bluewave

The cool pattern during the last week of May that I pointed signaled Newark not getting to 40 days reaching 90° this year. Most of the past Nino to Nina transitions like 2016 and 2010 made it to 40 days and were much warmer the last week of May. This is a result of the much stronger sea breezes than usual this summer. Notice how Harrison just inland from Newark further from the bay made to 41 days. It was also much warmer the last week of May than the airport. This is a rare event for Harrison going over 40 and Newark staying under. Data for May 25, 2024 through May 31, 2024 HARRISON COOP 88 NJ CANOE BROOK COOP 87 NY BAITING HOLLOW COOP 87 NJ CALDWELL ESSEX COUNTY AP WBAN 86 NJ TETERBORO AIRPORT COOP 86 CT DANBURY COOP 85 NY PORT JERVIS COOP 84 NJ NEWARK LIBERTY INTL AP WBAN 84 Number of 90° days Data for January 1, 2024 through September 14, 2024 Click column heading to sort ascending, click again to sort descending. NJ HARRISON COOP 41 NJ CANOE BROOK COOP 37 NJ NEWARK LIBERTY INTL AP WBAN 33 NJ CALDWELL ESSEX COUNTY AP WBAN 33 NJ TETERBORO AIRPORT WBAN 31 NJ TETERBORO AIRPORT COOP 30

That’s just how the CPC calculates the PNA. Most use the CPC since thats how people compare their seasonal PNA forecasts to what the CPC verified. The CPC method allows for a deep trough in the west and when heights are positive in Canada and calls that a +PNA. Usually if there is a ridge somewhere in SW Canada it’s considered a +PNA.

It’s interesting how the Euro seasonal can have a great summer temperature forecast for the U.S. but miss on the hurricane forecast. My guess is that the seasonal forecasts can’t handle competing marine heatwave interactions with the base ENSO climate state. Same way the winter forecasts were way too cold and missed the record warmth last two winters. The model had the stock La Nina and El Nino composites but missed the much warmer MJO interactions.

By one degree but a few days early. THE NEWARK NJ CLIMATE SUMMARY FOR SEPTEMBER 14 2024... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1931 TO 2024 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 87 212 PM 94 2016 79 8 81 MINIMUM 63 547 AM 45 1975 62 1 63 AVERAGE 75 70 5 72

What we saw in 20-21 matches the theme of the blocks becoming more AO and KB dominant since the 15-16 super El Niño. Just check out the winter spread between the AO and NAO indices during recent years. Some months had strong -AO readings but hardly registered negative on the NAO scale. Our older stronger -AO winter months usually had a stronger -NAO response also. So a combination of more south based blocks linking up with the Southeast Ridge and lower heights near Iceland. This is why we see that cold pool frequently showing up near Iceland as the winds have increased there over time.

The PNA was weakly positive on the CPC site in January 2023. https://origin.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table 2023 0.21

This record increasing atmospheric moisture has become the become the real deal.

These brief dry vegetation patterns never last.

It was another case of 60°warmth around the snowstorm in ACY during January 2022 that we have also frequently seen around NYC with our snow events since 2015-2016. The overpowering +PNA and +AO was just a little too progressive west of a line from ACY to FRG and ISP. The interior areas like BGM did much better in 2020-2021 due to the south based -AO linking up with the WAR to the east of New England. So the storm track went over ACY instead of ACK especially in that December record snow of 40” for BGM. But the raging Pacific Jet was able to sneak in for the Christmas 2020 flood cuttter a few days later which caused the flood damage to the ski resorts and they lost the whole snowpack of 40” from a few days earlier.

The last time that raging Pacific Jet was tamed to some extent was way back in January 2022. But it was still a little too strong combined with the +AO so the best snows that January ended up east of NYC rather further west. The storm track was just a little too far east along the East Coast for areas in NJ to do as well as Suffolk County did on Long Island. It was the result of the brief MJO 8 shifting the pattern. But that December 2021 had one of the fastest Pacific Jets and DFW went +13. Then in February it was back to the regularly scheduled fast Pacifc jet programming. In all my years tracking the weather I haven’t seen as hostile a stretch for fast and dominating Pacific flow as we have seen from 18-19 through 23-24. It was like someone flipped a switch after the November 2018 snowstorm.

The key with the La Niña background state and +PNAs is that we need very strong +PNAs to prevent an upper low from undercutting the +PNA ridge. This coming week is an example of the +PNA not being strong enough to prevent the upper low from undercutting the ridge. This is the issue we have had during many recent winters. We need a stronger monthly +PNA to prevent the upper low from undercutting the ridge. Jan 2023 La Niña and the +PNA was too weak at only +0.21 for the month allowing deep trough underneath and +10 warmest January on record in the Northeast December 2011 +PNA too weak at only +0.36 allowing Baja Trough underneath and one of the warmest Decembers on record Jan 2022+1.01 +PNA allowed heavy snows especially east of NYC Dec 2020 +1.58 +PNA one of the strongest on record allowing historic 40” snow for BGM with -AO

Looks like the models have shifter to weaker WAR next week so the low can come further north. 588 dm seems to be the key level. Higher and you get suppression like older runs. Lower like new and we get a wetter pattern developing. These are the highest tides with the full moon of the month so we only need around .5 to 1 foot of surge for minor coastal flooding. With the high to north and low to south we are looking at days of easterly flow. New run Old run Minor coastal flooding begins at 6.5 to 7.0 ft tide level

Can’t really use any years as an ACE comparison to this one. All the other years with this level of activity by Mid-September were due to colder SSTs or El Niños. This is the first time that the Atlantic was this warm and only had 6 named storms by September 15th. The big shift in the ITCZ is probably playing a role.

Luckily, we haven’t had major drought conditions here since 2002. While the South Shore has had brown lawn episodes from time to time, it was nothing like what we had in 1995, 1999, and early 2000s with those droughts. Plus many times there were watering restrictions in those days so you couldn’t even water in some areas if you wanted to. But it’s nearly impossible to avoid nuisance soil moisture dry patterns from time to time. We learned this growing up on the South Shore when the sea breeze fronts often favor the North Shore especially early to mid summer. Long Beach always had issues with trees dropping leaves in the summer . All those Long Beach Sycamores were notorious for early leaf drops before all the Sandy damage. Then nearly all of them that were left had to be removed due to the salt water damage from the surge. The last 15 year period has also featured the most wind damage to trees we have ever seen across the area. So the tree removal and trimming business probably has never been better. We had to have a bunch of trees removed when I was back in SW Suffolk due to wind damage.

We’ll gladly take some drier weather up here as parts of CT have seen over 100” of precipitation since last July. Some spots in Rockland are also getting close. In NJ the areas around 90” are north of 80. So I can see how areas south of 80 haven’t been able to get the amounts the areas further north did. Even though Central NJ has had great long term totals, they have been in and out of short term soil moisture dryness. Mainly a function of how hot the summer was. Parts of Central NJ saw their first year with over 20 days reaching 95°. So it’s tough for spots with that much heat not to have the vegetation get dry when much of the convection was riding north of 78 and 80. Data for July 1, 2023 through September 13, 2024 Click column heading to sort ascending, click again to sort descending. CT PROSPECT 1.9 ENE CoCoRaHS 101.74 CT NEWTOWN 4.6 SE CoCoRaHS 98.99 CT NAUGATUCK 1.7 NNE CoCoRaHS 97.95 CT BROOKFIELD 3.3 SSE CoCoRaHS 97.27 CT MIDDLEFIELD 1.4 W CoCoRaHS 96.85 CT SOUTHBURY 2.3 W CoCoRaHS 96.31 CT RIDGEFIELD 2.4 NNE CoCoRaHS 96.16 NY WEST POINT COOP 94.95 CT WATERBURY 1.3 WNW CoCoRaHS 94.81 CT NORTHFORD 0.8 SW CoCoRaHS 94.53 NY STONY POINT 0.7 NW CoCoRaHS 94.26 Data for July 1, 2023 through September 13, 2024 Click column heading to sort ascending, click again to sort descending. NJ MINE HILL TWP 0.4 NE CoCoRaHS 91.06 NJ HIGHLAND LAKES 1SW COOP 90.12 Time Series Summary for HIGHTSTOWN 2 W, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending most 95° days on record 1 2024 21 2 2002 17 0 3 1955 16 8 4 1953 14 0 5 2021 13 0 - 2018 13 1 - 2016 13 2 - 2010 13 4 - 1988 13 0 - 1949 13 0

Places in Canada that recently saw the record early snow will also have the highest departures as these over the top warm ups have become the new normal.

The interesting thing this time is that the 500mb low will be near the deepest on record on the West Coast for the month of September. It would be average for the winter. Also record positive 500 mb heights for Eastern Canada.

If not next week then perhaps some time later in the month. Very rare to get a top 10 driest month these days. But if the WAR keeps flexing then who knows. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of Sep Click column heading to sort ascending, click again to sort descending. 1 2024 0.08 19 2 1941 0.14 0 3 2005 0.45 0 4 1951 0.95 0 5 1972 1.03 0 6 1948 1.14 0 - 1939 1.14 0 7 1931 1.19 0 8 1953 1.25 0 9 1964 1.30 0 10 1967 1.35 0

Models struggling with the energy digging into the West and the ridge over the Northeast. This is why every run has been different with the rainfall forecast next week. On one hand this ridge has been correcting stronger in the long range. But the other side of the coin is that these shallow drier patterns seldom last long. So a tug of war between these competing patterns. New run Old run

Even the summer of 2022 was nothing like how brown the lawns were back on the Long Island South Shore in July 1999.

The lawns and all the grass around Tweed look really great.

We have had such a huge surplus of rainfall that everything is just as green and lush looking here as it was before the recent drier period.

Parts of Long Island and CT have had 15-20” over the same period. Data for July 13, 2024 through September 12, 2024 Click column heading to sort ascending, click again to sort descending. NY ST. JAMES COOP 19.35 CT NEWTOWN 4.6 SE CoCoRaHS 19.20 NY PORT JEFFERSON STATION 0.3 SSW CoCoRaHS 19.11 CT STAMFORD 1.0 S CoCoRaHS 17.96 CT NAUGATUCK 1.7 NNE CoCoRaHS 16.75 NY SEAFORD 0.4 SE CoCoRaHS 16.55 CT SOUTHBURY 2.3 W CoCoRaHS 16.45 CT NEWTOWN 5.3 S CoCoRaHS 15.95 CT DARIEN 2.4 NW CoCoRaHS 15.92 CT MONROE 0.8 W CoCoRaHS 15.90 CT RIDGEFIELD 3.7 NNE CoCoRaHS 15.86 NY CENTEREACH 1.3 NE CoCoRaHS 15.64

The real heat was always forecast to go north relative to the averages. New run Old run

The Southeast Ridge or Western Atlantic Ridge has been the most dominant feature of the last 9 winters. This is why the Northeast has seen an historic 9 warmer winters in a row. We have never seen a run like this going back to 1950 regardless of what the other teleconnections were doing. So it may be time for a new custom index.