bluewave

This could be the first spring that one of our stations like Newark recorded at least a trace of rain on every spring weekend. Newark May 25-25…..T May 18-19…..0.04 May 11-12…0.38 May 4-5…..0.31 Apr 27-28…0.11 Apr 20-21…0.05 Apr 13-14…0.04 Apr 6-7…….T Mar 30-31…0.01 Mar 23-24….3.10 Mar 16-17…..T Mar 9-10….1.46 Mar 2-3…..1.31

A recent study confirms that a fundamental shift occurred with the Arctic sea ice around the 2007 season. The Arctic lost so much older ice that it makes it harder to set new extent records. This is why the 2012 low extent record has been so difficult to beat. While the 2020 season came close, it came up short of the 2012 record. This is also why no season since 2007 has been able to see a recovery to pre-2007 extents and thickness. Most seasons since then finished in the 4 to 5 million sq km range for extent since extents change more slowly with younger ice dominating the Arctic instead of older. https://www.nature.com/articles/s41586-022-05686-x Manifestations of climate change are often shown as gradual changes in physical or biogeochemical properties1. Components of the climate system, however, can show stepwise shifts from one regime to another, as a nonlinear response of the system to a changing forcing2. Here we show that the Arctic sea ice regime shifted in 2007 from thicker and deformed to thinner and more uniform ice cover. Continuous sea ice monitoring in the Fram Strait over the last three decades revealed the shift. After the shift, the fraction of thick and deformed ice dropped by half and has not recovered to date. The timing of the shift was preceded by a two-step reduction in residence time of sea ice in the Arctic Basin, initiated first in 2005 and followed by 2007. We demonstrate that a simple model describing the stochastic process of dynamic sea ice thickening explains the observed ice thickness changes as a result of the reduced residence time. Our study highlights the long-lasting impact of climate change on the Arctic sea ice through reduced residence time and its connection to the coupled ocean–sea ice processes in the adjacent marginal seas and shelves of the Arctic Ocean. Our analysis demonstrates the long-lasting impact of climate change on Arctic sea ice through reduced residence time, suggesting an irreversible response of Arctic sea ice thickness connected to an increase of ocean heat content in areas of ice formation. The large reduction of summer ice extent in the Alaskan and Siberian sectors in 2005 and 2007 triggered intensive ice–albedo feedback42,45 and initiated the perennial increase of ocean heat content in these areas44. This resulted in the stepwise reduction of residence time of sea ice in the Siberian sector of the Arctic, and hence a nonlinear response of the system. https://www.jpl.nasa.gov/news/with-thick-ice-gone-arctic-sea-ice-changes-more-slowly The Arctic Ocean's sea ice blanket has already lost most of its old ice and two-thirds of its thickness. The younger ice is thinning more slowly and variably. The Arctic Ocean's blanket of sea ice has changed since 1958 from predominantly older, thicker ice to mostly younger, thinner ice, according to new research published by NASA scientist Ron Kwok of the Jet Propulsion Laboratory, Pasadena, California. With so little thick, old ice left, the rate of decrease in ice thickness has slowed. New ice grows faster but is more vulnerable to weather and wind, so ice thickness is now more variable, rather than dominated by the effect of global warming. Working from a combination of satellite records and declassified submarine sonar data, NASA scientists have constructed a 60-year record of Arctic sea ice thickness. Right now, Arctic sea ice is the youngest and thinnest its been since we started keeping records. More than 70 percent of Arctic sea ice is now seasonal, which means it grows in the winter and melts in the summer, but doesn't last from year to year. This seasonal ice melts faster and breaks up easier, making it much more susceptible to wind and atmospheric conditions. Kwok's research, published today in the journal Environmental Research Letters, combined decades of declassified U.S. Navy submarine measurements with more recent data from four satellites to create the 60-year record of changes in Arctic sea ice thickness. He found that since 1958, Arctic ice cover has lost about two-thirds of its thickness, as averaged across the Arctic at the end of summer. Older ice has shrunk in area by almost 800,000 square miles (more than 2 million square kilometers). Today, 70 percent of the ice cover consists of ice that forms and melts within a single year, which scientists call seasonal ice. Sea ice of any age is frozen ocean water. However, as sea ice survives through several melt seasons, its characteristics change. Multiyear ice is thicker, stronger and rougher than seasonal ice. It is much less salty than seasonal ice; Arctic explorers used it as drinking water. Satellite sensors observe enough of these differences that scientists can use spaceborne data to distinguish between the two types of ice. Thinner, weaker seasonal ice is innately more vulnerable to weather than thick, multiyear ice. It can be pushed around more easily by wind, as happened in the summer of 2013. During that time, prevailing winds piled up the ice cover against coastlines, which made the ice cover thicker for months. The ice's vulnerability may also be demonstrated by the increased variation in Arctic sea ice thickness and extent from year to year over the last decade. In the past, sea ice rarely melted in the Arctic Ocean. Each year, some multiyear ice flowed out of the ocean into the East Greenland Sea and melted there, and some ice grew thick enough to survive the melt season and become multiyear ice. As air temperatures in the polar regions have warmed in recent decades, however, large amounts of multiyear ice now melt within the Arctic Ocean itself. Far less seasonal ice now thickens enough over the winter to survive the summer. As a result, not only is there less ice overall, but the proportions of multiyear ice to seasonal ice have also changed in favor of the young ice. Seasonal ice now grows to a depth of about six feet (two meters) in winter, and most of it melts in summer. That basic pattern is likely to continue, Kwok said. "The thickness and coverage in the Arctic are now dominated by the growth, melting and deformation of seasonal ice." The increase in seasonal ice also means record-breaking changes in ice cover such as those of the 1990s and 2000s are likely to be less common, Kwok noted. In fact, there has not been a new record sea ice minimum since 2012, despite years of warm weather in the Arctic. "We've lost so much of the thick ice that changes in thickness are going to be slower due to the different behavior of this ice type," Kwok said. Kwok used data from U.S. Navy submarine sonars from 1958 to 2000; satellite altimeters on NASA's ICESat and the European CryoSat-2, which span from 2003 to 2018; and scatterometer measurements from NASA's QuikSCAT and the European ASCAT from 1999 to 2017.

Would be a great winter KU pattern with +PNA -AO blocking.

Yeah, the warmer minimums are driving the departures again with the onshore flow keeping the high departures smaller than the lows. EWR Max…+2.1 Min….+3.3 LGA Max….-0.1 Min….+1.4

Models have scattered showers tonight or early Sunday. So we have a shot at having at least a trace of rain on every weekend this spring. I wonder if this has happened before? Newark May 18-19…..0.04 May 11-12…0.38 May 4-5…..0.31 Apr 27-28…0.11 Apr 20-21…0.05 Apr 13-14…0.04 Apr 6-7…….T Mar 30-31…0.01 Mar 23-24….3.10 Mar 16-17…..T Mar 9-10….1.46 Mar 2-3…..1.31

This May is a little warmer so far at +1.0 in NYC vs -0.5 last year.

The SST pattern in the North Atlantic began to shift around May 2023 from a record warm pool east of New England to a colder one. It has been associated this spring with all these backdoor cold fronts and low pressure east of New England. Unfortunately, models just aren’t very good beyond 10-15 days to know how much longer this pattern will persist. I am still not sure if this represents a shift to a newer SST and 500mb pattern or it’s just temporary blip associated with the strong Canadian blocking pattern which emerged last May. Plus trying to figure out seasonal hurricane track forecasts beyond 2 weeks out can be low skill. We usually have to wait for the tropics to become active and see what the 500mb steering forecasts look like. Beyond this hurricane season, it will be interesting to see if we can eventually get another cold winter month here. Some blocking and more of a trough to our east could get it done. Our last cold winter month was way back in January 2022.

Newark only made it to 90° this spring which is the 3rd coolest since the warmer pattern began back in 2010. While the planet is setting records for SSTs daily, we are one of the few places with a cold pool nearby. So it goes to show how strong that easterly flow has been. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Mar through May Click column heading to sort ascending, click again to sort descending. Rank Year Highest Max Temperature Missing Count 2020 86 0 2014 88 0 2024 90 8 2019 90 0 2015 91 0 2012 92 0 2011 92 0 2023 93 0 2018 94 0 2017 94 0 2013 94 0 2010 95 0 2021 96 0 2016 96 0 2022 98 0

Tough to keep track of all these rainfall records in recent years. https://x.com/tararosenblum/status/1793651432765186428

While we are averaging above normal, the high end temps here this spring have been muted. Places like Newark will finish spring near the low end of the 90° day count. Plenty of rainfall and convection like this morning along with enhanced onshore flow. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Mar through May Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 90 Missing Count 1 1991 8 0 2 1986 6 0 3 2002 5 0 - 1959 5 0 4 2022 4 0 - 2021 4 0 - 2018 4 0 - 2000 4 0 - 1987 4 0 - 1977 4 0 - 1965 4 0 - 1939 4 0 - 1936 4 0 5 2023 3 0 - 2017 3 0 - 2016 3 0 - 2010 3 0 - 2009 3 0 - 2001 3 0 - 1999 3 0 - 1996 3 0 - 1993 3 0 - 1992 3 0 - 1985 3 0 - 1974 3 0 - 1964 3 0 - 1962 3 0 - 1934 3 0 - 1931 3 0 6 2015 2 0 - 2013 2 0 - 2012 2 0 - 2007 2 0 - 2004 2 0 - 1998 2 0 - 1994 2 0 - 1990 2 0 - 1979 2 0 - 1976 2 0 - 1970 2 0 - 1957 2 0 - 1956 2 0 - 1949 2 0 - 1944 2 0 - 1943 2 0 - 1942 2 0 - 1941 2 0 7 2024 1 9

Nice Canadian airmass for the cooler weather fans by this time next week. So we still haven’t reached the point of extended heat yet. It’s been a challenge with all the onshore flow and clouds along with the rain.

The HRRR has convection with a MCV.

Yeah, it was my warmest day of the spring so far at 82° here just east of KHVN.

Just enough SE flow at Newark today so POU was warmer for a 2nd day in a row. THE POUGHKEEPSIE NY CLIMATE SUMMARY FOR MAY 22 2024... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD: 1991 TO 2020 CLIMATE RECORD PERIOD: 1931 TO 2024 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 89 2:37 PM 98 1941 73 16 77 MINIMUM 58 5:00 AM 31 2002 50 8 45 AVERAGE 74 61 13 61 THE NEWARK NJ CLIMATE SUMMARY FOR MAY 22 2024... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1931 TO 2024 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 87 1241 PM 98 1992 74 13 78 MINIMUM 64 457 AM 44 1957 56 8 56 2002 AVERAGE 76 65 11 67

Memorial Day could feature near record tropical PWATS approaching 2.00” for our area along with near record highs close to 100° in Florida. There will be a deepening low crossing the Great Lakes. So strong to severe storms could be an issue with very heavy downpours and possible flooding where the best training sets up.

Yeah, I just noticed the same thing.

We would be closer to 100° rather than 90° if the historic heat dome over Mexico didn’t get suppressed to our south across Florida. https://x.com/OSUWXGUY/status/1792912484979835203 Sweltering heat looks to continue across Mexico with the ECMWF ensemble mean showing mid level height anomalies as high as 4.7 STD DEV above the climate of just the past 20 years. Suggests a probability of ~1 in 769K

Yeah, it’s probably related in some way to the many marine heatwaves across the planet right now. The Euro shifts back to cooler and wetter again from Memorial Day into the start of June. So no pattern change showing up just yet. May 27 to June 3 EPS forecast

We got a south based blocking pattern in the summer of 2020 which was really wet so it held the 90° days down at Newark.

The blocking pattern became more south based over the winter which featured the record warmth.

This record blocking pattern near Hudson Bay has been in place since last May. It’s why we had a cooler summer last year. The only extended warmth with this pattern has been during the winter when it linked up with the Southeast ridge. So we need to see this pattern weaken in order to finally get some extended summer warmth. All the warm ups since March 20th have lasted a few days before more rains and onshore flow. Also notice how this pattern has resulted in the only cool spot in the Atlantic sea of record warmth has been to our east. https://x.com/WeatherProf/status/1793089595552456781

It was their warmest winter on record followed by the warmest spring so far. Time Series Summary for WATERTOWN INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Dec 1 to May 20 Missing Count 1 2024-05-20 38.1 0 2 2012-05-20 37.0 0 3 1998-05-20 35.5 0 - 1953-05-20 35.5 2 4 2023-05-20 34.8 0 - 2002-05-20 34.8 0 5 1991-05-20 34.6 1 6 2016-05-20 34.2 0 7 2017-05-20 34.1 0 8 2013-05-20 34.0 1 9 1952-05-20 33.5 2 10 2021-05-20 33.1 2 11 2020-05-20 33.0 0 12 2010-05-20 32.9 2

The record heat stayed to our north today. RECORD EVENT REPORT NATIONAL WEATHER SERVICE BUFFALO NY 0442 PM EDT TUE MAY 21 2024 ...RECORD HIGH TEMPERATURE SET AT WATERTOWN NY... A RECORD HIGH TEMPERATURE OF 85 DEGREES WAS SET AT WATERTOWN NY TODAY. THIS BREAKS THE OLD RECORD OF 83 DEGREES SET IN 2022.

Just enough SE flow today for POU to beat EWR. THE POUGHKEEPSIE NY CLIMATE SUMMARY FOR MAY 21 2024... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD: 1991 TO 2020 CLIMATE RECORD PERIOD: 1931 TO 2024 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 88 2:57 PM 95 1941 73 15 71 1996 MINIMUM 57 5:00 AM 29 2002 49 8 49 AVERAGE 73 61 12 60 THE NEWARK NJ CLIMATE SUMMARY FOR MAY 21 2024... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1931 TO 2024 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 87 244 PM 96 1996 74 13 75 MINIMUM 58 514 AM 42 1950 55 3 57 2002 AVERAGE 73 65 8 66

The big block this month near Hudson Bay continues to be a factor in the long range forecast. Low pressure begins crossing the Great Lakes as we head into Memorial Day. It could potentially slow down and cutoff next week near the Northeast.