bluewave

The south based blocking down into Northern New England has been very impressive since the summer.

Yeah, most of the DMI posts on twitter follow the one from the article and link I posted.

It was according to the DMI index used in the NOAA article a few years ago. https://stateoftheocean.osmc.noaa.gov/sur/ind/dmi.php https://www.climate.gov/news-features/blogs/enso/meet-enso’s-neighbor-indian-ocean-dipole Typically, the strength of the IOD is monitored with the so-called Dipole Mode Index, which is a measure of the surface temperature difference between the western and eastern tropical Indian Ocean. The monthly Dipole Mode Index time series reveals other extreme positive phase IOD events, like in 1994 and 1997, but 2019 brought the most extreme event over past 40 years, at least according to this particular index. This event reached its peak in October and November before rapidly weakening in December—a rather typical seasonal evolution for an IOD event. According to the Australian Bureau of Meteorology, which regularly monitors the IOD, the current Dipole Mode Index is near zero (3), indicating that the IOD has returned to neutral conditions. The Dipole Mode Index measures the strength of the Indian Ocean Dipole, with positive values indicating the positive phase and negative values indicating the negative phase. The index is calculated as the monthly difference between the western (10°S-10°N, 50°-70°E) and eastern Indian Ocean (10°S-0°, 90°-108°E) sea surface temperature departures from average. The index value in October 2019 is the highest value since at least 1979, indicating that the recent positive event was quite extreme. Climate.gov figure from ERSSTv5 data.

This is actually a pretty strong blocking pattern for a October.

Yeah, Gavin Schmidt brought up that point in a recent tweet.

We won’t know any of this for sure until the winter is over. If we have a dominant -PDO with Aleutian ridge north or northwest of Hawaii, then this raises the prospects of a trough near or over the Western US. The Nino influence could pump the +PNA ridge in Canada. But combined with a trough in the West could push the ridge into the Northeast. Also remember absolute PDO values are less important when they don’t match what is happening north of northwest of Hawaii. So this is why using raw PDO values doesn’t always work out. Plus we do have intervals when the PDO can’t couple. That is probably what we would like to see. Most Nino winters are judged by what happens after January 15th or 20th so we have plenty of time to evaluate.

There aren’t enough superlatives to describe 09-10 for you guys. Just like 95-96 around NYC and 14-15 near Boston. I just feel fortunate that the best winters for snowfall were in our lifetimes. This makes the winter warming trend easier to take.

Especially if this El Niño continues to underperform and we hold onto the warm pool and Aleutians Ridge north and northwest of Hawaii.

It’s impressive how big an influence the PDO has for us. Our last really cold winter in 14-15 was a solid +PDO combined with a weak Modoki. We got lucky during the first half of 20-21 when the -PDO couldn’t couple and the +PNA emerged. Same went for January 2022. The 20-21 non-canonical -PDO +PNA may have had its roots in the October 2020 MJO.

14-15 was in the 81-10 climate normals period which went into effect in the spring of 11. 09-10 was still in the 71-00 climate normals period which began in the spring of 01 like 04-05 and 02-03. The 94-95 winter was the 61-90 period. The only complete winters so far in the warmest 91-20 climate normals period so far were 21-22 and 22-23. But we can use the 91-20 normals period if you like and the outcome is the same.

Of course. But each composite has a single climate normals period. Notice how the outcome is the same if you use 71-00 or 81-10 climate normals periods.

You can only use one climate normals period for a single composite and 4 of those 5 winters were after 2000 when the period began. There is no difference if we use 1981-2010 climate normals period.

The -PDO Modoki composite is drastically warmer in the East than the more +PDO-like Modoki composite.

For the entire CONUS, the 04-05 winter was 12th warmest and 94-95 was 10th warmest.

2004-2005 was a very warm winter across the US.

94-95 and 04-05 were both warmer Modokis. That’s why they were grouped together. When you get a more -PDO-like Modoki which matches the region north of Hawaii it’s just not as cold as the +PDO counterparts.

I was talking about cold not snow. We can always get snowier winters with warmer patterns with the right storm track. I had better quality snowstorms in my area from 15-16 to 17-18 even though it was much warmer than 13-14 and 14-15.

The more significant SST anomaly pattern that fall was closer to a strong +PDO with very cold SSTs north of Hawaii. It didn’t matter that the SSTs were colder along the West Coast since the pattern further west was driving the bus on the Pacific side. Notice the cold pool and more +PDO-like Aleutian Low.

The 09-10 winter was very different in regard to having the cold pool north of Hawaii. That was associated with the stronger Aleutian low in thst area instead of ridge. So the actual PDO index that winter didn’t match the area north of Hawaii. That’s why I look closely at that area to see if it’s in sync with the PDO. Some years the PDO index is contrary to that region and 09-10 was one of them. So that cold pool north of Hawaii and Aleutian low was actually more like a +PDO. It matched the colder and snowier Modokis in 02-03 and 14-15.

Remember, the whole east based vs west based argument is moot if we get a -PDO. Modoki El Niño’s are warm with a -PDO that has a warm pool north of Hawaii and Aleutians ridge. The sample size is small but the 94-95 and 04-05 Modkis were warm.

5th lowest JUN to SEP -NAO on record.

It’s been a while since the 50/50 low and confluence to our north trended stronger instead of weaker. New run Old run

Our last impressive Arctic shot in October came with the super El Niño in 2015. One of the few times that Newark dropped below freezing during October. Widespread 20s in suburbs. for October 19, 2015 through October 19, 2015 Click column heading to sort ascending, click again to sort descending. State Name Station Type Lowest Min Temperature NY WESTHAMPTON GABRESKI AP WBAN 20 CT MERIDEN MARKHAM MUNICIPAL AP WBAN 21 CT DANBURY MUNICIPAL AP WBAN 21 NY CARMEL 4N COOP 21 NY MONTGOMERY ORANGE COUNTY AP WBAN 22 CT NEW HAVEN TWEED AP WBAN 23 NY SHRUB OAK COOP 23 CT MIDDLETOWN 4 W COOP 23 NY PORT JERVIS COOP 23 CT DANBURY COOP 23 NY YORKTOWN HEIGHTS 1W COOP 23 CT ANSONIA 1 NE COOP 23 CT GROTON NEW LONDON AP WBAN 24 NJ CRANFORD COOP 24 CT SAUGATUCK RESERVOIR COOP 24 CT MOUNT CARMEL COOP 24 CT NORWICH PUBLIC UTILITY PLANT COOP 25 NJ CHARLOTTEBURG RESERVOIR COOP 25 CT STAMFORD 5 N COOP 26 NJ CANOE BROOK COOP 27 NJ CALDWELL ESSEX COUNTY AP WBAN 27 NY WESTCHESTER CO AP WBAN 27 NY UPTON COOP - NWSFO NEW YORK COOP 27 NJ TETERBORO AIRPORT COOP 28 CT GROTON COOP 28 NJ TETERBORO AIRPORT WBAN 28 CT BRIDGEPORT-SUCCESS HILL COOP 28 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 28 NY ISLIP-LI MACARTHUR AP WBAN 29 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 30 NJ NEWARK LIBERTY INTL AP WBAN 31 NY MOLLOY CERCOM COOP 32 NJ HARRISON COOP 32 NY MATTITUCK COOP 32 NY FARMINGDALE REPUBLIC AP WBAN 33 NY BRIDGEHAMPTON COOP 33 NY MOUNT SINAI COOP 34 NY NY CITY CENTRAL PARK WBAN 35 NY CENTERPORT COOP 35 NY BAITING HOLLOW COOP 35 NY JFK INTERNATIONAL AIRPORT WBAN 36 NY MONTAUK AIRPORT WBAN 36 NY LAGUARDIA AIRPORT WBAN 37 NY SETAUKET STRONG COOP 37 NY RIVERHEAD RESEARCH FARM COOP 38 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Oct Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1936 25 0 2 1969 28 0 3 1976 29 0 - 1975 29 0 - 1937 29 0 4 1997 30 0 - 1965 30 0 - 1948 30 0 - 1940 30 0 5 2015 31 0 - 1988 31 0 - 1974 31 0 - 1972 31 0 - 1966 31 0 - 1952 31 0 - 1944 31 0 - 1933 31 0

We have been the wettest part of the country.

Close to average next 10 with some milder days and cooler ones mixed in. Then maybe moderating a bit week 2. But the means are falling this time of year anyway. The coolest departures look like they will set up over the SE.