bluewave

Numerous stations in the Northeast had a top 5 warmest and wettest first half of the summer.

They should send these guys over to the Central Park ASOS.

Posters have been talking about July specifically in areas of the forum that are closest to New England. We all know how hot June was. But Northern and Central NJ had the 4th warmest first half of summer on record. Even our coolest recent summers like 2017 are still plenty hot for outdoor work in this part of the country. You would need to go up to the Canadian Maritimes to experience comfortable outdoor working conditions in July. 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 15 Missing Count 1 1994-07-15 79.2 0 2 1993-07-15 78.9 0 3 2010-07-15 77.9 0 4 2021-07-15 77.1 0 5 1981-07-15 77.0 0 - 1966-07-15 77.0 0

By post 2010 standards, this hasn’t been one the hottest Julys so far. We have had too much in the way of clouds, convection, and onshore flow. While the heat the next few days will boost the means, we will be off the averages of our warmest Julys since 2010. The drought areas of the West will end up with the most extreme July heat this year. Northern NJ has been the warmest part of the region since it has been able to escape some of the onshore flow influence. The cooler easterly flow behind the backdoors has kept LGA at the coolest relative to the 2010s so far. 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 1 2020 82.9 0 2 2010 82.8 0 3 2019 81.5 0 4 2013 81.2 0 5 2016 81.1 0 6 2012 80.4 0 - 2011 80.4 0 7 2018 79.8 0 8 2015 79.2 0 9 2017 78.1 0 10 2014 77.0 0 11 2021 76.9 16 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 2010 82.3 0 3 2013 80.9 0 4 2020 80.8 0 - 2012 80.8 0 5 2019 80.6 0 6 2016 79.9 0 7 2015 79.0 0 8 2021 78.8 16 9 2018 78.2 0 10 2017 77.3 0 11 2014 77.0 0

Looks like the record heat will be focused over Montana next week. EPS July 19-26

No surprise that the Northern Hemisphere mid-latitude land set a new June heat record by a significant margin.

We have had so much record July heat since 2010, that the new 30 year climate normals have risen from 77.4 to 78.2 at Newark. So Newark only needs a +1.8 July departure for a top 10 warmest 80° or higher July. That’s why using departures can really underestimate heat in a warming climate. https://www.ncei.noaa.gov/access/us-climate-normals/#dataset=normals-monthly&timeframe=30&station=USW00014734 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

There is actually lower pressures closer to North American side this year compared to 2013 and 2006. But since there is so much record warmth surrounding the Arctic, warmer air is being drawn north. The warmer spring this year also allowed more of a head start on the melt than 2013. But this pattern is still more favorable than the raging dipole pattern last year. That is why we are falling behind 2020s pace. I also suspect that we will fall behind 2012 going forward. .

This amount of heat and heavy rainfall combined since late May is unprecedented. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation May 22 to Jul 14 # 90° days and Max Tempersture 1 1984-07-14 16.63 12 97° 2 2003-07-14 13.46 10 95° 3 2013-07-14 13.10 14 96 4 2021-07-14 12.86 20 103°

This is been one of the most persistent heatwave followed by heavy rain patterns since late May. We are currently in the heatwave phase. So we are on track for another heavy round of convection after this heatwave peaks. Data for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Date Max Temperature Precipitation 2021-05-22 96 0.00 2021-05-23 94 0.00 2021-05-24 68 0.00 2021-05-25 81 0.00 2021-05-26 94 0.09 2021-05-27 87 0.01 2021-05-28 71 1.15 2021-05-29 52 0.58 2021-05-30 53 1.15 2021-05-31 76 T 2021-06-01 80 0.00 2021-06-02 79 T 2021-06-03 77 0.41 2021-06-04 83 0.19 2021-06-05 95 0.00 2021-06-06 97 0.00 2021-06-07 95 0.04 2021-06-08 93 2.19 2021-06-09 96 0.53 2021-06-10 85 0.00 2021-06-11 73 T 2021-06-12 72 T 2021-06-13 78 T 2021-06-14 78 0.16 2021-06-15 85 0.01 2021-06-16 81 0.00 2021-06-17 81 0.00 2021-06-18 88 0.00 2021-06-19 93 0.05 2021-06-20 91 0.00 2021-06-21 92 T 2021-06-22 80 0.17 2021-06-23 80 0.00 2021-06-24 79 0.00 2021-06-25 83 0.00 2021-06-26 86 0.07 2021-06-27 95 0.00 2021-06-28 99 0.00 2021-06-29 102 0.00 2021-06-30 103 0.54 2021-07-01 89 0.94 2021-07-02 81 1.53 2021-07-03 70 0.05 2021-07-04 84 0.00 2021-07-05 89 0.00 2021-07-06 97 0.55 2021-07-07 97 T 2021-07-08 88 0.08 2021-07-09 91 1.60 2021-07-10 86 T 2021-07-11 82 T 2021-07-12 93 0.69 2021-07-13 78 0.01 2021-07-14 93 0.07

91° at Newark and 90° at Caldwell. So they are both near the top of the list for 90° days by mid-July with 21. The observational record at Caldwell only goes back to 1999. Time Series Summary for CALDWELL ESSEX COUNTY AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Number of Days Max Temperature >= 90 Jan 1 to Jul 14 Missing Count 1 2021-07-14 21 1 2 2012-07-14 17 4 3 2020-07-14 14 0 - 2010-07-14 14 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Number of Days Max Temperature >= 90 Jan 1 to Jul 14 Missing Count 1 2010-07-14 23 0 2 1993-07-14 22 0 3 1994-07-14 21 0 - 1987-07-14 21 0 2021-07-14 21 0 4 1966-07-14 20 0

Looks like the usual warm spots will have chance at another heatwave next several days. The Euro has the 850s reaching +16c today and tomorrow with breaks of sun. The HRRR also shows 90° at the usual warm spots today. The Euro has 850s peaking near +18 C on Friday which support mid 90s if we can get enough sun. Humidity levels will be high with dew points back into the 70s. Today Friday

Updated for 3.46 in Ringwood, NJ. Station Number: NJ-PS-22 Station Name: Ringwood 3.0 SSE Observation Date 7/13/2021 8:30 AM Submitted 7/13/2021 8:36 AM Total Precip Amount 3.46 in.

A storm chaser did a great job documenting the water rescues in Bensalem, PA.

The warm front will come back north tomorrow with more 90° heat in the warm spots and widespread 70s dew points.

They were going to close the site in the early 1990s when the NWS moved. So maybe they made the trade off just to keep the site going. But how hard can it be to manage the tree growth around the ASOS? https://vlab.noaa.gov/web/nws-heritage/-/100-years-of-weather-observations-at-belvedere-castle-in-central-park http://www.weather2000.com/ASOS/NYC_ASOS.html

The big story is how much lower the sea ice extent is on this date than in 2013. That was the last time we had Arctic pressures nearly as low as this season so far. But as I noted in an earlier post, this season is much warmer on several fronts than 2013. The average pressure is the lowest since before the big 2007 shift. 1991 995.748 1992 993.569 1993 997.705 1994 989.170 1995 993.511 1996 993.554 1997 997.323 1998 999.264 1999 989.996 2000 991.390 2001 994.393 2002 991.603 2003 995.133 2004 998.124 2005 998.190 2006 989.570 2007 998.159 2008 995.824 2009 998.525 2010 996.097 2011 998.625 2012 996.246 2013 990.278 2014 997.406 2015 993.244 2016 992.118 2017 992.755 2018 992.805 2019 997.164 2020 992.695 2021 988.088

I am wondering if it would take a scientific journal article on the cooling of NYC summer high temperatures? We have shown on this forum how there has been a cooling since around 1990. Perhaps a well publicized scientific paper on how the quality of weather observations in our biggest city has been compromised would get the attention need for improvement.

They found the effect was greater on daily maximum temperatures than the minimums. Variability in daytime air temperature within the urban landscape averaged 3.5 °C (range, 1.1–5.7 °C). Temperature decreased nonlinearly with increasing canopy cover, with the greatest cooling when canopy cover exceeded 40%. The magnitude of daytime cooling also increased with spatial scale and was greatest at the size of a typical city block (60–90 m). Daytime air temperature increased linearly with increasing impervious cover, but the magnitude of warming was less than the cooling associated with increased canopy cover. Variation in nighttime air temperature averaged 2.1 °C (range, 1.2–3.0 °C), and temperature increased with impervious surface. Effects of canopy were limited at night; thus, reduction of impervious surfaces remains critical for reducing nighttime urban heat. Results suggest strategies for managing urban land-cover patterns to enhance resilience of cities to climate warming.

Yeah, that is probably the case. Recent studies have shown how much lower the temperatures are under an urban tree canopy. The older Central Park observations weren’t located under the canopy like they are now. So it’s no surprise that NYC had more 90° and 100° days back then. This recent study found significant temperature differences between open and forested parts of parks. The differences in Central Park summer high temperatures before 1990 and after seem to match their study. The paper in the link goes into more detail than the news article. The 1990 date is around the time that the canopy began to cover the observation site. https://www.ncel.net/2019/09/01/canopy-tree-cover-can-drastically-reduce-heat-island-effect/ Results: Researchers found an urban tree canopy of at least 40% results in the most cooling – as much as four to five degrees Celsius (seven to nine degrees Fahrenheit). Anything less than 40% canopy cover results in very small amounts of cooling. Since this threshold was previously unknown, researchers hope this will guide strategies for increasing tree cover. Trees are often planted in wealthier neighborhoods. Therefore, distributing planting to be more equitable can help to not only lower temperatures but also bring mental and physical health benefits to the community. Resources: Read the full study through PNAS.

This is probably our first mid-July backdoor pattern with such a strong ridge. In the past, these near record heights were associated with around 100° heat. So all the clouds, onshore flow, and rain are keeping temperatures significantly lower.

The regional signal from the models was very strong for a high end flash flooding event. But pinpointing the exact location is always going to be a challenge before the convection forms. NYC was able to add a 2nd hourly rainfall record in under a week. So the most extreme portion of the event occurred near the southern edge of the outlook zone issued earlier in the day by the WPC. https://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=519&yr=2021

It may be easier to do this at the airport since the ASOS units are placed on open grassy strips away from the paved surfaces. In the downtown parts of the city, it may be harder to find grassy areas away from buildings or pavement. So you can see how our only really compromised site is Central Park since it sits underneath trees.

Newark is accurate.This summer is an over the top heat pattern. So DCA to Philly is running cooler than points further north. Notice how Corona, Queens reached 103° like Newark at the end of June. The Caldwell station to the NW also has 20 days that reached 90° this year so far. Summer 2021 highs so far Boston…….100° Hartford…..99° LGA…….….100° Corona……103° Newark…..103° Philly……….97° DCA………..95° Time Series Summary for CALDWELL ESSEX COUNTY AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Number of Days Max Temperature >= 90 Missing Count 2021 20 172 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Number of Days Max Temperature >= 90 Missing Count 2021 20 172