bluewave

None of the El Niño events following 09-10 evolved in a way that were familiar to us from what happened in the past. Models were indicating an El Niño in 12-13 that began to dissipate after Labor Day with the strong trades and -PDO. But it still acted in some ways like like an El Niño winter. Front loaded warmth and the historic Nemo in February. The spring of 2014 saw strong WWBs and the talk turned to a strong El Niño in 14-15. But the trades picked back up and we had one of the farthest west Modokis for that winter. The big event was delayed a year to 15-16 and produced the record Nino 4 temperatures. Front loaded historic warmth with the first strong MJO 4-6 in December during a super El Niño. But the westward lean back to the CP during the 2nd half of the winter with blocking gave us the historic January snowstorm. The 18-19 El Niño never coupled due to all the warm water in the WPAC mimicking a La Niña. So we got the Aleutian Ridge-Western Trough-SE Ridge combo. This event is starting out east based before Nino 3.4 had a chance to catch up. So we could see Nino 1-2 begin to decline before an actual El Niño is declared using 3.4. Not many analogs for what happens when these two regions are out of phase. We will probably need much stronger and sustained CP WWBs to get a trimonthly ONI of +1.5 or higher in Nino 3.4. This could happen if the trades can relax enough. But we have never seen a super before with such strong trades like we had in March. Seems like the atmosphere gets an early start in March ahead of super El Niño’s. But some strong events can see a pick up in WWB activity later in the spring. So these individual model forecasts may not yet have a good handle of how this El Niño will develop until the CP WWB activity comes into better focus.

This link gives you a very good explanation. I can remember my class learning the Skew-T back in meteorology 101. Gives a great image of the whole atmosphere in one diagram. http://www.theweatherprediction.com/thermo/skewt/

Yeah, true east based El Niño events have become very rare since the 1980s. The 82-83 and 97-98 events developed with strong WWBs in the CPAC in March. That didn’t happen this year. So we haven’t had strong east based event developing from the rare EPAC WWBs like we recently saw. That’s why we don’t have any good analogs for how this one may evolve.

Pretty cool soundings.

Thanks. do they have these same assorted charts on the site somewhere back to 1979?

Plenty of extra precipitation for the warming Gulf Stream.

Do you have a direct link to those TAO Triton charts with an archive of previous events back in time? See them posted online but can’t find the link to make the charts.

Yeah, the very strong -PDO signature pattern has probably delayed the WWB response until now west of the Dateline compared to the top El Niño events. https://psl.noaa.gov/enso/dashboard.html https://www.cpc.ncep.noaa.gov/data/indices/cpac850 850 MB TRADE WIND INDEX(175W-140W)5N 5S CENTRAL PACIFIC ANOMALY 2023 3.4 3.7 1.6 2015 -2.1 -1.2 -0.6 1997 -0.6 2.2 -1.6 1982 0.8 -0.8 -0.9

Wonder if Nino 1.2 peaks early in the next few months like 57-58 did? These Nino 1+2 maxes typically occur later on in the event. Then there is the possibility of a secondary peak a few months after that like we saw with 97-98 and 82-83.

Impressive temperature gradient around the snowpack in North Dakotas.

It’s the 3rd warmest Nino 1.2 reading according to that dataset. The warmest was in March 2017 which never developed outside Nino 1+2. The March 1998 2nd place occurred near the end of that El Niño rather than the beginning. Same for the warmest reading in 82-83 which was near the end. So not many analogs for this one. https://www.cpc.ncep.noaa.gov/data/indices/ #1…..15 March 2017…28.9° #2….11 March 1998…28.8° #3…05 April 2023.…28.7° #4…23 March 1983….28.6° https://earthobservatory.nasa.gov/images/151183/warming-water-and-downpours-in-peru The changes have been large enough that Peru's National Meteorology and Hydrology Service (Senamhi) has said the area is now experiencing a coastal El Niño. The map below shows sea surface temperature anomalies on April 4, 2023. Surface waters were roughly 6°C (10.8°F) warmer than usual offshore of Peru for that date, according to data from the Multiscale Ultrahigh Resolution Sea Surface Temperature (MUR SST) project. MUR SST blends measurements of sea surface temperatures from multiple NASA, NOAA, and international satellites, as well as ship and buoy observations. (Scientists also use instruments The unusually warm waters have played a role in energizing intense rainfall onshore, with northern Peru, Ecuador, and parts of western Brazil receiving frequent heavy rains since mid-March. The rains became especially intense after the rising ocean temperatures helped fuel Tropical Cyclone Yaku, which pumped even more rain into the normally dry region. The storm, the first tropical cyclone to hit the area in decades, was disorganized and lacked an eye, but it dropped record amounts of rain in semi-arid northern Peru on March 9, 2023. Pacasmayo received 13.7 centimeters of rain in a 24-hour period, and Chiclayo saw 8.7 centimeters. The warm sea surface temperatures coincided with the part of the year when Peru normally sees its highest water temperatures offshore, explained René Garreaud, an environmental scientist at the University of Chile. This pushed sea surface temperatures above 27°C (80°F), speeding evaporation, making the air more humid, and fueling the formation of tall convective clouds that produce downpours and thunderstorms. The situation is similar to 2017, the last time a coastal El Niño flooded the area with rain.

December 2015 which had the +13 historic temperature departures around NYC had very unusual MJO activity for a super. Was the first time during a super that there was a Niña-like strong MJO 4-6 in December. I think the combination of those features along with the strong December +AO drove the anomalous ridge in the Northeast that December. But the MJO progressing through 7-8 into January with the great blocking turned things around. Never saw such a warm WPAC with a super El Niño before. https://link.springer.com/article/10.1007/s00376-020-0261-x Distinctive MJO Activity during the Boreal Winter of the 2015/16 Super El Niño in Comparison with Other Super El Niño Events Abstract Many previous studies have demonstrated that the boreal winters of super El Niño events are usually accompanied by severely suppressed Madden-Julian oscillation (MJO) activity over the western Pacific due to strong descending motion associated with a weakened Walker Circulation. However, the boreal winter of the 2015/16 super El Niño event is concurrent with enhanced MJO activity over the western Pacific despite its sea surface temperature anomaly (SSTA) magnitude over the Niño 3.4 region being comparable to the SSTA magnitudes of the two former super El Niño events (i.e., 1982/83 and 1997/98). This study suggests that the MJO enhanced over western Pacific during the 2015/16 super El Niño event is mainly related to its distinctive SSTA structure and associated background thermodynamic conditions. In comparison with the previous super El Niño events, the warming SSTA center of the 2015/16 super El Niño is located further westward, and a strong cold SSTA is not detected in the western Pacific. Accordingly, the low-level moisture and air temperature (as well as the moist static energy, MSE) tend to increase in the central-western Pacific. In contrast, the low-level moisture and MSE show negative anomalies over the western Pacific during the previous super El Niño events. As the MJO-related horizontal wind anomalies contribute to the further westward warm SST-induced positive moisture and MSE anomalies over the western tropical Pacific in the boreal winter of 2015/16, stronger moisture convergence and MSE advection are generated over the western Pacific and lead to the enhancement of MJO convection.

This paper does a good job classifying the various El Niño events. In terms of snow and colder temperatures, the Modoki events in 02-03, 09-10, and 14-15 were the forum favorites. Even the basin wide super in 15-16 had a CP forcing lean later on with the record Nino 4 SSTs. This gave us around NYC the record snowstorm in late January and below 0° in February. Notice how much further west the forcing was than the 97-98 super. So each one of these events has unique characteristics. https://www.pnas.org/doi/10.1073/pnas.1911130116

The -PNA -AO -NAO patterns from the mid 1950s to around 1970 were much colder and snowier than we have seen recently. While I know the sample size is smaller, our recent versions of this pattern have been milder with less snow. The one thing I can come up with is the 7° rise in the Gulf Stream is leading to a stronger SE Ridge.

Areas south of NYC can be favored for the heaviest snows during some El Niño seasons with the stronger STJ. But during other El Niño years the STJ can position further north and jackpot our area. Same goes for La Ninas which can favor areas to our north with the Pacific Jet riding further north. Then we have the fantastic La Niña years for snowfall which our area does very well.

While the SST maxes in 86-87 were split between 3.4 and 1.2, the actual forcing was pretty far west. So there were elements of that winter than could be called Modoki-like. It was the snowiest winter of the 1980s in Central NJ Data for October 1, 1986 through April 30, 1987 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall SUSSEX 1 NW COOP 70.0 LAKEHURST NAS WBAN 65.0 HIGH POINT PARK COOP 53.9 ESTELL MANOR COOP 48.1 NEW BRUNSWICK 3 SE COOP 47.3 New Brunswick Area ThreadEx 47.3 POTTERSVILLE 2 NNW COOP 46.1 OAK RIDGE RESERVOIR COOP 45.5 INDIAN MILLS 2 W COOP 45.4 HIGHTSTOWN 2 W COOP 44.8 NEWTON COOP 44.5 CHARLOTTEBURG RESERVOIR COOP 44.0 GREENWOOD LAKE COOP 43.5 MILLVILLE MUNICIPAL AIRPORT WBAN 43.2 MORRIS PLAINS 1 W COOP 41.9 Time Series Summary for New Brunswick Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 1980-04-30 21.5 0 1981-04-30 21.2 0 1982-04-30 30.9 0 1983-04-30 34.6 0 1984-04-30 37.7 0 1985-04-30 25.8 0 1986-04-30 24.6 0 1987-04-30 47.3 0 1988-04-30 25.3 0 1989-04-30 10.5 0

It’s probably related to the warming of the climate since the 97-98 super El Niño. https://www.nature.com/articles/s41558-019-0663-x The Pacific Decadal Oscillation less predictable under greenhouse warming Abstract The Pacific Decadal Oscillation (PDO) is the most prominent form of decadal variability over the North Pacific, characterized by its horseshoe-shaped sea surface temperature anomaly pattern1,2. The PDO exerts a substantial influence on marine ecosystems, fisheries and agriculture1,2,3. Through modulating global mean temperature, the phase shift of the PDO at the end of the twentieth century is suggested to be an influential factor in the recent surface warming hiatus4,5. Determining the predictability of the PDO in a warming climate is therefore of great importance6. By analysing future climate under different emission scenarios simulated by the Coupled Model Intercomparison Project phase 5 (ref. 7), we show that the prediction lead time and the associated amplitude of the PDO decrease sharply under greenhouse warming conditions. This decrease is largely attributable to a warming-induced intensification of oceanic stratification, which accelerates the propagation of Rossby waves, shortening the PDO lifespan and suppressing its amplitude by limiting its growth time. Our results suggest that greenhouse warming will make prediction of the PDO more challenging, with far-reaching ramifications.

The only current analog for March into April significant warmth in the EPAC and cooler Nino 3.4 is March 2017. But the subsurface across the Pacific has more of a developing El Niño signature than that year. The Euro was forecasting a moderate El Niño that year which never verified. So not many good analogs yet for this one. https://www.frontiersin.org/articles/10.3389/fmars.2018.00367/full The latest extreme coastal El Niño occurred in austral summer 2017. A strong surface temperature anomaly developed off northern Peru, reaching a maximum of +5°C at the coast, while very weak temperature anomalies were found in the Central Equatorial Pacific (Figure 1). Coastal precipitations attained a maximum of 8 mm day-1(monthly average), thus being almost as intense as during the 1997–98 El Niño event (10 mm day-1, Figure 1). The event was triggered by a decrease of the southerly trade winds in January 2017 (Figure 2A) which reduced the latent heat release and ocean cooling (Garreaud, 2018; Hu et al., 2018). Climate reanalysis data suggest that the wind relaxation was related to the weakening of the free tropospheric westerly flow impinging the subtropical Andes, remotely forced by anomalously intense deep convection in the western Pacific (Garreaud, 2018). However, the impacts of the wind relaxation and local air-sea feedbacks on the coastal upwelling have not been investigated in detail.

The difference between this event so far and 82-83 and 97–98 is the big spread between Nino 1+2 and 3.4. So it’s much more east based than those events early on. It looks like a result of the weaker WWBs in the Central Pacific. Nino 3.4 is still neutral while 1.2 has been near +2 in recent weeks. When 1.2 first reached +2 in 82-83 and 97-98, 3.4 was already above +0.5 and into Nino territory. So the WWBs will need to pick up down the road for more significant warming in 3.4. The other difference is that the PDO Is currently even lower than in the beginning of the 72-73 El Niño. That one also had stronger CP WWBs early on than this year with more Nino 3.4 warming when 1+2 reached +2. So this event seems to be unique in its early development. Perhaps the anomalous WPAC warm pool and strong -PDO are slowing the CP WWB response and allowing the WWBs to be more east based than usual. Still early in the game so things can change. https://www.cpc.ncep.noaa.gov/data/indices/sstoi.indices https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

The PDO intervals were much longer from 1950 to 1998. We had multi decade long +and - phases .Notice the rapid shifts after 5-7 years following the 97-98 super El Niño.

Very impressive backdoor pushing through the Southeast. https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=se&band=GEOCOLOR&length=24

The Central Pacific Trade Wind Index was stronger this March than before the the 82-83, 97-98, and 15-16 events. So the WWBs were displaced closer to the EPAC than in March those years. The stronger event years began with much stronger WWBs in the CPAC. This event is featuring very strong east based warming in March which took longer to occur in even east based years like 97-98. Not sure what if any influence this will have on the ultimate strength and location of the warmest SST anomalies later on. But the CPAC trades will need to relax in the coming months if this is to become a stronger event. Still early in the game so a lot can change. https://www.cpc.ncep.noaa.gov/data/indices/cpac850 850 MB TRADE WIND INDEX(175W-140W)5N 5S CENTRAL PACIFIC ANOMALY 2023 3.4 3.7 1.6 2015 -2.1 -1.2 -0.6 1997 -0.6 2.2 -1.6 1982 0.8 -0.8 -0.9

Great pattern for record snow in the West.