2013 Steering Pattern / Early indicators

[Kingarabian]

Well at least the high shear over the Atlantic is on cue with these Warm-Neutral predictions.

[Alyono]

the same models that predicted el niño last year are doing the same.

I'm also reminded that the models have very little skill in predicting ENSO. Even when it was clear there would be no el niño last year, they still predicted it.

What does CLIPER say?

[Alyono]

Well at least the high shear over the Atlantic is on cue with these Warm-Neutral predictions.

ITS JUNE!

[TheStormExpert]

Well at least the high shear over the Atlantic is on cue with these Warm-Neutral predictions.

Actually shear is about average to slightly below average in The Tropical Atlantic (MDR). Overall shear is still high throughout the Atlantic Basin in June.

Tropical Atlantic Shear

East Coast Shear

Gulf of Mexico Shear

Caribbean Shear

Subtropical Atlantic Shear

[cycloneye]

the same models that predicted el niño last year are doing the same.

I'm also reminded that the models have very little skill in predicting ENSO. Even when it was clear there would be no el niño last year, they still predicted it.

What does CLIPER say?

Weak La Nina.

Code: Select all

Landsea/Knaff CLIPER   -0.5   -0.5   -0.6   -0.6   -0.6   -0.6   -0.5   -0.5   -0.4

http://iri.columbia.edu/climate/ENSO/cu ... table.html

[cycloneye]

I have seen in other sites that after the information that has been posted in this thread in the past few hours and has spread to the other forums in the internet,there are some talking about downgrading the numbers for the season. Levi Cowan puts this situation in a good perspective in a tweet.

Levi Cowan ‏@TropicalTidbits 10h
It's not time to throw in the towel, but either the models or the humans are going to be horribly wrong about this hurricane season.

https://twitter.com/tropicaltidbits

[crownweather]

Yep, I agree with Levi. Not reducing my storm numbers, I think this is just too big of a flip in the guidance to be trusted.

I am currently working on writing up a blog post on this new information & the flip in the parameters forecast.

[tolakram]

I'm still on board with my non-scientific call that we are due an El Nino and it's going to sneak up on us. Law of averages and all that.

[cycloneye]

It will be interesting to see if the experts (CSU,TSR,NOAA etc) tune down the numbers in their August forecasts. I don't think it will happen without El Nino but who knows. As Levi Cowan said "Or the Models or Humans are wrong about the season".

[Alyono]

the same models that predicted el niño last year are doing the same.

I'm also reminded that the models have very little skill in predicting ENSO. Even when it was clear there would be no el niño last year, they still predicted it.

What does CLIPER say?

Weak La Nina.

Code: Select all

Landsea/Knaff CLIPER   -0.5   -0.5   -0.6   -0.6   -0.6   -0.6   -0.5   -0.5   -0.4

http://iri.columbia.edu/climate/ENSO/cu ... table.html

I remember hearing before that that can be the most skillful model

[Bocadude85]

Well if the Euro forecast verifies then South Florida very well may escape another year without a tropical cyclone landfall. If we do not have a landfall in South Florida this year then it will be the longest stretch in history that my area has gone without a impact.

[WeatherEmperor]

Well if the Euro forecast verifies then South Florida very well may escape another year without a tropical cyclone landfall. If we do not have a landfall in South Florida this year then it will be the longest stretch in history that my area has gone without a impact.

What does the Euro forecast show that would indicate that south florida may escape another year of tropical cyclone landfall?

Sent from my HTC EVO 4G LTE

[Riptide]

Another aspect to consider is that above normal high pressures do not necessarily imply decreased TC activity. Instead, a pattern featuring very strong and above average high pressure systems would create the illusion that there is no low pressure on the long-term average activity but rather these regions are punctuated briefly by occasional tropical cyclones may be the theme this season and I don't necessarily think that it represents which areas are protected from hurricanes this year.

Quality over quantity per se.

[hurricanetrack]

Question: could the GOES 13 outage have affected data that went in to these models? We went quite a number of weeks with no GOES 13 data, correct? Just wondering if that had an impact. You never know....

[cycloneye]

Question: could the GOES 13 outage have affected data that went in to these models? We went quite a number of weeks with no GOES 13 data, correct? Just wondering if that had an impact. You never know....

That is a good observation Mark. Let's see if we find out the why question but your point has to be explored.

[Alyono]

we had GOES 14 and that almost certainly was assimilated into the models.

[chaser1]

...there are some talking about downgrading the numbers for the season. Levi Cowan puts this situation in a good perspective in a tweet.

Levi Cowan ‏@TropicalTidbits 10h
It's not time to throw in the towel, but either the models or the humans are going to be horribly wrong about this hurricane season.

https://twitter.com/tropicaltidbits

I enjoy reading Levi's blog/video's and previously wrote him on the topic for his added perspective to my line of thought on the subject. Am posting this here since we're on the subject (and seemingly in the right thread") and would be eager for anyone else's take on my general observation/analysis regarding the present Atlantic conditions and unfolding season. I believe Levi also twittered (or bloged) "UKMET has abruptly shifted to showing an unfavorable setup for the Atlantic hurricane season, along with the CFS...." I think he also referenced other models were now suddenly switching around and no longer being "bullish" on an active Atlantic Hurricane season.

While there is no evidence to anticipate a late summer/early fall El Nino to take place, I do think there is something else at play here and can't quite put my finger on it. I realize that the month to month MDR upper level winds have shown to be near (or even below average), I have 2 thoughts regarding recent and current Atlantic conditions.

1) If I am correct, analysis of the different Atlantic regional upper level winds are based on a "deep layer mean" which consist of 250mb levels down to the 850mb levels and thus believe that the persistent strength of upper level 200mb winds which have been nearly consistent through most of the Atlantic basin, have been slightly "muted" by some of the lower level winds used to determine deep layer mean. Thus perhaps suggesting a "less than hostile" upper level environment than what one can more plainly see if simply looking at present 200mb data and recent historical 200mb flow.

2) I think some of us (and nearly everyone in the media or general public) tend to over examine El Nino/La Nina to the point where every weeks data is analyzed to determine if we are soon to experience one or the other as if this were the number 1 condition likely to impact our hurricane season each year. That said, there remains this one sole persistent condition that continues to trouble me, at least from a perspective of quite grasping its origin along with its potential evolution. A sub tropic band of upper level westerly winds exists now and has been sonsistantly strong now for nearly 60 days. It may be solely transitory, but I think this large feature may have a longer range impact on our season.

It's a given that moderate or strong El Nino/La Nina events impact global weather. Throw in Kelvin Waves, NAO's, Long Wave patterns, etc. and just when we think we're starting to figure much of it out, Mother Nature throws a new curve ball at us (cosmic radiation, etc. - who knows? LOL). So, if newer models begin to suggest that the summer months "could show" lower mid level heights (less ridging), this could certainly have an impact on greater pole-ward potential storm motion. Might lower heights also aid to the present increased Atlantic instability? On the flip side, indications might be that models are now indicating possibly "higher" surface pressures through much of the Atlantic (though lower in the Caribbean during Sept. I think), and finally indications of present upper level shear conditions to likely to continue to be persistent through at least the remainder of the month.

Though less intense through the MDR, it is this band of winds that have been an oddly strong and persistent band of strong westerlies which has continued to traverse the Gulf, across Florida and continuing Eastward to Africa. It's appearance would seem more like a "sub tropical jet max", in that this band has existed south of decent upper level ridging that seemed to be holding on over the East Conus and parts of the North Atlantic. El Nino is most typically regarded as a buffer to development due the the stronger westerly shear conditions over much of the lower latitudes of the Caribbean and Central Atlantic MDR. I seem to recollect that here in S. Florida this flow would indeed cause a sub tropical "split flow" under the main Westerlies that would cause warmer than normal S. Florida winters. While Pacific SST's would indicate that no El Nino is presently in play, I can't help but notice the never ending flow of strong Upper level winds that have continued to blow in from the west and extending over much of the Atlantic sub tropical regions and actually throughout much of the Atlantic MDR as well.

Some who I have talked to have been quick to simply state, "well, its just May" (and then "June"). I think this significantly underscores the point, the prior 60 days persistence of this UL flow, and that this feature seems far more prominent than perhaps a small band of westerlies being funneled into some pole-ward East Coast TUTT. In fact, I would almost characterize this feature to appear more like a "trans-Atlantic" east/west running TUTT (contrary to how East Coast TUTT features are normally oriented).

Still though, assuming greater than recent year average atmospheric instability and minimal SAL conditions, coupled with average or slightly above average SST's a heightened quantitative number of tropical cyclones might well still occur. But assuming the persistent (not El Nino, but like El Nino) upper level conditions, I now think this could cause a decreased number of named storms, at least as compared to the number of named storms that most (I included) had originally anticipated. I now would anticipate fewer (or no?) Cape Verde "long tracks". Assume that most of the tropical cyclone development will occur in the farther south latitudes where upper level shear is less impacting, along with another zone of development to occur in the N.W. Atlantic - north of 35N, and developing north of this split layer of strong upper level winds. Finally, I would guess that we might see faster "spin ups" such as Andrea to occur and depending on the location of the less dominant but likely enhanced height & smaller upper level anticyclones....still think we'll see a couple of quick developing (but shorter lived) major hurricanes which may well impact the Greater Antilles, Central America, and Gulf regions.

[HURRICANELONNY]

I hope Levi is right and the pro mets were way off. I hope they all go poleward and away from the US. Things can change quickly in the tropics. So best to be prepared and hope he's right. At least it would bring down the probability of a landfalls. I have a bad feeling about this year.

[Kingarabian]

I think it's gonna be a compromise of both Human and Computer model forecasts. Something in between.

Humans can't make do without Computer models.
Computer models can't make do without Humans.

We need each other, <3.

[Stormlover2012]

I think they are jumping the gun, I mean flip flop on models one time and we are going to jump the gun now, just bite the bullet and stick with what ur first thought was for this hurricane season and if ur wrong then u can say ur wrong in the end.