bluewave

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.

Yeah, you guys will manage to hold onto traditional winters longer than the I-95 coastal crew on this forum. Being closer to the center of the continent and away from the rapidly warming Atlantic are a real plus for you. The posters especially near the LES zones have been benefitting from the warmer lakes staying open longer. Even during the warmest winter in 23-24 for Marquette at +8.4, it was still 25.2°. While not great by local standards, the 126.5” of snow for Marquette in a place like NYC would wildly exceed anything in the modern record. This past warmest winter for Marquette was about the same temperature as the coldest on record for NYC in 1917-1918 at 25.7°. If NYC should ever run a +8 departure in this much warmer climate, than something close to a snowfall shutout could occur with potentially only a T to 1” for the whole season.

January 2022 was the last month for parts of the region that could be considered a great winter month. Monthly Total Snowfall for Atlantic City Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 0.1 8.0 1.6 T 0.0 9.7 2019-2020 0.0 T 0.5 T T 0.0 0.0 0.5 2020-2021 0.0 0.0 T 1.0 6.3 0.0 0.0 7.3 2021-2022 0.0 T T 33.2 0.1 T 0.0 33.3 2022-2023 0.0 0.0 T T 0.3 T 0.0 0.3 2023-2024 0.0 0.0 T 5.9 1.4 T 0.0 7.3

A bunch of spots under .50 since August 20th. NY MONTAUK AIRPORT WBAN 0.19 NY WANTAGH 0.3 ESE CoCoRaHS 0.26 NY MASSAPEQUA PARK 1.2 N CoCoRaHS 0.26 NY MASSAPEQUA 1.1 SE CoCoRaHS 0.26 NY SMITHTOWN 2.0 SSW CoCoRaHS 0.28 NJ CRANFORD TWP 1.1 ESE CoCoRaHS 0.29 NY BELLMORE 0.9 SSE CoCoRaHS 0.29 NY AMITYVILLE 0.6 NNE CoCoRaHS 0.30 NY ISLIP-LI MACARTHUR AP WBAN 0.30 NY FARMINGDALE REPUBLIC AP WBAN 0.43 NY WESTHAMPTON GABRESKI AP WBAN 0.43 NY SHIRLEY 2.9 N CoCoRaHS 0.43 NJ VERONA TWP 0.8 W CoCoRaHS 0.44 CT CENTRAL WATERFORD 2.7 SSW CoCoRaHS 0.44 CT OLD LYME 3.4 ESE CoCoRaHS 0.44 CT DARIEN 3.6 N CoCoRaHS 0.45 NY STATEN ISLAND 1.4 SE CoCoRaHS 0.46 PA PHILADELPHIA 2.1 NE CoCoRaHS 0.13 NJ HAMMONTON 1.9 S CoCoRaHS 0.13 NJ EWING TWP 1.2 N CoCoRaHS 0.13 PA PHILADELPHIA 2.7 WNW CoCoRaHS 0.14 NJ WEST DEPTFORD TWP 1.9 SSE CoCoRaHS 0.14 NJ PITTSGROVE TWP 1.9 NNE CoCoRaHS 0.14 PA GREEN LANE 1.7 E CoCoRaHS 0.15 NJ DENNIS TWP 2.5 S CoCoRaHS 0.15 PA CHURCHVILLE 0.3 SSW CoCoRaHS 0.15 PA SPRINGFIELD 0.1 NNW CoCoRaHS 0.16 NJ HAMILTON TWP 4.5 NW CoCoRaHS 0.16 NJ EAST WINDSOR TWP 1.6 W CoCoRaHS 0.16 NJ TOMS RIVER TWP 3.6 WSW CoCoRaHS 0.16 NJ JACKSON TWP 4.9 ENE CoCoRaHS 0.16 DE LEWES COOP 0.17 NJ HAMMONTON 3.3 WSW CoCoRaHS 0.17 NJ MONROE TWP 0.6 WNW CoCoRaHS 0.17 NJ UNION TWP 1.2 SW CoCoRaHS 0.17 NJ METUCHEN 0.5 E CoCoRaHS 0.17 PA ARDMORE 0.5 NW CoCoRaHS 0.18 NJ EGG HARBOR CITY 3.6 SW CoCoRaHS 0.18 NJ MONROE TWP 1.8 SE CoCoRaHS 0.18 NJ BEACHWOOD 0.7 S CoCoRaHS 0.18 PA PERKASIE 1.6 SSE CoCoRaHS 0.19 NJ MEDFORD LAKES 0.6 W CoCoRaHS 0.19 NJ WINSLOW TWP 5.7 SSE CoCoRaHS 0.19 NJ PRINCETON 1.7 SSE CoCoRaHS 0.19

Models coming in stronger next week with the dew point drop. Now indicating dews possibly dropping below freezing. This will really make it feel like fall but will probably increase the dry pattern further.

At least in the first 5 winters of the 2020s, the snowfall deficits from Boston down to DC are pretty equally distributed from north to south relative to their past 5 year lowest levels. The snowfall deficit is only half of the equation. As even though NYC wasn’t able to surpass their lowest 5 year runs like Boston, Philly, and DC did this last winter, the lean 5 year periods from the past were much colder. So this adds to why people are saying it hasn’t really felt much like winter during the 2020s so far except for some good periods briefly in Jan 22 and during 21-22. Let’s hope we can stage some type of snowfall comeback during the 2nd half of the decade so we can avoid going from the snowiest decade in the 2010s to least snowiest decade in the 2020s. Lowest 5 year snowfall averages at Boston, Philly, and DC with NYC in 2nd place BOS…..19-20 to 23-24….26.1”….past record 50-51 to 54-55….28.0” NYC…..19-20 to 23-24….14.2”….past record 27-28 to 31-32….11.8” PHI…….19-20 to 23-24…..9.7”….past record 48-49 to 52-53…11.8” DCA…..19-20 to 23-24…..5.5”….past record 97-98…to 01-02…7.5”

The current 9 year winter average at DET is 31.1°or +1.6° warmer than the previous peak in 1957 which was 29.5°. NYC is at 38.5° or +2.1 above the previous peak of 36.4° set back in 2002. The effects of this record warm winter run since 15-16 are more pronounced closer to the East Coast.

The way they calculate their numbers doesn’t really do justice to the magnitude of the pressure swing from August to September at the surface to 500mb.

While these much lower dew points forecast for next week won’t help our dry pattern, at least it will really feel like fall.

We were living in a much colder climate back then so the below normal snow years were the result of drier conditions and unfavorable storm tracks. These days our below normal years are the result of too much warmth and unfavorable storm tracks. Also remember that the bad seasons back then had more snowfall than our poor do seasons now. It wasn’t always that way. From the 1960s into the early 1990s especially on Long Island there was a balanced mix of below, near normal, and above normal snowfall seasons. Many seasons with mid 20s snowfall. Since the 90s it’s almost exclusively well below or well above with hardly any mid 20s seasons. As the climate continues to warm it will be harder to get the above normal seasons so the below normal seasons will become the new normal.

The patterns becoming more persistent are the result of the warming atmosphere and oceans. So observing these changes and incorporating them into forecast techniques is just pattern recognition. I take a very data driven approach so it’s more pattern persistence than persistence forecasting.

That Western Ridge has been very persistent for the La Niña years during the 2020s from summer into fall.

At least we aren’t getting the all-time October heat like out West which would equate to mid 90s here.

I would just leave out the regression to the mean part since the volatility in our snowfall since the 1990s in places like the NYC Metro has been beyond any historical mean. Islip has seen an all or nothing snowfall pattern since the 1990s with hardly any average seasons. The previous 30-40 year period was defined by mostly mean seasons with higher and lower seasons more rare. These days it’s either record high or low snowfall with very few average seasons which were much more common in the old days. The Western droughts continue to this day. But they have been moving around with the shifting stuck record 500 mb ridge positions. This has come with an acceleration of the water cycle which has lead to big swings between wet and dry against the overall drier pattern. Just noting the changes that have occurred. Since 2010 NYC Metro and other regional spots have experienced 12 out of 15 warmer to record warmer summers. So we have a 15 year period of observations for the summer new summer pattern. The same areas have experienced a record 9 consecutive warmer to record warm winters since 15-16. The remaining winters of the decade will give us more data to make a winter determination.

I get it. Sometimes you just have to laugh. But these patterns have been getting stuck in place and repeating across years and seasons in a way we haven’t seen before.