bluewave

Yeah, Nino 1+2 and 3 aren’t having the same forcing influence like they did at this point in 1997 due to the WPAC being so much warmer.

We are getting to the time of the year when Nino 1+2 departures have less influence due to the cooler SSTs. Notice how the WPAC warm pool continues to run the forcing show due to the peak SSTs around +30C. So Nino 4 is much warmer than 1+2.

The model run by Will Gregory at CPOM based on May conditions is going for an average September extent of 4.46 million sq km. This is solidly within the range since 2013. The model has been very accurate. So the 2012 record should be safe for another year https://www.arcus.org/files/sio/panarctic/2023_june_sio_cpom_ucl_gregory_et_al.pdf Executive summary" of your Outlook contribution (using 300 words or less) describe how and why your contribution was formulated. To the extent possible, use non-technical language. This statistical model computes a forecast of pan-Arctic September sea ice extent . Monthly averaged May sea ice concentration and sea-surface temperature fields between 1979 and 2023 were used to create a climate network (based on the approach of Gregory et al 2020). This was then utilised in a Bayesian Linear Regression in order to forecast September extent. The model predicts a pan-Arctic extent of 4.46 million square kilometres. Sea ice concentration data were taken from NSIDC (Cavalieri et al., 1996; Maslanik and Stroeve,1999) and sea-surface temperature data were taken from ERA5 (Hersbach et al., 2019) Average September extents since 2012 2022….4.87 2021……4.92 2020……3.92 2019……4.32 2018…...4.71 2017……4.87 2016……4.72 2015…..4.63 2014…..5.28 2013…..5.35 2012…..3.60

70.6 is much closer to 2009 than 1985. But I see what you are saying. Time Series Summary for Philadelphia Area, PA (ThreadEx) - Month of Jun Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1903 65.8 0 2 1907 66.8 0 3 1881 67.3 0 4 1878 67.4 0 5 1958 67.8 0 6 1916 67.9 0 7 1926 68.0 0 8 1977 68.6 0 - 1927 68.6 0 9 1982 68.7 0 - 1972 68.7 0 10 1985 68.8 0 11 1897 68.9 0 12 1979 69.0 0 13 2023 69.2 7 - 1955 69.2 0 - 1946 69.2 0 14 1924 69.3 0 15 1886 69.5 0 16 1915 69.6 0 - 1910 69.6 0 17 1947 69.7 0 - 1918 69.7 0 18 1928 69.8 0 19 1961 69.9 0 20 1965 70.0 0 21 1974 70.3 0 - 1902 70.3 0 - 1896 70.3 0 - 1875 70.3 0 22 1963 70.4 0 23 1980 70.6 0 - 1960 70.6 0 24 1950 70.7 0 - 1912 70.7 0 25 1905 70.8 0 - 1904 70.8 0 26 2009 71.1 0 - 1997 71.1 0

It’s fairly typical for developing El Niños to feature a cooler June. The list below is the coolest Junes so far since 1981. The El Niño years are bolded. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jun 23 Missing Count 1 2003-06-23 64.9 0 2 2009-06-23 65.9 0 3 1998-06-23 67.0 0 4 1982-06-23 67.1 0 5 2023-06-23 68.6 0 - 1997-06-23 68.6 0 6 2002-06-23 69.0 0

6th coldest reading so far at Atlantic City and Charleston, WV. Time Series Summary for Atlantic City Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jun 22 Missing Count 1 1980-06-22 62.7 0 2 1997-06-22 64.8 0 3 2003-06-22 65.1 0 4 1946-06-22 65.4 0 5 1992-06-22 65.6 0 - 1958-06-22 65.6 0 6 2023-06-22 65.7 0 7 1951-06-22 65.8 0 8 1948-06-22 66.0 1 9 1977-06-22 66.1 0 10 1972-06-22 66.2 0 Time Series Summary for Charleston Area, WV (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jun 22 Missing Count 1 1955-06-22 64.8 0 2 1972-06-22 65.8 0 3 1927-06-22 66.1 0 4 2003-06-22 66.2 0 5 1910-06-22 66.3 4 6 2023-06-22 66.9 0 7 1980-06-22 67.0 0 8 1977-06-22 67.1 0 9 1907-06-22 67.7 0 10 1963-06-22 67.8 0

It’s actually the coolest June in Philly since 2009 and 3rd overall coolest since 2000. Time Series Summary for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jun 22 Missing Count 1 2003-06-22 68.0 0 2 2009-06-22 69.2 0 3 2023-06-22 69.3 0 4 2004-06-22 71.2 0 5 2000-06-22 71.4 0

Locally warmer version of the 2009 developing El Niño with the AMJ maximum temperature coming in April. Monthly Highest Max Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Apr May Jun Season 2002 97 90 96 97 1990 94 83 92 94 2023 93 90 91 93 2009 93 87 89 93 1976 93 83 93 93

So far the OISST has been averaging +0.9 for the first half of June. Its possible that the last 10 days can warm enough for June to average +1.0. The BOM looks like its call from May for June to finish at 1.25 will be a little high. More WWBs coming for the EPAC will continue the warming in the east gradually spreading west. The westward lean to the forcing continues this month.

The CPC uses OISST for its weekly SST temperature updates. Not sure of any agencies that use CDAS. They use ERSST for monthly and seasonal SSTs. https://www.cpc.ncep.noaa.gov/data/indices/

Pretty impressive.

It’s been the persistent trough and lack of SE Ridge causing the cooling.

This could have been a good pattern with winter wavelengths.

Probably the strongest +AMO signature that we have ever seen.

Long range forecasts verifying slightly cooler due to the cold pool to our east. This is the opposite model bias of recent years. So it will be interesting to see how long it lasts. New run Old run

The east based forcing would provide our 9th milder winter in a row. The forcing near the Dateline could help out with a rogue blockbuster snowstorm like 2016. So a relative improvement over the poor snowfall showing last winter.

Big change in the North Atlantic SST configuration. First time with a cold pool off the Northeast in years. Not sure how long this will last.

The Euro seasonal is going for split forcing near the Dateline and EPAC.

Nothing has been able to shut down the the Nina MJO phases. Remember the MJO 4-6 activity with the record IOD in the fall of 2019 into 2020. Then the record MJO 4-6 in December 2015. The record WPAC warm pool has had been a big player.

We got the WWBs but they were in the WPAC and EPAC instead of near the Dateline. Would be an interesting study to see what lead to this particular evolution. The WPAC kelvin wave development from last winter was in response to the IO WWBs crossing into the WPAC. Then the anomalous EPAC WWB in March rapidly warmed the EPAC.

Yeah, this could be only the 3rd June after 1997 and 2015 with a +1 or greater anomaly in Nino 3.4. https://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii

The EPAC subsurface spreading west plus the new kelvin wave puts +2C in Nino 3.4 within reach. Never saw this happen before with WWBs in the EPAC and WPAC with little near the Dateline. The quick Nino 3.4 rise to near + 1C is matching some of the more aggressive model forecasts. Could result in our first 1.5C global temperature departure coming earlier than projected. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtm

At least it isn’t 758 like a few years ago in Oregon but this is bad enough. https://www.insider.com/west-coast-hazardous-air-quality-worst-on-earth-wildfire-smoke-2020-9 But PurpleAir's monitors around Salem, Oregon, reported AQIs as high as 758 on Friday morning.

Another one of these off the charts blocking ridges.

Little bigger than pea sized hail here in SW Suffolk with giant rain drops.