bluewave

All we can say for sure is that the fall has featured a blend of El Niño and La Niña influences to the 500 mb sensible weather pattern. So a continuation of that during the winter would probably have differences from the consensus. More in the way of an undercutting trough in the SW US even with +PNA ridge in Canada. This would greatly limit the available cold. But I would like our snowfall chances better than last year if we get some decent +PNA -AO intervals. Plus we are running a record breaking 8 warmer than average winters in a row for the Northeast. So we would probably need a cold Modoki pattern like the JMA has to break that streak. It would also require a complete uncoupling from the -PDO influence like we got in early in 20-21 and Jan 22.

I was just pointing out the skill of the 18-19 forecast. Not that we will verify the same outcome. The JMA forecast for this winter has the same -EPO +PNA blocking as 14-15. But we have a much different PDO state across the NP.

The Euro and the JMA completely missed the last El Niño forecast issued in November 2018. Plus your analogs are different from what the JMA is showing.

Why do you take these 3 month runs seriously when the EPS can hardly get the pattern correct beyond 6-10 days? Same for all the other models. Remember the Euro October forecast for the Nino 3.4 issued in September of +2.0 and we verified closer to +1.66. The one common denominator to all these winter model forecasts since 15-16 has been a cold bias in the East. I pointed out 18-19 since it that was the last time we had an El Niño pattern being forecast.

But it did the same thing with the 18-19 winter forecast issued in November 18. It missed the La Niña or -PDO influence and just went with a cold Modoki pattern for DJF. 18-19 forecast Verification

My first freeze date in Long Beach was usually around the same time as NYC. It’s remarkable how shallow these radiational cooling inversions are. The 85m temperature at BNL near the NWS office was the same as the surface in NYC and at the shore.

NYC and LGA along with the immediate shoreline like Long Beach and Breezy Point will probably have to wait until after Thanksgiving for the first freeze. Lows Jones Beach…37 Breezy point…37 Montauk…37 EWR…32 NYC…35 LGA….37 JFK…31 FRG…30 ISP….27 HPN…28 HVN…27 TEB….28 BDR….30 East Hampton…20 MJG….19

With the very fast Pacific split flow, the models haven’t been very reliable beyond 8-10 days. So we probably can’t forecast much beyond Thanksgiving at this point.

Yeah, continuation of the northern stream dominant pattern suppressing the southern stream. Our next more significant rain and wind event looks to come in a few days before Thanksgiving. Models are predicting a Great Lakes cutter track to our west. So probably a decent warm up ahead of the front. With a little luck we sneak in a dry Thanksgiving without too much wind for the parade.

The unusually poor TSI for a strong El Niño is another factor inhibiting this from going super. Translation The difficulty in forecasting Niño 1+2 in the long term is linked to the multiplicity of variables that dominate it: It is not only the Anticyclone. Even with a not very intense anticyclone, there are oceanographic phenomena, such as the inclination of the thermocline that make it difficult for the massive entry of warm Kelvin waves. This event is being characterized by a relatively poor index of inclination of the thermocline, which is the layer of the ocean that separates warm (above) and cold (below) waters, compared to previous #ElNiño events. For further analysis, it can be seen in the attached figure that the concentration of red tones (strong subsidence of the thermocline) occurred between April and August in our area of the Equatorial Pacific (80º-100º), today we are much more normalized. The last Kelvin formed does not show a major subsidence as it advances to South America (again). If this continues to materialize, as has happened in recent months, the #NiñoCostero would lose magnitude (in fact, in the latest ENFEN report, the probabilities that grow are that of weak (mainly) and neutral at the expense of strong (the that decreases the most) and moderate).

NYC should stay above freezing again tomorrow morning.

We will probably need the northern stream to relax enough in order to allow the southern stream low to come up the coast. The theme of recent years has been for the northern stream to suppress the southern stream. Still have the lingering La Niña influence in the northern stream and the El Niño southern stream trying to push back. So a split flow pattern.

The heat islands both around NYC and Philly have been fairly stable since the 1980s. Just look at the US migration trends. People leaving the big cities of the Northeast and heading south to the sunbelt. Places like Phoenix and Las Vegas have seen the greatest UHI growth in recent years.

The actual WWB is weaker and further west than some of the more impressive November WWBs of the past.

Great job by GFS and NAM as everyone near NYC stayed above freezing. Nov 12 low temperatures EWR…34 NYC….36 LGA….37 JFK….35 HPN…32 FRG….33 ISP……30 HVN….28 TEB….31

Continuation of the competing El Niño and La Niña influences heading into late November.

The NAM and the GFS are the only 2 models which seem to be able to resolve the NYC heat island. So these models keep the low above freezing in NYC next few mornings. The Euro, GEM, and HRRR don’t show the heat island and go below freezing. So not sure why the other models can’t see what the GFS and NAM do. At least the NWS NDFD corrects for this.

The one common denominator with Decembers in the Northeast since 2011 has been warmth regardless of El Niño or La Niña. 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 December 2022…30.2….+1.2….La Niña -PDO 2021….33.5….+4.5….La Niña -PDO…4th warmest on record 2020…30.9…..+3.2….La Niña -PDO…17th warmest 2019….29.0…..+1.3….Neutral 2018….29.3….+1.6…..Uncoupled El Niño -PDO 2017….24.2….-3.5….La Niña Neutral PDO 2016….28.3….+0.6…La Niña +PDO 2015….39.4…..+11.7….Super El Niño +PDO record MJO 4-6 warmest December on record by a wide margin. 2014….31.6…..+3.9….Modoki El Niño +PDO 14th warmest on record 2013….26.1….-1.1….Neutral 2012….32.4…..+4.7…El Nino peaked on Labor Day and went neutral with a -PDO….winter followed backloaded El Niño theme with Nemo in February 2011…32.7….+5.0…..La Niña -PDO….8th warmest December

But the more amplified Aleutians ridge NW of Hawaii and Southeast ridge is a La Niña feature in December. So the long range Euro looks more like a La Niña in early December. Since the EPS or GEFS don’t have such great skill beyond 10 days, it’s just speculation at this point. We can say if the -PDO pattern is dominant, then it could look like that.

Record warmth in the higher latitudes will be the culprit this time.

Looks more like the -AAM and -PDO are destructively interfering with the El Niño holding it back from going super like some of the more aggressive models were forecasting. https://earthscience.stackexchange.com/questions/966/why-is-the-warm-phase-of-the-pacific-decadal-oscillation-associated-with-stronge According to the State Climate Office of North Carolina webpage Global Patterns - Pacific Decadal Oscillation (PDO), experts believe Essentially, almost analogous to constructive and destructive interference in sound.

The CAA has been very weak this fall. So the stronger radiational cooling days just affected the suburbs. NYC needs the winds to stay up in order to transport the colder air in from the NW.

Yeah, we’ll see if this is one of the few years that NYC can avoid a first freeze until December. Frost/Freeze Summary for NY CITY CENTRAL PARK, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Year Last Value First Value Season Length 1998 03-23 (1998) 32 12-22 (1998) 22 273 2001 03-28 (2001) 30 12-16 (2001) 32 262 1948 04-04 (1948) 32 12-11 (1948) 31 250 2011 03-29 (2011) 31 12-10 (2011) 32 255 2016 04-10 (2016) 31 12-09 (2016) 29 242 2009 03-24 (2009) 27 12-07 (2009) 32 257 1902 03-20 (1902) 31 12-05 (1902) 24 259 2010 03-27 (2010) 29 12-04 (2010) 32 251 2006 03-22 (2006) 31 12-04 (2006) 31 256 1907 04-03 (1907) 32 12-03 (1907) 30 243 1985 04-10 (1985) 28 12-02 (1985) 30 235 1963 03-23 (1963) 30 12-01 (1963) 29 252

Yeah, Euro forecasting a new record also.

The new baseline may not be that much warmer than 81-10 since the equatorial East Pacific has been one of the slowest warming parts of the Pacific. https://news.climate.columbia.edu/2019/06/24/pacific-ocean-cold-tongue/