bluewave

The northeast is very fortunate that we haven’t seen a warm season ridging event yet reach the magnitude above all previous seasonal climatology as 2-20-18 did when parts of the Northeast reached 80° for the first time in winter. This was a full 4°-5° degrees warmer than any previous winter day. Such a jump above past summer warmth would result in areas of the Northeast reaching or exceeding 110°. The Pacific Northwest heatwave of a few years ago exceeded their previous all-time highs by around 5° to 8°. So while we have seen numerous warm season heat and 500mb records in recent years, they have paled in comparison to what has happened during the cold season in the past decade. December 2015 going +13.3° in portions of the Northeast was one of the most extreme cold season departures relative to past climatology experienced anywhere in the U.S. That December finished around 50° near NYC which was warmer than many Novembers have been at around the 15th warmest November. We have had 9 warmer than average to record warm winters in a row. While the summers have been impressive also, it has been 7 out of 9 above normal to record warm.

Top 3 warmest June across whole area. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 1994 77.8 0 2 2024 77.5 0 3 2021 76.2 0 - 2010 76.2 0 4 1993 75.8 0 5 1943 75.4 0 Time Series Summary for WESTCHESTER CO AP, NY - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2024 71.9 0 2 2010 71.4 1 3 1999 71.3 1 - 1957 71.3 0 4 2005 70.9 2 5 2008 70.8 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 1943 76.4 0 2 2024 76.1 0 3 2010 76.0 0 4 2020 75.9 0 5 2008 75.7 0 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2010 74.5 0 2 1984 73.9 0 3 2024 73.8 0 4 2008 73.4 0 5 2001 72.5 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2024 72.0 0 2 2010 71.9 0 - 1999 71.9 0 3 2008 71.6 0 4 1994 71.3 0 5 2001 70.9 0 Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2024 72.6 0 2 2008 72.2 0 3 2010 71.8 0 4 1994 71.7 0 5 1957 71.6 0 Time Series Summary for NEW HAVEN TWEED AP, CT - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2024 72.9 0 2 1976 71.4 0 3 2021 71.3 0 4 2010 71.0 0

Comfortable start to July with lows in the 40s for the interior Northeast. So we get a break from the major 95°+ heat and very high dew points for a few days.

This was very cool here in Southern CT. I was under that anvil when it was getting side illuminated by the setting sun. It remained overcast here and everything outside turned a beautiful golden color. You can see the effect along the western edge of the anvil on the satellite pseudo-color feature.

1.82” appears to be the 2nd heaviest June hourly rainfall at SMQ since the records began in 1999 and 4th overall. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=155&network=NJ_ASOS&zstation=SMQ&var=max_p01i&w=all&threshold=100&hour=12&sdate=0101&edate=1231&month=all&_r=t&dpi=100&_fmt=png

These were some of the highest dew points there I can remember this early in the season. https://www.weather.gov/wrh/timeseries?site=KSMQ&hours=72 Jun 30, 3:40 pm 88 79

SNJ was the jackpot zone today for the heaviest rainfall with the record dew points. Areas got over 6.00” of rain today while recording under 1.00” from June 1st to 29th. So the month will finish with well above normal rainfall in those areas. A continuation of the heavy rains at the end of dry patterns being more impressive than the dry patterns were.

I have been getting the heavy downpours here just east of HVN but the severe has been to my north this month.

What was interesting about the 09-10 and 10-11 winters is that the record Atlantic blocking developed during June and July of 2009 and carried over into early 2011. The record NE Pacific blocking also developed in June and July of 2013 and carried into early 2015. Someone should do an in depth study as to why the winter patterns emerged during the summer first. Plus to set records for NE Pacific and Atlantic blocking from 2009 to 2015 so close together was very impressive. All-time snowfall records were set in this period from DC to Philly and Boston. NYC and Long Island couldn’t rival 95-96 since the snowfall ended too soon near the end of January in 2011.

Very obvious error since there is no way Phoenixville would ever have that many more 95° days than Baltimore. The most 95° days Baltimore had during that period was 19 in 1931. Time Series Summary for Baltimore Area, MD (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 1931 19 0 2 1941 18 0 3 1944 17 0 4 1930 16 0 5 1943 14 0 - 1934 14 0

3rd highest June dew point on record here at KHVN. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=155&network=CT_ASOS&zstation=HVN&var=max_dwpf&w=all&threshold=100&hour=12&sdate=0101&edate=1231&month=jun&_r=t&dpi=100&_fmt=png

Plenty of fuel for the severe storms today as JFK just tied its all-time highest June dew point of 75°. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=155&network=NY_ASOS&zstation=JFK&var=max_dwpf&w=all&threshold=100&hour=12&sdate=0101&edate=1231&month=jun&_r=t&dpi=100&_fmt=png

Some of the recent studies found that it was a coincidence and others not. Just a coincidence https://news.climate.columbia.edu/2019/01/22/debunking-solar-cycle-north-atlantic-winter-weather-connection/ Some signal possible in February https://acp.copernicus.org/articles/22/7893/2022/

Most unstable sounding of 2024 so far with over 4000 CAPE forecast around lunchtime. Also the highest dew points around 78°. So storms should quickly become severe with torrential downpours which such high moisture content.

They didn’t find much relation to the low sunspots in the paper. suggesting that the unusually low solar activity contributed little, if any, to the observed NAO anomaly during the 2009/10 winter. 17] The origin and predictability of the extremely negative phase of the NAO during the winter of 2009/10 have been explored by means of numerical experimentation. Different possible forcing mechanisms have been tested such as El Niño, the QBO, and reduced solar insolation. However, none of the forcings considered in this study was able to reproduce the negative phase of the NAO, especially in terms of its magnitude. The results of this study, therefore, support the hypothesis that both the development and persistence of negative NAO phase resulted from internal atmospheric dynamical processes. This may explain why most operational seasonal forecasting systems had problems in predicting the negative NAO winter when started in late autumn (e.g., forecasts issued in October and November 2009). The results of this study suggest that internal atmospheric dynamics are an important source of low-frequency atmospheric interannual variability [see also James and James, 1989] including extreme atmospheric circulation anomalies. Furthermore, this study suggests that internal atmospheric dynamics are able to produce extremely persistent atmospheric circulation anomalies which are associated with substantial extended-range predictive skill. From a dynamical point of view it will be interesting to better understand the processes responsible for the persistence of the negative NAO throughout most of the 2009/10 winter.

My is guess is that 10-11 was more about the 150 year -NAO event lingering from the previous year than it was about the La Niña. That historic blocking pattern began during the 09 summer with one of the coolest June-July periods on record around NYC. It carried through the 09-10 winter and reversed in early February 11. So it’s unlikely that we ever see the 09-10 all-time snowfalls in the Mid-Atlantic surpassed during an El Niño or any other ENSO state. Same goes for over 60” of snow in only 33 days around NYC in 10-11 during a La Niña or any other ENSO state. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL046786 The winter of 2009/2010 was one of the most negative winters of the North Atlantic Oscillation (NAO) during the last 150 years. While most operational extended-range forecasting systems had difficulties in predicting the onset of the negative NAO phase, once established, extended-range forecasts were relatively skilful in predicting its persistence. Here, the origin and predictability of the unusual winter of 2009/10 are explored through numerical experimentation with the ECMWF Monthly forecasting system. More specifically, the role of anomalies in sea surface temperature (SST) and sea ice, the tropical atmospheric circulation, the stratospheric polar vortex, solar insolation and near surface temperature (proxy for snow cover) are examined. None of these anomalies is capable of producing the observed NAO anomaly, especially in terms of its magnitude. The results of this study support the hypothesis that internal atmospheric dynamical processes were responsible for the onset and persistence of the negative NAO phase during the 2009/10 winter.

At least some measurable rainfall which was the case going back to March 1st.

We are back to the rain on weekends theme since March 1st after a brief break.

The only preseason metric which has worked for all La Ninas since 2010 has been the October early MJO indicator. This has helped out with the snowfall potential. But every La Niña since 11-12 has been warmer than average here in the Northeast.

We are probably better off using the SSTs west of the Dateline in the tropics and subtropics rather than what is happening in the official Nino regions. It seems to me the WPAC warm pool has been driving the bus since 15-16. The RONI has been trying to do this but it still feels incomplete to me. Since the MJO in the 4-7 regions has become so dominant regardless of El Niño, La Niña, or neutral.

After the really comfortable dew points on Friday ,we are headed for our first mid 70s dew points of the season on Sunday. This will push the HX into the upper 90s in NJ. Some spots may approach a 100 HX.

It looks like the -PDO has been driving the strong La Niña background state with the 100° June heat we have just seen in the East. As the actual La Niña has been slower out of the gate than usual. May be related to the ongoing record marine heatwaves slowing the drop in SSTs east of the Dateline. But as long as the -PDO is so negative, we are getting a very strong La Niña background state regardless of what happens east of the Dateline. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Jun Click column heading to sort ascending, click again to sort descending. 1 2021 103 La Niña 2 2011 102 La Niña - 1994 102 El Niño - 1993 102 Neutral - 1952 102 Neutral - 1943 102 7 1988 101 El Niño to La Niña - 1966 101 El Niño to La Niña 9 2024 100 El Nino to La Niña - 1959 100 El Niño to neutral - 1953 100 El Niño - 1934 100

The best the PDO has been able to do has been a rise back to around -1.5 before dropping again to the -2 to -3 range.

It felt great today. Quick turnaround for weekend with parts of area challenging the all-time PWAT record for June near 2.5”.

The record breaking 500 mb heights and surface high pressures just keep coming out there.