40/70 Benchmark

My mentality is to take things a bit further each successive season; building off of the conceptual framework and supporting data (composites) from prior works. I've done that over the past several years if you scrolle through the outlooks.

It goes on the show how the placement of the SST anomalies within the ENSO region and the resultant forcing schemes at least partially explains the vastly different outcomes in terms of sensible weather.

No recollection of that.

Man, you have a way of authoring posts that just drain the soul of a weather weenie, at least for those courageous enough to endure the entire length of them.

I was just thinking that RE the flip....I remember you commenting on the EURO death ridge. The way things are going, I'll get the heat ridge, but the timing will be such that the tropics still whiff lol

Yea, will probably end up OTS.

Well, we have the Carol's, Donna's, Gloria's and Bob's sprinkled in that at a greater rate of return, which are destructive enough in their own right. We are overdue for one of those.

Oh, I misread his question.

Yea, I said the same thing...but who knows regarding track, at that range.

And as far as weenies go....

CMC ends up in the GOM, and ICON near the Bahamas...NAVGEM looks like it may recurve east of Bahamas..

That actually could be worse.....it crosses near the tip of LI, as is, so much of LI would be spared the catastrophic surge. Send that 50-70mi westward if you would like to wipe them.

No. @ Pit

One day it won't-

One thing worth noting is not all East-based Nina's are frigid, as there is variability due to the relatively weak ocean-atmosphere coupling. This is because many east-based events, as is the case with modoki el nino events, are weaker. You can have warmth, especially if the event is weaker, and one such case is 2005-2006. Likewise, there were some weak modoki events that were fairly cold across the eastern US, such as 2000-20001. This is further proof that there does indeed exist a structural mechanism beyond strength that dictates the overall character of la nina events and one of the focal points of this writing is to elucidate that point. There are some "hybrid" events that share both east-based and modoki traits. You can have a Nina that is a mix of east-based versus central-based, or "basin-wide", such as both this season and last.

This is what I try to address by binning the ENSO events by structure...you can't explain everything because there are so many extemporaneous factors, but it does illuminate the issue somewhat. Given that a strong la nina is not anticipated this season, here is our running composite of successive la nina events, which remains largely unchanged. However, the composite is heavily skewed by the very anomalously mild 2011-2012, as composite is much cooler if this season is subtracted. An examination of cool ENSO events by intensity confirms that the outlier of 2011-2012 heavily skews the dataset of weak to moderate successive la nina events warm. Cool Neutral: Weak La Nina: Moderate La Nina: Strong La Nina: Clearly there are significant differences with respect to the pattern across the northern hemisphere that are at least partially governed by the intensity of the cold ENSO event. Thus it is important to focus not necessarily on whether or not the la nina event is successive, or as we will come to learn not even solely on the intensity itself, but rather precisely what structural nuances are attributable to these differences in order to properly diagnose and forecast a la nina season. Indeed, the primary difference as it pertains to North America is with respect to the Aleutian Low and its interaction with the polar fields. The stark contrast between the 2011-2012 season, which peaked with a marginally moderate ONI at -1.1, and the robust la nina of 2010-2011 with a peak of -1.6 ONI demonstrates this disparity quite well. What is also clear is that intensity, while undoubtedly a contributing factor, is not the only determinant, otherwise the strong la nina season of 2010-2011 would have been much milder for the eastern US than the rather modest la nina event of the 2011-2012 season. And for those wondering, yes, the 2010-2011 la nina was the first event, and the 2011-2012 episode was the second consecutive. However, the remaining "mild second year la nina in the east" crowd should also ponder why the strong, second year la nina event of 1955-1956, which peaked with an ONI -1.7, evolved in much the same manner as the 2010-2011 event. Thus far it has been illustrated that while stronger la nina events tend to be milder for the eastern US due to a flat Aleutian ridge and dearth of high latitude blocking, there are some stronger events such as 1955-1956 and 2010-2011 that seem to have a more poleward Aleutian ridge, similar to the weaker la nina composite. Likewise, there are also more modest la nina events, such as 2011-2012, that behave similarly to the stronger ONI composite in that the Aleutian ridge is very flat and the eastern US is very mild. This tends to correlate to a very active Pacific jet that inundates most of N America, save for Alaska, with mild Pacific air masses.

The blocking is key to avoid the inevitable and inexorable eastward leak in track upon approach that is often so crucial to averting disaster at this latitude. Surprising how many forecasters miss that.

Up to that point, its similar to Bob, but the difference is that Bob was allowed to leak east beyond that....this one is blocked, so all hell breaks lose.

I am the first one to down play potential SNE tropical scenarios, but that would be scenario to assume a different posture. That ever showed up inside of 4 days or so, I'd be guns blazing...

From reality, probably.

I like what you did for individual seasons, though...I may adopt that.

Not going to lie...this just prompted me to view a model for the first time in 6 months. That run is a special kind of "oh shit", as it intensifies on approach to the latitude of Hateras, before taking a track perhaps just east of 1938 and Gloria....that would even spell trouble for MEHthuen.

The ensembles will probably have like half of the members buried over the tallest peaks of Hispaniola, and half through the goal post.

Wasn't "at" you...obviously you know this...

Only above 700' in Tolland