bluewave

Dewpoints above 80° in Canada set all-time record in Winnipeg.

The Euro has our warmest week in a while. Temperatures exceed 95° from Tuesday into the weekend. The usual warm spots could also reach 100° on the days with the highest temperatures.

Tropical airmass on Monday with PWATS over 2.00” and dewpoints in the mid 70s to fuel the convection.

DFW is almost tied on the list with 2011 for the most 100° days by July 17th. Time Series Summary for Dallas-Fort Worth Area, TX (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Number of Days Max Temperature >= 100 Jan 1 to Jul 17 Missing Count 1 1980-07-17 30 0 2 1998-07-17 25 0 3 2011-07-17 23 0 4 2022-07-17 22 0 5 1978-07-17 18 0 - 1953-07-17 18 0 Time Series Summary for Dallas-Fort Worth Area, TX (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 100 Missing Count 1 2011 71 0 2 1980 69 0 3 1998 56 0 4 1954 52 0 5 1956 48 0

There was also another recent paper published on the seasonality of Arctic warming.

DMI has a nice discussion about the summer Arctic temperatures near the North Pole since 2002. https://skepticalscience.com/DMI-data-on-Arctic-temperatures-Intermediate.html it seems that a cooling temperature trend in the Arctic summer is present, throughout the past approximately 10 years. Where 'summer' is defined as the period where the +80N mean temperature is above 273K. However, I very much doubt that a simple conclusion can be drawn from that, as there are complicating aspects to that analysis, e.g.: 1) The surface in the +80N area is more or less fully snow and ice covered all year, so the temperature is strongly controlled by the melting temperature of the surface. I.e. the +80N temperature is bound to be very close to the melt point of the surface snow and ice (273K) and the variability is therefore very small, less than 0.5K. I am sure you will find a much clearer warming trend in the same analysis applied to the winter period. The winter period is more crucial for the state of the Arctic sea ice, as this is the period where the ice is produced and the colder the winter the thicker and more robust the sea ice will become. 2) The +80N temperature data after 2002 are based on the operational global deterministic models at ECMWF, at any given time. Before 2002 the ERA 40 reanalysis is used. I.e. the +80N temperatures are based on 4 different models, the model used for the ERA 40 data set and the operational models T511, T799 and T1279. The point is that there can be a temperature bias in one or more of the models, that can cause the lower temperature level since approximately 2002. http://ocean.dmi.dk/arctic/meant80n_anomaly.uk.php

That one hour deluge got them closer to normal July rainfall since the XMACIS records began there in 2012. Monthly Total Precipitation for UPTON COOP - NWSFO NEW YORK, NY Click column heading to sort ascending, click again to sort descending. Year Jul Season Mean 4.22 4.22 2022 3.15 3.15 2021 6.48 6.48 2020 6.32 6.32 2019 2.97 2.97 2018 4.18 4.18 2017 3.22 3.22 2016 3.16 3.16 2015 1.34 1.34 2014 2.78 2.78 2013 4.26 4.26 2012 8.53 8.53

East Setauket was Long Island rainfall leader yesterday at 2.27”. Daily Precipitation Report Station Number: NY-SF-76 Station Name: Setauket-East Setauket 0.3 SSE Observation Date 7/17/2022 9:22 AM Submitted 7/17/2022 9:24 AM Gauge Catch 2.27 in. Notes --

The EPS temperature departure forecast for the rest of the month in °C would translate into at least +3 ° to 5° F across the area. So this means that several of our stations will finish with another top 10 warmest July. Since July is one of our fastest warming months, the bar for top 10 has been lowered when looking at the new warmer 1991-2020 climate normals. Below are the necessary departures for our local stations to reach top 10 warmest July average temperatures. The numbers to the right are the current departures ahead of the warm up. EWR…+2.2…..+3.4 NYC...+2.1…….+1.1 LGA….+1.4….+0.6 JFK…..+1.9…..+1.5 HPN….+2.0…..+1.5 ISP……+0.9…..+0.2 BDR….+1.3……+0.2

Radar estimates of 2.00 inch rainfall amounts where the best training set up today.

Short dry patterns have been the rule with our much warmer SSTs and higher dewpoints. The SSTs were much cooler for the last significant drought in 1999-2002. The 500 year drought in the 1960s had very cold SSTs.

An average July at LGA is 79.2 with the new much warmer 1991-2020 climate normals. That new normal is the 17th highest temperature recorded for July. So it puts 2022 currently at 14th warmest with less than a +1 departure so far. LGA will only need a +1.4 departure by the end of the month to make it into the top 10 warmest. So while departures are useful for recent temperature comparisons, they don’t really work well for comparisons to our climate before 2010. https://www.ncei.noaa.gov/access/us-climate-normals/#dataset=normals-monthly&timeframe=30&location=NY&station=USW00014732 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 +3.7 2 2010 82.8 0 3 1999 81.9 0 4 2019 81.5 0 5 2013 81.2 0 6 2016 81.1 0 7 1955 80.9 0 8 1966 80.8 0 9 2006 80.7 0 10 1994 80.6 +1.4 11 2012 80.4 0 - 2011 80.4 0 - 1952 80.4 0 12 2008 80.0 0 - 1993 80.0 0 13 2018 79.8 0 - 1995 79.8 0 14 2022 79.6 15 2002 79.5 0 16 1949 79.4 0 17 2015 79.2 Normal

The higher dewpoints and mid 70s SSTs are doing their job. Some spots have picked up over 1.00” this morning. We’ll probably see more widespread convection in the coming days.

Yeah, the usual warm spots around the region on the Euro make a run on 100°. Even the Long Island North Shore goes over 95°. But the highest dewpoints should be closest to the coast.

Next week looks like and unusual similarity between our pattern and the one in the UK. Both heatwaves are getting an assist from a closed low to the west pumping in the heat from a drought region. While the one in the UK can deliver all-time heat, parts of our area may approach 100°. These type of concurrent heat waves are becoming more common. 850 mb temperatures in excess of +20C in both regions

The Euro is going for 15 named storms with the bulk of the activity from the Gulf to the Carolinas near the warmest SST anomalies.

Unfortunately, that’s always the case with their maps. But we can use XMACIS2 for the individual stations. The sea breeze has kept the maximum temperatures down on Long Island so far. Places like White Plains and Danbury are having one of their warmest Julys for maximum temperatures. The Danbury record is shorter starting in 1998. Time Series Summary for DANBURY MUNICIPAL AP, CT Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Max Temperature Jul 1 to Jul 14 Missing Count 1 2010-07-14 87.3 0 2 2012-07-14 86.8 0 3 2022-07-14 86.0 0 4 2018-07-14 85.5 0 5 1999-07-14 85.0 5 Time Series Summary for WESTCHESTER CO AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Max Temperature Jul 1 to Jul 14 Missing Count 1 1966-07-14 91.8 0 2 2012-07-14 88.3 0 3 2010-07-14 88.0 0 4 1993-07-14 87.6 0 5 1955-07-14 86.9 0 6 2018-07-14 86.4 0 7 2022-07-14 85.9 0 - 1994-07-14 85.9 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Max Temperature Jul 1 to Jul 14 Missing Count 1 1966-07-14 90.9 0 2 2010-07-14 87.8 0 3 1993-07-14 87.1 0 4 1999-07-14 86.9 0 5 2012-07-14 86.6 0 6 2019-07-14 86.5 0 7 1994-07-14 86.0 0 8 1974-07-14 85.7 0 9 2011-07-14 85.6 0 10 2018-07-14 84.7 0 - 2002-07-14 84.7 0 11 2013-07-14 84.4 0 12 2020-07-14 84.1 0 13 2014-07-14 83.6 0 - 1997-07-14 83.6 0 14 2022-07-14 83.5 0

The coming higher dewpoints will allow the minimum temperature departures to catch up to the warmer maximum departures.

The EPS, GEFS, and GEPS all begin to finally weaken the blocking pattern during the 2nd half of July. So the 50/50 low confluence that has been keeping us dry is set to relax. This means the 2nd half of July will be wetter than the 1st half. It continues to look like several surges of 95°+ heat between July 20th and 31st. The local warm spots may be able to make a run on 100°.

Sea breeze fronts usually start producing for the South Shore when the SSTs reach the mid 70s south of Long Island. NY Harb Entrance 2050 74 20 S Fire Island 2050 74 Great South Bay 2030 23 SSW Montauk P 2050 15 E Barnegat Li 1956 76

The climate models predict a local cooling effect near Northern Greenland and the Central Arctic during summers later in the century. This may be related to a weakening AMOC. But the Northern Hemisphere land masses continue to warm. The provided link below has a very interesting recorded presentation on the topic. So the Arctic may still have some summer sea ice north of Greenland and the Canadian Archipelago later this century. https://ams.confex.com/ams/94Annual/webprogram/Paper235210.html https://ams.confex.com/ams/94Annual/videogateway.cgi/id/25848?recordingid=25848 Tuesday, 4 February 2014: 11:30 AM Room C101 (The Georgia World Congress Center ) Stephen J. Vavrus, University of Wisconsin, Madison, WI; and J. Francis Recorded Presentation Climate models typically simulate enhanced heating and pronounced drying during summer over mid-latitude continental regions of the Northern Hemisphere under greenhouse forcing. Various plausible explanations have been offered for this response, including strengthened land-sea temperature contrasts, favorable SST patterns, and locally depleted soil moisture. Changes in the large-scale atmospheric circulation have also been proposed, but these have generally been regarded as secondary mechanisms originating in low and middle latitudes. Here we present an alternative perspective, by proposing that a major reason for the mid-latitude continental response is an atmospheric circulation change that is regulated by high-latitude processes. Based on an analysis of the RCP8.5 scenario in the Community Climate System Model (CCSM4), we find that the amplified heating ( > 7 K) and drying ( > 20%) of the U. S. Great Plains during summer stems from a shift toward locally weakened westerlies aloft and somewhat stronger northerlies. This circulation change is directly tied to enhanced ridging to the north of the region that is part of a nearly hemispheric-wide band of ridging in high latitudes extending from Eurasia across North America. This band of maximum geopotential height increases aloft is well correlated with the location of greatest summertime snow cover loss in northern Siberia and North America. The circulation pattern appears to be further modulated in high latitudes by residual sea ice coverage around the Canadian Archipelago and by a weakening of the Atlantic Meridional Overturning Circulation. Both of these changes promote troughing locally around northeastern Canada and thus a southward displacement over North America of the high-latitude ridging band to a location where its outflow favors drier and hotter conditions in the continental interior. The resulting circulation shift affects not only the mean summertime climate but also sets up very suitable synoptic conditions for extreme weather events in the form of droughts and heat waves.

It all comes down to how much blocking we get. The La Niña influence during the winter is a SE Ridge/WAR pattern. The 20-21 La Niña featured strong blocking that merged with a piece of the WAR east of New England.This allowed 40”+ at Newark. Last winter the SE Ridge/WAR was the dominant pattern. So only parts of Long Island had record January snowfall with the progressive +PNA +AO. The 17-18 La Niña had more blocking than 16-17 so it was snowier. 11-12 was a disappointment since the +EPO ran the table. Our last La Niña when the blocking erased the SE Ridge influence was 10-11 with 60”+ at Newark in just 33 days. It was also the last time we had a cold La Niña winter.

We got officially included in the D0 dry category today.

Yeah, this La Niña background state has been on steroids since the super El Niño . July temperature departures across the area would probably be +3 to +5 at all local stations if the blocking wasn’t suppressing the La Nina ridge to our SW. Those big departures are setting up over the Plains. But we are getting a dry NW flow aloft between the block and 50/50 low.

Lowest dewpoint July so far at JFK since before the super El Niño. 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&_r=t&dpi=100&_fmt=png