bluewave

First July at JFK with an average dewpoint above 70 degrees. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=76&network=NY_ASOS&station=JFK&season=jul&varname=dwpf&year=1893&hours=0-23&dpi=100&_fmt=png 115 degrees in 1999 and 2011. JFK made it to 114 this July. Also numerous hourly dewpoint record highs and ties. So a continuation of the unprecedented dewpoint surge since 2016. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=153&network=NY_ASOS&zstation=JFK&month=all&var=max_feel&dpi=100&_fmt=png    

At least for the time being, the harshest melting conditions are focused over Greenland. NSIDC had a very small drop yesterday of 44k down to 6.192. It maintains a narrow lead over 2012 of 176k which was at 6.368. August 1-11, 2012 experienced the record breaking decline down to 5.021. This year would require an average daily decline rate of 106k to keep pace by August 11th.

https://mobile.twitter.com/xavierfettweis/status/1156848174599942144 1/4 The last MAR based numbers for the current heat wave over Greenland are 31-JUL: Record of ice sheet temperature! T2m=+0.55°C (vs -0°C in 11-JUL-2012). Anomaly:6.8°C 01-AUG: Record of ablation rate (minimum SMB)! -12.5 GT/day (vs 11.7 in 2012) https://mobile.twitter.com/xavierfettweis/status/1156848178819411975 2/4 31-JUL: melt extent (2nd record) -> using 5 mm/day as melt threshold as on my Fig5: 61% (vs 79% in 2012) -> using 1mm/day as HARMONIE on @PolarPortal : 81% (vs 97%) -> using 0.1mm/day: 90% (vs 99%) 31-JUL: meltwater production (2nd record) 24Gt/day (vs 26 in 2012)

July was another top 10 warmest around the area. 7...2019....EWR...7.....NYC..10...LGA...3....JFK....4....BDR...3.....ISP...2

Continuation of the July 2010’s above normal temperature departures 80% to 90% of the years. EWR....8 out of 10 years above normal NYC....9 out of 10 years above normal LGA....9 out of 19 years above normal  July......EWR....NYC...LGA 2019....+3.2....+3.1.....+4.1 2018....+0.8....+1.1.....+2.4 2017....-0.1.....+0.3.....+0.7 2016...+2.5.....+2.2.....+3.7 2015...+1.6.....+2.3.....+1.8 2014....-0.4.....-0.4.......-0.4 2013....+3.5...+3.3......+3.8 2012....+3.4...+2.3......+3.0  2011....+5.3...+3.7......+3.0 2010...+4.9....+4.8......+5.4 https://mobile.twitter.com/Climatologist49/status/1126293596909367301

Boston gusted to 74 mph.

Looks like a peak gust to 53 mph with the warmed cell at the SI mesonet. http://www.nysmesonet.org/data/meteogram#?stid=STAT

NSIDC extent is only 163k above 2012 as of 7-30. 7-30-19...6.237 7-30-12....6400 2019 needs to increase the decline rate next 10 days in order not to fall below 2012 on August 9th. The average daily decline rate last 10 days was 81k. This year would need an average 115k daily to keep up with 2012 over the next 10 days. 8-9-12.....5.088 9-16-12...3.340....lowest daily September minimum on record The area is tracking a bit behind 2012 as of 7-30.

Discuss...

Top 3 warmest July for many of our stations through July 30th. Boston is on track for a new warmest July on record. 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 2012 80.8 0 - 1999 80.8 0 7 2019 80.7 1 Time Series Summary for WESTCHESTER COUNTY AP, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1999 78.5 1 2 2013 77.0 0 - 2010 77.0 0 3 2019 76.8 1 Time Series Summary for LA GUARDIA AP, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2010 82.8 0 2 1999 81.9 0 3 2019 81.6 1 Time Series Summary for JFK INTL AP, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2010 80.7 0 2 2011 79.8 0 3 2013 79.5 0 4 2019 78.8 1 Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 1999 78.6 0 2 2019 78.1 1 3 2013 78.0 0 Time Series Summary for IGOR I SIKORSKY MEMORI AP, CT - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2013 78.5 0 2 1994 78.4 0 3 2019 78.3 1 Time Series Summary for Boston Area, MA (ThreadEx) - Month of Jul Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Missing Count 1 2019 78.5 1 2 1983 78.0 0 3 1994 77.5 0

Wind damage report from the earlier North Shore storms. Hail report from News12 https://mobile.twitter.com/iembot_okx/status/1156289066771603456 At 1:53 PM EDT, Rocky Point [Suffolk Co, NY] PUBLIC reports TSTM WND DMG. TREES DOWN ON ROCKY POINT BUSINESS DISTRICT BYPASS. https://mobile.twitter.com/pcavlin/status/1156262345041223682 Impressive hail from a storm in Rocky Point this afternoon taken by Susan Blake

https://mobile.twitter.com/mikarantane/status/1156248654883229697 Weather balloon released from Danmarkshavn, #Greenland E-coast (77°N) recorded today 850 mb temperature of 14.4°C, which is their all-time record high. 500 mb geopotential height was 5860 gpm, which is also a new record. Soundings began in 1950. https://mobile.twitter.com/mikarantane/status/1156258216575213573 This warmth in Greenland originates from Europe. The blocking high located last week in Scandinavia has propagated west and dragged the hot air mass along with it towards Greenland.

EWR and LGA made it to 95 just before the thunderstorms and clouds moved in.

The sea breeze front from the ocean often runs up to the North Shore and meets the convergence zone where the local winds are more NW. Stony Brook gusted to 30 mph with a quick .35. You can see the CU field along the sea breeze front starting out near ISP a few hours back. The convection developed when it reached the local sound breeze.

Heavy thunderstorms are firing now along the sea breeze front in the North Shore of Suffolk.

Summary of key findings: https://andthentheresphysics.wordpress.com/ There are some who argue that natural/internal variability can play a role in driving long-term warming, and – hence – could explain a substantial fraction of recent warming. This, however, creates a bit of a paradox; if the system responds strongly to internally-driven warming, then it should also respond strongly to externally-driven warming. Consequently, we’d expect climate sensitivity to be high which would then make it difficult for a large part of our recent warming to be due to natural/internal variability. Credit: Figure 1b from Nijsse et al. (2019). The reason I thought I’d mention this again is that I came across a recent paper by Femke Nijsse and colleagues that consider this issues. The paper is called Decadal global temperature variability increases strongly with climate sensitivityand the title pretty much gives away the punch-line. The paper shows that models that are more sensitive to GHGs emissions (that is, higher equilibrium climate sensitivity (ECS)) also have higher temperature variability on timescales of several years to several decades, which is illustrated in the figure on the right. The paper also points out that and consequently, that So, rather than the supposed slowdown being an indication of a low climate sensitivity, it could well imply the opposite. The paper then concludes that Full paper: https://www.nature.com/articles/s41558-019-0527-4.epdf?author_access_token=J-KyNPgaJjxqrOa7xDZqZdRgN0jAjWel9jnR3ZoTv0OBndQURhCsdUJ8UFlXX4uk6-ZhfEDlQ1ZVbSTbVVkwvTm8iW6Edp92vOc-lxlZOU0EYxumMyxUwh_xP8lBAiYB3-N-mPkH8GtRI4DbWmndkA%3D%3D Abstract Climate-related risks are dependent not only on the warming trend from GHGs, but also on the variability about the trend. However, assessment of the impacts of climate change tends to focus on the ultimate level of global warming1, only occasionally on the rate of global warming, and rarely on variability about the trend. Here we show that models that are more sensitive to GHGs emissions (that is, higher equilibrium climate sensitivity (ECS)) also have higher temperature variability on timescales of several years to several decades2. Counter-intuitively, high-sensitivity climates, as well as having a higher chance of rapid decadal warming, are also more likely to have had historical ‘hiatus’ periods than lower-sensitivity climates. Cooling or hiatus decades over the historical period, which have been relatively uncommon, are more than twice as likely in a high-ECS world (ECS = 4.5 K) compared with a low-ECS world (ECS = 1.5 K). As ECS also affects the background warming rate under future scenarios with unmitigated anthropogenic forcing, the probability of a hyper-warming decade—over ten times the mean rate of global warming for the twentieth century—is even more sensitive to ECS.

115 degrees in 1999 and 2011. JFK made it to 114 this July. Also numerous hourly dewpoint record highs and ties. So a continuation of the unprecedented dewpoint surge since 2016. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=153&network=NY_ASOS&zstation=JFK&month=all&var=max_feel&dpi=100&_fmt=png

Looks like LGA tied the record high minimum temperature of 81 degrees. http://wxweb.meteostar.com/meteogram/link.shtml?choice=Klga

It looks like the old thermometer was located on the castle in the sunlight before the 1990’s. That’s why NYC had more 90 days before the 1990’s than after. High temperatures on the castle were often warmer than LGA and very close to Newark. But putting the thermometer under the thick canopy and vegetation around November 95 caused an artificial decline in high temperatures. So we really can’t compare pre-1995 temperature data with post. Here is another NYT article about when the thermometer in the castle got vandalized in 1977. They had to start taking temperatures at LGA for a while. https://www.nytimes.com/1977/12/31/archives/castle-is-secure-but-weathermen-are-still-moving.html Vandals’ destruction of equipment in the castle had disrupted the Weather Service's collection of meteorological data so frequently that the service had decided not to bother with repairing the station after a particularly severe incident of vandalism two months ago, Instead, the service took all its temperatures at an alternative station at La Guardia Airport in Queens,

87/75/96 now at JFK. Another day with the dewpoints beating guidance. http://wxweb.meteostar.com/meteogram/link.shtml?choice=Kjfk

This is what happens when you get the strongest Pacific Northwest Jet streak on record for the entire warm season. It pumps the ridge over the Northeast.

Several of our stations are in the top 3 warmest Julys on record through the 28th. Temperature departures are running +2.9 to +4.3. Large area of +3 to +5 from around Chicago to Boston this July. EWR...+2.9 NYC....+2.8 LGA.....+3.7 JFK......+2.9 ISP.......+4.3 BDR.....+3.7

Another day that the dewpoints beat guidance. Miami dewpoints returned to the South Shore. JFK is at 75 and Wantagh 74. http://www.nysmesonet.org/mesonow#?stid=WANT Dewpoint: 74 °F http://wxweb.meteostar.com/meteogram/link.shtml?choice=Kjfk

Big dewpoint spread between North Shore and South Shore today. JFK feels warmer than LGA due to the much higher dewpoint. Kennedy Intl FAIR 86 73 65 S17 30.06F HX 93 LaGuardia Arpt FAIR 92 58 31 SW14G21 30.03F HX 91

7-27-19 has a narrow lead of 214k over 7-27-12 for NSIDC extent. 2019 needs to maintain an average daily drop rate of 106k next 13 days in order not to fall behind 2012. This first 9 days of August was when 2012 experienced the record breaking decline. There was a 3 day interval with over 500k of losses during the deep Arctic storm. So it may be tough to catch up with 2012 later in the season if 2019 falls much behind next few weeks. We’ll see how it goes. 7-27-19...6.463 7-27-12...6.677 8-9-12.....5.088 9-16-12...3.340....lowest daily September minimum on record