bluewave

Though it’s not as extreme as we saw last year, models have the first dipole of the season in late July. So a reversal of the lower pressure pattern which has dominated the Arctic for the first half of summer. Several parts of the Arctic had near the lowest pressures on record for this time period. It’s a departure from recent years which had strong dipole patterns early and shifted to lower pressures later in the season.

It’s not surprising that we are tracking near the 2011-2020 mean in late July since it’s only 2021. The NSIDC site has the 10 year average September daily sea ice extent minimums. After big melt out years like 2012 and 2020, we have seen a bounce the following years. So it’s no surprise that we have recently fallen behind 2020. Just like 2013 had a nice rebound back above the 2012 lows. But the long term trend is downward which is probably the most significant feature which can get lost in the year to year noise. 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

JFK is on track for the first 6 year stretch of 10 or more days reaching a 75° or higher dew point. 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

Much of what you are getting at is determined by wind direction since we live on the coast. LGA essentially tied its 2010 JJA average high temperature last year. But since the flow was more onshore, JFK couldn’t. We finally got more westerly flow in June when Newark got the new all-time June high of 103°. Corona Queens also made to 103° away from the sea breeze. But the westerly flow couldn’t make it down to the coast. For westerly flow to make it to places like JFK and ISP, the ridge needs to centered over the Great Lakes and Ohio Valley. This summer has seen a spilt between the WAR and Rockies Ridge. The last several summers have featured a dominant WAR. This allows a much wetter pattern for higher humidity heat. So we have had numerous top 10 summers for heat and individual summer months since 2015. An all-time summer maximum high temperature generally requires a severe drought in the source region of the heat like Seattle just experienced. The last all-time summer max for us was the 108° at Newark in July of 2011. That historic heat originated over the record drought of the Southern Plains.

Updated for 4.30 at Hillside, NJ https://www.wunderground.com/dashboard/pws/KNJHILLS84/table/2021-07-17/2021-07-17/daily 4.30 in

Looks like the highest rainfall near NYC Metro was 4.30 at Hillside, NJ https://www.wunderground.com/dashboard/pws/KNJHILLS84/table/2021-07-17/2021-07-17/daily 4.30 in Also see a 6.11 to our west. Station Number: NJ-HN-58 Station Name: Flemington 2.9 ESE Observation Date 7/18/2021 7:00 AM Submitted 7/18/2021 7:53 AM Total Precip Amount 6.11 in. Notes -- Taken at registered location Yes Snow Information New Snow Depth NA New Snow Water Equivalent NA Total Snow Depth NA Total Snow Water Equivalent NA Duration Information Precipitation Began -- Precipitation Ended -- Heavy Precip Began -- Heavy Precip Lasted -- Duration Time Accuracy -- Additional Information Additional Data Recorded No Submitted 7/18/2021 7:53 AM Flooding --

We are on track for a cooler late July than the last few years. So the record heat at the end of June will hold as the warmest part of the summer so far. Tough to restart 100° heat once a pattern becomes so wet.

This is probably the 3 wettest Julys in a row that our area experienced. Notice how this is the 3rd top 10 wettest July since 2019 at BDR. Two consecutive years at Newark. Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Total Precipitation Missing Count 1 1971 12.84 0 2 1988 8.53 0 3 1960 8.13 0 4 2021 7.74 14 5 2019 7.57 0 6 1973 6.55 0 7 1984 6.54 0 8 1975 6.48 0 9 1950 6.29 0 10 2020 6.10 0 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 1996 8.27 0 6 1975 8.02 0 7 1938 7.96 0 8 1961 7.95 0 9 2021 7.80 14 10 1967 7.53 0 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 1897 9.56 0 4 2021 9.11 14 5 1928 8.89 0 6 1880 8.53 0 7 1919 8.50 0 8 1997 8.36 0 9 1960 8.29 0 10 1988 8.14 0

The flip from June to July has been especially dramatic in Boston. They had their warmest June on record. Now the average temperature in July is lower than June through the 16th. If Boston can stay cool enough next few weeks, then it will only be the 4th cooler July than June. Monthly Mean Avg Temperature for Boston Area, MA (ThreadEx) Click column heading to sort ascending, click again to sort descending. Year Jun Jul Season 2021 74.4 71.1 72.8 1976 73.4 72.9 73.2 1930 72.4 72.8 72.6 1994 71.9 77.5 74.7 1949 71.6 76.3 73.9 1957 71.3 74.1 72.7 2001 71.1 69.9 70.5

The SI mesonet picked up 1.05” in just 15 minutes. https://www2.nysmesonet.org/weather/meteogram#network=nysm&stid=stat

A wunderground site in Hillside,NJ has 3.12 so far. https://www.wunderground.com/dashboard/pws/KNJHILLS84/table/2021-07-17/2021-07-17/daily PRECIP RATE 1.72 in/hr PRECIP TOTAL 3.12 in

Yeah, it doesn’t take that big a departure anymore for a top 10 warmest summer. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature 91-20 Departure 1 1993 79.2 +3.5 2 2010 78.7 +3.0 3 1994 78.5 +2.8 4 2011 78.0 +2.3 5 2021 77.8 +2.1 - 2005 77.8 +2.1 6 1988 77.7 +2.0 7 2020 77.6 +1.9 - 2016 77.6 +1.9 - 1973 77.6 +1.9 8 1999 77.1 +1.4 9 1995 77.0 +1.3 10 2012 76.9 +1.2

The less warm pattern coming up may prevent Newark from getting 3 top 10 warmest Julys in a row. 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 2021 79.3 15

It’s the reason that EWR has 23 days of 90° and LGA only 14 through yesterday.

This is an odd looking departure map for July. Looks more like a spring backdoor pattern. Warmer west of NYC away from the onshore influence.

We should see a break in the heat after tomorrow during what is typically our hottest time of the year.

The HREF has another strong flash flooding and severe signal. But it will probably take a few more runs to pin down the exact locations. It has done very well with these general signals recently.

It gives new meaning to over the top heat. Time Series Summary for Dallas-Fort Worth Area, TX (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 99 169 Time Series Summary for Seattle Tacoma Area, WA (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 108 169 Time Series Summary for Portland Area, OR (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 116 169 Time Series Summary for Boise Area, ID (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 107 169 Time Series Summary for Billings Area, MT (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 105 169 Time Series Summary for Bismarck Area, ND (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 107 169 Time Series Summary for Boston Area, MA (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 100 169 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Year Highest Max Temperature Missing Count 2021 103 169

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