2007 in regards to tornadoes

[HurricaneBill]

I think 2007 will go down as a memorable year in regards to tornadoes.

There have been many significant tornadoes this year:

The Groundhog Day Tornadoes that struck central Florida were a reminder of Florida's vulnerability to strong tornadoes during an El Nino. These tornadoes were the first to be rated using the Enhanced Fujita Scale.

The tornado that struck Lake Mack, Florida killed 13 people. This makes it the deadliest tornado of 2007 so far. It is also the third deadliest of the decade. The only two that were more deadly have been the 2006 Newbern, TN tornado (16 dead) and the 2005 Evansville, IN tornado (25 dead).

The March 1st Outbreak produced 6 deadly tornadoes, killing a total of 20 people. Georgia and Alabama were particularly hit hard.

The most infamous tornado of the outbreak was probably the Enterprise Tornado. This was one of the deadliest tornadoes to strike a school in recent memory.

The Eagle Pass Tornado will probably be an infamous tornado due to the NWS not issuing a tornado warning despite a tornado being detected.

The 8-year "F5 drought" finally ended with the Greensburg Tornado. Warnings well in advance of the tornado allowed many residents in Greensburg to take cover. Nevertheless, 95% of the town was destroyed and 10 people lost their lives.

New Mexico and Colorado also experienced their first tornado fatalities since 1974 and 1960, respectively.

Overall, about 74 have lost their lives to tornadoes so far in 2007. This makes 2007 the deadliest year since 1999 and the deadliest of the decade.

[Aquawind]

Wow that is pretty impressive and we have 5.5 months to go..

[CrazyC83]

Who knows what the summer and fall will bring? The summer fatalities are usually from northern Plains and Great Lakes mini-outbreaks and from tornadoes spawned from tropical storms and hurricanes. However, the fall (late September to mid-December) has been deadly and destructive with major outbreaks in 6 of the last 7 years...

Actually it is 6 1/2 months left, and interestingly enough, the 42 days that have passed since the last tornado fatality is the longest stretch since from September 16 to November 15 last year (60 days).

Periods between tornado deaths in 2006 and 2007:

January 13 to March 11 - 57 days
March 11 to 12 - 1 day
March 12 to 30 - 18 days
March 30 to April 2 - 3 days
April 2 to 7 - 5 days
April 7 to 13 - 6 days
April 13 to May 9 - 26 days
May 9 to August 24 - 110 days
August 24 to September 16 - 23 days
September 16 to November 15 - 60 days
November 15 to 16 - 1 day
November 16 to December 1 - 15 days
December 1 to 29 - 28 days
December 29 to January 4 - 6 days
January 4 to February 2 - 29 days
February 2 to 13 - 12 days
February 13 to March 1 - 16 days
March 1 to 23 - 22 days
March 23 to 28 - 5 days
March 28 to April 13 - 16 days
April 13 to 15 - 2 days
April 15 to 24 - 9 days
April 24 to May 4 - 10 days
May 4 to 5 - 1 day
May 5 to present - 42 days

[WindRunner]

Still one of the more interesting SPC pages to look at . . . http://www.spc.noaa.gov/climo/torn/mont ... stats.html
Particularly the image at the bottom:


Shows us up in terms of number of tornado reports over any of the recent years . . . though we could be giving that up to 2004 here shortly. I could have sworn that the chart showed more years at one point, like back to 2002 or so, but I guess that's all it does. Wish it did, though . . .

[Category 5]

We're behind 2003 I'm almost positive.

However it's been a bad year. A bunch of tornadoes will go down in history.

[CrazyC83]

We're behind 2003 I'm almost positive.

However it's been a bad year. A bunch of tornadoes will go down in history.

For up to this point I think so too. But there were no major outbreaks in the second half of 2003 (the one year this decade without at least one major fall outbreak - 2005 had four) to bring up the numbers...

[HurricaneBill]

Ironically, 2005 would have broke the record for fewest tornado fatalities had it not been for the Evansville tornado.

The current record-holder is 1986 with only 15 fatalities from tornadoes. (Ironically, the deadliest tornado that year occured in July. July tends to be the least deadly month.)

[MiamiensisWx]

Actually, it is a common misconception that June through October does not receive major tornado outbreaks. Some particularly intense outbreaks were associated with a MCS or less than ideal environment. The Palm Sunday event (1960s) is a great example; it also exemplifies the fact that many deadly tornadoes occurred before (and after) May. Many of these events occurred in June; this includes some recent events during the '80s, '90s, and 2000s.

The severe event for today is primarily producing elevated supercells, but subsidence (and lack of instability) is another mitigating factor. When you observe a MCS, the tornado threat depends upon the type of supercells (elevated or sfc-based). In addition, the juxtaposition of the warm front, helicity values, and LLJ (low-level jet) are important in these events. The amount of mid-level subsidence (and backdoor sfc winds) is a critical element, too.

[Category 5]

Usually we see one good fall outbreak.

[wxmann_91]

Actually, it is a common misconception that June through October does not receive major tornado outbreaks. Some particularly intense outbreaks were associated with a MCS or less than ideal environment. The Palm Sunday event (1960s) is a great example; it also exemplifies the fact that many deadly tornadoes occurred before (and after) May. Many of these events occurred in June; this includes some recent events during the '80s, '90s, and 2000s.

The severe event for today is primarily producing elevated supercells, but subsidence (and lack of instability) is another mitigating factor. When you observe a MCS, the tornado threat depends upon the type of supercells (elevated or sfc-based). In addition, the juxtaposition of the warm front, helicity values, and LLJ (low-level jet) are important in these events. The amount of mid-level subsidence (and backdoor sfc winds) is a critical element, too.

While I can't say big outbreaks never occur from late June through early October (better revision would be July through September), they are very rare. 2006 and 2004 was the exception rather than the rule. Actually let's revise that to non-tropical related outbreaks.

In my tornado outbreak database, the only significant outbreaks I have for July, August, & September are:
-September 20, 1967
-September 15 & 22, 2006 (still pending)

So yes, they are rare. Simple explanation: lack of dynamics and huge subtropical high keeps things capped. So even when a supercell can pop, it will likely be a slow mover and thus longer lead time. June can harbor some big outbreaks, but again, they tend to involve slower moving supercells and thus longer lead times (this June was a major exception).

Palm Sunday 1965 was in April, which is one of the deadlier months for tornadoes. (alongside March & May).

I don't know where you are getting MCS's and supercells from, because they are two totally different entities. MCS is pretty much a line. Supercells are discrete cells. But yes, due to a lack of a strong LLJ in summer, evening boundary layer decoupling is more likely to happen, so thus less nocturnal tornadoes (also contributing to the fact that the summer months are the least deadly for tornadoes).

[Category 5]

We're behind 2003 I'm almost positive.

However it's been a bad year. A bunch of tornadoes will go down in history.

For up to this point I think so too. But there were no major outbreaks in the second half of 2003 (the one year this decade without at least one major fall outbreak - 2005 had four) to bring up the numbers...

True, but May of 2003 was insanity. Wasn't there 401 in a week?

[MiamiensisWx]

While I can't say big outbreaks never occur from late June through early October (better revision would be July through September), they are very rare. 2006 and 2004 was the exception rather than the rule. Actually let's revise that to non-tropical related outbreaks.

In my tornado outbreak database, the only significant outbreaks I have for July, August, & September are:
-September 20, 1967
-September 15 & 22, 2006 (still pending)

So yes, they are rare. Simple explanation: lack of dynamics and huge subtropical high keeps things capped. So even when a supercell can pop, it will likely be a slow mover and thus longer lead time. June can harbor some big outbreaks, but again, they tend to involve slower moving supercells and thus longer lead times (this June was a major exception).

Palm Sunday 1965 was in April, which is one of the deadlier months for tornadoes. (alongside March & May).

I don't know where you are getting MCS's and supercells from, because they are two totally different entities. MCS is pretty much a line. Supercells are discrete cells. But yes, due to a lack of a strong LLJ in summer, evening boundary layer decoupling is more likely to happen, so thus less nocturnal tornadoes (also contributing to the fact that the summer months are the least deadly for tornadoes).

Thanks for the clarification. I remembered some recent outbreaks, but you are correct that most cells are elevated during these months. With regards to the MCS, I mentioned the fact that some extensive outbreaks (including elevated and sfc-based cells) were associated with a MCS as a trigger factor. Despite the presence of a MCS, a brief window for tornadic activity is extant before the sfc low occludes into a mesoscale convective system. This occurred during the progression of some outbreaks (in June through October).

[wxmann_91]

Thanks for the clarification. I remembered some recent outbreaks, but you are correct that most cells are elevated during these months. With regards to the MCS, I mentioned the fact that some extensive outbreaks (including elevated and sfc-based cells) were associated with a MCS as a trigger factor. Despite the presence of a MCS, a brief window for tornadic activity is extant before the sfc low occludes into a mesoscale convective system. This occurred during the progression of some outbreaks (in June through October).

I'm sorry, I don't know what you're saying. Some of the bigger tornadic events these months are related to either upslope flow in the High Plains or some supercell developing in an environment with insane instability, and subsequently attaching to a boundary. Keep in mind that MCS's usually develop at the tail end of an outbreak.

[wxmann_91]

We're behind 2003 I'm almost positive.

However it's been a bad year. A bunch of tornadoes will go down in history.

2003 had 1054 tornadoes in the first half of the year, but that includes about 100 from June 22-24. So as of right now, we're pretty darn close. 2003 was very inactive actually (no tornadoes in January, below average March-April, mostly inactive late May and early June... early May was the only active time period up until late June).

[MiamiensisWx]

Thanks for the clarification. I remembered some recent outbreaks, but you are correct that most cells are elevated during these months. With regards to the MCS, I mentioned the fact that some extensive outbreaks (including elevated and sfc-based cells) were associated with a MCS as a trigger factor. Despite the presence of a MCS, a brief window for tornadic activity is extant before the sfc low occludes into a mesoscale convective system. This occurred during the progression of some outbreaks (in June through October).

I'm sorry, I don't know what you're saying. Some of the bigger tornadic events these months are related to either upslope flow in the High Plains or some supercell developing in an environment with insane instability, and subsequently attaching to a boundary. Keep in mind that MCS's usually develop at the tail end of an outbreak.

You're correct. I meant most severe tornadic events associated with a pre-MCS system occur within a narrow timeframe before the MCS actually forms. During this narrow window, instability is at its peak. I apologize for my vague description.

[wxmann_91]

Thanks for the clarification. I remembered some recent outbreaks, but you are correct that most cells are elevated during these months. With regards to the MCS, I mentioned the fact that some extensive outbreaks (including elevated and sfc-based cells) were associated with a MCS as a trigger factor. Despite the presence of a MCS, a brief window for tornadic activity is extant before the sfc low occludes into a mesoscale convective system. This occurred during the progression of some outbreaks (in June through October).

I'm sorry, I don't know what you're saying. Some of the bigger tornadic events these months are related to either upslope flow in the High Plains or some supercell developing in an environment with insane instability, and subsequently attaching to a boundary. Keep in mind that MCS's usually develop at the tail end of an outbreak.

You're correct. I meant most severe tornadic events associated with a pre-MCS system occur within a narrow timeframe before the MCS actually forms. During this narrow window, instability is at its peak. I apologize for my vague description.

Well, that goes for most major outbreak situations regardless of the time of year. But thanks for the clarification

[CrazyC83]

Actually, it is a common misconception that June through October does not receive major tornado outbreaks. Some particularly intense outbreaks were associated with a MCS or less than ideal environment. The Palm Sunday event (1960s) is a great example; it also exemplifies the fact that many deadly tornadoes occurred before (and after) May. Many of these events occurred in June; this includes some recent events during the '80s, '90s, and 2000s.

The severe event for today is primarily producing elevated supercells, but subsidence (and lack of instability) is another mitigating factor. When you observe a MCS, the tornado threat depends upon the type of supercells (elevated or sfc-based). In addition, the juxtaposition of the warm front, helicity values, and LLJ (low-level jet) are important in these events. The amount of mid-level subsidence (and backdoor sfc winds) is a critical element, too.

While I can't say big outbreaks never occur from late June through early October (better revision would be July through September), they are very rare. 2006 and 2004 was the exception rather than the rule. Actually let's revise that to non-tropical related outbreaks.

In my tornado outbreak database, the only significant outbreaks I have for July, August, & September are:
-September 20, 1967
-September 15 & 22, 2006 (still pending)

So yes, they are rare. Simple explanation: lack of dynamics and huge subtropical high keeps things capped. So even when a supercell can pop, it will likely be a slow mover and thus longer lead time. June can harbor some big outbreaks, but again, they tend to involve slower moving supercells and thus longer lead times (this June was a major exception).

Palm Sunday 1965 was in April, which is one of the deadlier months for tornadoes. (alongside March & May).

I don't know where you are getting MCS's and supercells from, because they are two totally different entities. MCS is pretty much a line. Supercells are discrete cells. But yes, due to a lack of a strong LLJ in summer, evening boundary layer decoupling is more likely to happen, so thus less nocturnal tornadoes (also contributing to the fact that the summer months are the least deadly for tornadoes).

When there are summer outbreaks, they are usually in the northern Plains (like the Dakotas, Minnesota and Wisconsin) and in the central Great Lakes. June has had its fair share of outbreaks, such as June 2, 1990 and June 15, 1992.

Last September was unusual in that they had a fall outbreak feel to them.

Tropical-related events don't count. (They are the main producer for summer outbreaks)

[Category 5]

We're behind 2003 I'm almost positive.

However it's been a bad year. A bunch of tornadoes will go down in history.

2003 had 1054 tornadoes in the first half of the year, but that includes about 100 from June 22-24. So as of right now, we're pretty darn close. 2003 was very inactive actually (no tornadoes in January, below average March-April, mostly inactive late May and early June... early May was the only active time period up until late June).

Early may 2003 was incredible. 401 tornadoes in 10 days.

However, it's not how many tornadoes we have, it's what they do. A single tornado can define a year. (when you think of the 1979, 1991, and 1999, you likely think of one tornado. Wichta Falls, Andover, and Moore respectively). Just like a tornado outbreak almost always has a tornado or two that stands out from the rest.

It hasn't been the most active tornado season, but we've had alot of bad tornadoes. Lady Lake, Forest Hills, Enterprise, Eagle Pass, and of course Greensburg, which was likely the defining tornado of the year, maybe the decade.

[CrazyC83]

This fall will be quite active too I think. One thing it seems is that in the November 9-18 period seems to be the secondary peak. (November 15 has been remarkably active in recent years, since 1988 there have been at least four outbreaks on that day)