2020 EPAC Season

[StruThiO]

[Astromanía]

Interesting, it seems early activity this year its almost a fact now, I'm on it! Bring the activity EPAC!

[CyclonicFury]

Interesting, it seems early activity this year its almost a fact now, I'm on it! Bring the activity EPAC!

I don't know if I would say almost a fact, it's only April and there has never been a TC in this basin during April on record. Probably a small chance if we're being realistic.

[cycloneye]

Interesting area in the monsoon trough.

[Kingarabian]

Interesting area in the monsoon trough.

https://i.imgur.com/Qydm4hO.jpg

Abundance of low level westerlies will do that

[Yellow Evan]

I don't think this has any model support. With that said, it's impressive for mid April but we're not at the point yet where we can get storm prior to around May 5-10 or so.

[Yellow Evan]

https://psl.noaa.gov/cgi-bin/data/times ... Timeseries

2014 22.960 23.397 23.989 24.531 25.226 25.828 26.403 26.953 26.477 26.362 25.208 24.403
2015 23.775 23.811 24.167 25.251 25.677 25.988 26.726 27.321 27.385 27.247 26.263 24.934
2016 23.804 23.654 24.204 24.767 25.385 25.761 26.339 26.773 26.648 26.366 25.780 24.365
2017 23.677 23.522 24.058 24.522 25.060 25.245 26.008 26.641 26.422 26.074 25.657 24.603
2018 23.660 23.841 24.104 24.779 25.373 25.581 26.242 26.740 26.790 26.073 25.073 24.103
2019 23.587 23.760 24.137 24.574 25.167 25.452 25.886 26.813 26.682 26.033 25.209 24.412
2020 23.530 23.292 23.990

SST's lowest since the most recent active era began in 2014. Not good but I'll make post on this more later.

[cycloneye]

Long range hint from GFS.

[Kingarabian]

Impressive for this time of the year for sure.

[Yellow Evan]

What we know:

-EPAC SST values have been very underwhelming all in all. March was the lowest since 2014, and only barely, while February was the lowest since 2013. Eyeballing SST anomaly graphs, the area east of Hawaii, which has had above average waters for several years, has cooler than average water temperatures. Considering we are coming off of a borderline El Nino, you would expect fairly high ocean temperatures to persist before dropping significantly as a potential La Nina would emerge, leading to a below average season in this hypothetical scenario. SSTs near Mexico on the other hand are generally above average and is a little warmer compared to the last two years.
-Confidence is increasing (see ENSO thread) that a La Nina will develop at some point. On average, the basin is by far the least active during La Ninas, especially during the first year of one in the case of a prolonged multiyear event. They, however, are more quality driven than neutral seasons historically. Activity during La Nina seasons also tend to shift eastward and tropical cyclone tracks are often clustered off the Mexican coast rather than west of 115-125W.
-Vertical instability is below average for the second year in a row.
-Wind shear was running above average for the month of March but is closer to normal this month at least thus far.
-PMM is slightly positive, but PDO is slightly negative, suggesting not the most conductive atmospheric environment given the expected ENSO state. Would not surprise me to see the values turn increasingly negative as the year progresses.
-I do not see any evidence that we are no longer in a long term active phase that began in 2014 and said phase is largely controlled by long term changes in PDO/PMM though there is uncertainty with how long such phase could last.

With the above into account, I should note or anticipate:

-Intraseasonal variability is large in this basin. I don't necessarily think the season will be frontheavy just because a La Nina is pending, although I'd say the odds are higher than normal that it will be. Still, don't season cancel or elevate expectations after the first month or so is or is not quiet. Sustained activity over multiple months is generally the pathway for an above normal season, but even those will have quiet stretches (see July 2018 as an example).
-Given the confidence in La Nina and unimpressive PDO/PMM to override it, activity in the season will likely shift eastward. Activity should be sparse west of around 120W, though in a strong MJO pulse, some activity near 130-145W is probable.
-Landfall risk along the coast of Mexico is medium given the shift in activity expected, which could be offset by an overall lack of activity in general.
-Not sure whether the season will be more quality-based than normal given the projected La Nina and current vertical instability above.
-This is the least favorable I've seen the Eastern Pacific prior to the season since 2013, possibly since 2011. 2020 could provide a floor for how quiet an active era season could be (by comparison during the height of the last active era, the primary quiet season was 1988, though 1977, 1979, and 1980 also exhibited below normal activity, the last active regime, although underway, didn't intensify until 1982).
-A well below average season much like 2010 or 2007 or even 2013 is at least somewhat unlikely just because those seasons were part of a lesser active cycle but can not be ruled out due to uncertainty in how much influence mutlidecadal trends have on an individual season.
-In the short term, I don't think we'll see anything this week despite the passing MJO. Will have to wait for MJO to come around again in about four to six weeks. Do expect occasional GFS phantom storms in the meantime, however.
-As we move towards next year, one leading indicator of an El Nino event starting the following season is a higher number of landfall tropical cyclones along the west coast of Mexico.

Overall, I am anticipating 15 named storms, 8 hurricanes, and 4 major hurricanes and an ACE of 85. Confidence is higher in this projection than normal, although it is easier to envision this outlook busting on the lower end than this outlook busting on the higher end.

[hurricanes1234]

Excellent summary!!!

I do also think that this year will be a somewhat less active year. I guess we still have to wait and see where ENSO ends up going but based on all that's going on and being forecast, I'm thinking that a La Niña is possible as well.

[TheStormExpert]

Hard to see this season coming close to or even exceeding last years numbers of 19/7/4. With the potential of the Atlantic producing a blockbuster season this season could be the least active since 2010.

[Kingarabian]

The Euro actually has a pretty good atmospheric setup for EPAC hurricane activity till August.

 https://twitter.com/BenNollWeather/status/1249841692477251584




We could see a 2016-2017 scenario where the EPAC pushes out a bunch of storms before the Atlantic dominates.

[aspen]

The Euro actually has a pretty good atmospheric setup for EPAC hurricane activity till August.

https://twitter.com/BenNollWeather/status/1249841692477251584

We could see a 2016-2017 scenario where the EPAC pushes out a bunch of storms before the Atlantic dominates.

2017 might be a good analogue here. Remember how the Atlantic had the least amount of ACE for its first five storms out of any season before going nuclear in August-September? We could see a hyperactive July in the EPac and a tame July in the Atlantic before the roles switch.

[cycloneye]

One month left to the start of the season.

[Yellow Evan]

The Euro actually has a pretty good atmospheric setup for EPAC hurricane activity till August.

https://twitter.com/BenNollWeather/status/1249841692477251584

We could see a 2016-2017 scenario where the EPAC pushes out a bunch of storms before the Atlantic dominates.

Keep in mind that the ECMWF typically shows favorable conditions west of around 120W and hostile conditions in the deep tropics in the Atlantic in this time frame and doesn't have the greatest track record of verifying.

[Yellow Evan]

The Euro actually has a pretty good atmospheric setup for EPAC hurricane activity till August.

https://twitter.com/BenNollWeather/status/1249841692477251584

We could see a 2016-2017 scenario where the EPAC pushes out a bunch of storms before the Atlantic dominates.

2017 might be a good analogue here. Remember how the Atlantic had the least amount of ACE for its first five storms out of any season before going nuclear in August-September? We could see a hyperactive July in the EPac and a tame July in the Atlantic before the roles switch.

Perhaps. 2017 was perceived to have underachieved some at the time, partially due to an unexpected La Nina. It looked more favorable at this point in the year, with warm waters in the Nino 1+2 region in particular, although the upper level environment for that season never appeared perfect. In retrospect, the SST profile wasn't that favorable and vertical instability didn't promote robust hurricane formation. Still, given the more pronounced Nina signal shown in models and that so far wind shear seems to be higher and SST's are running lower, we may be lucky to pull out a 2017-esque season.

[aspen]

The ECMWF+UKMET “superblend” model, while raising the odds of an active Atlantic hurricane season, is predicting drier air just off the Mexican coast and increased precipitation further W/SW, as well as lower shear in that area: https://mobile.twitter.com/BenNollWeath ... 4750668800

[DorkyMcDorkface]

I wouldn't get too excited since it's the ICON, buuuuut:


Also has some support from the GFS ensembles:

[cycloneye]

Does anyone has the earliest date the first named storm formed before May 15? Not saying what some models have will develop,only to find out about that.