bluewave

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.

Yeah, the rate of Nino 3.4 warming peaked back in August. This coincided with the actual peak in 1+2 and peak in WWB activity so far. While the WWBs have picked up in October relative to September, there is less of a warm water supply in 1+2 to spread out west like we had in August. So Nino 3.4 SSTs continue around 1.43 even with better WWBs this month. The current lack of a strong oceanic kelvin wave and lower upper ocean heat content is slowing things down relative to what we have seen during past El Niño events.

August was our only decent WWB month. So that’s why we had the steep Nino 3.4 rise. The CP trade wind index for August says it all. We can see the decline in WWBs for September leading to the Nino 3.4 drop in recent weeks. https://www.cpc.ncep.noaa.gov/data/indices/cpac850

October 2009 was the last time the CONUS had a top 5 coldest month. https://www.ncei.noaa.gov/access/monitoring/monthly-report/national/200910#:~:text=The average October temperature of,reinforced unseasonably cold air behind Temperature Highlights - October The average October temperature of 50.8°F was 4.0°F below the 20th Century average and ranked as the 3rdcoolest based on preliminary data. For the nation as a whole, it was the third coolest October on record. The month was marked by an active weather pattern that reinforced unseasonably cold air behind a series of cold fronts. Temperatures were below normal in eight of the nation's nine climate regions, and of the nine, five were much below normal. Only the Southeast climate region had near normal temperatures for October.

The one thing that I would add is that this October is running much warmer than years like 2009 and 1976. October 2009 was actually the 4th coldest for the CONUS on record and 1976 2nd coldest. Same way like this summer was much warmer than 2009 even though both years had great summer blocking patterns.

No problem. Not saying I know for sure what is going to happen. Just not a big fan of this persistent -PDO La Niña background state .I don’t mind it as much when it’s uncoupled like Jan 22 and Dec 20 to Jan 21. But it’s very tricky to try and figure out ahead of time when it’s going to couple or not. Plus we have these interference patterns which can arise when the ENSO and PDO our out of phase. Also these troughs seem to find a way to sneak in out West during recent years.

The relevant part is how even a weak -PDO with an El Nino can put a trough in the West like 72-73.

The issue with WWBs coming on so late is that any oceanic kelvin wave generated would also be too late to move the El Niño much more past what we have already seen. Most fall oceanic kelvin waves that have sharp El Niño warming get generated by WWBs during late summer into September. This year we had stronger trades and an absence of WWBs. So any potential kelvin wave warming would come after the El Niño has already peaked.

Tug of war between El Niño in the tropics and -PDO in subtropics or extratropical regions.

It doesn’t have to if the -PDO is coupled well. We can remember back in the 18-19 El Niño that struggled to couple how the well coupled -0.42 -PDO was enough to place the trough in the West. But each winter is different so we’ll just have to see how things play out. Plenty of variables and combinations to factor in.

MJO 7 region forcing west of the Dateline like we are currently getting can mimic a MJO 5 when the PDO is very negative.

Hopefully, the MJO 4-6 doesn’t rebound as much as we saw with the last record +IOD back in 19-20. That event only suppressed convection near the Maritime Continent into early December. So IODs are mainly a fall event and the influence wanes by the winter. Once the IOD dropped under +1 in December 2019, the Maritime continent convection returned.

OCT…….6-8…..0.49

The only real winters in the 90s were 93-94 and 95-96.

Crazy how Sandy was exactly a year later.

Those were the glory days for the Euro when it believe it was the first model to show an unusually early season snowstorm in the Northeast. Even though it was too snowy at the immediate coast, it was still the greatest early season snowstorm on record.

This would actually be a good trend if we got it in the winter. Much stronger blocking to the north preventing the primary from cutting to the Lakes. So we get a forced redevelopment to our south. If this was the winter, we would be hoping later runs don’t correct north. New run Old run

With the current upper ocean heat value just under +1, we continue to see Nino 3.4 pulling back from the highs in late September. The current daily value of +1.44 is well below the Euro monthly average forecast of 2.03 for October. So this could be one of the greatest Euro forecast misses issued in September for October. https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table ECMWF 2.03

Yeah, the NPAC firehose jet is knocking down the +PNA ridge too quickly so primary runs to the lakes. The STJ can’t completely take over like we would want to see. There has been quite a bit of this type of storm track behavior in recent years.

The cold coming up doesn’t look too impressive for October. But it will certainly feel that way due to the 80s to start the month. So it’s all relative.

The Euro is already running too warm for October. It has a monthly average of 2.03. As of 10-07 Nino 3.4 is +1.52. So the dailies would have to increase to at least above +2.25 in the coming weeks for that monthly average number to verify. But there are no big WWBs in the forecast plus the OHC is currently to low to support such a steep rise. https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table ECMWF 2.03