bluewave

Plenty of PNA volatility which leads to big model shifts from run to run. So the models can’t figure out whether the El Niño or -PDO will be running the show leading to big swings from run to run.

But we had hints. The OHC decline and the lack of WWBs were working against El Niño strengthening. Also the extremely Niña-like -PDO and associated trade wind pattern. We can remember the very strong -PDO in September 2012 and trades staying up that caused all the models to miss the decline. We still got the backloaded El Niño February with NEMO so all was forgiven.

The daily -2.52 -PDO is lower than any readings with the La Niña from last fall into winter. I believe it’s also the lowest -PDO reading for a Nino 3.4 reading near +1.4. https://s2s.worldclimateservice.com/climatepanel/

Nino 3.4 back to moderate levels near +1.4 as the Niña-like lack of any appreciable WWBs continues. The much lower RONI and MEI isn’t allowing the trades to fully relax like we typically see during Ninos. So the competing influences are currently acting as brake on El Niño development.

September matches a -PDO El Niño composite blend.The strong Aleutian ridge NW of Hawaii is classic -PDO in September. The ridge over Southern Canada is indicative of El Niño. There is some overlap in Northern Canada between the two composites also. The lower heights in Alaska also have a -PDO flavor.

We got lucky in Long Beach since Gloria hit a low tide instead of high tide. It had a higher storm surge than Irene but Irene came in at high tide. So the actual tide levels for both storms in Long Beach were the same. The wind gusts over portions of Eastern Long Island were estimated at 100+.

Low of 46° this morning here at KHVN is coldest of season so far. https://www.weather.gov/wrh/timeseries?site=khvn

Off course, and we have all been saying this. Competing influences and degree of coupling adds more uncertainty going forward.

Yeah, what we actually said is that the summer composite matched a weaker +MEI composite and that the Aleutian low was on the weaker side for a developing El Niño. Plus we are seeing mixed influences early on so far during the fall. These are very important distinctions in how the summer forecast did. A warmed up weaker MEI composite was a better summer forecast that the other stronger ones relying solely on the warmer 3.4s and a quieter hurricane season. So acknowledging the competing or overlapping patterns would have resulted in a better summer forecast had it been issued. Strong MEI composite… strong Aleutian low less blocking Weak MEI composite more blocking..less expansive Aleutian Low 2023 warmed up weak MEI worked

That’s what I have been saying for a while now. The subsurface cooling from a June peak of +1.4 to under +1.0 now has never happened with any strong to super event we have subsurface records of. While the sample size of super events is smaller, they were all near +2 during this time of year. So we are at 50% of those levels.

While the CFS may be exaggerated in its decline, the drop in OHC may be we we see the slight decline and leveling off effect. Not many cases to draw from with and OHC decline from 1.4 in June to under +1.0 in late September. Not sure how much warmer we can get with a break in momentum like this.

October is another rapidly warming month from the old days like September has been. The monthly temperature increases from 81-10 to 91-20 have been more pronounced during certain months. Newark and Islip are compared below. The +1.0 or warmer months for either station were bolded. ……….EWR…..ISP Dec…+1.5….+1.5 Jan….+1.2…+1.3 Feb….+0.5….+0.5 Mar….+0.4….+0.6 Apr….+0.5…..+0.6 May...+0.6….+0.9 Jun….+0.3….+0.6 Jul…..+1.4…..+1.1 Aug...+0.6….+0.9 Sep….+1.0….+1.3 Oct…..+0.9..+1.4 Nov….+0.2..+0.5

Relative to the historic rankings, the warmest departures shifted over closer to the Dateline in August. Some areas in that zone had the warmest August SSTs on record. Same goes for the warm pool east of Japan. But the overall warmth of the entire WPAC is still there. We have seen month to month fluctuations across different zones of the WPAC in recent years. Big decline with the IOD in the fall of 2019 followed by rapid rebound in the winter. So this part of the basin keeps finding ways to maintain its heat even with short term fluctuations. Quite an extensive reservoir of +30C SST warmth.

It’s no secret that the warmth imbalance to the west is keeping the trades up and letting the Nino 3.4 SSTs decline a bit in recent days.

The resolution on those charts is pretty poor. The WPAC is very warm for this time of year. Plus it’s much warmer than all the previous very strong El Niño years. Also notice the unusual -PDO signature for such warm ENSO SSTs. Nino 4 is close to all-time record warmth for this time of year.

That historic marine heatwave east of Japan is probably helping to push the -PDO to even lower values than we saw during last fall. A daily reading of -2.6 must be near the record lows for this date. Hoping we don’t see some odd combo going forward of higher Canadian heights from the Nino and a Western Trough tucked underneath like we see with -PDO patterns. That would lead to a stronger NPAC Jet pushing the +PNA ridge too Far East and possibly overshadowing the STJ. Want to see the STJ dominate with some decent blocking for the NE snowfall fans. https://s2s.worldclimateservice.com/climatepanel/

I am not sure. But the biggest influence study I found was with the IOD back in 2019 which was twofold. That event had very intense Western-Central IO forcing which is believed to have driven the raging SPV and +NAO pattern that winter. But so far, we aren’t seeing anything like that forcing this year. Maybe related to the much warmer SSTs near SE Asia. The other factor to be aware of is rapid SST recovery near Java in December. That was associated with the MJO 4-6 wave in December 2019 which warmed what started as a cold December as the month progressed.

There isn’t as much interest in the DMI for us since it peaks before our winter starts. It’s usually a bigger story for people in that region. But sometimes the rapid recovery if the SSTs around Java can enhance unfavorable MJO phases for us. So that always bears monitoring.

I would just note that the entire area around the WPAC into the Eastern IO is much warmer than at the same time in 2019. So we can’t expect to see the same outcomes as that year. These competing marine heatwaves add a new level of complexity to the forecast patterns. So we can’t just rely on the old correlations under colder SST eras. Using just one index like Nino 3.4 or IOD exclusively in this new era just isn’t going to cut it anymore.

There are a few differences here. Cycles, oscillations, and teleconnections, will always exist whether the climate is warming or not. But there have been an increasing number of studies linking changes to these climate modes as the climate warms. So in effect we get the steady background warming combined with the familiar patterns warming also. So when these intersect, we can get such an extreme pattern of warmth like in the PAC NW summer 2021 that it surprises many. But we can look at waves in the ocean and and see how this happens when they combine. These extreme weather and climate events are akin to constructive interference with rogue waves in the ocean. Just substitute atmospheric Rossby wave behavior. Also these more stuck weather patterns seem to lock in in warmer states like standing waves. The other challenge is that our climate is changing faster than the technology that creates the regional climate models. Plus waiting 30 years to confirm a pattern or trend doesn’t help when we need to forecast extreme events on much shorter time scales.

My guess is that that the timing is somehow related to these frequent December MJO 4-6 intervals which have been increasing in duration and intensity in recent years. But we would probably need a formal study which hasn’t been done yet.

Nobody is making light of the implications considering the historic and rapid global temperature rise in recent months. This is the first El Niño year with so much planetary warming in the early months of the event. Past instances like 15-16 were later in the winter. Whether the atmosphere has been in La Niña or El Niño, both 22-23 and 15-16 both tied for 2nd warmest Northeast winter. We recognize how every winter since the 15-16 super El Niño has been warmer to record warm. So our questions with this El Niño vs competing La Niña influences are strictly about any snowfall potential, STJ vs NPAC Jet, +PNA vs-PNA intervals, WPAC warm pool, MJO, ambient record NATL SSTs etc…

The real mystery is why the rate of December warming during recent decades has accelerated around the solstice at a number of Northeast stations in relation to the rest of the month? So we get the annual spike in temperatures leading up to holiday periods each year. This has been especially pronounced around the NYC Metro. It also shows up at stations further north. 1981-2022 December temperature change by time of month NYC….12-1 to 12-15…..+1.4……..12-16 to 12-31….+3.8 ALB…12-1 to 12-15…..+3.2………12-16 to 12-31…..+5.4

Since the warmer December pattern emerged in the Northeast most noticeably in 2011, our only two cold teleconnection years were 2017 and 2013. Those required strong 500 mb -EPO blocking. But it was by far the rarest teleconnection pattern pattern of the last 12 Decembers. So we are running 10 warmer to record warmer to only 2 colder with no cold ranking records. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/regional/time-series/101/tavg/1/12/1895-2023?base_prd=true&begbaseyear=1981&endbaseyear=2010 Northeast December temperature departures 2022….+1.2…..La Niña 2021…..+4.5….4th warmest….La Nina 2020…+3.2….17th warmest….La Nina 2019…..+1.3….weak warm ENSO 2018….+1.6…..El Nino coupling issues 2017….-3.5…..La Niña 2016….+0.6….La Niña 2015…+11.7….1st warmest..Super Nino MJO46 2014….+3.9….14th warmest…weak El Nino 2013….-1.1…….Neutral 2012…+4.7….10th warmest…Neutral 2011….+5.0….8 th warmest….La Niña

We got a Niña background in December 2015 which was warmer than any previous December by a wide margin. Perhaps it was the interaction with the super El Niño that made it so extreme. The one paper on the event was focused on the strong MJO 4-6 which was the first for a super El Niño. We had mixed forcing elements in December 2018 with a Nina-ridge north of Hawaii and an eastward displaced +PNA El Niño ridge in Canada. But NYC did get the colder front loaded La Niña start to December before the warmer MJO 4-6 kicked in during the mid to later portion of the month. So we don’t have a great sample size of competing Niña-like influences December patterns in El Niño years since the super El Niño in 15-16. Dominant La Niña or El Niño patterns will usually be great in December with blocking like we saw in the 2009 Nino, 2010 Niña, and 2020 Niña. But last December was disappointing with a strong La Niña background and 2nd strongest -AO. So we missed out on the frontloaded La Niña period in December before the warmer mid to late winter Nina portion arrived. Decembers have really struggled to produce wintery weather for us regardless of ENSO or degree of coupling since 2011. Maybe it’s a shorter winter thing in warmer world when December sometimes act like a late fall month rather that early winter. Sometimes a great March can make it feel like we are getting our 2nd or third winter month.