2017 EPAC Season

[Yellow Evan]

So it's time to make this thread, with 2016 basically done.

I thought 2016 was a tricky forecast ahead of time. However, so far, I don't feel that way about 2017. With similar +PDO and similar ENSO state, I think a season similar to 2016 is likely in all basins to be honest, in what was a remarkable year for tropical cyclones globally. Wind shear should be low, I can't see SST's getting much if any cooler, and I'd say something like 1985 is a good early analogue for 2017. Not ready to pull out initial preliminary numbers though.





























Poll numbers from Storm2k users: (will close at 12:00 AM June 1 PDT, you can change your numbers at any point before then. Counting CPHC AOR storms.)
1. Ntwx- 21/13/7 ACE:184
2. cycloneye- 20/11/5 ACE: 160
3. Kingarabian- 20/12/5
4. Hurricanes1234- 19/12/5
5. Weathaguyry- 17/9/4
6.

[Alyono]

Not as confident that next year will be the hyperactive season that this one was

[hurricanes1234]

Me neither. I think we may just get an average season next year. Personally I believe the active streak of seasons could be drawing to a close, unless somehow ENSO manages to flip back to El Niño.

IMO the chance of a hyperactive season still lingers, but a normal one seems more likely at this point.

However, it's still very early and it's anybody's game.

[Yellow Evan]

Why would it shift back to normal assuming the conditions aren't very different? 1983-85 was one of the busiest stretches (after 1982-84 and 2014-16) in EPAC history, yet 1984 and 1985 were definitely La Ninaish. Expect basin SST's to drop after being high for 3 years?

Also be careful what you wish for. An El Nino could mean a lesser active season like 1991 and 1986, especially if it's west based/Modoki.

[Yellow Evan]

December EPAC SST (24.365 C) 3rd highest on record after the last 2 years.

[Kingarabian]

For me it all comes down to the PDO. It's very likely we wont be having a La Nina for the summer of 2017, instead we should see ENSO at warm neutral/Nino.

If the PDO remains as strong as it was for 2016, there should be no problem in seeing activity happening in bunches.

[Ntxw]

For me it all comes down to the PDO. It's very likely we wont be having a La Nina for the summer of 2017, instead we should see ENSO at warm neutral/Nino.

If the PDO remains as strong as it was for 2016, there should be no problem in seeing activity happening in bunches.

All signs pointing to +PDO returning for 2017. 2016 many tried to kill off the PDO second half of the year but it remained positive the entire time.

[Yellow Evan]

Yea I can't see PDO turning negative, given how consistent it's been the past 3+ years.

[cycloneye]

Key words from Levi are "Very uncertain this early"

 https://twitter.com/TropicalTidbits/status/820329738992578561




 https://twitter.com/TropicalTidbits/status/820330149967265794

[Kingarabian]

Key words from Levi are "Very uncertain this early"

 https://twitter.com/TropicalTidbits/status/820329738992578561




 https://twitter.com/TropicalTidbits/status/820330149967265794

2009 and 2015 were active EPAC seasons in my book.

[Yellow Evan]

Every season but 1953 of those listed were active.

[Yellow Evan]

https://www.esrl.noaa.gov/psd/cgi-bin/d ... Timeseries

EPAC SST's for Jan lowest since 2014, but 4th highest overall behind 1994, 2015, and 2016.

[Yellow Evan]

https://www.esrl.noaa.gov/psd/cgi-bin/d ... Timeseries

Feb 2017 only 6th warmest SST's on record (behind 2015, 2016, 1994, 1995 and 1996). March 2017 tied with 1994 for 3rd warmest behind 2015 and 2016.

[cycloneye]

Interesting information by Levi about the tracks density anomalies in EPAC.

 https://twitter.com/TropicalTidbits/status/851430254128357379

[Yellow Evan]

SST's plot of similar east-based El Ninos. I don't know what this means for the PHS. I don't trust the dataset prior to like 1980, and 1993's El Nino went nowhere.

[Yellow Evan]

Get ready to watch the EPAC in the not too distant future. The NASA model- the best at long term genesis model there is when the other models are less bullish- shows a system forming in the South Pacific near Tonga in early May, a sign of increased upward motion that would likely carry over to the EPAC around May 10. The GFS and ECMWF show MJO entering Phase 8 as early as a week from now, and either weakening, likely in response to the atmosphere feeling the effects of more of an El Nino based state which contrasts from the traditional MJO phases observed in 2016, or entering Phase 1 around May 3. The CFS ensembles in the long-range seem to agree, showing an uptick in activity around the start of the second week of May. The CFS itself seems to call for a similar uptick form May 13 to May 27.

[cycloneye]

Right on Yellow Evan. GFS responds with a long range close to CentralAmerica system.

[Yellow Evan]

Biggest takeaway from the above is the NPac high looks like its in its normal hurricane season spot. The GFS will drop this system in a row or two if that isn't obvious.

[Hurricaneman]

My thoughts are an early season flurry of activity then a less than normal peak potentially aiding the Atlantic so we'll see how the walker cell sets up

[Yellow Evan]

18z GFS dropped that but it came back at 0z. Expect this to be dropped fairly soon again though it may appear in a few more runs until then.