bluewave

All the long range guidance continues to advertise a very warm pattern this month. The only other highly amplified Aleutians Ridge, -PNA, +AO, and SE Ridge La Niña December was 1984. But that doesn’t mean the rest of the winter will resemble 84-85 since we are in such a warmer climate now. A weaker match may mean that this winter tries to mount some sort of a comeback after December. Still way too early to speculate on the rest of the winter. EPS Dec 6 to 13 Dec 13-20 Dec 20-27

Central Park getting back closer to reality now the leaves blocking the sensor are falling. Regional Weather Roundup National Weather Service New York NY 200 PM EST THU DEC 02 2021 Note: "FAIR" indicates few or no clouds below 12,000 feet with no significant weather and/or obstructions to visibility. NYZ071-072-176-178-NJZ106-104-022000- New York City Metro Area CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park PTSUNNY 57 43 59 VRB6 29.67F World Trd Ctr NOT AVBL Bronx Lehman C N/A 55 43 62 SW8 N/A LaGuardia Arpt CLOUDY 58 42 55 SW10 29.65F Queens College N/A 57 43 58 SW12 N/A Kennedy Intl CLOUDY 55 45 68 S6 29.67F Breezy Point N/A 55 N/A N/A S3 N/A Brooklyn Coll N/A 57 43 58 S7 N/A Staten Island N/A 57 43 58 SW8 N/A Newark/Liberty CLOUDY 59 44 57 SW13 29.64F Teterboro PTSUNNY 54 44 69 SW8 29.63F $$ NYZ177-179-078>081-022000- Long Island New York CITY SKY/WX TMP DP RH WIND PRES REMARKS Jones Beach N/A 54 N/A N/A S9 N/A Wantagh N/A 54 48 82 S8 N/A Hempstead NOT AVBL Matinecock Pt N/A 55 N/A N/A SW9 N/A Farmingdale CLOUDY 54 45 71 SW10 29.67F MacArthur/ISP CLOUDY 53 46 77 SW10 29.67F Stony Brook N/A 55 45 67 S5 N/A Shirley CLOUDY 54 45 71 S8 29.67F Mt Sinai Harb N/A 55 N/A N/A S5 N/A Westhampton CLOUDY 53 47 79 SW10 29.68F East Hampton PTSUNNY 53 46 77 SW8 29.67F Southold N/A 54 45 71 S9 N/A Montauk N/A 54 48 80 SW9G17 29.68F

19-20 gave new meaning to the term backloaded winter. https://gothamist.com/news/videos-nyc-reacts-freaky-may-snowfall

Yeah, just goes to show how much warmer the models have corrected in recent days. The long range forecasts were about 30° colder. Somebody in NJ can make a run on 70° with enough sun. New run Old run

We don’t even need to look that far out to see how ridiculously warm this month is starting in the US and Southern Canada.

The monthly temperature increases from 81-10 to 91-20 have been more pronounced during certain months. Newark and Islip are compared below. The +1.0 or warmer months for either station were bolded. ……….EWR…..ISP Dec…+1.5….+1.5 Jan….+1.2…+1.3 Feb….+0.5….+0.5 Mar….+0.4….+0.6 Apr….+0.5…..+0.6 May...+0.6….+0.9 Jun….+0.3….+0.6 Jul…..+1.4…..+1.1 Aug...+0.6….+0.9 Sep….+1.0….+1.3 Oct…..+0.9..+1.4 Nov….+0.2..+0.5

I guess it isn’t a surprise that December is the fastest warming winter month around the area. It’s like the seasons are getting pushed back. Summer into fall and fall into December. It was another top 5 or top 10 warmest fall for a large part of the country.

With the recent model runs correcting warmer for December, areas around NYC may be on track for another 40° or warmer December. A 40° December used to be a rarity before recent times. Now they are occurring more frequently.

The first two days of December are verifying warmer than model forecasts. We are currently in the 50s for early in the morning. The model error with the fast Pacific flow and record Atlantic SSTs is too cool. Regional Weather Roundup National Weather Service New York NY 600 AM EST THU DEC 02 2021 Note: "FAIR" indicates few or no clouds below 12,000 feet with no significant weather and/or obstructions to visibility. NYZ071-072-176-178-NJZ106-104-021200- New York City Metro Area CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park CLOUDY 52 47 83 VRB3 29.91F World Trd Ctr NOT AVBL Bronx Lehman C N/A 52 46 82 S6 N/A LaGuardia Arpt CLOUDY 52 46 80 S9 29.88F Queens College N/A 52 48 87 S13 N/A Kennedy Intl MOCLDY 52 48 86 S14 29.90F Breezy Point N/A 52 N/A N/A S12 N/A Brooklyn Coll N/A 52 48 87 S10 N/A Staten Island N/A 50 46 87 S9 N/A Newark/Liberty CLOUDY 50 46 86 S6 29.89F Teterboro DRIZZLE 49 46 90 SW5 29.88F $$ NYZ177-179-078>081-021200- Long Island New York CITY SKY/WX TMP DP RH WIND PRES REMARKS Jones Beach N/A 54 N/A N/A S13G18 N/A Wantagh N/A 54 50 87 S10 N/A Hempstead NOT AVBL Matinecock Pt N/A 50 N/A N/A S5 N/A Farmingdale PTCLDY 51 46 83 S12 29.90F MacArthur/ISP MOCLDY 51 45 79 SE12 29.89F Stony Brook N/A 50 45 81 S7 N/A Shirley PTCLDY 51 43 74 SE15 29.91F Mt Sinai Harb N/A 50 N/A N/A S10 N/A Westhampton PTCLDY 52 44 74 SE10G18 29.92F East Hampton CLOUDY 51 43 73 S12 29.92F Southold N/A 50 45 81 S13 N/A Montauk N/A 51 44 77 S7 29.95F

I think that this wave break may be having a bigger influence. It eventually pumps the Aleutians Ridge. Then the -PNA trough digs into the Pacific Northwest boosting the Southeast Ridge during the 2nd week of December.

The Central Park leaves that were blocking the ASOS may have finally begun to drop. It’s near 50° now like JFK and LGA. All the stations are warmer than high temperature guidance today. 000 SXUS51 KOKX 011757 OSOOKX New York City Metropolitan Area Weather Roundup National Weather Service New York NY 100 PM EST WED DEC 01 2021 CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park MOSUNNY 49 24 37 VRB5 30.16F LaGuardia Arpt PTSUNNY 49 23 36 NW12 30.14F Kennedy Intl PTSUNNY 49 25 39 W14 30.16F

Those record warm Atlantic SSTs and the faster Pacific Jet allowed the ridge over our area to verify stronger than forecast today. Verification already 50° at Newark Old forecast was colder for today Record warm Atlantic SSTs https://mco.umaine.edu/gom_sst/

We have gotten used to the +PDO La Niña Decembers of recent years. But the December La Niña composite with a strong -PDO features a strong Aleutians Ridge like the models are advertising. This creates more of +EPO and -PNA pattern in December. The near record warm Atlantic SSTs will enhance the Southeast Ridge by mid-December.

Multiple 5 sigma North Pacific and East Asian Jet maxes is as extreme as it gets to start December. This really pumps the ridge out near the Dateline and Aleutians. So it keeps reinforcing the +EPO -PNA pattern. The Atlantic is of no help at this time with a strong +AO +NAO pattern.

Several stations across the region has their warmest fall on record. Nearly all finished in the top 10 warmest. This record fall warmth has been a common theme in recent years. Time Series Summary for SUSSEX AIRPORT, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2021 54.9 0 2 2011 54.3 6 3 2017 54.2 0 4 2015 54.1 0 5 2020 53.8 0 Time Series Summary for CALDWELL ESSEX COUNTY AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2021 59.5 3 2 2020 58.4 0 3 2015 58.0 0 4 2016 57.6 0 5 2017 57.2 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2021 61.3 0 2 2015 60.9 0 3 1971 60.4 0 - 1961 60.4 0 4 2017 60.3 0 - 1990 60.3 0 5 2016 60.1 0 - 2011 60.1 0 Time Series Summary for FARMINGDALE REPUBLIC AP, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 59.8 0 2 2021 59.2 0 3 2016 59.0 7 4 2020 58.9 2 - 2017 58.9 0 - 2005 58.9 1 5 2011 58.0 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2017 58.8 0 2 2015 58.6 0 3 2021 58.5 0 - 2011 58.5 0 4 1990 58.1 0 5 2016 58.0 0 6 2020 57.7 0 - 2005 57.7 0 Time Series Summary for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2016 62.5 0 2 2021 62.1 0 3 2015 61.9 0 - 2007 61.9 0 - 2005 61.9 0 4 2020 61.8 0 5 2017 61.7 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2015 61.1 0 2 1971 60.8 0 3 2016 60.2 0 4 2021 60.0 0 - 2017 60.0 0 5 1983 59.8 0 - 1961 59.8 0 6 2011 59.5 0 7 2005 59.4 0 8 2020 59.2 0 - 1985 59.2 0 9 1990 59.1 0 10 2010 59.0 0 - 2007 59.0 0 - 1970 59.0 0 Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2016 59.1 0 2 2011 59.0 0 3 2015 58.9 0 4 2017 58.8 0 5 1973 58.6 0 6 2021 58.4 0 7 2020 58.3 0 8 1977 58.2 0 9 1975 57.9 0 10 2007 57.8 0 Time Series Summary for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2011 58.4 0 2 1931 58.3 0 3 2021 58.1 0 4 1975 57.7 0 5 1927 57.5 0 6 2017 57.4 0 - 1946 57.4 0 7 2015 57.3 0 - 1983 57.3 0 8 1990 57.1 0 9 1953 57.0 0 10 1971 56.9 0 - 1961 56.9 0 Time Series Summary for Caribou Area, ME (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2011 47.8 0 2 2017 47.7 0 3 2021 47.5 0 4 2016 47.3 0 5 1961 46.7 0 6 2001 46.4 0 7 2015 46.2 0 8 2020 45.8 0 9 1999 45.6 0 10 1970 45.3 0 - 1957 45.3 0

It’s ridiculous how extreme the Pacific Jet that’s driving this pattern has become.

The EPS weeklies first started showing this pattern for mid-December back on November 11th.

Classic -PDO pattern showing up now for mid-December. Mild +EPO and -PNA with a +AO/+NAO. This is why we’ll need blocking down the line to push back against such an unfavorable Pacific.

It’s tough to generalize about ENSO sequences during the winter. Last winter was more like an El Niño than a La Niña. Something happened in the late summer this year which lead to the supercharged fall +EPO vortex. That’s what caused the record -PDO drop. So the Pacific Jet is setting records more than we would typically see from just a La Niña alone. This is pretty much the opposite of the 13-14 and 14-15 record NE Pacific warm blob and +PDO/+NPM. Those record warm SSTs were driven by the record -EPO blocking. So the North Pacific has experienced unprecedented volatility in a single decade. Expressions of ENSO states have often been influenced and altered by these extreme pattern swings. Past analogs don’t really do what has been happening over the last decade justice.

The December long range forecasts were looking more interesting at the start of December last year.

Yeah, just going a few miles from the water in weak CAA patterns makes a big difference. This month has been very dry with light winds at night. So the areas away from the direct influence of SSTs still in the 50s were able to radiate. Islip had warmer high temperatures this month and cooler lows. Novembers with true Arctic outbreaks like we had a few years ago usually have colder highs and lows. ISP NOV Max…+0.8 Min….-2.3

It’s representative of all our local stations on the water. The SSTs have been running very warm. Plus the CAA hasn’t been very impressive this month due to the strong Pacific influence. Stations right on the water bolded Regional Weather Roundup National Weather Service New York NY 700 AM EST TUE NOV 30 2021 Note: "FAIR" indicates few or no clouds below 12,000 feet with no significant weather and/or obstructions to visibility. NYZ071-072-176-178-NJZ106-104-301300- New York City Metro Area CITY SKY/WX TMP DP RH WIND PRES REMARKS Central Park CLOUDY 34 21 59 CALM 30.04S World Trd Ctr NOT AVBL Bronx Lehman C N/A 34 23 64 W3 N/A LaGuardia Arpt MOCLDY 35 20 54 CALM 30.03S Queens College N/A 34 23 64 S2 N/A Kennedy Intl MOCLDY 31 24 75 SW5 30.05R WCI 26 Breezy Point N/A 36 N/A N/A W6 N/A WCI 31 Brooklyn Coll N/A 34 25 69 S5 N/A WCI 30 Staten Island N/A 32 25 74 S3 N/A Newark/Liberty MOCLDY 32 23 69 SW5 30.03S WCI 27 Teterboro CLOUDY 29 22 75 CALM 30.02S $$ NYZ177-179-078>081-301300- Long Island New York CITY SKY/WX TMP DP RH WIND PRES REMARKS Jones Beach N/A 34 N/A N/A W5 N/A WCI 30 Wantagh N/A 30 23 74 SW3 N/A Hempstead NOT AVBL Matinecock Pt N/A 36 N/A N/A SW8 N/A WCI 29 Farmingdale PTCLDY 29 20 69 CALM 30.04R MacArthur/ISP PTCLDY 24 19 81 SW3 30.03R Stony Brook N/A 30 25 80 SW2 N/A Shirley PTCLDY 23 18 81 CALM 30.03R Mt Sinai Harb N/A 32 N/A N/A SW2 N/A Westhampton PTCLDY 16 12 84 CALM 30.04R East Hampton FAIR 28 20 70 CALM 30.02R Southold N/A 32 25 74 NW5 N/A WCI 27 Montauk N/A 33 22 63 NW12G20 30.02R WCI 24

The good news is that expectations were lowered when we saw the record -PDO drop this fall. The discussion was about needing impressive Atlantic blocking to counter the record Pacific Jet. Since December has been one of the more +AO + NAO winter months over the last decade, the biggest winter snows have usually occurred later on. NYC in La Ninas generally requires 3” or more of snow in December for normal to above normal seasonal snowfall since the 1990s. But if we don’t make that number in December, a well placed block in JFM can still produce a nice snowstorm.

Another top 5 warmest fall from the Mid-Atlantic to New England.

You can see why all the long range models eventually flatten the MJO 6 ridge out West. It’s another case of the MJO weakening around phase 6 like recent years. So the mid portion of a December will probably see warmer departures than the early part of the month. Bias corrected GEFS and ECMWF