bluewave

10-28-76 was the last time that NYC dropped into the 20s in October. Data for October 28, 1976 through October 28, 1976 Click column heading to sort ascending, click again to sort descending. CT STAMFORD 5 N COOP 16 NY WALDEN 1 ESE COOP 17 NY PORT JERVIS COOP 18 CT DANBURY COOP 20 NY YORKTOWN HEIGHTS 1W COOP 20 NY CARMEL COOP 20 CT WESTBROOK COOP 20 NJ CANOE BROOK COOP 20 CT MIDDLETOWN 4 W COOP 21 NY SCARSDALE COOP 21 CT NORWALK GAS PLANT COOP 22 NY WEST POINT COOP 22 CT MOUNT CARMEL COOP 23 NJ CHARLOTTEBURG RESERVOIR COOP 23 NY SUFFERN COOP 23 CT GROTON COOP 24 CT NORWICH PUBLIC UTILITY PLANT COOP 24 NY BEDFORD HILLS COOP 24 NJ TETERBORO AIRPORT WBAN 24 NY MIDDLETOWN 2 NW COOP 24 NY WESTCHESTER CO AP WBAN 25 NY PATCHOGUE 2 N COOP 25 NJ PLAINFIELD COOP 25 NJ ESSEX FELLS SERVICE BLDG COOP 26 NY MARYKNOLL COOP 26 NY MINEOLA COOP 27 NJ CRANFORD COOP 27 NY DOBBS FERRY-ARDSLEY COOP 27 NJ JERSEY CITY COOP 28 NY NY WESTERLEIGH STAT IS COOP 28 NJ LITTLE FALLS COOP 28 NY NEW YORK BOTANICAL GARDEN COOP 28 NY WANTAGH CEDAR CREEK COOP 29 NY BRIDGEHAMPTON COOP 29 CT NEW HAVEN TWEED AP WBAN 29 CT NEW HAVEN COOP 29 NJ NEWARK LIBERTY INTL AP WBAN 29 NY NY CITY CENTRAL PARK WBAN 29

Yeah, this dry weather will allow spots to radiate very well if the winds can fall off enough before we warm up into the weekend. This rainfall pattern since late August may be a first for the CONUS. A spot like Port Jefferson Station may have been the first U.S case of having a 12.82 historic rainfall event followed by only .39 of rain in the following 45 days. https://www.cocorahs.org/ViewData/StationPrecipSummary.aspx NY-SF-100 Port Jefferson Station 0.3 SSW Lat: 40.919969 Lon: -73.069407 * indicates Multi-Day Accumulation Report Station NY-SF-100 Date Precip in. 08/17/2024 0.00 08/18/2024 0.27 08/19/2024 9.56 08/20/2024 3.26 08/21/2024 0.00 08/22/2024 0.00 08/23/2024 0.00 08/24/2024 0.00 08/25/2024 0.00 08/26/2024 0.00 08/27/2024 0.08 08/28/2024 0.00 08/29/2024 0.00 08/30/2024 0.01 08/31/2024 0.00 09/01/2024 T 09/02/2024 0.06 09/03/2024 0.00 09/04/2024 0.00 09/05/2024 0.00 09/06/2024 0.00 09/07/2024 0.00 09/08/2024 0.08 09/09/2024 0.00 09/10/2024 0.00 09/11/2024 0.00 09/12/2024 0.00 09/13/2024 0.00 09/14/2024 0.00 09/15/2024 0.00 09/16/2024 0.00 09/17/2024 0.00 09/18/2024 0.00 09/19/2024 0.00 09/20/2024 0.00 09/21/2024 0.00 09/22/2024 0.00 09/23/2024 0.00 09/24/2024 0.01 09/25/2024 0.00 09/26/2024 0.00 09/27/2024 0.04 09/28/2024 0.02 09/29/2024 0.14 09/30/2024 0.03 10/01/2024 0.00 10/02/2024 0.00 10/03/2024 0.00 10/04/2024 0.00 10/05/2024 0.00 10/06/2024 0.00 10/07/2024 T 10/08/2024 -- Totals : 13.56 in.

Very low dew points moving in the next several days. Highs in the upper 60s in NJ and dew points falling near freezing. Should drop the relative humidity below 30% in the driest spots.

Milton is unique in that it was the first rapidly intensify while moving southeastward earlier.

CNJ had that great snowband last February with the record jet max.

Just a really extreme pattern with Helene and Milton going under these near to record 500mb ridges. Even the jet stream will be much stronger than normal this week for any flights headed east. The GFS has a near record October 185KT jet streak this week east of Cape Cod. More like a strong Jan jet streak but in October

Tough to get much rainfall away from the tropical systems with so much record ridging and warmth over North America since late August.

Very dry pattern continuing for the CONUS away from the track of Milton.

Good to finally see some brief heavier downpours here but the heaviest totals were just north of me.

Hearing some thunder now to my south.

Probably the strongest -EPO cutter pattern we have experienced in November. https://downloads.psl.noaa.gov/Public/map/teleconnections/epo.reanalysis.t10trunc.1948-present.txt 2022 11 14 -145.88 2022 11 15 -312.70 2022 11 16 -417.28 2022 11 17 -401.21 2022 11 18 -331.21 2022 11 19 -227.44

Yeah, this cutter pattern has been great for snow lovers in your area with the Great Lakes so warm. https://www.drought.gov/sites/default/files/2022-12/Great Lakes Fall 2022.pdf From November 4-6, temperatures were up to 30°F (17°C) above normal in the east. On November 5th, Toronto, Ontario had its warmest November day (records began in 1937) when it reached 77°F (25.1°C). That same day, Buffalo, New York, had its second warmest November day, with 79°F (26.1°C), and Syracuse and Rochester, New York, recorded their warmest low November temperatures at 63°F (17.2°C) and 62°F (16.7°C), respectively. Water temperatures in Lakes Huron, Erie, and Ontario were unusually stable (not decreasing) in October, leading to near- record water warmth by early November. Arctic air moved across the basin mid-month producing massive lake-induced snowfall.

Yeah, over 50.00” on the year in spots like Port Jefferson Station in Suffolk with only .24 since August 20th. Data for January 1, 2024 through October 6, 2024 Click column heading to sort ascending, click again to sort descending. CT PROSPECT 1.9 ENE CoCoRaHS 55.66 CT NEWTOWN 4.6 SE CoCoRaHS 55.48 CT NAUGATUCK 1.7 NNE CoCoRaHS 55.10 CT MIDDLEFIELD 1.4 W CoCoRaHS 54.89 NY ST. JAMES COOP 54.53 CT SOUTHBURY 2.3 W CoCoRaHS 54.45 CT RIDGEFIELD 2.4 NNE CoCoRaHS 53.97 CT BETHEL 3.5 NNE CoCoRaHS 53.71 CT WALLINGFORD CENTER 3.3 NNW CoCoRaHS 53.58 CT BROOKFIELD 3.3 SSE CoCoRaHS 53.49 CT OAKDALE 2.6 WNW CoCoRaHS 52.85 NY PORT JEFFERSON STATION 0.3 SSW CoCoRaHS 52.42 CT EAST LYME 0.5 SW CoCoRaHS 52.22 CT MERIDEN 2.8 WSW CoCoRaHS 52.07 CT RIDGEFIELD 3.6 N CoCoRaHS 51.97 CT SALEM 3.6 SE CoCoRaHS 50.86 CT WALLINGFORD CENTER 1.9 WNW CoCoRaHS 50.82 CT BETHEL 0.5 E CoCoRaHS 50.71 NY CENTEREACH 1.3 NE CoCoRaHS 50.28 Data for August 20, 2024 through October 6, 2024Click column heading to sort ascending, click again to sort descending NY PORT JEFFERSON STATION 0.3 SSW CoCoRaHS 0.24 CT GRISWOLD 0.9 N CoCoRaHS 0.24 NJ LITTLE FALLS TWP 0.2 NE CoCoRaHS 0.26 NY AMITYVILLE 0.6 NNE CoCoRaHS 0.26 NY BELLMORE 0.9 SSE CoCoRaHS 0.26 CT OAKDALE 2.6 WNW CoCoRaHS 0.26 NY ISLIP-LI MACARTHUR AP WBAN 0.30

The one early snowfall indicator which has worked for every La Niña winter in NYC going back to the 95-96 has been the December La Niña snowfall. Years with 3 or more inches December have gone on to above normal seasonal snowfall. Every December with under 3” has had a below average snowfall season. This is why December is so important with La Ninas around NYC. 22-23….Dec snow…..T……season….2.3 21-22…..Dec snow….0.2…season…..17.9 20-21…..Dec snow….10.5…season…38.6 17-18……Dec snow….7.7…..season…40.9 16-17…….Dec snow…3.2…..season…30.2 11-12…….Dec snow….0…….season….7.4 10-11…….Dec snow….20.1….season….61.9 08-09…..Dec snow….6.0……season….27.6 07-08…..Dec snow…..2.9…..season….11.9 05-06…..Dec snow…..9.7…….season…40.0 00-01……Dec snow….13.4……season….35.0 99-00…..Dec snow…..T……….season….16.3 98-99…..Dec snow…..2.0……..season….12.7 95-96…..Dec snow…..11.5……..season….75.6

I was happy for PA into NJ with the event on 2-13 and the narrow snowband on the 2-17 just north of your area. The forcing finally got east of the Dateline for about a week. But the window was too brief and many other areas weren’t able cash in.

The record September warmth has continued into October for North America. My focus is on temps and snowfall. When the fall temps in Canada and the U.S. are skewed very warm or cold it has historically continued over into winter in some manner. Sometimes more localized regional hints for winter and other times nationally.

Big temperature and dew point swings coming up this week. First 40s of the season for NYC with afternoon dew points dropping near freezing. Then a quick bounce back to 70s for the weekend.

Fall temperatures over North America are one of the parameters we look at in judging the amount of cold that could be available in North America during the winter.

One wild card may be how warm Canada is this fall. It’s even warmer than last year which was an El Niño. So we never had this precede a La Niña winter before. I am not sure if the Euro seasonal is just rolling this forward from the initialization. Since it has Canada warmer this winter than the other La Niña winters of the 2020s.

Looks like some Monday morning elevated convection but not much in the way of drought relief.

The Euro 500 mb forecast is nearly identical to the ones it issued for 22-23 and 21-22.

Another great job from the model. https://nsidc.org/sea-ice-today/analyses/new-abnormal Average Arctic sea ice extent for the month of September was 4.38 million square kilometers (1.69 million square miles), sixth lowest in the 46-year-satellite passive microwave record

Thanks for the kind words. I think we got used to the linear warming pattern from the 1970s into 2000s. While it was getting warmer the blocking was also increasing along with the atmospheric moisture. So when everything lined up we had the record snows even if it also had periods of record warmth. But the 15-16 super El Nino feels like it may have ushered in more of a non-linear shift. This has been leading to patterns getting stuck in place for much longer periods of time than we had been accustomed to in the past. Plus we just experienced and even stronger global temperature rise and new higher baseline. While the WPAC warm pool has been leading to more frequent La Ninas and MJO 4-7 patterns since 1980, we were able to get some more favorable +PDOs in the mix. The question now becomes does the configuration of SST warming favor more frequent and intense -PDOs than +PDOs along with +AMOs over -AMOs. I don’t think we have enough data yet to make that determination. But it may have to be something we have to address if this very hostile Pacific continues and the Atlantic SSTs keep increasing. But I agree with you that the increasing moisture is there for snow storms if we can switch back periodically to some elements of a 21-22 season or even 20-21 where the Pacific can briefly become more favorable.

We have two issues at work along the 1-95 corridor in the NYC Metro forecast zones. First, it was like someone flipped switch to warmer with the +13.3 December 2015. But we were still working with more of a favorable +PDO-like pattern into 17-18. The Benchmark storm track was still going strong since the 09-10 or even 02-03 winter with regular record snowfalls. But especially from 15-16 to 17-18 record warmth very close to our big snowfalls. We had blizzards when it was in the record 60s days before or after the snows. I got used to rapid snowmelts following the storms. So the snow cover days were declining relative to past colder and snowier seasons. We went from record warmth with 70s near Christmas in 2015 to one of our greatest snowstorms in January near 30” in NYC. Then a brief Arctic shot in February for the first below 0° since 1994. But a quick recovery back to the 60s following this. 16-17 was also one of our warmest winters but we managed some great snowstorms even if the 60s were close by. Then the 17-18 winter started with a great Arctic shot after Christmas and record 950 mb Benchmark blizzard in early January. But a quick reversal in mid-January and then record 80° warmth in February before record 30” inch snows in March. Much of this volatility was a combination of record MJO 4-7 activity interacting with the lingering +PDO. A great November snowstorm in 2018 before the Pacific began to shift. This takes us to the second factor which was how hostile the Pacific has become with a -PDO signature in this warming climate. 18-19 witnessed a rare El Niño failure due to the record WPAC warm pool which has been driving the warm MJO phases. So we went most of the winter with only a snow squall to show for the pattern while the Chicago area was seeing record cold in the -20s. Then we got into the turn of the new decade in 19-20 with a raging polar vortex and Pacific Jet with more warmth and well below normal snows. 20-21 was a nice reprieve but it was still warmer than average even with a great +PNA -AO. This would have been a much colder pattern in the past like 10-11 was with similar levels of blocking. But the block became too south based favoring places like BGM for the record 40” smowstorm before Christmas. But then the raging Pacific Jet returned on Christmas with the 40” snow pack melting rapidly and causing flash flooding and landslides at the ski resorts. 21-21 started with record warmth in December before seeing our last good winter month in January. The most recent stretch since February 2022 to this past winter was our warmest and least snowiest so close together with numerous locations setting records for stretches with under 4” and 2” snowstorms. We made it to a record 9 warmer winters in a row with some degree of Southeast Ridging. Now we are faced with another extreme global temperature jump even exceeding the 15-16 one. So I am waiting to see what this new even warmer baseline jump looks like in the coming years. So you see we were able to manage the warmth for great snowstorms before the Pacific shifted. But this hostile storm track plus the warmth has been a very challenging winter mix. When we did shift the MJO to 8 in January 2022 places like ACY were able to manage a record 30” month. But that was a fleeting pattern before the MJO went right back to 4-7. So even a short term favorable Pacific period can still produce to some extent. The question now becomes over the next few winters can we still manage a few of these favorable periods even with this new higher temperature baseline. I will remain open and take a wait and see approach. All these new marine heatwaves are really distorting how our past climate used to operate.