2018 Indicators: SST's / MSLP / Sal / Steering / Shear / Instability (Graphic updates at first post)

[cycloneye]

To refresh the memory about the tracks of the systems that formed in 2014.



EPAC was very active that year with Odile making landfall in Cabo San Lucas as cat 4.

[wxman57]

But like I said, SSTs are only one factor. Interesting, though, in light of GWO's proclamation of a well above-normal season with 4 U.S. hurricane landfalls...

[CyclonicFury]

To refresh the memory about the tracks of the systems that formed in 2014.

https://i.imgur.com/JrhtVP6.gif

I have a hard time believing we’ll see a season that quiet. 2014 was coming off 2013 and we all know how that season went. I don’t think the deep tropics will be as hostile as 2014, either, where all the hurricanes occurred north of 20N. Subtropics should be more favorable than usual yet again this season. Could be an active Gulf year as well, though this is challenging to predict the activity of that part of the basin well in advance. Models are mostly showing near or slightly below average shear for most of the Atlantic.

This forecast is very challenging, much like recent years. I think the major forecasting agencies will predict a near average season in April because of the mixed signals.

[CyclonicFury]

EPAC activity is another possible wild card. If the EPAC is not very active, we could see more Atlantic activity. If the EPAC is very active, that could limit the Atlantic quite a bit. Last season the Atlantic did not take off until the EPAC slowed down, and that was also the case in 2016. +PDO signal could help the EPAC and hurt the Atlantic a bit.

[wxman57]

I'm not forecasting a quiet season like 2014, only pointing out the similarities in the SST anomalies as of March compared to 2014.

[NDG]

I like 1985 as an analog year since I think the ENSO will stay neutral to cool neutral for the rest of the season. IMO.

[TheStormExpert]

I like 1985 as an analog year since I think the ENSO will stay neutral to cool neutral for the rest of the season. IMO.

1985 had 6 of the 7 hurricanes strike the U.S. with all three of the major hurricanes hitting the U.S. as well. Of course there was only 11 named storms that year but overall it was a West Atlantic based season with an active Gulf of Mexico.

A season like that would be more devastating than 2017 if it were to occur in this day and age.

[Shell Mound]

I like 1985 as an analog year since I think the ENSO will stay neutral to cool neutral for the rest of the season. IMO.

1985 had 6 of the 7 hurricanes strike the U.S. with all three of the major hurricanes hitting the U.S. as well. Of course there was only 11 named storms that year but overall it was a West Atlantic based season with an active Gulf of Mexico.

A season like that would be more devastating than 2017 if it were to occur in this day and age.

Respectfully, I would tend to disagree. Of the three majors of the season, only one, Elena, was actually still a major hurricane at the time of its landfall on the United States (100 knots). Gloria and Kate had weakened to below major status at the time of their impacts. None of the majors was strong for a very long time, compared to several of the majors in 2004 and 2017, including Frances, Ivan, Irma, Jose, and Maria. Additionally, the seasonal and individually generated ACE was far lower in 1985 than in 2017. One does not need a large quantity of storms to generate a high ACE index, but a large proportion of strong, long-lived ones—especially strong, long-lived cyclones that make landfall at high intensity. 2017 had multiple Cat-4 and Cat-5 landfalls each, in TX (Harvey, Cat-4), Barbuda (Irma, Cat-5), St. Martin (Irma, Cat-5), the USVI (Irma, Cat-5), Cuba (Irma, Cat-5), FL (Irma, Cat-4), Dominica (Maria, Cat-5), and PR (Maria, Cat-4), while 1985 had one low-end Cat-3 impact, in MS. A below-average season of ten named storms, with six Irma-, Jose-, or Maria-type majors, would produce a higher ACE than 2012, which had nineteen named storms but only two that briefly attained major status. 1985 was destructive, to be sure, but it was far from a season like 2004, 2005, or 2017. If I recall correctly, 2017 had more Cat-4+ landfalls, basin-wide, than any other Atlantic season on record.

If 2018 were to stay in neutral ENSO in time for peak season, as in 2017, I would potentially expect a large proportion of intense long-trackers relative to the total number of storms, which may indeed be lower than in 2017. Therefore, 2018 could still produce an ACE comparable to that of 2017, even should it generate fewer named storms. This, of course, depends on how intense the majors get, and the duration of their peak winds. What makes a season destructive, though, is neither the number of storms nor the ACE by itself, but the number, intensity, and location of landfalls, which are dependent on steering currents and atmospheric conditions, including vertical wind shear.

[Shell Mound]

 https://twitter.com/MJVentrice/status/972137488088223747



 https://twitter.com/MJVentrice/status/972137993116028929



 https://twitter.com/PaulRoundy1/status/972139048562241537



 https://twitter.com/MJVentrice/status/971846442003427328




...




Overall, the prospects for the 2018 season, predictably, remain uncertain, as the signals are mixed at this time. On the one hand, the far North Atlantic (50-60°N, 50-10°W) exhibits colder SST anomalies than at this time in 2017, as does the MDR on balance (10-20°N, 20-60°W). However, the western MDR and much of the Caribbean are running at or above 2017-type levels, in terms of SST anomalies. Additionally, the relative warmth near the Azores, which is greater than in 2017, is typically a +AMO signature, as is the relative cold to the south (but not east) of Newfoundland. Another complication is that the +IOD (cold eastern Indian Ocean, warm western), if sustained, could favour westerly wind bursts later and hence promote the development of El Niño. Nevertheless, until the NAO went strongly positive over the past few months, the wintertime +AMO was notably stronger than in 2017, and Atlantic SSTs are currently recovering rapidly, as the NAO has recently been sharply negative. Thus, as in 2017, we may not know for some time how this upcoming season may evolve.

 https://twitter.com/webberweather/status/971822015807180800



 https://twitter.com/webberweather/status/971826889122775041

[Andrew92]

I have my own theory for this upcoming hurricane season if it doesn't go El Nino, but is warm neutral. One important thing to consider is that it has been three years since the last El Nino year. With that, what seasons were three years after an El Nino, and were warm neutral?

I can think of just two such seasons in recent memory: 1990 and 2012. Both years had an impressive number of named storms, and a decent number of hurricanes too. But there were also very few major hurricanes. 1990 just had Gustav for less than a day, and 2012 had Michael for a short period of time and Sandy.

Most of the storms in those two years stayed out to sea, but there nonetheless were some solid threats. Diana deluged Mexico, Klaus did something to warrant retirement in the Lesser Antilles I think, Marco caused flooding in the Southeast (combined with the remnants of Klaus), and Lili briefly threatened the East Coast. Didn't Bertha also hit Newfoundland too? Meanwhile in 2012, we all know about Isaac and Sandy, but Ernesto followed a similar path to Diana (just a longer version really), and Beryl and Debby were early-season troublemakers for Florida too.

All in all, a season like 1990 or 2012 is probably what I would expect. An active season overall with some decent threats, but the majority of the activity staying out to sea. Then again, this is a very small sample size. One thing I have discovered though is that hurricanes have a harder time reaching the US when it's been three years since the last El Nino. It happened twice in 2012 though, so I definitely still advise that you be prepared if you live in hurricane territory.

-Andrew92

[CyclonicFury]

CFS shows the MDR warming up quite a bit by July, could be big if El Niño doesn’t form.

[NotSparta]

CFS shows the MDR warming up quite a bit by July, could be big if El Niño doesn’t form.

Wouldn't be surprising, not much to change for that to happen

[Shell Mound]

 https://twitter.com/MJVentrice/status/973148667782877184



 https://twitter.com/antmasiello/status/973161902560989184



 https://twitter.com/antmasiello/status/973166558053847044




...


Note the pronounced warming of the MDR since mid-February, coincident with the -NAO.

This persistent -NAO regime probably portends (ongoing) continued warming of the tropical Atlantic through early April, at the very least.

[TheStormExpert]

It seems from the looks of things and knowing that it will likely be the third year after an El Niño season unless one was to form that this season may be another quantity over quality type season a lot like 1985, 1990, or 2012.

Steering pattern wise I’m think something like 1985 with several mainland U.S. impacts especially along the northern Gulf Coast region which the current record warm SST’s in the Gulf could easily backup.

Way too soon to go more into specifics and what I currently think likely and hopefully won’t pan out but these are my thoughts at the moment.

[Pressure]

 https://twitter.com/MJVentrice/status/973148667782877184



 https://twitter.com/antmasiello/status/973161902560989184



 https://twitter.com/antmasiello/status/973166558053847044




...


Note the pronounced warming of the MDR since mid-February, coincident with the -NAO.

This persistent -NAO regime probably portends (ongoing) continued warming of the tropical Atlantic through early April, at the very least.

This is pretty interesting, the pattern of warming under the -NAO that may persist is coming out to be a textbook +AMO horseshoe, similar to an early 2000's signature

[StruThiO]

accidently posted to wrong thread but long range NAO may be going negative again

[AnnularCane]

accidently posted to wrong thread but long range NAO may be going negative again

What does that mean again?

[cycloneye]

AnnularCane Means more warmer sst's in MDR.

[StruThiO]

accidently posted to wrong thread but long range NAO may be going negative again

What does that mean again?

(someone feel free to correct me if i am wrong) a -NAO means a weaker than normal subtropical high and ridging over Greenland, +NAO means a robust subtropical high.
 https://twitter.com/philklotzbach/status/961663911362666497


<-- this is from when the NAO was in its positive phase. SO a -NAO = weaker trade winds that otherwise upwell the water, allowing it to warm.

[cycloneye]

The March MSLP update by ECMWF for June,July and August has very high pressures over most of Atlantic.