bluewave

This winter was nothing like 1979-1980. As I pointed out in the La Niña thread back in October, there were early indications that this would be a La Niña mismatch winter. So the near record +PNA from December into a January wasn’t a surprise to me. But I also said that there were differences between this year and other La Niña +PNA mismatches. This turned out to be a correct observation since the snowfall was dramatically below the La Niña +PNA mismatches we experienced in 20-21, 17-18, 10-11, 05-06, 00-01, and 95-96. The difference this winter was that the Pacific Jet didn’t relax enough to allow the benchmark track to lock in like it did during those La Niña winters. My guess is that this could be related to features like the ongoing record marine heatwave east of Japan leading to the frequent jet extensions when interacting with the Siberian air masses exiting the Asian continent. So we continued with the cutter, hugger, and suppressed Southern Stream storm tracks which have dominated since 18-19. We even had a -5 -AO which used to be associated with much snowier Februaries like 2021, 2010, 1978, and 1969. So now even great +PNAs and -AO patterns during La Ninas can’t produce the 25-50” or even 50” outcomes in this new climate state of the 2020s. Plus there were several posts on twitter back in December that we were on track for some type of 13-14 and 14-15 outcome based on the early December pattern. So those were both 50”+ seasons here. But I pointed out in the December threads that the Pacific Jet wasn’t following the weakening script necessary to produce those outcomes for cold and snow in spots like the NYC Metro region. The cold also didn’t approach the magnitude of the cold we saw back in 13-14 and 14-15 in the northeast.

It’s pretty simple actually. The competing marine heatwaves and warmer background conditions shift the storm tracks and lead to less cold and snowy outcomes. This winter would have been an easy 25-50” snowfall season around NYC and several degrees colder just a little over a decade ago.

These record swings in a short period time have become the new normal as the Arctic has rapidly warmed. We just experienced one back in October. Then our last -5 back in 2021 also experienced a steep rise. So these -AOs don’t lock in for longer periods like they used to in the past. Greatest AO swings on record in around a month or less since 1950 and the date on which the maximum difference from low to high or high to low occurred with the numerical value of the swing https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.daily.ao.nao.pna.aao.gdas.120days.csv https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.ao.index.b500101.current.ascii #1……+10.790……3-11-21 #2…...+9.401…….1-16-16 #3……+9.256……3-2-56 #4……+9.039……4-21-13 #5……+8.522……1-25-05 #6…...+8.462…..1-15-77 #7…….+8.268….3-16-68 #8…….+7.793….2-25-01 #9…….+7.731….3-23-86 #10……+7.720…2-4-11 #11……+7.641…..3-5-70 #12…..+7.502…..1-19-85 #13……+7.387….3-20-78 #14……+7.240….10-23-24 #15……+7117……1-23-52 #16…..+7.066…1-24-08 #17……+7.043…3-19-15 #18……+7.038…2-10-76

While the departures will be cooling off, the coldest anomalies will stay west. Then the temperatures will moderate next week. So nothing too cold by past February standards. But compared to all the +5 Februaries in recent years it will feel cold especially with the stronger winds.

10”+ daily snowfalls at State College have become few and far between after 03-04 with the storm track shift for that part of the country. Maximum 1-Day Total Snowfall for STATE COLLEGE, PA Click column heading to sort ascending, click again to sort descending. Period of record: 1893-01-01 to 2025-02-17 1 26.6 1994-03-03 2 25.0 1993-03-14 3 17.6 1964-01-13 4 17.5 1942-03-30 - 17.5 1902-03-05 5 17.3 1928-04-28 6 16.5 1961-02-04 7 16.2 1996-01-08 8 15.1 1995-11-15 - 15.1 1965-03-06 9 15.0 2020-12-17 - 15.0 1922-01-11 10 14.8 1928-03-18 11 14.5 1925-01-29 12 14.0 2003-02-17 - 14.0 1936-01-19 13 13.8 1968-11-13 14 13.5 2010-02-06 15 13.0 2002-01-07 - 13.0 1942-03-29 - 13.0 1914-01-04 - 13.0 1894-04-11 16 12.8 1967-03-07 17 12.6 1966-01-23 18 12.5 1992-12-11 - 12.5 1971-03-04 - 12.5 1932-03-28 - 12.5 1923-01-14 19 12.2 1942-03-03 20 11.8 1935-02-22 21 11.7 1940-02-14 22 11.5 2018-11-16 - 11.5 1947-02-21 - 11.5 1920-02-04 23 11.3 2004-02-04 24 11.0 1921-02-20 - 11.0 1915-01-12 25 10.8 1969-12-26 26 10.5 1998-02-24 - 10.5 1978-01-18 - 10.5 1914-02-14 - 10.5 1908-02-19 - 10.5 1908-02-01 - 10.5 1901-04-03 27 10.2 1970-03-13

Another piece of the puzzle as to why global temperatures have been rising so quickly recently.

The first 16 days of the month have been +0.4°. EWR…+0.7 NYC….-0.7° LGA…..-0.4° JFK….+3.1° HPN….-0.5° BDR…..-0.4° ISP……+1.1°

Against the last several winters this one definitely feels more wintery in terms of temperatures ,extended snowcover, and windchills. This is the most snowcover days we have seen for so little seasonal snowfall. December wasn’t really that cold since the small cold departure was only due to the much warmer 91-20 normals. January was a little below average but the winds made it feel more like -5°. This month so far is running a little warmer than average but the stronger winds are making it feel colder.

It just shows how sensitive our snowfall has become to benchmark snowstorms since the 1990s. So we’ll need to see a return of these during the rest of the decade in order to see the snowfall averages areawide go back to the 20-30” range. Something similar happened to State College when they lost the big Appalachian snowstorms over 20 years ago. Their snowfall hasn’t been the same without the major Central PA snowstorms storm tracks which were common up to the early 2000s.

Another big EPAC WWB like we have been seeing in recent years boosted Nino 1+2 back above +1 again.

We are currently on pace for a new 10 year snowfall low average across the area if we don’t get a big increase over the next 3 seasons. This current 7 year lower running snowfall average began in 18-19. The past slumps were followed by 50” seasons boosting the totals back up in the following years. But reaching such heavy totals in recent years has been a significant challenge. Lowest 10 year averages and ending year and current 7 year average since 18-19 EWR…..1977……19.4”…….2025….17.3” NYC…..1993……18.8”…….2025….14.9” LGA…..1977…….17.7”……..2025….16.0” JFK…..1993….…18.0”…….2025…..14.5” ISP……1995…….19.3”……..2025…..16.8”

This is the first time that the combined 3 year snowfall average at EWR, NYC, JFK, LGA, and ISP dipped under 10”. The current 3 year mean is at 8.9”. The old record low from 96-97 to 98-99 was 10.5”.

This very strong westerly flow had been a persistent feature this winter.

One aspect of a fast Northern Stream of the Pacific Jet is shortwaves too close together like we are seeing this week leading to a suppressed outcome. So when you have lows coming into the West at the same time as one is trying to amplify along the East Coast it acts as a kicker low or trough. The next pattern is a hugger track. These were the string of small snows around NYC this month. Too much amplitude on the Southeast Ridge so we get the lows riding too far north leading to mixed precipitation events. And then this weekend was a record setting cutter for an -AO below -5 and a Greenland Block of +500 meters. In the old days we wouldn’t have had a Southeast Ridge link up with such an intense Greenland Block. My guess is that warm water feedback from the record Atlantic SSTs are combining with the faster Pacific to create this pattern. I posted composites a while back showing how in the 1950s to early 1970s when we had troughs in the West and a -AO there would often be a trough in the East instead of a Southeast Ridge. So in this case a little too much spacing between lows leading to one amplifying too much. So we have been seeing multiple ways not to get the benchmark track which has been a prerequisite since the 1990s for seasons in the 20-30” range and above. This has been a frequent occurrence since the 18-19 winter. It’s possible that this is related to competing marine heatwaves in the Pacific and Atlantic Basins. Could even be the IO marine heatwaves also. But we would probably need a research effort in order to confirm why the Pacific Jet has been following this type of pattern.

Snowfall across the coastal zones has pretty much reverted to the 2020s mean this season. Our new 6 year average for the 2020s has been generally between 10-20 inches. There have been a few exceptions like 20-21 areawide and locally in eastern sections during 22. This is the new average snowfall range with the very fast Northern Stream of the Pacific Jet. It leads to cutter, hugger, and suppressed Southern Stream storm tracks beginning in 18-19. Since we have need benchmark tracks to go over 20” in the local means since the 1990s. It will be interesting to see if we can change up this storm track pattern through 28-29 in order to avoid a permanent shift under 20” if this continues into the 2030s and beyond. The current 7 station average for the 2020s is 16.3”. Monthly Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Mean T 0.0 3.3 4.6 8.4 0.3 T 16.5 2024-2025 0.0 0.0 3.5 3.7 6.2 M M 13.4 2023-2024 0.0 T T 3.1 9.1 T 0.0 12.2 2022-2023 0.0 T 0.1 T 2.0 0.6 0.0 2.7 2021-2022 0.0 0.1 0.1 14.6 2.3 0.8 0.0 17.9 2020-2021 T 0.0 11.9 3.2 30.6 T 0.0 45.7 2019-2020 0.0 T 4.2 2.7 T T T 6.9 Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.7 4.2 7.0 0.1 T 13.9 2024-2025 0.0 0.0 2.8 3.0 6.7 M M 12.5 2023-2024 0.0 T T 2.3 5.2 T 0.0 7.5 2022-2023 0.0 0.0 T T 2.2 0.1 0.0 2.3 2021-2022 0.0 T 0.2 15.3 2.0 0.4 0.0 17.9 2020-2021 0.0 0.0 10.5 2.1 26.0 T 0.0 38.6 2019-2020 0.0 0.0 2.5 2.3 T T T 4.8 Monthly Total Snowfall for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.7 5.6 7.1 0.3 T 15.7 2024-2025 0.0 0.0 3.2 4.5 7.3 M M 15.0 2023-2024 0.0 T T 3.9 6.6 T T 10.5 2022-2023 0.0 0.0 0.4 T 2.9 0.1 0.0 3.4 2021-2022 0.0 T 0.6 20.4 2.7 1.6 0.0 25.3 2020-2021 0.0 0.0 10.2 1.9 23.2 T T 35.3 2019-2020 0.0 T 2.0 2.6 T T T 4.6 Monthly Total Snowfall for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.1 4.3 8.0 0.2 T 14.5 2024-2025 0.0 0.0 3.0 2.5 6.4 M M 11.9 2023-2024 0.0 T T 2.4 10.4 T 0.0 12.8 2022-2023 0.0 T T T 1.7 0.4 0.0 2.1 2021-2022 0.0 T 0.2 17.8 3.2 0.5 0.0 21.7 2020-2021 0.0 0.0 7.2 0.9 26.4 T T 34.5 2019-2020 0.0 T 1.9 1.9 T T T 3.8 Monthly Total Snowfall for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Mean T 0.0 2.4 6.9 7.6 0.6 T 17.5 2024-2025 0.0 0.0 2.1 2.7 6.7 M M 11.5 2023-2024 0.0 T T 3.1 7.8 0.0 0.0 10.9 2022-2023 0.0 0.0 0.4 T 3.0 1.6 0.0 5.0 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 Monthly Total Snowfall for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Mean T T 3.0 6.4 10.4 0.4 T 20.0 2024-2025 0.0 0.0 1.3 4.1 12.6 M M 18.0 2023-2024 0.0 T T 5.5 10.1 0.0 T 15.6 2022-2023 0.0 T 0.8 T 4.1 T 0.0 4.9 2021-2022 0.0 T 0.2 20.8 4.7 2.0 0.0 27.7 2020-2021 T T 10.0 3.1 30.7 0.0 0.0 43.8 2019-2020 0.0 T 5.5 4.6 T T T 10.1 Monthly Total Snowfall for New Brunswick Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. Mean 0.0 T 2.1 4.2 9.2 0.4 T 15.9 2024-2025 0.0 0.0 4.0 5.0 4.1 M M 13.1 2023-2024 0.0 0.0 0.0 6.3 16.0 T 0.0 22.3 2022-2023 0.0 0.0 T T 2.0 1.3 0.0 3.3 2021-2022 0.0 T T 12.0 2.6 0.9 0.0 15.5 2020-2021 0.0 0.0 6.5 0.2 30.6 0.0 0.0 37.3 2019-2020 0.0 0.0 2.0 1.8 T 0.0 T 3.8

Gusts to 61 mph at MPO.

Small hail and flooding possible with that storm moving across NNJ.

NW of Philly already gusting to 62 mph.

Yeah, the HRRR has gusts around 70mph in the highest elevations.

Tree damage likely in areas which got the heaviest icing once the winds pick up as this is the first high wind warming in years right after an ice storm.

The Tremont Micronet just made it to 40°. But these warm fronts pushing up against snow pack can struggle to cross the Sound. It’s always easier for warm front to come in aloft and change the snow to an icy mix and then just plain rain.

15° jump in one hour when the warm front came through Montauk. Feb 16, 2:54 pm 57 53 87 SSW 24G43 Feb 16, 1:54 pm 42 39 89 37 NE 8

52° at JFK with southerly flow gusting to 36 mph. Feb 16, 2:05 pm 52 48 87 S 29G36

Warm front has made it through JFK with 50° and strong SSW flow. Feb 16, 1:40 pm 50 48 94 SSW 18G26

The wind just shifted to SE at JFK and they are up to 47°.