bluewave

You can see why the GEFS and GEPS link the Greenland block up with the SE Ridge on todays runs. Notice how they are showing more of a MJO 5-6 than they were a few days ago. This is why the cutter storm track is showing up early in the month. It’s also another example of how day 11-15 forecasts can be so uncertain especially with the data sparse Pacific. So it takes patience with Pacific improvement when we have a La Niña background state.

Peak gust to 66 mph so far in Westchester. https://nwschat.weather.gov/p.php?pid=202211302208-KOKX-NOUS41-PNSOKX LARCHMONT HARBOR 66 MPH KINGS POINT 55 MPH FIRE ISLAND CG 55 MPH KEW GARDEN HILLS 51 MPH 1 ESE NORWALK 57 MPH

Long Island could see some peak gusts in the 50-60 mph range with the heavier downpours later. There isn’t much of an inversion to prevent the 975mb 50KT LLJ from mixing down. So this should be one of our stronger frontal passages in a while.

You are thinking of 1779-1780 when Philly may have had one day above freezing in January which hasn’t happened since then.

Yes.

They can’t since model skill quickly degrades beyond the 1-5, 6-10, and 11-15 day intervals. The study below is only noting the increase in Greenland blocking. We have seen similar record blocks near Alaska over the same period. Plus other regions have seen record blocking. Also notice the range of increasing highs and lows of the NAO with more amplitude to the index. https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/joc.4673 Greenland Blocking Index 1851–2015: a regional climate change signal We present an extended monthly and seasonal Greenland Blocking Index (GBI) from January 1851 to December 2015, which more than doubles the length of the existing published GBI series. We achieve this by homogenizing the Twentieth Century Reanalysis version 2c-based GBI and splicing it with the NCEP/NCAR Reanalysis-based GBI. More recently, since 1981 there are significant GBI increases in all seasons and annually, with the strongest monthly increases in July and August. A recent clustering of high GBI values is evident in summer, when 7 of the top 11 values in the last 165 years – including the two latest years 2014 and 2015 – occurred since 2007. Also, 2010 is the highest GBI year in the annual, spring, winter and December series but 2011 is the record low GBI value in the spring and April series. Moreover, since 1851 there have been significant increases in GBI variability in May and especially December. December has also shown a significant clustering of extreme high and low GBI values since 2001, mirroring a similar, recently identified phenomenon in the December North Atlantic Oscillation index, suggesting a related driving mechanism. We discuss changes in hemispheric circulation that are associated with high compared with low GBI conditions. Our GBI time series should be useful for climatologists and other scientists interested in aspects and impacts of Arctic variability and change.

Still a top 5 and 10 warmest November with a few days to go. Time Series Summary for WESTCHESTER CO AP, NY - Month of Nov Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1994 49.2 2 2 2006 48.8 0 3 2011 48.7 0 4 2022 48.5 4 - 2015 48.5 0 - 2009 48.5 0 5 2001 48.0 0 - 1975 48.0 0 6 2020 47.9 0 7 1963 47.5 0 8 2016 46.6 0 9 2003 46.3 0 - 1964 46.3 0 10 1999 46.2 9 - 1966 46.2 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Nov Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2020 53.0 0 2 2015 52.8 0 3 2001 52.7 0 4 1979 52.5 0 5 1948 52.4 0 6 1975 52.3 0 7 2011 51.9 0 - 2006 51.9 0 - 1994 51.9 0 - 1931 51.9 0 8 2022 51.5 3 9 1902 51.4 0 10 2009 51.1 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Nov Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1975 52.7 0 2 2015 52.5 0 3 2009 51.0 0 - 2001 51.0 0 4 2022 50.9 3 - 2020 50.9 0 - 1994 50.9 0 5 2011 50.8 0 - 2006 50.8 0 6 1948 50.7 0 7 2016 50.6 0 8 1982 50.4 0 9 1985 50.1 0 10 1999 50.0 0

Record number of 15”+ snowstorms in recent years at Islip. Maximum 3-Day Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 27.8 2013-02-10 0 - 0 2 25.9 1978-02-08 0 - 0 3 24.9 2015-01-28 0 - 0 4 24.7 2022-01-30 0 - 0 5 23.9 2009-12-21 0 - 0 6 23.7 2016-01-25 0 - 0 0 0 7 20.1 1983-02-13 0 - 0 8 19.9 2006-02-13 0 - 0 9 18.4 2018-03-23 0 - 0 10 18.0 2003-02-18 0 11 17.8 1978-01-21 0 - 0 0 12 17.1 1996-01-09 0 0 - 0 - 0 13 17.0 1969-02-11 0 - 0 14 17.0 1967-03-23 0 - 0 0 - 0 0 15 16.0 2018-01-06 0 - 0 - 0 16 16.0 1982-04-08 0 - 0 - 0 1 0 17 15.2 2011-01-13 0 - 0 18 15.2 2005-01-24 0 0 19 15.0 1969-02-09 0 - 0

There are a few ways to get a -NAO pattern. One way is for MJO 8 forcing near South America to pump - NAO block over Greenland. The bottom up process in the forecast is faster. A SSW higher up in the stratosphere can take up to 3 weeks to work down to the troposphere. This is what happened in February 2018 so we hit 80° before the blocking emerged in March. While there is La Niña forcing initially maintaining the -PNA trough in the West, a retrogression west of the -NAO block can turn the -PNA more neutral and even positive. This is what happened in December 2010.

This is a classic early season bottom up blocking event with a forecast for a record weak vortex at 100 mb.

They just restored all the missing snowfall before 2004 for Islip. Notice the missing count of days is now 0 for nearly all the years. They quietly did this within the last few months. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Oct 1 to Apr 30 Missing Count 2022-04-30 37.0 0 2021-04-30 33.5 0 2020-04-30 6.8 0 2019-04-30 12.8 0 2018-04-30 65.9 0 2017-04-30 39.3 0 2016-04-30 41.4 0 2015-04-30 63.7 0 2014-04-30 63.7 0 2013-04-30 46.9 0 2012-04-30 4.7 0 2011-04-30 55.3 0 2010-04-30 53.8 0 2009-04-30 36.2 0 2008-04-30 10.7 0 2007-04-30 9.0 0 2006-04-30 36.0 0 2005-04-30 58.8 0 2004-04-30 41.4 0 2003-04-30 54.6 0 2002-04-30 3.7 1 2001-04-30 38.9 1 2000-04-30 9.0 0 1999-04-30 19.4 0 1998-04-30 2.6 0 1997-04-30 12.4 1 1996-04-30 77.1 0 1995-04-30 5.1 0 1994-04-30 37.1 0 1993-04-30 28.6 0 1992-04-30 13.4 0 1991-04-30 13.8 0 1990-04-30 19.0 0 1989-04-30 19.0 0 1988-04-30 19.5 0 1987-04-30 22.5 0 1986-04-30 15.2 0 1985-04-30 26.9 0 1984-04-30 27.5 0 1983-04-30 31.9 0 1982-04-30 35.4 0 1981-04-30 20.8 0 1980-04-30 9.0 0 1979-04-30 28.1 0 1978-04-30 68.0 0 1977-04-30 28.0 0 1976-04-30 30.2 0 1975-04-30 14.5 0 1974-04-30 34.0 0 1973-04-30 4.5 0 1972-04-30 15.6 0 1971-04-30 18.9 0 1970-04-30 27.0 0 1969-04-30 33.5 0 1968-04-30 22.6 0 1967-04-30 50.8 0 1966-04-30 15.7 0 1965-04-30 39.5 0 1964-04-30 39.7 6

The trend analysis is the same across the whole area. Snowfall has nearly doubled from 2002-2022 over the previous 20 years. Islip averages 38.6 “ now vs only 22.1.” from 1982-2002 .That’s why its so hard to talk averages anymore in regard to snowfall since it has been so variable since the early 1980s. Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.0 0.5 6.5 13.0 11.8 6.3 0.5 38.6 2021-2022 0.0 T 0.3 31.8 3.3 1.6 0.0 37.0 2020-2021 T 0.0 7.5 1.1 24.9 T T 33.5 2019-2020 0.0 0.1 4.2 2.5 0.0 T T 6.8 2018-2019 0.0 4.3 T 0.9 3.5 4.1 T 12.8 2017-2018 0.0 T 6.0 22.0 1.4 31.9 4.6 65.9 2016-2017 T T 3.2 14.0 14.7 7.4 T 39.3 2015-2016 0.0 0.0 T 24.8 13.2 3.2 0.2 41.4 2014-2015 0.0 T 0.4 30.2 13.4 19.7 0.0 63.7 2013-2014 0.0 0.3 8.1 25.2 24.5 5.4 0.2 63.7 2012-2013 0.0 4.2 0.6 3.3 31.4 7.4 0.0 46.9 2011-2012 0.3 0.0 T 3.8 0.6 T 0.0 4.7 2010-2011 0.0 T 14.9 34.4 3.9 2.1 T 55.3 2009-2010 0.0 0.0 25.3 6.4 21.7 0.4 0.0 53.8 2008-2009 0.0 T 10.4 8.9 3.3 13.6 T 36.2 2007-2008 0.0 0.0 2.6 0.8 7.3 T 0.0 10.7 2006-2007 0.0 T 0.0 1.0 4.2 3.8 T 9.0 2005-2006 0.0 0.5 7.6 4.7 19.9 3.2 0.1 36.0 2004-2005 0.0 T 7.0 21.5 17.0 13.3 0.0 58.8 2003-2004 0.0 0.0 15.5 19.1 1.1 5.7 0.0 41.4 2002-2003 0.0 1.0 16.0 2.6 26.3 3.7 5.0 54.6 Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean T 0.6 3.6 6.0 6.7 4.5 0.8 22.1 2001-2002 0.0 0.0 0.0 3.7 T T 0.0 3.7 2000-2001 T 0.0 10.8 9.2 8.6 10.3 T 38.9 1999-2000 0.0 T 0.4 5.8 2.6 0.2 T 9.0 1998-1999 0.0 0.0 3.0 4.5 2.8 9.1 T 19.4 1997-1998 0.0 T 1.0 T T 1.6 T 2.6 1996-1997 0.0 T 1.2 3.3 2.2 3.7 2.0 12.4 1995-1996 0.0 3.0 13.3 20.2 19.0 12.0 9.6 77.1 1994-1995 0.0 T T T 5.1 T 0.0 5.1 1993-1994 0.0 T 3.3 8.8 20.0 5.0 0.0 37.1 1992-1993 0.0 0.0 2.1 2.3 10.9 13.3 0.0 28.6 1991-1992 0.0 0.0 2.0 2.3 1.5 7.6 T 13.4 1990-1991 0.0 0.0 4.0 3.6 4.3 1.9 0.0 13.8 1989-1990 0.0 7.6 0.2 2.0 2.0 4.2 3.0 19.0 1988-1989 0.0 0.0 10.4 4.4 1.2 3.0 T 19.0 1987-1988 0.0 1.1 4.2 10.7 0.1 3.4 0.0 19.5 1986-1987 0.0 T 3.4 8.8 8.6 1.7 0.0 22.5 1985-1986 0.0 T 2.1 2.6 10.4 0.1 T 15.2 1984-1985 0.0 T 4.7 13.5 8.7 T T 26.9 1983-1984 0.0 T 2.6 11.9 T 13.0 0.0 27.5 1982-1983 0.0 0.0 3.2 1.5 26.1 T 1.1 31.9

I think it’s more of a geographic location thing like you mentioned sticking out into the Long Island Sound. While the nearby success hill COOP was still recording snowfall, its snowfall was nearly identical to the airport from 2010 to 2018. Unfortunately, looks like that COOP hasn’t reported snow in several years. The difference between snowfall at both sites was only 0.4”. Monthly Total Snowfall for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.4 1.0 6.7 14.1 15.6 7.1 0.7 45.5 2017-2018 0.0 0.0 8.7 11.4 5.3 14.5 6.0 45.9 2016-2017 T T 6.0 11.0 12.8 11.1 0.0 40.9 2015-2016 T 0.0 0.7 10.3 13.9 2.3 0.1 27.3 2014-2015 0.0 0.2 0.7 18.7 21.5 18.6 T 59.7 2013-2014 0.0 0.1 10.9 13.4 32.1 0.8 0.1 57.4 2012-2013 0.0 8.4 7.8 4.7 30.4 13.0 0.0 64.3 2011-2012 4.0 0.0 0.0 7.4 2.2 T T 13.6 2010-2011 0.0 0.4 12.0 42.0 5.0 3.2 T 62.6 2009-2010 T 0.0 13.4 7.7 16.9 0.1 T 38.1 Monthly Total Snowfall for BRIDGEPORT-SUCCESS HILL, CT Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr Season Mean 0.4 1.0 6.5 14.0 16.3 7.0 0.7 45.9 2017-2018 0.0 0.0 8.7 11.4 5.4 15.0 6.0 46.5 2016-2017 T T 6.0 8.5 17.4 11.1 0.0 43.0 2015-2016 T 0.0 0.7 10.6 14.1 2.3 0.1 27.8 2014-2015 0.0 0.2 0.7 17.5 21.5 18.7 T 58.6 2013-2014 0.0 0.1 10.9 13.6 32.1 0.4 0.5 57.6 2012-2013 0.0 8.4 7.8 4.2 30.5 12.0 0.0 62.9 2011-2012 4.0 0.0 0.0 7.5 2.2 T T 13.7 2010-2011 T 0.4 12.2 42.0 5.0 3.2 T 62.8 2009-2010 T 0.0 11.3 10.6 18.4 0.1 T 40.4

It’s tough to to say for sure since there is often big difference between Danbury and the immediate coast. Bridgeport isn’t that different from the other surrounding coastal sites. But the interior of Fairfield gets more snow since it’s often north of the rain snow line. Data for October 1, 2021 through May 31, 2022 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall DANBURY COOP 35.1 SHELTON 1.3 W CoCoRaHS 31.2 NEWTOWN 4.6 SE CoCoRaHS 29.4 BETHEL 3.5 NNE CoCoRaHS 29.2 NEW CANAAN 3.8 N CoCoRaHS 28.3 NEW CANAAN 1.9 ENE CoCoRaHS 28.0 IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 27.7 BETHEL 0.5 E CoCoRaHS 26.5 BROOKFIELD 3.3 SSE CoCoRaHS 24.8 NORWALK 2.9 NNW CoCoRaHS 23.2 Data for October 1, 2020 through May 31, 2021 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall RIDGEFIELD 3.6 N CoCoRaHS 53.8 DANBURY COOP 53.7 NEW CANAAN 1.9 ENE CoCoRaHS 47.8 BETHEL 3.5 NNE CoCoRaHS 46.8 DANBURY 3.0 W CoCoRaHS 46.0 BETHEL 0.5 E CoCoRaHS 45.7 SHELTON 1.3 W CoCoRaHS 44.4 IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 43.8 NEWTOWN 4.6 SE CoCoRaHS 43.7 NEWTOWN 4.6 SSW CoCoRaHS 43.0 TRUMBULL 1.2 S CoCoRaHS 39.1 NEW CANAAN 3.8 N CoCoRaHS 38.6 BROOKFIELD 3.3 SSE CoCoRaHS 38.1 NORWALK 2.9 NNW CoCoRaHS 37.3 Data for October 1, 2019 through May 31, 2020 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall NEWTOWN 4.6 SE CoCoRaHS 16.5 SHELTON 1.3 W CoCoRaHS 13.4 BETHEL 3.5 NNE CoCoRaHS 13.3 BETHEL 0.5 E CoCoRaHS 12.5 BROOKFIELD 3.3 SSE CoCoRaHS 12.4 MONROE 0.8 W CoCoRaHS 12.4 NEW CANAAN 1.9 ENE CoCoRaHS 10.5 IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 10.1 NORWALK 2.9 NNW CoCoRaHS 8.4 RIDGEFIELD 1.9 SSE CoCoRaHS 8.0 DARIEN 2.8 NW CoCoRaHS 7.9 MONROE 0.1 SE CoCoRaHS 7.7 DANBURY COOP 6.9 Data for October 1, 2018 through May 31, 2019 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall DANBURY COOP 36.4 NEW CANAAN 1.9 ENE CoCoRaHS 31.9 SHELTON 1.3 W CoCoRaHS 31.8 NEW CANAAN 3.8 N CoCoRaHS 31.4 NEWTOWN 4.3 E CoCoRaHS 31.3 BETHEL 0.5 E CoCoRaHS 29.4 BETHEL 3.5 NNE CoCoRaHS 28.7 NORWALK 2.9 NNW CoCoRaHS 28.6 BROOKFIELD 3.3 SSE CoCoRaHS 27.8 DARIEN 2.8 NW CoCoRaHS 27.1 MONROE 0.1 SE CoCoRaHS 25.8 IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 24.6 SHELTON 2.7 SSE CoCoRaHS 23.3 RIDGEFIELD 1.9 SSE CoCoRaHS 23.1 DARIEN 1.8 ENE CoCoRaHS 22.2 Data for October 1, 2017 through May 31, 2018 Click column heading to sort ascending, click again to sort descending. Name Station Type Total Snowfall DANBURY COOP 77.1 BETHEL 0.5 E CoCoRaHS 65.6 SHELTON 1.3 W CoCoRaHS 65.0 BETHEL 3.5 NNE CoCoRaHS 63.0 NEW CANAAN 1.9 ENE CoCoRaHS 61.1 BROOKFIELD 3.3 SSE CoCoRaHS 59.9 NEWTOWN 4.6 SSW CoCoRaHS 58.6 NORWALK 2.9 NNW CoCoRaHS 50.9 NEWTOWN 4.3 E CoCoRaHS 50.2 DARIEN 2.8 NW CoCoRaHS 49.5 BRIDGEPORT-SUCCESS HILL COOP 46.5 IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 45.9 STAMFORD 3.3 NW CoCoRaHS 44.1 DARIEN 1.8 ENE CoCoRaHS 43.8 RIDGEFIELD 1.9 SSE CoCoRaHS 36.5

The average for your area is around 40” since 2010. It was around half that much from 1980 to 2000. So who knows what is average snowfall anymore. Monthly Total Snowfall for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr May Season Mean 0.3 1.1 5.9 12.0 13.8 6.1 0.5 T 39.7 2021-2022 0.0 T 0.2 20.8 4.7 2.0 0.0 0.0 27.7 2020-2021 T T 10.0 3.1 30.7 0.0 0.0 0.0 43.8 2019-2020 0.0 T 5.5 4.6 T T T T 10.1 2018-2019 0.0 5.8 0.5 1.2 3.6 13.5 0.0 0.0 24.6 2017-2018 0.0 0.0 8.7 11.4 5.3 14.5 6.0 0.0 45.9 2016-2017 T T 6.0 11.0 12.8 11.1 0.0 0.0 40.9 2015-2016 T 0.0 0.7 10.3 13.9 2.3 0.1 0.0 27.3 2014-2015 0.0 0.2 0.7 18.7 21.5 18.6 T 0.0 59.7 2013-2014 0.0 0.1 10.9 13.4 32.1 0.8 0.1 0.0 57.4 2012-2013 0.0 8.4 7.8 4.7 30.4 13.0 0.0 0.0 64.3 2011-2012 4.0 0.0 0.0 7.4 2.2 T T 0.0 13.6 2010-2011 0.0 0.4 12.0 42.0 5.0 3.2 T 0.0 62.6 2009-2010 T 0.0 13.4 7.7 16.9 0.1 T 0.0 38.1 Monthly Total Snowfall for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Year Oct Nov Dec Jan Feb Mar Apr May Season Mean 0.0 0.7 3.3 7.0 6.2 4.2 1.2 0.0 22.6 1999-2000 0.0 0.0 T 6.5 5.7 0.1 1.0 0.0 13.3 1998-1999 0.0 M 1.1 6.2 3.0 9.6 0.0 0.0 19.9 1997-1998 0.0 T 6.7 1.7 T 0.5 0.0 0.0 8.9 1996-1997 0.0 T 1.0 3.8 2.1 3.8 4.0 0.0 14.7 1995-1996 0.0 2.6 13.8 20.5 16.8 10.2 11.8 0.0 75.7 1994-1995 0.0 T T 1.3 8.0 T T 0.0 9.3 1993-1994 0.0 0.0 1.9 17.3 27.9 7.9 0.0 0.0 55.0 1992-1993 0.0 0.0 2.4 3.3 9.5 13.7 0.0 0.0 28.9 1991-1992 0.0 0.0 2.1 1.8 2.4 10.2 0.0 0.0 16.5 1990-1991 0.0 0.0 7.1 6.3 5.6 3.0 0.0 0.0 22.0 1989-1990 0.0 6.6 4.1 5.2 9.3 4.4 1.7 0.0 31.3 1988-1989 0.0 0.0 7.5 1.6 2.1 1.8 0.0 0.0 13.0 1987-1988 0.5 0.9 1.8 15.5 2.1 2.1 T 0.0 22.9 1986-1987 0.0 1.8 3.3 11.4 2.9 2.7 0.0 0.0 22.1 1985-1986 0.0 1.0 3.5 2.0 11.0 T T 0.0 17.5 1984-1985 0.0 T 1.5 11.2 6.5 0.5 0.0 0.0 19.7 1983-1984 0.0 T 0.6 11.6 T 8.4 0.0 0.0 20.6 1982-1983 0.0 0.0 3.2 5.1 14.2 T 0.5 0.0 23.0 1981-1982 0.0 0.0 3.1 9.0 T 1.6 6.0 0.0 19.7 1980-1981 0.0 1.0 3.6 5.4 T 1.5 0.0 0.0 11.5 1979-1980 T 0.0 0.9 0.7 1.7 6.3 0.0 0.0 9.6

The past stratospheric analogs may not be as useful this time due to the Hunga Tunga eruption. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL100982 While the stratosphere (15–55 km) region of the atmosphere contains the ozone layer, it is typically very dry, especially when compared to the troposphere. However, the remarkable eruption of the Hunga Tonga-Hunga Ha'apai underwater volcano on 15 January 2022 injected a record amount of water directly into the stratosphere. Winds in the stratospheric soon carried this excess water vapor around the globe to all longitudes and spread the water vapor in latitude as well. Since water vapor can cool to space more rapidly than the stratospheric air, enhanced cooling in the stratosphere is expected. This study quantifies this cooling, as well as the subsequent changes to the stratospheric circulation, during the months following the eruption. The extreme nature of the stratospheric temperature, wind, and circulation changes are tracked through comparisons of the first six months of 2022 with the previous 42 years. Details of the stratospheric perturbations in latitude and pressure are presented for June 2022, where anomalously low temperatures are found at near 20 km altitude from 60 to 30°S. In response to this cooling the atmosphere adjusts by creating strong westerly winds above the temperature anomaly and large changes to the downward and poleward mean meridional circulation.

But we are getting a -NAO pattern into early December. So the stronger SPV isn’t able to propagate downward into the troposphere. Our pattern will again come down to how much cooperation we can get from the Pacific.

We went from a record -EPO +PNA to a +EPO -PNA in just a few days. So models have a had time figuring out the individual shortwave details. Plus we are getting a 5 sigma Pacific Jet near Alaska.

Very fast Pacific Jet with a storm cutting through the lakes every few days into early December.

Models have been in full push back mode recently. The upper upper low in SW that was supposed to come through Friday is delayed even more. Yesterday the models had a early Sunday passage. Now the morning looks dry with a later day or evening for the storm to come through. Maybe the high temperatures can overperform with 60° possible on Long Island. 12 Wednesday run 12z Tuesday run

We’ll probably need another week or so to see if they hold. The EPS has the best looking early December pattern we have seen in a while. But the model skill recently has been very low even at 5 days so we have to be patient on this one.

The long range models have a pretty wide spread by the first week of December. The EPS is the only model to have a more favorable Pacific pattern. It is showing height rises along the West Coast which is different from the typical La Niña. The GEFS and GEPS maintain a La Niña trough near the west coast. So we probably need to wait for the models to settle down before buying into any scenario. This is especially true with how much the models have been jumping from run to run with the storm for Friday that got pushed back to Sunday. So if the models can’t even handle a 5 day forecast, then a week 2 forecast may not be very accurate either.

We can always get +PNA intervals during a La Niña winter. This was the case through much of the 20-21 winter and January 22. But last winter we had the record -PNA reversal from December to January and the NAO didn’t play ball. So Long Island cashed in with record snows while the flow was too progressive west of NYC.

The CMC went from a 959 mb low in New England on Saturday to a suppressed system and no storm in one run. Similar reversal on the GFS. The Euro seems to be slowly backing away from the stronger solution at 6z as the southern stream low lags behind. So this could be one of the worst model performances of the year so far.

I can’t remember the last time that all 3 models were so different at 5 days out. The CMC and GFS squash the southern stream with no wave break to pump the -NAO into early December. The Euro and EPS have a more amplified southern stream storm resulting in a wave break and stronger -NAO into early December. There was a strong storm at the end of November 2020 causing a wave break which flipped the -NAO going into December with 60-70 mph gusts on Long Island.