of how it works. Yesterday was the first time I saw a lot of the new wording to alert people of the catastrophic damage possible from tornadoes in the severe weather statements (I blogged that 2 weeks ago http://blogs.kxan.com/2012/04/01/new-warning-system-for-severe-weather-being-tested/).
Now there were cases where people were still injured and killed, as was the case early this morning in Woodward, Oklahoma. From that graphic above, the very last tornado report listed on it, came in at 12:18am local time Sunday morning, and it was for the only reported fatal tornado of the day. People in Woodward were prepared for tornadoes yesterday and even went through a round of storms, but it was the overnight round that was fatal.
The first of 4 tornado reports in Woodward County yesterday occurred around 4pm yesterday. There were also several reports of golf ball to baseball sized hail in the county around the same time. The tornado sirens went off giving people warning of the tornado that was about to roll through the area. The storm continued to drop tornadoes on its northeast track that took it into Wichita, KS, causing significant damage in and around the city. The track continued to the northeast for a while longer before losing steam.
I think a few factors went into the late night tornado being deadly:
1. It occurred at night when it’s very difficult to see weather (because it’s dark)
2. It occurred at night when many people are asleep
3. There are mixed reports of who was able to hear the sirens at night, the fear was there may have been damage due to earlier tornadoes that day
4. It appears this may have been a more destructive tornado than the one early in the day
5. This tornado seemed to be more of a direct hit on the community of Woodward
6. The area that took a direct hit was at a mobile home park. That’s where most of the injuries and deaths occurred