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andyhb

Predict/Guess the Number of Tornadoes and the First High Risk of 2015

Number of Tornadoes in 2015  

64 members have voted

  1. 1. Number of Tornadoes



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Well it's that time of year again as the new year rapidly approaches. We are breaking out of the multi-year neutral ENSO phase into a Nino which may offer some promise to the High Plains/W TX for the first time in several years. After we thought things couldn't get much quieter overall after 2013...they did, with this year likely being the quietest on record in the modern detection era, despite a couple of more impressive events in late April and mid June. It seems a +PDO is likely to hold through at least a part of Spring, and Nino climo suggests that May and June may be the months to watch.

 

Analog wise, at least for the winter in terms of what they did in the following springs, it is a bit of a mixed bag with years such as 2003 and 1977 being pretty active and some of the 1980s analogs (1980, 1987 and 1988) being ones best left forgotten. I'll post a poll for this year in terms of numbers of tornadoes, but it would be good to hear everyone's thoughts as always on what could be in store for 2015. I do think this should be a more active year for chasers in the Plains. Years with strong +PDOs, however, tended to be on the quieter side.

 

For number of tornadoes, I'll go with 1065.

 

For the first high risk, I will go with April 29th.

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1124 

 

First high risk May 16th. If this winter plays out like some people (hope) it will then the severe season might be delayed a bit again next spring. 

 

1124 is 1100-1200.

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This is the first time since 2009-10 we've had > +0.5°C SSTAs in Nino 3.4 during the late fall and early winter months. Before that, the last instance was 2006-07. Looking strictly at the Nino 3.4 timeseries, the second half of 2014 resembles 2006, albeit with the magnitude of warmth a bit muted in the current case. Also, all the cases since 1990 for which the SSTA was ~1.0-1.5°C at this time of year after trending upward through the autumn (1991-92, 1994-95, 2002-03, 2006-07, 2009-10) were fairly active for the southern and central Plains. While none of this means a lot in isolation, I'll go ahead and predict a fairly average year nationally (~1350) with substantially improved prospects for the southern and western areas of the Plains versus the past several years (not saying a lot). Drought improvement will hopefully come in earnest by late January or February, as was the case in 2007.

 

EDIT (Jan 31): after looking into the issue raised by andy of +PDO climo (see post 31), I'm going with 1000-1100 and wouldn't be surprised to see yet another relative dud year on the Plains.

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This is the first time since 2009-10 we've had > +0.5°C SSTAs in Nino 3.4 during the late fall and early winter months. Before that, the last instance was 2006-07. Looking strictly at the Nino 3.4 timeseries, the second half of 2014 resembles 2006, albeit with the magnitude of warmth a bit muted in the current case. Also, all the cases since 1990 for which the SSTA was ~1.0-1.5°C at this time of year after trending upward through the autumn (1991-92, 1994-95, 2002-03, 2006-07, 2009-10) were fairly active for the southern and central Plains. While none of this means a lot in isolation, I'll go ahead and predict a fairly average year nationally (~1350) with substantially improved prospects for the southern and western areas of the Plains versus the past several years (not saying a lot). Drought improvement will hopefully come in earnest by late January or February, as was the case in 2007.

 

Yeah I agree with this to a degree, although I still think a relatively below avg year is on tap especially if March and April turn out quiet. I've looked at some composites of springs following a strong +PDO (>1 degree anomaly) winters as well and they seem to favour the western portions of the Plains. Panhandle magic might be on tap again for the first time in what seems like an eon.

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This is the first time since 2009-10 we've had > +0.5°C SSTAs in Nino 3.4 during the late fall and early winter months. Before that, the last instance was 2006-07. Looking strictly at the Nino 3.4 timeseries, the second half of 2014 resembles 2006, albeit with the magnitude of warmth a bit muted in the current case. Also, all the cases since 1990 for which the SSTA was ~1.0-1.5°C at this time of year after trending upward through the autumn (1991-92, 1994-95, 2002-03, 2006-07, 2009-10) were fairly active for the southern and central Plains. While none of this means a lot in isolation, I'll go ahead and predict a fairly average year nationally (~1350) with substantially improved prospects for the southern and western areas of the Plains versus the past several years (not saying a lot). Drought improvement will hopefully come in earnest by late January or February, as was the case in 2007.

It's funny you bring up '06-'07 a couple times because that's basically what I formed my guess off of.  I'm not a climate guy, but I remember that winter, and it just feels (for what little that's worth) kinda like a deja vu right now, from the December warmth up here (I'm home for Christmas) all the way down to the Christmas week tornadoes down south.  I know ENSO is similar as you mentioned, and given that we've had a few events this December, I feel it's going to be an active early season (Jan-Mar) along the Gulf Coast states.

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I kind of thought the strong +PDO this cold season (assuming it continues into March and beyond at least to some degree) would differentiate this case a bit from 06-07, since that winter was basically neutral with that particular index.

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While none of this means a lot in isolation, I'll go ahead and predict a fairly average year nationally (~1350) with substantially improved prospects for the southern and western areas of the Plains versus the past several years (not saying a lot). Drought improvement will hopefully come in earnest by late January or February, as was the case in 2007.

 

Not sure if you've seen the Stormtrack thread for this, but there are some thoughts being tossed around.

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If we get another few years of sub-1000 tornadoes, we might have to at least consider that possibility.

 

I think it will have to do more with the insanely strong +PDO taking over everything, if we do get another sub-1000 season.

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I'd totally be fine with a season similar to the past two chase wise.

 

Quality>quantity.

 

I'd rather have a bit more quantity in the quality though than last year...

 

May was pretty much a dud unless you like RFD-dominant/undercut/HP messes. If you weren't out in the 6/16-18 span, it was probably the worst chase season (especially tornado wise) on record.

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Consensus as of now appears to be slightly below average in the 1000-1200 range, with some going for yet another sub-1000 year.

 

That western ridge is definitely going to have to either shift out of its short-range position, be undercut by the ST jet or be broken down somewhat by spring to get towards average.

 

Boy, the next year that even just reaches the climatological average will seem hyperactive, let alone one in the 1999/2008 category.

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Here are a few stats. Since 1988, (data is limited prior to this year) the "week" with the most high risk outlooks was April 23-29, with 10 out of 27 years (37%) having a high risk outlook in that period. The majority of these outlooks have been issued between April and May. Some spill out into June and occasionally both the winter and fall seasons have seen one.

 

As far as the first high risk outlook in a given year, the average comes out to be April 24th. If 2000 is excluded, as there were no high risk outlooks that year, the average shifts to April 14th. 

post-533-0-14111900-1421856759_thumb.gif

Month breakdown of first high risk outlook in a given year since 1988:
Jan: 1

Feb: 2

Mar: 7

Apr: 10

May: 2

Jun: 3

Nov: 1 

 

One consideration is that the confidence in issuing a high risk outlook may have increased in recent years, but I did not take a look at the frequency of high risk outlooks issued per year by time period, or the verification of high risk outlooks in the past.

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