bluewave

I will update it when the verifying numbers come in but the colder groupings were near or stronger than +3. That being said, it’s just one potential indicator and no guarantee it will workout again. Just something to keep in mind. October 2022…Phase 6 peak +2.177…..ONI….-1.0 October 2021….Phase 5 peak +2.087….ONI….-1.0 October 2020…Phase 5 peak +2.818….ONI…..-1.3 October 2017….Phase 6 peak +3.353….ONI….-1.0 October 2016….Phase 5 peak +1.800….ONI….-0.7 October 2011….Phase 6 peak +1.674….ONI….-1.1 October 2010….Phase 5 peak +2.880…ONI…..-1.6 Latest daily value http://www.bom.gov.au/climate/mjo/#tabs=Monitoring 5 2.3287644

Feels cooler than it usually does approaching 80° with the very low dew points and humidity. Newark/Liberty MOSUNNY 77 35 21

We have a shot at the driest October on record especially if the late month 590 DM Southeast Ridge verifies.

The forcing will be on the move so may not spend much time in phase 8.

Probably one of the strongest AO rises we have ever seen in October as the AO and NAO volatility has been off the charts in recent years.

Sometimes there is a lag and other times it’s almost instant. The lags can be longer when the AO needs to shift like we saw earlier this month since it has more moving parts. But when forcing shifts to near South America and Mexico a trough can pop up out West relatively quickly.

The actual forcing is forecast to be closer to 8 the end of the month with strong subsidence over the Maritime Continent.

Yeah, this is why we are forecast to get such a deep -PNA trough in the West later in the month. It’s one of the few times of the year when the MJO 8 is this warm. Especially combined with La Niña and -PDO.

Yeah, this is one of the few times of the year with a La Niña and -PDO that a MJO 8 is so warm in the East.

At least the 80° heat will feel more comfortable with such low dews and humidity. We would probably be talking 95-100 if this was back during the summer. But this should allow the vegetation and soil moisture to dry out further with future drought monitor updates.

Looks like the 2nd and 3rd greatest October daily temperature range for your area back to 1997. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=139&network=NY_ASOS&zstation=MGJ&v=largest&month=oct&_r=t&dpi=100&_fmt=png

The warming this fall is even exceeding Hansen’s predictions. So this may be a signal that this record warming is going beyond just aerosol reductions like Schmidt recently mentioned. It will be interesting to see how long the global temperatures hold in above the +1.5. https://mailchi.mp/caa/the-world-will-cool-off-a-bit-and-other-good-news The relatively “cooler” period that should be ushered in by September this year, i.e., the period in which global temperature remains lower than its present +1.6°C peak, may last a few years.

At least this happened after the peak of the warm season. 2022 was the 2nd driest summer on record at Newark. It allowed them to go into 3rd place for most 100° days. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jun through Aug Click column heading to sort ascending, click again to sort descending. 1 1966 4.46 0 2 2022 4.87 0 3 1949 5.68 0 4 1957 5.69 0 5 1965 5.83 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. 1 1993 9 0 2 1949 8 0 3 2022 6 0 - 1953 6 0 5 1988 5 0 - 1966 5 0

The GFS is the only operational model that runs beyond 240 hrs. The other models have a control run and an ensemble mean. So we use the ensemble means to put together a long range forecast. But even the ensemble means have had a cold bias in the long range. The GFS is prone to fantasy snowstorms after 240 hrs but the ensemble mean doesn’t have this error. Remember in recent winters how the big snowstorm was always 2 weeks away on the GFS OP. So this is why we use ensemble means in the long range. New run 60s to possible 70s near the end of the month when the average high is only around 59°. More in line with the EPS and GEFS. Old run fantasy snowstorm

That GFS OP is a big outlier among its ensembles.

Newark only needs another week for the new longest run without measurable rainfall. Number of Consecutive Days Precipitation < .01 for Newark Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 26 1949-06-24 2 25 1939-11-30 3 24 1995-09-08 - 24 1980-02-15 - 24 1963-10-27 - 24 1959-09-27 - 24 1942-05-05 4 23 1991-11-09 5 22 1941-10-02 6 21 2023-11-20 - 21 2000-11-08 - 21 1985-11-03 - 21 1968-10-02 - 21 1935-05-28 7 20 2001-05-11 - 20 1999-06-13 8 19 2024-10-18

Yeah, the near record low dew points and humidity give the usual spots a boost in the radiational cooling department on mornings like this. https://forecast.weather.gov/product.php?site=BTV&issuedby=BTV&product=AFD&format=CI&version=1&glossary=1&highlight=off It`s also notable just how dry the airmass is, with Whiteface`s dewpoint of -13F.

It’s tough to get sustained cold any time of the year these days when what was originally forecast to be a modest ridge a few weeks ago expanded into a near record 591 dm ridge. Old forecast Verification

My guess is that the extreme AO shift this month is related to that nearly off the charts burst of forcing in the IO. It’s short term changes like this which can be tough to access much ahead of time due to the competing marine heatwaves across the tropics right now. It goes to the how extreme polar domain volatility has become over the last decade.

Yeah, there were hopes that the relationship prior to 14-15 would work out for the 16-17 winter. But the extensive fall Siberian snow cover strengthened the Pacific Jet instead. So after 14-15 and 16-17 it hasn’t really been used as much. https://www.aer.com/science-research/climate-weather/winter2017/ Summary Winter 2016/17 was characterized by warmth in Central and Eastern North America, Northern Europe, Central and East Asia but cold in much of Europe, the Middle East and Siberia. The dominant story in the fall was extensive October Siberian snow cover that resulted in very cold temperatures across Northern Asia in November. The strong temperature gradient across Asia provided fuel for a strong North Pacific Jet Stream that cooled sea surface temperatures in the mid-latitudes of the North Pacific. The strong sea surface temperature (SST) gradient in the mid-latitudes of the North Pacific maintained an active Jet Stream into the West Coast of the United States (US) resulting in cool temperatures and record rainfall along the US West Coast but flooded the rest of North America east of the Rockies with mild, maritime air. Low sea ice in the Barents Kara seas helped anchor high pressure in the region, especially Northern Europe, for much of the winter. Northeasterly flow around the high pressure, especially in January, resulted in an overall cold winter for Europe except near the center of the high across Northern Europe. Analysis of the relationship between warming in the Barents-Kara Seas and surface temperatures across the Northern Hemisphere (NH) suggest the record low sea ice in the Barents-Kara seas may have contributed to warm temperatures both across Northern Europe and the Eastern US. Extensive Eurasian snow cover and low Arctic sea ice in October contributed to an early and strong Siberian high that favors a weak polar vortex. However the most impressive polar vortex weakening and subsequent coupling with the troposphere took place in the fall followed by a relatively strong polar vortex and a positive Arctic Oscillation (AO) in mid-winter. This contributed to front ending cold temperatures with the back end relatively mild across the NH. There was a brief major mid winter warming (wind reversal at 60°N and 10 hPa) in early February but its impact was relatively minor and short lived in the troposphere. It is possible that the westerly phase of the quasi-biennial oscillation played a role in reducing the strength and duration of the major warming and its impact on the weather.

Wouldn’t be that big of a surprise since November and March have been warmer during the 2020s than they used to be back in the 2010s when those were pretty reliable cold months. Newark NOV…23….-0.4 NOV...22….+4.0 NOV…21….+0.1 NOV….20..+4.5 Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Mean 49.0 49.1 2023 46.6 46.6 2022 51.0 51.0 2021 47.1 47.1 2020 51.5 51.5 Monthly Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Mean 45.7 45.7 2019 42.8 42.8 2018 43.7 43.7 2017 46.1 46.1 2016 49.7 49.7 2015 52.0 52.0 2014 43.9 43.9 2013 44.4 44.4 2012 43.3 43.3

It seems to have had the opposite effect in 14-15 with one of the strongest +NAO +AO winters into March on record. October 2014 featured the 2nd fastest snow advance index on record to that point. Was reading some studies that the rapid Arctic warming could have altered the correlation from when the Arctic was more stable in the old days. Tough to know for sure since it hasn’t been used as much since the 14-15.

A number of locations across the region with either the driest first half of fall or very close. Time Series Summary for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 1884-10-16 0.53 0 2 2024-10-16 0.77 0 3 1970-10-16 0.89 0 4 1878-10-16 1.06 0 5 1879-10-16 1.13 0 Time Series Summary for Trenton Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 2024-10-16 0.43 0 2 1970-10-16 0.97 0 3 1941-10-16 1.26 0 4 1897-10-16 1.49 1 5 2007-10-16 1.58 0 Time Series Summary for New Brunswick Area, NJ (ThreadEx) Click column heading to sort ascending, click again to sort descending. 1 1994-10-16 0.52 1 2 2024-10-16 1.06 0 3 1941-10-16 1.09 0 4 1953-10-16 1.56 0 5 1914-10-16 1.80 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 1 2024-10-16 0.89 0 2 1941-10-16 1.36 0 3 1953-10-16 1.78 0 4 2013-10-16 1.92 0 5 1948-10-16 2.01 0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. 1 1884-10-16 0.83 0 2 1886-10-16 1.19 0 3 2024-10-16 1.58 0 - 1881-10-16 1.58 0 4 1892-10-16 1.59 0 5 1910-10-16 1.68 0 Time Series Summary for WESTCHESTER CO AP, NY Click column heading to sort ascending, click again to sort descending. 1 2024-10-16 0.83 0 2 2009-10-16 1.40 0 3 1964-10-16 1.85 0 4 1986-10-16 2.16 0 5 2013-10-16 2.18 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. 1 2024-10-16 0.34 0 2 1982-10-16 1.43 0 3 1973-10-16 1.88 0 - 1967-10-16 1.88 0 4 1997-10-16 1.92 0 5 2013-10-16 1.98 0 - 1985-10-16 1.98 0 Time Series Summary for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. 1 1997-10-16 0.74 0 2 1964-10-16 0.76 0 3 2024-10-16 0.84 0 4 1948-10-16 1.54 0 5 1953-10-16 1.84 0

Near record 500mb ridge next few days followed by low 80s for the usual warm spots Monday into Tuesday. Then a few days closer to normal later next week. The next warm up near the end of the month should at least make it to 70s.

It’s new Pacific pattern outlined in this recent paper. This is why trying to compare this -PDO the pre 2015 Pacific hasn’t been working out. So we get this new persistent pattern with record marine heatwaves and Aleutian ridging. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101078 Remarkable Changes in the Dominant Modes of North Pacific Sea Surface Temperature The analysis revisits the calculation of the empirical orthogonal functions (EOFs) and principal components (PCs) of sea surface temperature (SST) in the North Pacific from 1950 to 2021. The first EOF and PC of SST has proven to be such a useful metric of variability in the North Pacific that it is called the Pacific Decadal Oscillation (PDO). We find that the period of persistent marine heatwaves beginning in 2014 caused a fundamental change to the first EOF and PC of SST (calculated using data from 1950 to 2021) as compared to the established PDO spatial pattern (calculated using data from 1950 to 1993). The second EOF of SST has also changed during this period, both in spatial pattern and in the amount of variance explained. A conclusion is that the PDO and other EOF based metrics may not be as useful in the future as climate continues to change. Key Points The calculation of empirical orthogonal functions and principal components of North Pacific sea surface temperature is revisited The period of persistent marine heatwaves since 2014 has caused most energetic modes to change A conclusion is that indices based on empirical orthogonal function analysis may not be as useful as climate continues to change Plain Language Summary The Pacific Decadal Oscillation (PDO) is a widely used measure of the temperature variability in the North Pacific Ocean. The PDO is the result of a well-known technique called empirical orthogonal function (EOF) analysis that isolates the most energetic modes of variability of the analyzed variable. The first time EOF analysis was applied to oceanographic data was in the 1970's when it was used to identify the most energetic modes of North Pacific sea surface temperature (SST). The first EOF of North Pacific SST has proved so useful as a measure that it received the moniker PDO. Our analysis suggests that a period of persistent marine heatwaves in the North Pacific since 2014 has been so powerful that this first mode of variability of SST has fundamentally changed and the PDO may not be as useful an indicator as it once was.