Tornado outbreaks: when does one end and another start

[janetjanet998]

I do believe that there has been continuous Tornado watches out since Thursday afternoon. I think(not sure) there has to be no more then a 6 hour gap in tornado reports(could be wrong) to be considered the same outbreak. Little Rock is still doing storm surveys from Thursday night lots of tornado warnings that night embedded in the line. That may fill the gap from thursday late evening into Friday morning. But there will be no such gap from Saturday to Sunday event but no gap in tornado watches

But the storms formed in same cases from the leftovers from the night before.

often in the plains, for example this will heat up in the aternoon and evening and calm down until afternoon the next day...long gaps in between watches and storms so an easy cut off. Not the case here.

so

a) is this one huge 3 day outbreak

b three seperate ones

c) two outbreaks, april 14-15 and april 16th

[tornadotony]

B...distinct separation of 6hr I believe between tornadic activity.

[janetjanet998]

B...distinct separation of 6hr I believe between tornadic activity.

LIT found at least 2 TOR's thursday overnight..not sure of the end times yet..more surveys coming

[Indystorm]

Yes, the same storm system can have multiple outbreaks depending on the time interval of breaks between tors as Tony mentioned. Arkansas had a lot of svr straight line wind damage but if tors are confirmed like those from Little Rock we could have a shorter interval. I think choice c might be a possibility dependent on future surveys.

[Mencken_Fan]

Because it's all due to the same synoptic system, I see this a single outbreak.

If a hurricane rakes the Caribbean on day one then slices across south Florida on day two followed by a day three landfall in Louisiana, is that considered three different storms? Of course not. I would apply the same rule to the recent tornadoes.

[janetjanet998]

for the 14-15th

LIT just found a tornado at 2:03 am.. the next tornado was at 10:23 am so a little over 8 hour gap

but there were a decent amount of winds/ hail severe storm reports and tornado warnings in between those reports including strong downbursts

[Amped]

Please don't encourage weenies to debate a pointless fact.

The correct answer here is who cares? Or flip a coin.

[janetjanet998]

Please don't encourage weenies to debate a pointless fact.

The correct answer here is who cares? Or flip a coin.

isn't this a weather discussion board? some us like to discuss more things then a few snowflakes

It's not a pointless fact if you want to compare it to historical outbreaks

typical east coast snow weenie response

[Amped]

isn't this a weather discussion board? some us like to discuss more things then a few snowflakes

It's not a pointless fact if you want to compare it to historical outbreaks

typical east coast snow weenie response

I'd say if iot's the same synoptic system, it's the same outbreak.

[janetjanet998]

a tornado was found at about 6am on Friday morning..this closes the 6 hour gap

so the thrusday and friday event is now definitely one outreak

[thewxmann]

I feel that tornado outbreaks should not be counted on the basis of time between tornadoes (if we had 74 tornadoes in 12 hr then 1 EF0 tornado the next 10 hours - situated at the 5 hr mark, followed by another 74 tornadoes in the subsequent 12 hr, should that be counted as one outbreak?). For my purposes I count 12Z-12Z days, but for more rigorous purposes we ought to count outbreaks by a minimum d(tornado)/dt for a minimum amount of hours threshold (or even a d(tornado index rating)/dt threshold, should one be developed - to account for 5 EF0's in contrast to 2 EF3's).

For example, if we use 3 tornadoes/hr for a minimum of 2 hours threshold, this would be counted as four separate outbreaks - the OK event, followed by the overnight AR event, then MS/AL, then NC.

It might even work better if we could use a tornado per unit time per unit geographical area thing, but that'd be difficult to compute.

Another way of doing this might be by combining a time component with a storm cluster component. In other words, outbreak counting would also involve looking at the evolution of the cells that caused the tornadoes. For instance, if the same cells produced tornadoes 6 hr apart, we could still count that as one outbreak, but if one cluster died and another tornadic storm formed, with a 5-6 hour gap in between, that'd be counted as two outbreaks. Using this method, we get three outbreaks - which I feel is ultimately the best count since 3 distinct storm clusters spawned almost all the tornadoes (the OK supercells congealed into the AR tornadic QLCS; the MS/AL supercell party which started ~5 hours after AR line produced its last tornado; the NC supercells which started well after the dissipation of the MS/AL clusters).

[Witness Protection Program]

Begins west of me, ends east of me.

YMMV