bluewave

Very thin ice pack this summer if these record low MYI area figures are correct.

The interior crew wouldn’t be happy if this was a snowfall forecast.

The latest PNA forecast is even more extreme. The GEFS maxes out near a ridiculous +4. The highest ever in August was just +3.1. I think that this is why the models have such a sharp rainfall cutoff west of NYC. A piece of the Western heat comes east when the PNA begins to flatten later this week.

I started a new thread to expand on the climate change link to recent PNA, NAO, and AO extremes.

I saw the near record +PNA rise being discussed in Don's great thread. So I did some research into how it’s becoming more extreme with climate change. The PNA index isn’t the only one becoming more amplified. A study from 2009 documented how the NAO has also exhibited much bigger swings from high to low as the climate has warmed. In fact, the summer of 2009 to the present has exhibited record breaking highs and lows. The AO is showing these same extremes from record lows in the summer of 2009 through March 2013. Then we experienced a rapid reversal with record positive levels in the winter of 14-15 while the PNA was also in a very positive phase. This past winter featured an historic February reversal from record daily negative readings to very positive. https://phys.org/news/2009-01-links-north-atlantic-oscillation-variability.html Study links swings in North Atlantic oscillation variability to climate warming Using a 218-year-long temperature record from a Bermuda brain coral, researchers at the Woods Hole Oceanographic Institution (WHOI) have created the first marine-based reconstruction showing the long-term behavior of one of the most important drivers of climate fluctuations in the North Atlantic. The North Atlantic Oscillation (NAO) is a wide-ranging pressure seesaw that drives winter climate over much of North America, Europe and North Africa. Past reconstructions of the NAO have relied mainly on terrestrial, or land-based records, such as tree ring chronologies combined with ice cores and historical climate data. Those records do not fully capture oceanic processes linked to NAO variability, and short instrumental records from relatively few locations limit the understanding of ocean-atmosphere dynamics with regard to NAO behavior. By analyzing the coral, we were able to look at changes in the ocean relative to changes on land," said Nathalie Goodkin, lead author of the study published in the December issue of the journal Nature Geoscience. "Because they are slow growing and have long life-spans, corals can provide high resolution records that are well dated and centuries long." As they grow, corals accrete seasonal and annual growth layers, similar to tree rings. The proportions of trace elements versus the major element (calcium) found in the layers of the skeleton largely depend on the temperature of the seawater in which it was formed. By analyzing the strontium to calcium ratio in the Bermuda brain coral, Goodkin and colleagues — WHOI scientists Konrad Hughen, Scott Doney and William Curry — were able to reconstruct monthly changes in ocean temperatures and evaluate variability of the NAO during both cold and warm periods from the Little Ice Age (1800�) to modern day. The research team found the variability of the NAO decade-to-decade (multi-decadal scale) has been larger, swinging more wildly, during the late twentieth century than in the early 1800s, suggesting that variability is linked to the mean temperature of the Northern Hemisphere. This confirms variability previously reported in past terrestrial reconstructions. "When the Industrial Revolution begins and atmospheric temperature becomes warmer, the NAO takes on a much stronger pattern in longer-term behavior," said Goodkin. "That was suspected before in the instrumental records, but this is the first time it has been documented in records from both the ocean and the atmosphere." The North Atlantic Oscillation is described by the NAO index, calculated as a weighted difference between the polar low and the subtropical high during the winter season. In a positive phase, both the low-pressure zone over Iceland and high pressure over the Azores are intensified, resulting in changes in the strength, incidence, and pathway of winter storms crossing the Atlantic. In a negative phase, a weak subtropical high and a weak Icelandic low results in fewer and weaker winter storms crossing on a more west-east pathway. The NAO index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting more than a decade. An unusually long period of positive phase between 1970-2000 led to the suggestion that global warming was affecting the behavior of the NAO. "Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales," said WHOI paleoclimatologist Konrad Hughen. "It does seem to be increasing variability. Clearly, this has implications for the future." "As temperatures get warmer, there's potential for more violent swings of the NAO — the phases becoming even more positive and even more negative," Hughen added. "If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe." The climatic influence of the NAO extends from the eastern United States to Western Europe, impacting human activities such as shipping, oil drilling, fisheries, hydroelectric power generation and coastal management. Improving the ability to predict shifts in the phase and intensity of the NAO is a prerequisite to mitigating the economic impacts of future climate change. While additional modeling and palaeoclimatic studies are needed, a broad distribution of marine records could advance our knowledge of NAO variability and serve to improve future projections, said Goodkin, now an assistant professor in the Department of Earth Sciences at the University of Hong Kong. Nature GeoScience paper: Increased multidecadal variability of the North Atlantic Oscillation since 1781 www.nature.com/ngeo/journal/va … nt/full/ngeo352.html Source: Woods Hole Oceanographic Institution https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL086309 Robust Increases in Extreme Pacific North American Events Under Greenhouse Warming Zhongfang Liu, Xiaogang He, Wentao Ma, Yue Wang First published: 03 January 2020 https://doi.org/10.1029/2019GL086309 Citations: 1 Read the full text PDF TOOLS SHARE Abstract The Pacific North American (PNA) pattern is an internal mode of the Northern Hemisphere atmosphere, which strongly affects the hydroclimate and ecosystems of the Pacific-North American sector. Recent studies have suggested a more positive PNA pattern in response to greenhouse warming, but how extreme PNA events will change remains unclear. Based on results from the Coupled Model Intercomparison Project Phase 5 multimodel ensemble, we find a 50% increase in the frequency of extreme positive PNA events and a 32% increase in extreme negative PNA events in the 21st century relative to the twentieth century. The increased frequency arises from a shift toward a more positive PNA pattern and is enhanced by more frequent ENSO events under greenhouse warming. Our study suggests that a continued increase in greenhouse-gas emissions is likely to cause increased occurrence of extreme PNA events, thus increasing the risk of extreme weather and climate in North America. https://www.nature.com/articles/s41467-021-21830-z The PNA, both in winter and summer, has exhibited a significant positive trend since the satellite era45,46, with a magnitude that seems unprecedented over the past millennium47. This trend is particularly strong for the summertime PNA during the period 1979–2016 (0.27 per decade, p < 0.01), with the pattern shifting from a negative phase in the 1980s through the mid-1990s to a strong positive phase after the mid-1990s (Fig. 1c).

It looks like the WAR will eventually push back against the near record +PNA ridge. But the models can’t agree on where the front stalls out with training convection. So the magnitude of any warm up week 2 will probably have to wait until the finer details get sorted out. Flip a coin

LGA is currently -1.3 for July and the 2nd coolest July since 2010. Almost like a spring backdoor pattern where Newark is warmer and LGA cooler. Very sharp departure dividing line across the area. Time Series Summary for LAGUARDIA AIRPORT, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 2020 82.9 0 2010 82.8 0 2019 81.5 0 2013 81.2 0 2016 81.1 0 2012 80.4 0 2011 80.4 0 2018 79.8 0 2015 79.2 0 2017 78.1 0 2021 77.9 1 2014 77.0 0

I use the dense rank like the NWS in Upton does on their climate page. https://docs.microsoft.com/en-us/sql/t-sql/functions/dense-rank-transact-sql?view=sql-server-ver15 If two or more rows have the same rank value in the same partition, each of those rows will receive the same rank. For example, if the two top salespeople have the same SalesYTD value, they will both have a rank value of one. The salesperson with the next highest SalesYTD will have a rank value of two. This exceeds the number of distinct rows that come before the row in question by one. Therefore, the numbers returned by the DENSE_RANK function do not have gaps, and always have consecutive rank values. The sort order used for the whole query determines the order of the rows in the result set. This implies that a row ranked number one does not have to be the first row in the partition. https://www.weather.gov/media/okx/Climate/CentralPark/warmcoldmonths.pdf

We are in the era now of a +1 July still finishing in the top 20 warmest. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2011 82.7 0 2 1993 82.5 0 3 2010 82.3 0 4 1994 81.9 0 5 2013 80.9 0 6 2020 80.8 0 - 2012 80.8 0 - 1999 80.8 0 7 2019 80.6 0 8 1955 80.5 0 9 1988 80.4 0 10 2002 80.0 0 11 2016 79.9 0 12 1983 79.6 0 - 1966 79.6 0 13 1995 79.5 0 - 1949 79.5 0 14 2006 79.4 0 - 1987 79.4 0 15 1981 79.2 0 - 1952 79.2 0 16 2021 79.1 1 17 2015 79.0 0 18 1980 78.8 0 19 2008 78.7 0 20 1973 78.6 0

Third year in a row that Newark finishes June 1st to July 31st with top 10 warmth. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jul 31 Missing Count 1 1994-07-31 79.8 0 2 2010-07-31 79.3 0 3 1993-07-31 79.2 0 4 2011-07-31 78.6 0 5 2021-07-31 77.7 1 - 2020-07-31 77.7 0 6 1999-07-31 77.5 0 7 2013-07-31 77.1 0 8 2008-07-31 77.0 0 - 1987-07-31 77.0 0 - 1981-07-31 77.0 0 9 1988-07-31 76.8 0 10 2019-07-31 76.7 0

Even in a much warmer Arctic, record low pressures are still going to cause a slow down in the rate of loss. Extent losses have been below average for this time of year. So this has allowed the extent to pull back to the 2011-2020 mean for late July. Should we continue to track along this 2010s dashed line, it would mean a September daily minimum extent in the mid 4s range. NSIDC September 10 year mean September daily minimum extents 2011-2020…..4.423 million sq km 2001-2010…..5.388 1991-2000…..6.499 1979-1990…...6.959

Looks like Islip tied the record low of 55°. FOK made it down to 47° Which is a tie of its record low. 31 Jul 5:56 am 55 49 31 Jul 5:53 am 47

The record ridge and drought allowed Boise to surpass their previous warmest June and July by nearly 3°. Time Series Summary for Boise Area, ID (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jul 31 Missing Count 1 2021-07-31 79.7 2 2 2007-07-31 76.9 0 3 2015-07-31 76.3 0

Concord, New Hampshire and Tucson, Arizona are an unlikely pair to have the wettest July at the same time. Several stations in the Northeast had their wettest July on record.The Port Washington Cocorahs station had nearly 15 inches. Time Series Summary for Concord Area, NH (ThreadEx) - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2021 13.04 2 2 1915 10.29 0 3 1897 8.56 0 4 1887 7.84 0 5 1872 7.72 0 Time Series Summary for Tucson Area, AZ (ThreadEx) - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 2021 7.39 2 2 2017 6.80 0 3 1921 6.24 0 4 1981 6.17 0 5 1919 5.53 0 NY-NS-27 Port Washington 0.8 N Lat: 40.839167 Lon: -73.68025 * indicates Multi-Day Accumulation Report Station NY-NS-27 Date Precip in. 07/01/2021 1.04 07/02/2021 1.12 07/03/2021 2.26 07/04/2021 0.79 07/05/2021 0.00 07/06/2021 0.00 07/07/2021 0.43 07/08/2021 0.01 07/09/2021 3.07 07/10/2021 2.06 07/11/2021 0.02 07/12/2021 0.21 07/13/2021 0.04 07/14/2021 0.02 07/15/2021 T 07/16/2021 0.00 07/17/2021 0.00 07/18/2021 0.28 07/19/2021 0.05 07/20/2021 0.01 07/21/2021 T 07/22/2021 0.34 07/23/2021 0.01 07/24/2021 0.00 07/25/2021 0.22 07/26/2021 2.33 07/27/2021 0.01 07/28/2021 0.31 07/29/2021 0.01 07/30/2021 0.12 Totals : 14.76 in.

Such an anomalous ridge centered near Montana for June and July doesn’t really match any ENSO composites for this time of year. It was the strongest June and July ridge that I could find for that area. 2006 and 2007 had the previous strongest ridge. But you can see this year has a more impressive 500mb anomaly.

That was just a temporary bridge put in place after the original bridge got washed away. https://www.yahoo.com/entertainment/suspension-bridge-collapses-flooded-russian-051203234.html The bridge, mainly made out of wood, was located in Uryum village, over 4,500 kilometres away from Moscow.As the truck reached the middle of the bridge, it started failing under the load, eventually falling into the swollen river along with the vehicle.The driver was later reported to have survived, but the truck could not be recovered from the water.The suspension bridge was constructed in place of a road bridge that was destroyed during one of the previous floods in the area. Currently, the residents of Uryum village do not have a way to cross the river after the accident.Bridge in Uryum is not the only one in the region that got damaged by extreme rainfall. Flooding has also damaged a bridge on Russia's Trans-Siberian railway, suspending traffic in the area.A also bridge gave way in Zabaikalsk region, some 300 km (190 miles) north of the border with China and Mongolia, The emergencies ministry said that no casualties were reported.TASS news agency said around 650 houses were reported flooded and five road bridges washed away in the flooding in the Zabaikalsk region on Thursday after heavy rain.

EPS has a cooler first week of August with the front stalling near the East Coast. Then the WAR builds during the second week of August with warmer temperatures. So maybe that’s when we’ll have a shot at our next heatwave. Aug 2-9 Aug 9-16

Models continuing with one of the strongest +PNA rises that we have seen in August. Looks like the GEFS mean gets to the +2.5 to +3.0 range. The record set in August 2009 was 3.1. So this is a continuation of the record ridging that we have seen this summer over Western North America. As the WAR begins to push back against the Eastern Trough, there may be a stalled frontal zone in the East which will be the focus of convection. Probably need a few more days to iron out the daily storm details. But it will be a high dew point and PWAT regime where the front stalls out.

Every warm up since late May has been followed by a cool down and heavy rain. So the pattern is continuing. After the highest temperatures peaked in late June, the warm ups haven’t been as intense. Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Max Temperature Departure Precipitation 2021-05-20 76 2.4 0.00 2021-05-21 83 9.1 0.00 2021-05-22 96 21.8 0.00 2021-05-23 94 19.6 0.00 2021-05-24 68 -6.7 0.00 2021-05-25 81 6.0 0.00 2021-05-26 94 18.7 0.09 2021-05-27 87 11.4 0.01 2021-05-28 71 -4.9 1.15 2021-05-29 52 -24.2 0.58 2021-05-30 53 -23.5 1.15 2021-05-31 76 -0.8 T 2021-06-01 80 2.9 0.00 2021-06-02 79 1.6 T 2021-06-03 77 -0.8 0.41 2021-06-04 83 4.9 0.19 2021-06-05 95 16.6 0.00 2021-06-06 97 18.2 0.00 2021-06-07 95 15.9 0.04 2021-06-08 93 13.6 2.19 2021-06-09 96 16.2 0.53 2021-06-10 85 4.9 0.00 2021-06-11 73 -7.4 T 2021-06-12 72 -8.8 T 2021-06-13 78 -3.1 T 2021-06-14 78 -3.5 0.16 2021-06-15 85 3.2 0.01 2021-06-16 81 -1.1 0.00 2021-06-17 81 -1.5 0.00 2021-06-18 88 5.2 0.00 2021-06-19 93 9.9 0.05 2021-06-20 91 7.6 0.00 2021-06-21 92 8.3 T 2021-06-22 80 -4.0 0.17 2021-06-23 80 -4.3 0.00 2021-06-24 79 -5.5 0.00 2021-06-25 83 -1.8 0.00 2021-06-26 86 1.0 0.07 2021-06-27 95 9.7 0.00 2021-06-28 99 13.5 0.00 2021-06-29 102 16.3 0.00 2021-06-30 103 17.1 0.54 2021-07-01 89 2.9 0.94 2021-07-02 81 -5.3 1.53 2021-07-03 70 -16.4 0.05 2021-07-04 84 -2.6 0.00 2021-07-05 89 2.3 0.00 2021-07-06 97 10.2 0.55 2021-07-07 97 10.1 T 2021-07-08 88 1.0 0.08 2021-07-09 91 3.9 1.60 2021-07-10 86 -1.1 T 2021-07-11 82 -5.2 T 2021-07-12 93 5.8 0.69 2021-07-13 78 -9.3 0.01 2021-07-14 93 5.7 0.07 2021-07-15 91 3.7 T 2021-07-16 96 8.7 0.00 2021-07-17 93 5.7 2.28 2021-07-18 86 -1.2 T 2021-07-19 86 -1.2 T 2021-07-20 90 2.8 0.00 2021-07-21 85 -2.1 0.05 2021-07-22 85 -2.1 0.00 2021-07-23 86 -1.0 T 2021-07-24 85 -1.9 0.00 2021-07-25 87 0.1 0.37 2021-07-26 93 6.2 0.08 2021-07-27 94 7.3 T 2021-07-28 87 0.4 0.04

The three stations Essex and Hudson are running warmer than all other stations by a wider margin than we usually see. 90° days Harrison...25 Caldwell...26 Newark..…27 SMQ..……..22 LGA…………17 JFK………….6 FRG………….8 ISP…………..3 BDR…………8

First time since 2007 that Newark had more 90° days in June than July. Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jun Jul Difference 2021 12 11 -1 2020 5 17 +12 2019 4 14 +10 2018 5 9 +4 2017 5 9 +4 2016 3 16 +13 2015 4 11 +7 2014 2 8 +6 2013 4 15 +11 2012 6 16 +10 2011 4 22 +18 2010 13 21 +8 2009 0 1 +1 2008 6 11 +5 2007 6 4 -2

The record MYI decline during and after the 2007 melt season was an important shift in the state of the Arctic. None of the more favorable summers since then have been able to bounce back above 6 million sq km for a NSIDC September daily minimum.There were two finishes below 4 million sq km and only three slightly above 5 million sq km. Most years since 2007 have finished somewhere in the 4s million sq km range. So a bit of a holding pattern lower range from 2013 to 2021. We’ll have to see when the next step down occurs. https://nsidc.org/news/newsroom/2007_seaiceminimum/20071001_pressrelease.html Arctic sea ice during the 2007 melt season plummeted to the lowest levels since satellite measurements began in 1979. The average sea ice extent for the month of September was 4.28 million square kilometers (1.65 million square miles), the lowest September on record, shattering the previous record for the month, set in 2005, by 23 percent https://nsidc.org/arcticseaicenews/2008/04/ New ice growth over winter 2007/2008 As the winter extent numbers indicate, new ice growth was strong over the winter. Nevertheless, this new ice is probably fairly thin. Thin ice is vulnerable to melting away during summer. Figures 4 and 5 indicate that relatively thin, first-year ice now covers 72% of the Arctic Basin, including the region around the North Pole; in 2007, that number was 59%. Usually, only 30% of first-year ice formed during the winter survives the summer melt season; in 2007, only 13% survived. Even if more first-year ice survives than normal, the September minimum extent this year will likely be extremely low. Why is there so much first-year ice this spring? Partly, it is because last summer’s record-breaking ice loss created extensive open-water areas in which new ice could form. Anomalous winds in winter can also flush thicker, older ice out of the Arctic, leaving the Arctic with a greater coverage of first-year ice. As noted by our colleague Ignatius Rigor of the University of Washington at Seattle, this winter saw a return of the Arctic Oscillation to its positive mode, an atmospheric pattern especially effective in flushing out thick, old ice. So what about the multi-year ice that remained after last year’s record ice loss? Jennifer Kay and colleagues at the National Center for Atmospheric Research found that last summer’s clear skies allowed for more intense melt of the multiyear ice, leaving it thinner than normal at summer’s end. For more on the Arctic’s transition towards younger ice, see an animation of changing sea ice age (scroll to Figure 4 of August 22, 2007 entry) by colleague Jim Maslanik and coauthors.

The GFS is close to the all-time +PNA record for the month of August. I believe the record was +3.160 at the beginning of August in 2009. Could lead to a stalled front scenario somewhere in the East when the WAR eventually pushes back against the trough. https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.pna.index.b500101.current.ascii 2009 8 1 3.160

15 inches is within reach at Port Washington. NY-NS-27 Port Washington 0.8 N Lat: 40.839167 Lon: -73.68025 * indicates Multi-Day Accumulation Report Station NY-NS-27 Date Precip in. 07/01/2021 1.04 07/02/2021 1.12 07/03/2021 2.26 07/04/2021 0.79 07/05/2021 0.00 07/06/2021 0.00 07/07/2021 0.43 07/08/2021 0.01 07/09/2021 3.07 07/10/2021 2.06 07/11/2021 0.02 07/12/2021 0.21 07/13/2021 0.04 07/14/2021 0.02 07/15/2021 T 07/16/2021 0.00 07/17/2021 0.00 07/18/2021 0.28 07/19/2021 0.05 07/20/2021 0.01 07/21/2021 T 07/22/2021 0.34 07/23/2021 0.01 07/24/2021 0.00 07/25/2021 0.22 07/26/2021 2.33 07/27/2021 0.01 07/28/2021 0.31 Totals : 14.63 in.