bluewave

We got an early hint how cold the 1976-1977 winter was going to be with the record cold outbreak at the end of August 1976. Data for August 31, 1976 through August 31, 1976 Click column heading to sort ascending, click again to sort descending. NY WALDEN 1 ESE COOP 37 NY PORT JERVIS COOP 38 CT DANBURY COOP 38 NJ CANOE BROOK COOP 39 NY CARMEL COOP 39 CT WESTBROOK COOP 39 CT MOUNT CARMEL COOP 39 CT STAMFORD 5 N COOP 40 NY SCARSDALE COOP 40 CT MIDDLETOWN 4 W COOP 40 NJ CHARLOTTEBURG RESERVOIR COOP 40 NJ PLAINFIELD COOP 41 CT NORWALK GAS PLANT COOP 41 NJ ESSEX FELLS SERVICE BLDG COOP 42 NY YORKTOWN HEIGHTS 1W COOP 42 NY WESTCHESTER CO AP WBAN 42 NY SUFFERN COOP 42 NY WEST POINT COOP 42 NJ TETERBORO AIRPORT WBAN 43 NY BEDFORD HILLS COOP 43 CT NEW HAVEN TWEED AP WBAN 43 CT GROTON COOP 43 NJ LITTLE FALLS COOP 44 NY MIDDLETOWN 2 NW COOP 44 NY PATCHOGUE 2 N COOP 45 NY NEW YORK BOTANICAL GARDEN COOP 45 CT NORWICH PUBLIC UTILITY PLANT COOP 45 NY NY WESTERLEIGH STAT IS COOP 46 NY MINEOLA COOP 46 NY DOBBS FERRY-ARDSLEY COOP 46 NY BRIDGEHAMPTON COOP 46 CT NEW HAVEN COOP 47 NY SETAUKET STRONG COOP 47 NJ NEWARK LIBERTY INTL AP WBAN 48 NJ MIDLAND PARK COOP 48 NJ JERSEY CITY COOP 50 NY NY CITY CENTRAL PARK WBAN 50 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 50 NY GREENPORT POWER HOUSE COOP 50 NY LAGUARDIA AIRPORT WBAN 52 NY JFK INTERNATIONAL AIRPORT WBAN 52 NY ISLIP-LI MACARTHUR AP WBAN 52 NY MONTAUK COOP 52 NY NEW YORK AVE V BROOKLYN COOP 53 NY NEW YORK LAUREL HILL COOP 53 NY RIVERHEAD RESEARCH FARM COOP 54 Data for August 31, 1976 through August 31, 1976 Click column heading to sort ascending, click again to sort descending. PA TOBYHANNA POCONO MOUNTAIN ARPT WBAN 34 PA BELTZVILLE DAM COOP 35 NJ INDIAN MILLS 2 W COOP 36 NJ NEWTON COOP 36 PA EAST STROUDSBURG COOP 37 NJ SUSSEX 1 NW COOP 37 NJ MORRIS PLAINS 1 W COOP 37 NJ FLEMINGTON 5 NNW COOP 38 NJ SOMERVILLE 4 NW COOP 38 PA PERKASIE COOP 39 PA PALMERTON COOP 39 NJ CHATSWORTH COOP 39 PA GEORGE SCHOOL COOP 39 MD CENTREVILLE COOP 40 NJ BELLEPLAIN STA FOREST COOP 40 NJ ATLANTIC CITY INTL AP WBAN 40 NJ PEMBERTON COOP 40 NJ ESTELL MANOR COOP 40 NJ TOMS RIVER COOP 40 PA PHOENIXVILLE 1 E COOP 41 NJ HIGHTSTOWN 2 W COOP 41 NJ LAMBERTVILLE COOP 41 NJ FREEHOLD-MARLBORO COOP 41 NJ BOONTON 1 SE COOP 41 DE GEORGETOWN 5 SW COOP 42 MD MILLINGTON 1 SE COOP 42 PA WEST CHESTER 2 NW COOP 42 PA GRATERFORD 1 E COOP 42 PA READING 4 NNW COOP 42 NJ WOODSTOWN PITTSGROV 4E COOP 42 NJ HAMMONTON 1 NE COOP 42 NJ BELVIDERE COOP 42 NJ TUCKERTON 2 NE COOP 42 NJ LAKEHURST NAS WBAN 42 DE MIDDLETOWN 3 E COOP 43 PA COATESVILLE 1 SW COOP 43 PA MORGANTOWN COOP 43 PA ALLENTOWN LEHIGH VALLEY INTERNATIONAL AIRPORT WBAN 43 NJ CHERRY HILL COOP 43 NJ LONG BRANCH-OAKHURST COOP 43 NJ NEW BRUNSWICK 3 SE COOP 43 DE MILFORD 2 SE COOP 44 NJ SEABROOK FARMS COOP 44 NJ WEST WHARTON COOP 44 MD EASTON COOP 45 DE BRIDGEVILLE 1 NW COOP 45 MD DENTON 2 E COOP 45 DE NEWARK AG FARM COOP 45 PA WEST GROVE 1 SE COOP 45 DE WILMINGTON PORTER RES COOP 46 NJ SHILOH COOP 46 NJ MILLVILLE MUNICIPAL AIRPORT WBAN 46 PA NORTHEAST PHILADELPHIA AIRPORT WBAN 46 NJ GLASSBORO 2 NE COOP 47 PA WILLOW GROVE NAS WBAN 47 MD CHESTERTOWN COOP 48 NJ AUDUBON COOP 48 NJ TRENTON WBAN 48 MD ROYAL OAK 2 SSW COOP 49 DE DOVER COOP 49 MD PRESTON 1 S COOP 49 DE WILMINGTON AIRPORT WBAN 50 PA DEVAULT 1 W COOP 50 PA NORRISTOWN COOP 50 NJ CAPE MAY 2 NW COOP 50 NJ SPLIT ROCK POND COOP 50 PA PHILADELPHIA INTL AP WBAN 51 DE LEWES COOP 53 PA DREXEL UNIV COOP 53 PA MARCUS HOOK COOP 54 PA PHILADELPHIA 23D & MARKET COOP 54 PA PHILADELPHIA WBAN 56 PA PHILADELPHIA WSFO COOP 56

The standards or 30 year climate normals originated back in a stable climate when there weren’t significant temperature rises with every new 10 year update. This is why your area had the warmest summer on record back in 2020 at 77.9° and the departure was only +2.9° using 1991-2020 climate normals. Under the 1951-1980 climate normals it would have been a +4.3 summer. It’s why NOAA is exploring using alternatives to the climate normals. Many organizations just set the climate normals to an earlier period before the climate began to rapidly warm so the departures more closely resemble the actual temperatures. https://yaleclimateconnections.org/2021/02/updated-yardstick-begs-question-whats-normal-in-a-changing-climate/ Time Series Summary for Middletown-Harrisburg Area, PA (ThreadEx) Top 10 warmest summers using dense rank sorting for temperature Click column heading to sort ascending, click again to sort descending. 1 2020 77.9 0 2 1966 77.6 0 3 2016 77.3 0 4 2021 77.1 0 5 2024 76.9 0 6 2010 76.8 0 7 2022 76.7 0 - 1999 76.7 0 8 2019 76.5 0 - 2005 76.5 0 9 1991 76.4 0 10 1900 76.2 0

I was using the extended climate record for your area which started back in 1888. Past Climatological Periods At Middletown-Harrisburg Area in Middletown-Harrisburg, PA (MDTthr) Period of record: 1888-07-01 to 2025-08-25 (current) - 138 Year(s) Time Series Summary for Middletown-Harrisburg Area, PA (ThreadEx) 20 warmest summers dense rank sorting by temperature Click column heading to sort ascending, click again to sort descending. 1 2020 77.9 0 2 1966 77.6 0 3 2016 77.3 0 4 2021 77.1 0 5 2024 76.9 0 6 2010 76.8 0 7 2022 76.7 0 - 1999 76.7 0 8 2019 76.5 0 - 2005 76.5 0 9 1991 76.4 0 10 1900 76.2 0 11 1943 76.1 0 12 2002 76.0 0 13 2025 75.9 6 14 2011 75.6 0 - 1995 75.6 0 15 1994 75.5 0 16 2018 75.4 0 - 1955 75.4 0 - 1949 75.4 0 17 1993 75.3 0 18 2012 75.2 0 - 2006 75.2 0 - 1988 75.2 0 19 1974 75.0 0 - 1973 75.0 0 - 1939 75.0 0 20 2015 74.9 0 - 1952 74.9 0

LOL at using hot button terms like agenda, shocked, and appalled. Try taking a step back and just looking at the actual data instead putting a strong emotional charge on it. Your area is further south than where the strongest Northeast warmth has occurred this summer. MDT is currently at an average summer temperature of 75.9°. That is the 13th warmest average summer temperature. You guys should slip back several spots with the cooler pattern to close out the summer. The current departure is only +0.7°. So the actual summer will finish up with top 20 warmth even if the departure isn’t that high.

What’s with you guys and the term agenda. Last time I checked thermometers didn’t have agendas. BTV is currently only +1.9 for the summer and they are tied for warmest summer on record. So it takes a smaller warm departure for record warmth when the current climate normals period is so warm. Time Series Summary for Burlington Area, VT (ThreadEx) top 10 warmest summers dense rank sorting for temperature Click column heading to sort ascending, click again to sort descending. 1 2025 72.3 6 - 2020 72.3 0 2 1949 72.2 0 3 2024 72.1 0 - 2018 72.1 0 4 2021 71.9 0 5 2005 71.5 0 6 2016 71.4 0 - 1995 71.4 0 7 1901 71.2 0 8 2022 71.0 0 - 1899 71.0 0 9 2012 70.9 0 - 1999 70.9 0 - 1895 70.9 0 10 1900 70.8 0

Maybe you don’t understand the difference between climate normals and rankings. Normals keep getting warmer with each 10 year update. So it takes a smaller warm departure for a top ten warmest month or season using the warmest 1991-2020 climate normals.

Can’t really go be departures anymore since the 1991-2020 climate normals are so much warmer. This has been a top 5 and top 10 warmest summer for the Northeast. Place like Long Island have seen one of their warmest summers like all the 2020s summers. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Top 10 warmest summers Click column heading to sort ascending, click again to sort descending. 1 2025 74.8 6 2 2010 74.7 0 3 2022 74.6 0 - 2020 74.6 0 4 1999 74.5 0 5 2016 74.4 0 6 2024 74.2 0 7 2011 73.9 0 8 2019 73.8 0 9 2021 73.7 0 10 2018 73.5 0 - 2005 73.5 0

This summer continued the theme of warm to record warm conditions during the 2020s with strong -EPO +PNA patterns. Very warm summers in the Northeast used to be more -PNA +EPO. This is also the strongest Southeast Ridge with this pattern. Warmer Northeast summer composite prior to 2015-2016 Super El Nino

We should finish with a slightly cooler August against the warmest 1991-2020 climate normals. But since we have been warming so fast, it would just be average for recent 30 year climate eras. Anytime we get a cooler month in recent years, we eventually see a warm departure of a greater magnitude than the cooler month was. This was the case with the spring warmth after the slightly cooler winter. Also last fall with some cooler conditions early on before we experienced record warmth by October and early November.

Numerous papers on this new summer warming pattern of cooler in the middle and record warmth in the East and West.

The main issue is how dry it has been. Newark is currently in the upper 80s on a dry downslope flow behind the cold front. It will get cooler again over the next week. Last year Newark only made it to 87° in September. So it hasn’t had two consecutive Septembers not reaching 90° since 2003 and 2004. So when the ridge returns in September, it wouldn’t take much for the warm spots like Newark to reach 90°.

First -1.2 IOD in 3 years as they have become much more common over time with the warming SSTs near the Maritime Continent.

Today could be the warmest day of the week for high temperatures in the upper 80s.

The below normal dewpoints and dry conditions this month are helping the daily lows drive the cool departures for a change. Looks like a slightly cooler pattern will continue for the rest of the month. If we don’t see a reversal of this drier pattern, then there could be more 90° heat on tap in September since it would be easy to warm up with such a dry pattern once the ridge returns.

Yeah, this has been the opposite of the Dust Bowl pattern over the last decade. Record summer warmth in the West and East with less warm over the middle section of the CONUS. The Dust Bowl pattern had the record summer heat in the middle and cooler along both coasts.

Yeah, all the warming at Philly has been since 1981. The climate from 1875 to 1980 was very stable like the rest of the world and the U.S. There was a slight -0.6° decline in winter temperatures over this period. Since 1981 Philly is up +4.3° during the winters. This is the main reason the U.S. hasn’t seen a top 10 coldest winter since the 1970s.

That’s why so many people are moving out to the Desert Southwest. Many people are OK with the extreme summer heat and drought. Then they can take weekend ski trips during the winter to get their fill of snow and cold.

We had a record Southeast Ridge in July. So record Atlantic warm pool is in the mid-latitude band off the East Coast The record ridge back in the summer of 2023 was east of Canada leading to the record SSTs at higher latitudes.

The most important factor for our area is how strong the Northern Stream of the Pacific Jet has been since 2018-2019. So this has found ways to overpower what has been favorable teleconnection patterns in the past. This is why we have experienced the lowest 7 year winter snowfall average on record for many spots from Philly to Boston. Last winter featured what would have been considered favorable teleconnections in the past for snow. Just looking at the seasonal 500mb map, you could make the assumption that it could have been a snowy winter from the means. But on the 11 days NYC had their heaviest precipitation of .25 or more the average temperature was 41° degrees and a strong Southeast Ridge. So the storm track was too warm even if the background temperature of 34.8° was much colder. So the only metric I am interested in at this point for next winter is where the storm track sets up. If it continues the Great Lakes cutter, I-78 to I-84 hugger, and suppressed Southern Stream storm tracks, then it won’t matter what kind of poleward extension we get with the ridge near Alaska. This has been the dominant storm track with the record Northern Stream of the Pacific Jet. If we get to December and the storm track is still unfavorable, then we’ll know that it will be another well below average winter for snowfall. Hoping to see some improvement in this department. We will know soon enough by December when we get the early La Niña snowfall indicator which has worked nearly all of the time since the 1990s like it did last winter. Last December was below 4” and the rest of the winter finished well below average again. But with the record mid-latitude warmth we are currently experiencing, it would tend to support the Southeast Ridge and strong PacificJet being a factor again. Don’t mind warm winters as long as the storm tracks that are cold like we got in 15-16, 16-17, and 17-18. But there is very little we can do with a warm storm track.

Really comfortable pattern here the rest of the month as the next heatwave will miss well to out north with record mid 90s staying up near the tundra. This should be one of the more extreme late season over the top warm ups we have seen. Unfortunately, it will promote more drought and wildfire activity up in Canada.

We’ll probably see some degree of 500mb height rebound by the 2nd week of September since it’s so tough to sustain a trough in the East this time of year beyond a few weeks.

2007 was a much greater regime shift when looking at the bigger picture. The NSIDC didn’t forecast an imminent technically ice free summer below 1 million sq km at that time. But there were a few individuals in the Arctic community who did. If the record Arctic dipole pattern of 2007-2012 had continued into the 2020s, then the 2012 record would have been surpassed by now. Perhaps even producing a season in the 1 to 2 million sq km range approaching technically ice free. But the dipole reversal since 2013 featuring much lower summer pressures over the CAB has prevented the 2012 record from being challenged. 2020 came the closest but the relaxation of the dipole in August and lack of record Arctic cyclone preventing it from surpassing 2012. The last decade has featured a summer record mid-latitude ridging pattern across the Northern Hemisphere leading to the record heatwaves not on land and sea. It has featured lower pressures near the pole preventing a new record low. It’s interesting that a study released back in 2014 showed this new pattern developing before it emerged. They speculated at the time that it could lead to a remnant of summer Arctic sea ice remaining pretty far into the future if lower pressures continued over the Arctic during the summers going forward.

Most people who moved out to Phoenix did it with the understanding that they would have to reduce outdoor activities as the later morning and afternoons approached. But what they are finding now is that even the early mornings for extended stretches are becoming too warm to do even basic outdoor exercise like walking. The record number of 90° minimums this decade in the urban center has probably forced many to do more indoor exercise like the treadmill during the times of peak heat. 20-40 days with 90° minimums has become the norm during the 2020s. Time Series Summary for Phoenix Area, AZ (ThreadEx) - Jan through Dec Top 5 years with 90° minimums Click column heading to sort ascending, click again to sort descending. 1 2024 39 0 2 2023 35 0 3 2020 28 0 4 2025 21 132 5 2013 15 0 - 2003 15 0

It’s possible for JFK since they have had several last 90° days in August during recent years. But the usual warm spots like Newark can always sneak in more 90° days. Looks like our next warm up in the long range forecasts is for mid-September. First/Last Summary for JFK INTERNATIONAL AIRPORT, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Minimum 05-19 (2017) 07-20 (2013) 25 Mean 06-16 09-01 76 Maximum 07-12 (2023) 10-02 (2019) 127 2024 06-21 (2024) 91 08-28 (2024) 95 67 2023 07-12 (2023) 90 09-07 (2023) 92 56 2022 05-31 (2022) 94 08-27 (2022) 91 87 2021 05-22 (2021) 94 08-27 (2021) 93 96 2020 07-02 (2020) 90 08-27 (2020) 92 55 2019 06-27 (2019) 91 10-02 (2019) 95 96 2018 06-29 (2018) 91 09-04 (2018) 93 66 2017 05-19 (2017) 92 09-24 (2017) 92 127 2016 06-22 (2016) 92 09-09 (2016) 91 78 2015 06-21 (2015) 90 09-08 (2015) 91 78 2014 06-18 (2014) 91 09-02 (2014) 92 75 2013 06-24 (2013) 90 07-20 (2013) 96 25 2012 06-20 (2012) 94 09-01 (2012) 92 72 2011 06-09 (2011) 93 08-08 (2011) 92 59 2010 05-26 (2010) 91 09-08 (2010) 92 104

Looks like another season ending in the 4-5 sq million range for September average extent. Years like 2012 and 2020 dropping under 4million sq km have been the exception. So have years finishing over 5 million sq km like 2009, 2013, and 2014. So a very stable September minimum regime since the record declines back in the strong 2007-2012 dipole era. This reversal of the dipole has prevented us from exceeding the 2012 minimum so far. So we can say with confidence that 2007 lead to a regime shift in the sea ice. Extent and thickness have not been able to recover to the much higher pre-2007 ice. Even with multiple summer seasons with very favorable lower pressure circulation patterns for sea ice retention. The annual warmth in the Arctic has just been too strong to allow any type of recovery. 2024…..4.38 2023…..4.37 2022….4.87 2021……4.92 2020……3.92…2nd lowest 2019……4.32 2018…...4.71 2017……4.87 2016……4.72 2015…..4.63 2014…..5.28 2013…..5.35 2012…..3.60….lowest 2011……4.61 2010…..4.90 2009….5.36 2008….4.67 2007…..4.28 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL114546 A regime shift is an abrupt, substantial, and persistent change in the state of a system. We show that a regime shift in the September Arctic sea-ice extent (SIE) occurred in 2007. Before 2007, September SIE was declining approximately linearly. In September 2007, SIE had its largest year-to-year drop in the entire 46-year satellite record (1979–2024). Since 2007, September SIE has fluctuated but exhibits no long-term trend. The regime shift in 2007 was caused by significant export and melt of older and thicker sea ice over the previous 2–3 years, as documented in other studies. We test alternatives to the traditional linear model of declining September SIE, and discuss possible explanations for the lack of a trend since 2007. Current Jaxa extent