bluewave

Yeah, looks like the onshore flow and backdoor season has officially begun. So plenty of onshore flow going forward. West of the Hudson will be favored for the best warmth over the next week.

We are beginning to shift into the spring pattern was has much less westerly flow than the winter did. Yesterday was the first day with stronger easterly flow. Every warm up will have to compete with onshore flow. So the 70° warmth will probably line up west of the Hudson on the warmer days. And the onshore flow will be very noticeable especially near the coast. We will probably have to wait a week for our next stronger westerly flow event behind one of the cuttters.

Part of it is that the drought peaked in mid-April 2002 with all the record heat and some spots approaching 100°. It started getting rainy in late April so we didn’t get the peak drought conditions during the summer like in 1995. Plus we didn't have the high winds in the spring of 2002 like we have been getting this year. So hopefully we can start getting wet again by mid to late spring so we avoid a drought peak during the summer with all that would entail. Monthly Data for April 2002 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. NJ HARRISON COOP 98 NJ ESSEX FELLS SERVICE BLDG COOP 98 NJ PLAINFIELD COOP 97 NJ CRANFORD COOP 97 NJ NEWARK LIBERTY INTL AP WBAN 97 NJ CANOE BROOK COOP 96 NY NY CITY CENTRAL PARK WBAN 96 NJ LITTLE FALLS COOP 96 NJ MIDLAND PARK COOP 96 NY DOBBS FERRY-ARDSLEY COOP 96 NY BRONX COOP 96 CT STAMFORD 5 N COOP 96 NJ TETERBORO AIRPORT WBAN 95 NJ CALDWELL ESSEX COUNTY AP WBAN 95 NJ WANAQUE RAYMOND DAM COOP 95 NY WEST POINT COOP 95 NJ TETERBORO AIRPORT COOP 95 NY OCEANSIDE COOP 95 CT DANBURY COOP 95 NY YORKTOWN HEIGHTS 1W COOP 95 CT MERIDEN MARKHAM MUNICIPAL AP WBAN 95 NY SETAUKET STRONG COOP 95 NY MOUNT SINAI COOP 95

It has been the 2nd driest late August to mid-March on record in NYC. The actual rainfall has been similar the same as the 2001-2002 drought. So those departures are legit since they match the actual amounts. There has only been 14.73” since August 23rd. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 1 2002-03-13 14.25 0 2 2025-03-13 14.73 1 3 1947-03-13 15.23 0 4 1932-03-13 16.08 0 5 1966-03-13 16.10 0 6 1880-03-13 16.64 0 7 1954-03-13 16.87 0 - 1876-03-13 16.87 0 8 1905-03-13 17.05 0 9 1897-03-13 17.07 0 10 1992-03-13 17.12 0

Part of the challenge in conveying that these winters just aren’t as cold as the used to be is making the bar lower for what constitutes a cold winter. Updating the climate normals every 10 years normalizes how much warmer the winters are getting. The NOAA NCEI should probably settle on a baseline from before the rapid increase in temperatures prior to 1980 like NASA, Berkeley Earth, and other centers do for determining the global temperatures.The record winter warmth in recent years made this winter seem like a cold one in comparison. But the actual temperature rankings place this winter closer to the old average or even warmer.

March has become too warm for much snow around NYC during the 2020s. Monthly Total Snowfall for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Mean 0.1 0.1 2025 0.0 0.0 2024 T T 2023 0.1 0.1 2022 0.4 0.4 2021 T T 2020 T T

Every weather event that occurs is in some way influenced by the average global temperatures around the time of the event. You wouldn’t expect the real world weather events to be the same during an ice age as they were during the PETM. So the background climate temperatures during each era sets the parameters or range of possibilities for the individual weather events.

6th earliest 70° day for Sussex airport in NW NJ yesterday. First/Last Summary for SUSSEX AIRPORT, NJ Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. 2018 02-21 (2018) 76 11-01 (2018) 71 252 2017 02-24 (2017) 74 11-03 (2017) 71 251 2012 03-08 (2012) 70 10-06 (2012) 70 211 2016 03-08 (2016) 71 11-08 (2016) 71 244 2020 03-09 (2020) 71 11-10 (2020) 74 245 2006 03-10 (2006) 71 12-01 (2006) 71 265 2025 03-11 (2025) 70 - - - 2024 03-13 (2024) 72 11-18 (2024) 71 24

This is actually a very rare aspect of a warming climate that we sometimes see with a record snowstorm following record warmth. The warmth in the preceding months in New Orleans was more impressive than the cold which followed during January. November 2024 was one of the most anomalous warm months there at nearly +3.0° above its previous warmest November. Time Series Summary for New Orleans Area, LA (ThreadEx) - Month of Nov Click column heading to sort ascending, click again to sort descending. 1 2024 70.2 0 2 2020 67.3 0 - 1985 67.3 0 4 1978 67.1 0 5 2015 67.0 0 6 1973 66.6 0 We saw a similar occurrence in NYC in January 2016 with the record snowstorm following the most extreme warm month on record with December 2015 going +13.3° and the first 50° December warmer than most Novembers. That December was a record breaking 6° warmer than the previous warmest December. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Dec Click column heading to sort ascending, click again to sort descending. 1 2015 50.8 0 2 2023 44.6 0 3 2001 44.1 0 4 2021 43.8 0 5 1984 43.7 0 6 2006 43.6 0 7 2011 43.3 0 8 1998 43.1 0 9 1982 42.7 0 10 1990 42.6 0 Another occurrence of this rare phenomenon happened back in 2011 in Newark NJ. They experienced their warmest reading on record reaching 108° in July 2011. Then their biggest October snowstorm on record a few months later. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 2011 108 0 2 2001 105 0 - 1993 105 0 - 1966 105 0 - 1953 105 0 - 1949 105 0 The one common denominator with these events was that they were isolated in nature and the snowstorms didn’t represent a new normal. As NYC still hasn’t had a snowstorm as big all this time after. And Newark is yet to have another October snowstorm like that one again. So my guess is that this isn’t the beginning of a shift to much snowier winters in New Orleans. And the warmth records will continue to be more impressive vs the cold ones over time.

It will be interesting to see how this drought progresses over the spring. Since areas away from the sea breeze during the last drought which was weaker in 2022 had a near record number of 100° days in NJ. But that was a continuing La Niña pattern from 20-21 to 22-23. This spring is more uncertain with the ENSO as there is currently a toss up between a continuing La Niña or an attempt to shift back into El Niño. We don’t have any analogs for such a quick shift back to El Niño. So the ENSO progress and drought progress could very well shape the coming summer details. Plus we have the coldest SSTs in over a decade to our east so backdoors this spring could be particularly strong. Any lingering cool spots to our east could enhance sea breezes here in the summer. So a number of factors to consider for our summer pattern.

3rd highest 9 hour temperature rise in March at spots like SMQ. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=SMQ&v=tmpf&hours=9&month=mar&dir=warm&how=over&_r=t&dpi=100&_fmt=png

This has been one of the most impressive 6-8 hr temperature rises that we have seen in the early spring.

Low 70s even made it to the Catskills today. https://www.weather.gov/wrh/timeseries?site=CKCN6&hours=72

New record low Arctic sea ice extent for February and a recent paper on increasing Atlantification in the Arctic. https://nsidc.org/sea-ice-today/analyses/february-made-me-shiver-not-arctic The average February 2025 Arctic sea ice extent was 13.75 million square kilometers (5.31 million square miles), the lowest February extent in the 47-year satellite record, 220,000 square kilometers (85,000 square miles) below the previous record low February set in 2018. Daily ice growth stalled twice during the month, which helped to contribute to low ice conditions and led to overall ice retreat in the Barents Sea. By the end of the month, extent was low nearly everywhere, the exception being the East Greenland Sea. Extent is far below average in the Labrador Sea and the Gulf of St. Lawrence. https://www.science.org/doi/10.1126/sciadv.adq7580 Changes associated with atlantification are extensive and fundamental for the state of the high-latitude climate system. The primary impact has been the rapidly diminishing sea ice in the Siberian Arctic over the past decade (Fig. 1, A and BOpens in image viewer). Here, we used mooring and satellite data to demonstrate the advancement of atlantification into the Siberian Arctic Ocean and its ramifications for the state of the upper ocean, sea ice, and air-sea interactions (Fig. 5Opens in image viewer). In particular, we show that the winter ventilation of the halocline in the eastern Eurasian Basin resulted in more than twofold rate in sea-ice loss caused by oceanic heat fluxes as compared to the 2010s. The transition of the Makarov Basin to conditions similar to those observed in the eastern Eurasian Basin 5 to 7 years ago is another critically important finding (this lag is depicted by in Fig. 5Opens in image viewer). The powerful ocean-heat/ice-albedo feedback mechanism is the primary cause of these changes (phase 2 of atlantification in Fig. 5Opens in image viewer). Deep ventilation and weak stratification increase upward AW heat fluxes, which promotes the wintertime suppression of sea-ice formation and subsequent more effective summertime reduction of sea ice by an ice-albedo feedback. This complex process was the key to establishing the diminished sea-ice cover in the Siberian Arctic in recent years. In contrast, no deep ventilation of AW heat was found in the eastern parts of the Makarov Basin and East Siberian Sea. Shoaling of the AW and halocline, however, indicates that the eastern Siberian Arctic Ocean is experiencing a preconditioning phase (phase 1 of atlantification in Fig. 5Opens in image viewer) similar to that found in the western Siberian Arctic Ocean in the 2000s. This ongoing transition not only mirrors earlier changes but also sets the stage for broader ecosystem impacts. While it was identified that the intrusion of Atlantic-origin water into the Chukchi Plateau is associated with biogeochemical impacts (33), our analysis reveals that these physical changes—particularly AW shoaling, halocline weakening, and seasonal variability in the Atlantic/Pacific halocline front—are establishing conditions for halocline stability disruptions and increased AW penetration. These atlantification-related physical changes have important ecological implications.

The highs have been winning out at SMQ as they are +6.3 for the maximum temperature departure this month and -0.9 on the minimums.

It was our driest winter since 21-22 across the area.

This was the first time NYC had 22 days with 1” of snow cover and under 20” of snow on the season. 2024-2025…..22 days…..12.9” 1984-1985……22 days…..24.1” 1965-1966……22 days…..21.4” 1959-1960……22 days….39.2” 1921-1922…….22 days….27.8” 1911-1912……..22 days….29.5”

LGA officially set the record for longest stretch without a daily 4” snowfall event this winter. Number of Consecutive Days Snowfall < 4 for New York-LGA Area, NY (ThreadEx) Click column heading to sort ascending, click again to sort descending. Period of record: 1940-01-01 to 2025-03-09 1 1135 2022-01-30 through 2025-03-09 2 1051 1961-02-05 through 1963-12-22 3 761 2018-11-16 through 2020-12-15 4 746 1950-02-14 through 1952-02-29 5 744 1979-02-20 through 1981-03-04 6 743 1996-03-09 through 1998-03-21 7 742 2011-01-28 through 2013-02-07 8 715 1972-02-24 through 1974-02-07 9 701 1975-02-13 through 1977-01-13 10 690 1941-03-09 through 1943-01-27

We were warmer than forecasts this winter even when we had the +PNA -EPO since the cold air extent was at record lows for the Northern Hemisphere.

It made it to 69° at Newark and a few other sites in NJ which is well above what guidance was printing out. So it’s close enough even if there will be more opportunities over the next week. Well above that 60° max that the EPS mean was running with recently.

The cold bias with the models in recent years has been ridiculous. They just can’t handle this new climate. It doesn’t make any sense to bet against warm ups beating model forecasts.

Hard to believe that there people doubting the 70° potential this week.

I knew it was going to be another underperforming snowfall season back in December when I saw that the jet and storm track pattern picking up where the last several seasons left off. The lower La Niña December snowfall which has done so well at prediction the outcomes last 30 years worked very well again. Since La Ninas are usually more frontloaded by nature and don’t require us waiting longer like El Niños which are more backloaded.

I never said anything about rules moving forward since my philosophy is always to take one winter at a time. Unfortunately, we don’t have multiyear storm track forecasts. But we can know with certainty what has happened up to this point.

I was able to create some custom charts to illustrate exactly how Philly to Boston had such low snowfall despite what used to be considered favorable teleconnections for snow before the 2020s. As I have shown in past posts, the Northern stream Pacific Jet has been a record levels since 18-19. But past instances with such a strong +PNA -EPO and -5 daily -AO had a relaxation of this jet. But not this time. You can see on the 11 days with .25 or greater precipitation around NYC how overpowering the Pacific Jet was. So the average temperature on these days was 41° which was too warm for heavy snow. Even though the average winter temperature was 34.8°. We again see the Southeast Ridge linking up with the Greenland -AO block on the storm days. So we are finding out that low seasonal snowfall totals can be the result of warmer storm tracks even in a seasonable average cold. 11 day winter storm composites for all the days with .25 or more of precipitation