Hope everyone is enjoying their summer. So far in Vegas, it's been pretty nice, and it's cloudy as I type this. The PHS is on to a record start, now the question is will it stay that way?
ENSO is a huge wildcard when forecasting EPAC seasons. Sure, recent research done by me has suggested that there are many other factors that need to be taken into account. But let's not understate the importance of ENSO.
Right now, as you probably know, we are in the midst of an El Nino event. El Nino has large effects on the weather across the globe, such as drought in India and Australia, and record rains across Peru, and certain parts of Africa. El Nino is the reversal of trade winds (from easterly to westerly) that turns the EPAC into the WPAC. In the Us, El Nino brings warm winters to the northern US if strong enough, and if weaker/a Modoki, snowy winters to that part of the world. Texas and the SE US gets lots of rain during the winter and below average temperatures. Meanwhile, the W US gets above normal rain in the winter.
As for the current event, El Nino is rapidly intensifying. It is warming very steadily, and both the GFS and ECMWF are becoming bullish on a historic WWB, similar to the ones observed prior to the super Nino of 1997, in the upcoming weeks. This should seal the deal on a strong El Nino, and makes the possibility of a super El Nino quite likely. As noted last month, there is somewhat of a myth that El Nino increases Eastern Pacific Hurricane activity. A super El Nino has good sides and bad sides to it. In years where a traditional/strong El Nino is present, you often see an active stretch or two. In 2009, a quasi-traditional year it was silent until August. 2006 had a zero storm June. 1986 didn't get on to the best start. 1991 was dead for late August/early September. 1997, while epic, was pretty meh till a 7 storm September happened. 172 had a very slow start. While El Ninos do favor more activity due to lower shear and warmer waters, the period of cyclonic formation is sometimes reduced.
With that said, the above is more true of weak to moderate and westerly-based. Stronger El Ninos tend to be more active than weaker and moderate ones. They tend to produce a lot of storms in in the SW part of the basin. Provided they don't form too close to the ITCZ, these storms can be very long lived and sometimes powerful. A good example of this Hurricane John in 1994.
The EPAC is on to a record start. Hurricane Andres is 1 of 5 major hurricanes in May of all time, while Hurricane Blanca was the earliest 2nd hurricane and 2nd major hurricane. Both systems were in my eyes, upper end Category 4's. Then, we had Hurricane Carlos, the earliest 34d hurricane. Since then, the EPAC has shut down. Despite this, the basin has the highest year to the date ACE record, highest June ACE and pre-July ACE.
The Hawaii door
With the record SST's, new possibilities are on the table for the EPAC season. SST's near Hawaii are in the 26C range and it is still late June. If they can warm up some more, to around 27-28C in a few weeks, it all of a sudden can open the possibilities of the EPAC swinging at Hawaii this season. That is of course, if the Great Hawaiian Shear is cooperative. Because if wind shear is low in the EPAC, it has been proven that EPAC hurricanes can become quit intensity even under 27C-28C waters. Look at Hurricane Andres last month for proof.
However, uncertainty in this seasons remains high. Wind shear has been lethal as of late and if this keeps up, this season can end up shockingly quiet. In the short-term, however, one can be optimistic. We have a CCKW coming, followed by an MJO pulse. In this pattern, you often see an outburst of tropical cyclones. At this point in the season, there are a number of different outcomes. This could end up active, or dead. But at this point, I am concerned, as such, my numbers have been lowered slightly, even though my ACE, hurricane count, and MH count have been raised. But the wind shear present is horrible, and is only forecast to weaken slowly by global models.
The reason for no storms right now is simple. In addition to the above shear, we currently have a very strong MJO event over the WPAC, favoring upward motion there. When this happens, subsidence rules elsewhere. CPAC will be next and then EPAC, and as mentioned above, the WWB is very impressive, development. On paper, activity would come in bursts once it arrives, but given how strange the season has been so far, confidence is low. It is worth noting the the reason I am fussing over this is the fact that in this basin, timing is crucial and the current timing of the MJO pulse could be the end of the hopes of a 1992-seque season, which I thought was a distinct possibility earlier. With that said, if everything goes out as planned, there remains a high likelihood that this season will be very active.
- 20 named storms
- 13 hurricanes
- 7 major hurricanes
- ACE: 180
Confidence: Low, per above