bluewave

It was just a little hard to follow the back and forth between the two forums since only snippets of what I was posting were quoted in the New England forum. So the crew there probably weren’t getting a complete picture of what was discussed in our local forum. All I was saying was that the Euro snowy run from last Thursday had a nearly identical TPV location when it was about to enter the US north of Canada. So the only difference between the warmer runs is that the SE Ridge was stronger before the low began to dig into the Plains. The neutral PNA could have worked better if we didn’t have the predisposition for even a slight SE Ridge a few days before storm time. But we always want as strong as a +PNA as we can get for our better snowstorm chance here. So by no means was I trying to say we had a great Pacific to work with. But a marginal Pacific would have worked out better without the SE Ridge linking up with the -AO block before the storm began to dig. The digging storm just enhanced the existing pattern that was in place. There was a recent paper that suggested the slowing AMOC and build up of warm waters off the East Coast could actually strengthen the trades and create more La Ninas in the future. So it can be difficult to access where one influence ends and another one begins. But we have been seeing more -AO patterns linking up with ridges extending down closer to the Midatlantic than we used to before the Gulf Stream warmed so much. There has never been an era from 2016 to 2022 with such an intense and persistent SE Ridge. No La Niña patterns from the past produced as strong and SE Ridge as I have shown earlier in this thread. Feel free to link to this post. But don’t leave anything out. That way there will be less confusion. https://www.nature.com/articles/s41558-022-01380-y Climate projections suggest a weakening or collapse of the Atlantic Meridional Overturning Circulation (AMOC) under global warming, with evidence that a slowdown is already underway. This could have significant ramifications for Atlantic Ocean heat transport, Arctic sea ice extent and regional North Atlantic climate. However, the potential for far-reaching effects, such as teleconnections to adjacent basins and into the Southern Hemisphere, remains unclear. Here, using a global climate model we show that AMOC collapse can accelerate the Pacific trade winds and Walker circulation by leaving an excess of heat in the tropical South Atlantic. This tropical warming drives anomalous atmospheric convection, resulting in enhanced subsidence over the east Pacific and a strengthened Walker circulation and trade winds. Further teleconnections include weakening of the Indian and South Atlantic subtropical highs and deepening of the Amundsen Sea Low. These findings have important implications for understanding the global climate response to ongoing greenhouse gas increases.

Our December snowfall since 2011 has been comparable to the late 70s to early 90s. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 2.8 2.8 2022 T T 2021 0.2 0.2 2020 10.5 10.5 2019 2.5 2.5 2018 T T 2017 7.7 7.7 2016 3.2 3.2 2015 T T 2014 1.0 1.0 2013 8.6 8.6 2012 0.4 0.4 2011 0.0 0.0 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Dec Season Mean 2.2 2.2 1994 T T 1993 6.9 6.9 1992 0.4 0.4 1991 0.7 0.7 1990 7.2 7.2 1989 1.4 1.4 1988 0.3 0.3 1987 2.6 2.6 1986 0.6 0.6 1985 0.9 0.9 1984 5.5 5.5 1983 1.6 1.6 1982 3.0 3.0 1981 2.1 2.1 1980 2.8 2.8 1979 3.5 3.5 1978 0.5 0.5 1977 0.4 0.4

NYC is in track for the lowest December snowfall with a daily -4 AO reading or lower during a La Niña. La Niña Decembers with a -4 or lower daily AO reading and NYC snowfall 2022…T 2010…20.1 2000…13.4 1995….11.5 1966…9.1 1950….3.8 El Nino 2009….12.4 1976….5.1 1968….7.0 1963….11.3 Neutral 1978….0.5 1962…4.5

It would be a first for 60° around New Years following single digits so close to Christmas. The only Christmas Eve or Christmas in the single digits to ever go over 50° on New Year’s Eve or day was 1989. So we have already gone colder than 1989 around Christmas. This year could be the greatest Christmas to New years warm up on record. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Lowest Min Temperature Dec 24 to Dec 25 Dec31 to Jan 1 highest Max Temperature 1 1980-12-25 -1 28 2 1983-12-25 4 32 - 1872-12-25 4 38 4 1883-12-25 7 37 5 1989-12-25 9 53 - 1960-12-25 9 44 - 1896-12-25 9 46

Caribou is usually below 0° when NYC gets into the single digits but the SW flow is keeping them at 20° instead. CARIBOU CLOUDY 20 11 68 SW12G22 Central Park CLEAR 7 -8 50 MISG

MARTHAS VNYRD SNOW 17 13 84 W14G20 29.65R VSB 1/2 WCI 3 $

Sea smoke and localized blizzard conditions south of Long Island in that 30 DBZ squall.

NYC is just 1° off the record low which hasn’t happened in late December since the 1980s. 12/23 -1 in 1883 6 in 1989 8 in 2022+ 12/24 6 in 1983 7 in 2022 7 in 1872 12/25 -1 in 1980 4 in 1983 4 in 1872 12/26 3 in 1914 6 in 1872 8 in 1983+ 12/27 6 in 1872 7 in 1914 8 in 1989+ 12/28 8 in 1917 10 in 1933 10 in 1880+ 12/29 -6 in 1917 -3 in 1933 4 in 1880 12/30 -13 in 1917 -6 in 1933 -6 in 1880 12/31 -7 in 1917 -3 in 1880 4 in 1962

This was the first 50° drop in 24 hrs for our area in December. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&hours=24&month=dec&dir=cool&how=exact&_r=t&dpi=100&_fmt=png

Several local stations will set the new record soon for the largest December calendar day temperature drop. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=139&network=NY_ASOS&zstation=LGA&v=largest&month=dec&_r=t&dpi=100&_fmt=png

This looks like a super La Niña atmospheric response with the +55 SOI and strong +EPO -PNA SE Ridge pattern by later next week.

Getting some light ocean effect snow now in SW Suffolk and 26°.

Gusted close to 80 mph near Buffalo earlier today on the skyway bridge. https://operations.nysmesonet.org/~nbassill/live/index.php?stid=SKYWAY

That’s incorrect. The SE Ridge linking up with the -AO occurred before the shortwave entered the US. Notice the TPV is in the same location north of Montana. So it wasn’t caused by the TPV digging more. New run Old run

Gusting near 60 mph at JFK.

8.45 was above Irene and below Sandy. 1) 10.12 ft on 10/29/2012(2) 7.35 ft on 08/28/2011

Yeah, a slowing Gulf Stream warms the waters off the East Coast and cools the SSTs south of Greenland.

The much warmer Gulf Stream circulation to our east looks like the reason the SE Ridge is linking up with the -AO more often. The Pacific side is nearly identical to the colder storm track run from last Thursday. So that leaves the models underestimating the SE Ridge influence from 8-10 days out. New run Old run

Impressive squall line for late December.

Gusts in excess of 60 mph possible near the South Shore with the cold front as we get some deeper mixing this afternoon.

We needed one of the most positive December +PNA patterns on record in 2020 to overcome that south based block and produce the double digit snowstorm in NYC.

Yeah, this is also the first December with an AO reading of -4 or lower to link up with the SE Ridge. Decembers in -4 or lower daily AO composite 2010…2009…2000…1995…1978…1976…1968…1966…1963…1962…1950 https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.index.b500101.current.ascii

High tide in Freeport came in above the Irene levels. https://water.weather.gov/ahps2/hydrograph.php?wfo=okx&gage=frpn6

Could be the strongest seiche on record for Lake Erie. Intense winds behind the cold front today will produce a SIGNIFICANT seiche event on Lake Erie which will rival the highest lake levels ever experienced. Sustained winds to at least 45 knots with frequent gusts over storm force in the central and eastern basin will push the lake level well above flood stage at Buffalo. Once the winds start ramping up this morning there will be a very rapid rise in the Lake Erie water level at the eastern end of the basin. Lake Erie water levels at Buffalo are expected to reach peak between 9 am today morning and 3 am Saturday morning, with the potential for lakeshore flooding continuing through Saturday. Peak lake levels exceeding 11 feet above low water datum at Buffalo are almost certain, with even the potential to exceed 12 feet looking quite likely. If this were to happen it would be near or even break the previous high lake level at Buffalo set back on 12/2/1985 of 12.08 feet above of low water datum. For historical perspective, peak winds for that event reached 66 mph, with this event we are looking at peak gusts at or exceeding these speeds. Only question is the actual level of the lake itself. The lake currently is at 2.5 feet above low water datum at Buffalo which is just under a foot above the long term monthly mean for December. The two most recent highest events at Buffalo were 11.12 feet on 11/15/2020 and 10.6 feet on 11/1/2019.