bluewave

Yeah, The -PDO ridge NW of Hawaii has been a dominant feature since 16-17. This tends to place a trough in the Western US and a ridge near the East. Last January even had the SW trough with a +PNA over the top. So I am hoping that we get a lucky uncoupled month or two like we got it 20-21 and January 22. I would gladly take my chances with a well coupled strong to even super El Niño without La Niña background interference. Just give me a clean STJ with no overpowering northern stream and some blocking. Don’t mind warmth as long as we get some good snowstorms.

The -PDO is the main issue right now. Nearly every winter since 1950 following a -PDO October lower than -1 has gone on to average negative during the winter also. So there is a strong fall to winter PDO correlation. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

We could finish November warmer than average if the advertised mid to late November warmth verifies.

While this has been a decent WWB west of the Dateline, the lower upper ocean heat has really limited the surface warming potential.

NW NJ actually came closest around the region to reaching 70° yesterday. Walpack NJ 2023-11-07 SafetyNet 69 46

Hopefully we can get enough of an El Niño atmospheric response this winter for a decent STJ. Right now we are seeing a very La Niña-like flash drought over portions of the Southeast. Record driest fall so far in locations that usually see this during years heading into La Niña winters. Time Series Summary for Chattanooga Area, TN (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Sep 1 to Nov 7 Missing Count 1 2023-11-07 0.42 0 2 1938-11-07 1.68 0 3 2016-11-07 1.71 0 4 1939-11-07 2.10 0 5 1931-11-07 2.24 0 6 1998-11-07 2.32 0 7 1978-11-07 2.39 0 - 1891-11-07 2.39 0 8 1886-11-07 2.53 0 9 1904-11-07 2.64 0 10 2005-11-07 2.68 0 - 1922-11-07 2.68 0

It makes sense that the MEI is so low when the -PDO was the lowest on record in October for a developing El Niño at -2.36. The increasing La Niña background state has been acting as a brake on El Niño development since Labor Day 2012. So the historic expansion of the WPAC pool even extending northward to Japan has proven to be a game changer for the global climate system. https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat

The latest MEI actually dropped to +0.3 with the unusually strong La Niña background state for Nino 3.4 SSTs in the strong range. https://psl.noaa.gov/enso/mei/ 7 November 2023 Current Value: 0.3

Urban and coastal stations still haven’t had their first freeze. NY LAGUARDIA AIRPORT WBAN 38 NY PORT AUTH DOWNTN MANHATTAN WALL ST HEL ICAO 38 NY MONTAUK AIRPORT WBAN 37 NY ORIENT POINT STATE PARK COOP 36 NY NY CITY CENTRAL PARK WBAN 35 NJ TETERBORO AIRPORT WBAN 35 NJ NEWARK LIBERTY INTL AP WBAN 34 NY JFK INTERNATIONAL AIRPORT WBAN 34 NJ HARRISON COOP 33 NY WESTHAMPTON GABRESKI AP WBAN 33 NY RIVERHEAD RESEARCH FARM COOP 33 NY MOUNT SINAI COOP 33

But notice the main trough axis still hangs back near the SW.

14-15 was the only really cold winter out of that bunch for the Northeast. It was the 20th coldest average winter temperature at 20.8°. 13-14 was -2.8 at 22.1 and 10-11 was -1.8 along with 23.6 and -0.5 for 08-09. But my guess is that with the warming since the super El Niño, it’s going to be difficult to rival the 14-15 cold in the warmer climate. Just as 14-15 couldn’t match the cold of 93-94 a few decades earlier at 19.7 and 10th coldest. Plus 93-94 could not rival the cold in the late 70s. 77-78 finished at 19.5 and 9th coldest while 76-77 was 18.4 and 5th coldest. So each cold pattern as the climate warms can’t match the ones from previous decades.

I am more focused on the Northeast since this is where I live. So we have a decadal pattern of anomalous warmth. Plus Nino influences combined a La Niña background favors warmer than average Northeast winter temperatures. Then we have this ridiculous global temperature spike over 5 months which has never happened before leading up to an El Niño winter. Past occasions of monthly temperature spikes occurred later in the winter like in 2016. This is something new and I am sure many papers are going to be written about it. Based on these factors alone, I think a record 9th warmer than average winter in a row for the Northeast has a good chance of playing out. But since I also have a ton of respect for variability, can’t say yet exactly how much above.

We will need some help from the much warmer 91-20 means to eventually get a colder winter season in the Northeast again. So a winter that was borderline warm before 20-21 will be borderline cold now. At least we have that. Last winter was as warm as 15-16 but the departure shrank from +5.8 to +4.9 due to the much warmer 91-20 averages. Northeast DJF average temperatures since 15-16 22-23….30.7…..+4.9….2nd warmest 21-22…..26.1…..+0.3 20-21…..27.1…..+2.2….16th warmest 19-20…..28.9…..+4.0…6th warmest 18-19…..25.6……+0.7 17-18…..25.3……+0.4 16-17…..29.5……+4.6….5th warmest 15-16…..30.7…..+5.8……2nd warmest

Multi-year winter patterns are important. We have had 8 warmer than average winters in a row. So just hoping that we can do better in the snowfall department than last year. Even if it we make it 9 warmer than average winters in a row. Regardless of El Niño or La Niña, the warm anomalies end up in the East and the cold departures somewhere out West. This has been the winning winter temperature forecast since the super El Niño.

Some of that is related to measuring snow differently now than we did back then. But the 09-10 to 17-18 snowfall was probably a 100 year event for rarity. We seem to be settling into a lower baseline since 18-19 than that epic period for snowfall. But we can still sneak in decent seasons with great snowstorms like 20-21 or January 22. https://news.ucar.edu/14009/snowfall-measurement-flaky-history

February 2015 was our biggest outlier month since 2010.

HRRR has us getting warm sectored to around 70° today.

The EPS is starting to show the winter pattern in a few weeks that we get when we have an El Niño +PNA ridge in Canada that gets undercut by the La Niña background or -PDO SW trough.

It will be a good WWB, but it’s coming a little late to move the needle much. I guess it’s possible we can get a daily or weekly OISST closer to super, but every spike had a pullback so the monthly will average below super.

Looks like Nino 3.4 is getting closer to peaking below super levels. Its one of the few years when the September and October were nearly the same. This event really ran out of momentum after August. Makes sense since we have never had a super El Niño after a 3 year La Niña before. Too much of a lag with the well established La Niña background state. https://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii ERSST JUL….1.02 AUG…1.35 SEP…..1.60 OCT….1.66

That’s why I am a big fan of using the 500 composites since where the anomalies are located can often add more value than just looking at the raw indices.

I meant the PNA. https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table

You are correct with the PNA coming in at +0.21 last January with a strong 500 mb ridge in Canada and a trough tucked underneath near the SW.

But we can still get a trough in the West with + PNA during an El Niño when the PDO is negative. That trough would pump the ridge over the East resulting in the 9th warmer than normal winter in a row for us. So this is why we don’t want a La Niña background state to combine with the El Niño this winter. If the PDO remains negative like all the models show with the big warm pool NW of Hawaii, it needs to be uncoupled to allow a clean El Niño response from late January into February.

But those years like 2009, 1972, and 2002 had very different 500 mb and forcing with the the MJO orbiting various phases.