bluewave

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.

I believe this is our first two consecutive Julys with 10.00”+ at any of our major stations. Hard to know if this has happened before at the smaller PWS or coop sites. But the strong subtropical flavor continues with very wet and high dew point regimes of recent summers. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 1889 11.89 0 2 1975 11.77 0 3 2021 10.48 4 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 Total Precipitation Missing Count 1 2020 11.22 0 2 1988 9.98 0 3 1984 8.65 0 4 2004 8.39 0 5 2021 8.30 4

Saturday looks like it will be the coolest morning.

The big story this summer is how we needed a record low pressure pattern to get back closer to the 2010s average following the near record finish last year.

Models hinting at a very cool ending to July. Be interesting to see if a spot like Newark can actually dip under 60°. The last time this happened on July 31st at Newark was 1956. KEWR GFSX MOS GUIDANCE 7/28/2021 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 WED 28| THU 29| FRI 30| SAT 31| SUN 01| MON 02| TUE 03| WED 04 CLIMO X/N 85| 69 78| 69 85| 59 82| 66 83| 65 82| 64 81| 67 85 67 86 Data for July 31 - NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Min Temperature Precipitation Snowfall Snow Depth 1932-07-31 83 56 T 0.0 M 1956-07-31 81 58 0.00 0.0 0 1936-07-31 79 58 0.00 0.0 0 1964-07-31 82 61 0.00 0.0 0

LGA gusting to 45 mph. 27 Jul 7:34 pm 83 58 43 NNW 25G45 10.00

All the July heat since 2010 has really raised the bar. Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jul Season Mean 79.9 79.9 2021 79.1 79.1 2020 80.8 80.8 2019 80.6 80.6 2018 78.2 78.2 2017 77.3 77.3 2016 79.9 79.9 2015 79.0 79.0 2014 77.0 77.0 2013 80.9 80.9 2012 80.8 80.8 2011 82.7 82.7 2010 82.3 82.3 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 5 17 2015 79.0 0 18 1980 78.8 0 19 2008 78.7 0 20 1973 78.6 0 21 2005 78.3 0 - 1982 78.3 0 22 2018 78.2 0

This was one of the cooler Julys for a top 10 warmest June and July period. Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Year Jun Jul Season 1994 77.8 81.9 79.9 2010 76.2 82.3 79.3 1993 75.8 82.5 79.2 2011 74.5 82.7 78.6 2021 76.2 79.1 77.7 2020 74.4 80.8 77.6 1999 74.2 80.8 77.5 2013 73.3 80.9 77.1 2008 75.3 78.7 77.0 1987 74.4 79.4 76.9 1981 74.6 79.2 76.9

Only the 7th time that Newark reached 90°on 27 days by the end of July. It’s also the first time on the list since 1991 that there were so few 90°days in July. So the May and June heat allowed Newark to make it 5th place by the end of 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 Apr May Jun Jul Season 2010 1 2 13 21 37 1993 0 3 9 22 34 1987 0 4 11 14 29 1994 1 1 10 16 28 2011 0 1 4 22 27 1991 0 8 10 9 27 2021 0 4 12 11 27

The unusually strong 500 mb anomaly over Canada allowed us to escape the major heat this July that has been common since 2010. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jul Click column heading to sort ascending, click again to sort descending. Year Mean Avg Temperature Missing Count 2021 79.1 5 2020 80.8 0 2019 80.6 0 2018 78.2 0 2017 77.3 0 2016 79.9 0 2015 79.0 0 2014 77.0 0 2013 80.9 0 2012 80.8 0 2011 82.7 0 2010 82.3 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Year Mean Avg Temperature Missing Count 2021 77.9 5 2020 82.9 0 2019 81.5 0 2018 79.8 0 2017 78.1 0 2016 81.1 0 2015 79.2 0 2014 77.0 0 2013 81.2 0 2012 80.4 0 2011 80.4 0 2010 82.8 0

So far this is the second most positive summer AO on record for the June into July period. 2016 wasn’t nearly as positive for this first half of summer interval. If the lower pressures were more aligned with the AO region, then it would be even more positive. That’s why the raw indices don’t always tell the complete story. It would be nice to have the daily AD anomaly to combine the two indices for a more complete picture. You can see the Arctic pressures were lowest in the series for the month of June just edging out 1970.

JFK was able to set its highest dew point record of 84° in 2016. But you can see how all the highest records were in recent years. The mid-July 1995 heatwave was impressive for several sites reaching the 100/80 mark.

This is actually the lowest Arctic pressures for the first half of summer since 1989. Looking at the raw indices like the AO doesn’t really do this pattern justice. While the core of the low pressure is closer to the Russian side this summer, the overall Arctic pressures haven’t been this low in the post 2007 era. In the much cooler late 80s with the healthier ice pack, we would be talking about a September daily minimum extent near 7 million sq km like 1989. But we’ll have to settle for whatever passes for good in the post 2007 Arctic this year.

That was 2018. JFK is currently at 7 days with a 75° or higher dew point . Only 3 more days needed for the first 6 year run. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=75&month=all&year=2021&dpi=100&_fmt=js

Yeah, more record rainfall and flooding.

Another top 10 highest dew point July at JFK and ISP. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=76&network=NY_ASOS&station=JFK&season=jul&varname=dwpf&year=1893&w=bar&hours=0-23&dpi=100&_fmt=png

A combination of a warmer atmosphere holding more moisture and slower moving systems.

Another 2.31 on the North Shore with the thunderstorms last night. This brings the Port Washington total to 14.31 for July so far. This probably ranks among the heaviest July rainfall totals ever recorded on Long Island. 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 Totals : 14.31 in.

Yeah, these rainfall extremes are occurring all across the world. This is officially the wettest monsoon on record to date in Tucson. Also notice how the intensity of the monsoon produced the record cool temperatures in Phoenix.