Thoughts about the upcoming 2015 chase season

[Andy Wehrle]

Thanks Dan, now I might have to fall off the wagon and start model watching again after two weeks of withdrawl when things looked so pessimistic. At least I haven't had to wear my winter jacket for a week, I've got the heater off, the patio door cracked, and the ceiling fan on downdraft. In 2013 and 2014, winter "hibernation" was enforced most of the way through March here in the great white north of southern Wisconsin.

 

[Justin Wilcox]

Thanks Dan, now I might have to fall off the wagon and start model watching again after two weeks of withdrawl when things looked so pessimistic. At least I haven't had to wear my winter jacket for a week, I've got the heater off, the patio door cracked, and the ceiling fan on downdraft. In 2013 and 2014, winter "hibernation" was enforced most of the way through March here in the great white north of southern Wisconsin.

Tell me about it. I just recently decided to try the old "A watched pot never boils" method. Now that its steaming I may have to start staring again lol.

 

[Justin Wilcox]

Attended a very informative seminar regarding El Nino/PDO and the central Pacific low-frequency variability today.

It turns out there are two types of El Ninos - the traditional/classic/"canonical", and a type that is more limited to the central Pacific, called a "central Pacific warming" type of El Nino. The current pattern of SST anomalies across the Pacific is highly correlated with the typical pattern of a CPW El Nino, so we are in that kind of El Nino. I don't think the traditional ENSO index measures this type of El Nino very well, which may in part explain why the current El Nino is so "weak" (although I don't know that even an index modified to measure this type would give a much stronger value in the current scenario). It turns out that CPWs are closely linked to a positive PDO phase as well as a positive NPO, which results in high pressures over the Aleutians/Gulf of Alaska where there would typically be a semi-permanent Aleutian low.

The CPW is also a lower frequency oscillation than the canonical ENSO - this is the kicker. What this means to me is that it isn't going to change much anytime soon. This means that the planetary scale pattern that is driving the synoptic scale pattern in the CONUS will probably not change in a mean sense anytime soon.

Bottom line: it will likely be another down year in terms of total tornado count. Don't expect to see many big time troughs/open waves swinging off the Pacific and across the Rockies or the related widespread major severe weather outbreaks this year. That doesn't mean there won't be outbreaks and it doesn't mean there won't be tornadoes. Many tornadoes and localized outbreaks occur when mesoscale setups are especially conducive for severe weather (regardless of the synoptic scale setup). It just means there won't be many instances where a bigtime outbreak will show up days ahead of time in the models. Forecasts will be more challenging because events will be harder to see coming since they probably won't be apparent until the day before or the day of.

Also, since CPW has a frequency of 7-10 years, it also probably explains the recent lean years of activity (the speaker actually explicitly mentioned that the wintertime patterns of 2013/2014 and the California drought have a significant causal contribution from the current CPW event). It was hypothesized in earlier posts that this may be climate change showing itself. I think this type of event further shows that this is not related to climate change, but rather a decadal scale oscillation. There are others at play. Just know that there are a handful or more of seasonal-annual-decadal-multidecadal oscillations around the world that are all doing their thing. The total signal (the weather that we experience) is associated with the sum of all of these oscillations. Sometimes they add up in such a way as to make tornadoes happen more frequently in the US; somtimes they add up in such a way as to make tornadoes happen less frequently. It appears that for the past few years, all these entities have added up in such a way as to make tornadoes less frequent. That's just how it is.

Man good stuff Jeff. I relayed this post to one of my local weather groups and two of the NWS mets I know here had no prior knowledge of this. Gold star post!

 

[Jeff Duda]

I see that the 1991 data is omitted from the OSPO charts given the contamination from the Pinatubo eruption, but 1990 does follow that general SSTA distribution in the equatorial Pacific.

Also totally anecdotal, but 1990 and 1991 were two of the best years of the 90s for chasers, with '91 of course being perhaps the greatest ever.

I'm a bit unclear about the CPW Nino and +PDO/+NPO link. Is it implying that it is generally coincident with a +PDO/+NPO or is it an indicator of a positive tendency in the PDO/NPO in the future (or both)?

I'm not a climate researcher, so I don't know the answer. I'm just relaying information I heard from the speaker. If you really want to dig into the nuts and bolts of the matter, look up papers by Jason Furtado on AMS. There are a few recent ones that will probably shine some light on this.

I don't know how you can really say how good a given chase season is since that is highly subjective, if even quantifiable. I know @Brett Roberts has attempted to do this, but again, his methodology is as subjective as anyone else's.

 

[Andy Berrington]

I'm not a climate researcher, so I don't know the answer. I'm just relaying information I heard from the speaker. If you really want to dig into the nuts and bolts of the matter, look up papers by Jason Furtado on AMS.

Will do.

 

[Michael Gavan]

2 1/2 months in. #stillwaiting.

 

[Adam Lucio]

A kink in the flow may offer some marginal play next week. I could post 10 different things I don't like about it, and as of now the thought of chasing is as laughable as my desperation, but it may give some of the S plains locals a chance to get out and test some new gear and get into some marginal hail. Sadly thats about all I'm seeing between now and April's opening days.

 

[Matthew Crowther]

From Dr. Forbes at TWC:

"There have not been any tornadoes reported yet in March 2015. The last time this occurred was in 1969.

2015 and 1969 are the only years in the official records since 1950 with no tornadoes in the March 1-16 period.

18 of the 65 years from 1950 to 2014 had 10 or less tornadoes in this period."

Looking at the latest ensemble runs, not seeing much hope for anything much the next two weeks, I wonder if we can get through all of March with no
tornadoes at all?

 

[Robert Forry]

A kink in the flow may offer some marginal play next week. I could post 10 different things I don't like about it, and as of now the thought of chasing is as laughable as my desperation, but it may give some of the S plains locals a chance to get out and test some new gear and get into some marginal hail. Sadly thats about all I'm seeing between now and April's opening days.

Man Adam, I almost caved and started a thread on that... but looked a little closer at 12Z at lunch today and though better of it...

 

[Adam Lucio]

Man Adam, I almost caved and started a thread on that... but looked a little closer at 12Z at lunch today and though better of it...

Yea the 12z run really squished what little there was out of that system. I can't say Im surprised. The models climatology bias is really causing it to try and cook up these more "traditional" systems in a flow regime that doesn't support them at all. It seems as we get closer the GFS goes "oh yea its an east coast trough." I suppose I don't mind, I would rather not be baited out based on desperation in hopes of seeing penny size hail and a grungy shelf cloud, ALSO at the same time I don't want to be jealous of any local folks getting to see storms while I sit and endure a thunder-less March

 

[calvinkaskey]

I'm saying that during a weak, or above, el nino the conditions seem bad for tornadoes. Maybe there are more numerous weak tornadoes in places like New York like there were in at least one year but for most people on here they wouldn't care about that. I'm not saying anything about after or before. We are in a weak El NIno right now.

 

[Donnie Beasley]

I'm saying that during a weak, or above, el nino the conditions seem bad for tornadoes. Maybe there are more numerous weak tornadoes in places like New York like there were in at least one year but for most people on here they wouldn't care about that. I'm not saying anything about after or before. We are in a weak El NIno right now.

Calvin, you keep repeating the same non-sense even though several people on here, including myself, have laid out the facts for you suggesting otherwise. You only have to go back 5 years to see that what you are saying is simply untrue. I personally laid out 3 years out of just the last 25 that should have shown you that what you are saying is incorrect, but you refuse to acknowledge it and respond with your own facts. Where are your facts to back up what you are saying?

I will repeat it again: 1992, 1998, 2010, all years where we were in an el nino during storm chasing season and all these years featured above average tornado numbers with large outbreaks.

 

[Brian Hartmann]

Yea the 12z run really squished what little there was out of that system. I can't say Im surprised.

I, too, was excited by the 6z run. I think I should just put a NetNanny block on the GFS for the time being.

 

[Mark Ellinwood]

From Dr. Forbes at TWC:
Looking at the latest ensemble runs, not seeing much hope for anything much the next two weeks, I wonder if we can get through all of March with no tornadoes at all?

It would certainly be a first in our recorded history... lowest was 6 back in 1951. http://www.ustornadoes.com/2012/03/01/u-s-tornadoes-the-month-of-march-by-the-numbers/

 

[Marcus Diaz]

One good thing I'm seeing is the coming cold fronts not completely scouring moisture through the GOM. I see quite a few days later this week and next week with some meager moisture in the Plains. These are the days you pay close attention to for mesoscale accidents with boundaries. Dan talked about this on The Ghost Train, that you won't see SPC make early morning outlooks on these days until later on. We might crack this tornado-less March yet!