bluewave

It’s tough to get extended heatwaves anymore since the shade is at least 2-3° cooler at peak heating then then the sensors were out in the open before the 90s. Plus when the foliage is wet there could be even increased cooling.

Not when the the trees block the thermometer and radiation shield from direct sunlight. More rural weather stations have the thermometers in clearings not under a dense canopy of trees. The Central Park great lawn is probably at least 2-3° warmer during the warm season at peak daily heating than under a tree canopy near the castle. Under some weather conditions the difference at peak heating could be even higher than 3°. So the great lawn isn’t that different in regard to highs than EWR and LGA. But the shaded areas are at least 2-3° cooler. That’s why the old site in the park used to average more 90° days than LGA but a few less than EWR. The taller trees are also reducing the winds at the park. This is why NYC hasn’t been able to beat its all-time highest wind gust from the early 70s. Notice how the sensors are located away from obstructions like trees.

Looks like the 3rd cloudiest January on record at ISP using the 9am observation time. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=45&network=NY_ASOS&zstation=ISP&hour=9&year=2024&month=1&_r=t&dpi=100&_fmt=png

You are talking about 2 different things. Sure greening of cities is important for many different reasons. But temperatures aren’t measured directly under trees even at rural weather observing sites. Before the 1990s the weather instruments in Central Park were out in the open. Now they are under mature fully leafed out trees during the warm season. So this has created an artificial high temperature cooling. Had the site been properly maintained, it’s summer highs would be more in line with the surrounding stations like EWR and LGA which it was before the 90s.

Would be higher like several regional surrounding sites if the tree growth since the mid 90s didn’t artificially suppress the high temperatures during the warm season.

Record breaking dense fog extent across the US with this warmth encountering the snow cover in many places.

We wound up getting the record warmth today that was originally forecast for Friday. Newark TEMPERATURE (F) TODAY MAXIMUM 59R 316 PM 59 1947 40 19 58

Several stations reached 70° in January 2020 with the near record MJO 5. Monthly Data for January 2020 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Highest Max Temperature CT ANSONIA 1 NE COOP 74 NJ NEWARK LIBERTY INTL AP WBAN 70 NJ TETERBORO AIRPORT WBAN 70 NJ CALDWELL ESSEX COUNTY AP WBAN 70 CT NORWICH PUBLIC UTILITY PLANT COOP 70 NY NY CITY CENTRAL PARK WBAN 69 NJ HARRISON COOP 69 NY FARMINGDALE REPUBLIC AP WBAN 69 CT NEW HAVEN TWEED AP WBAN 69 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 69 CT GROTON COOP 69 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 69 NJ CANOE BROOK COOP 68 NY JFK INTERNATIONAL AIRPORT WBAN 68 NY ISLIP-LI MACARTHUR AP WBAN 68 NY MOUNT SINAI COOP 68 CT GUILFORD COOP 68 CT MERIDEN MARKHAM MUNICIPAL AP WBAN 68 NY LAGUARDIA AIRPORT WBAN 67 NY SHRUB OAK COOP 67 NY WESTHAMPTON GABRESKI AP WBAN 67 NY RIVERHEAD RESEARCH FARM COOP 67 NY UPTON COOP - NWSFO NEW YORK COOP 67

We almost did last January but this current warm up is too wet with onshore flow. Almost like a summer version of rain and onshore flow shutting down any 100° potential. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Highest Max Temperature Missing Count 1 2007 72 0 - 1950 72 1 2 1932 70 0 3 2020 69 0 - 2002 69 0 - 1916 69 0 4 1967 68 0 - 1876 68 0 5 2023 66 0 - 2017 66 0 - 2005 66 0 - 1990 66 0 - 1974 66 0 - 1973 66 0 - 1937 66 0

First time since the early 30s that NYC had two consecutive winters that averaged over 40° through January 24th. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Dec 1 to Jan 24 Missing Count 1 2016-01-24 43.1 0 2 2007-01-24 42.3 0 - 1932-01-24 42.3 0 3 2002-01-24 41.1 0 4 1995-01-24 40.7 0 5 2024-01-24 40.6 0 6 2023-01-24 40.5 0 7 1950-01-24 40.4 2 8 2012-01-24 40.1 0 - 1933-01-24 40.1 0 9 1913-01-24 39.9 0 10 1937-01-24 39.6 0

The temperature forecast for Friday looks like an early preview of the spring backdoor season.

I am hoping the forcing can finally shift east of the Dateline by mid-February like the models show but no guarantees this far out in time.

The best chance NYC may have to get to 10” on the season is if we can get over to phase 8 by mid-February. The VP anomaly charts are actually similar to the RMMs. But this is no guarantee if the MJO get can’t get past 7 with so much SST warmth near the Dateline. Plus we made it to 8 last March and the big event occurred in the interior and disappointed the coast.

It’s the same pattern we had in December to start February with the warmest departures over the Upper Midwest and Canada.

Yeah, we are similar to BHO which has had 52 top 10 warmest months to only top 10 coldest since 2010.

I enjoy getting outdoors in the winter also. The Great Lakes region is one of most beautiful in winter if you like cold and snow. It’s one area that is really positioned well next few decades for potentially increasing Lake effect snowfall as the warmer lakes stay ice free longer. While winter surfing in my original hometown of Long Beach was very popular, this guy closer to your part of the country takes it to a whole new level.

I don’t like using whole month analogs for a snapshot of a 5 day forecast to start February, the warmth being forecast across Canada is more significant than at the peak of the February 1998 warmth. While the cold over the last 10 days was impressive, its magnitude and aerial coverage was weaker vs cold past extremes than the warm extremes in December. The CONUS finished with one of the warmest Decembers on record. The cold was too short and not extensive enough to rank very high for monthly January cold extremes for the CONUS. But it was impressive for cold on a regional level even if the duration was much shorter than the December warmth.

It’s going to take further research from a team that has access to university computer modeling. I have read numerous studies in the last 5 years on how important tropical convection is in either strengthening or weakening the polar vortex.

Let me give it a try. Back in December 2022 during a La Niña we saw one of the most negative monthly -AOs on record. Our previous 4 La Ninas with such a strong -AOs were 2010,2005,2000, and 1995. Those Decembers all produced 6” events around NYC. Last year we didn’t. Expectations were for a great frontloaded start to winter last year before the period finished. But the Pacific found a way to spoil the party. Now we are entering the typically backloaded part of an El Niño and the Pacific again is too overpowering at least onto the early part of February. So at this point I would say It’s still too early to write off mid to late February for the potential to produce snowfall in NYC. But if we get to February 10th and prospects still aren’t looking good, then NYC would have a shot at its first back to back under 10” seasons. But since it only takes one, it’s too early to call with certainty now. But all we can say for sure the typically backloaded January 15 to probably around February 7th probably won’t live up to past great El Niño periods.

But the +EAMT leading to the Jet extension is also related to the MJO propagating eastward. https://usclivar.org/working-groups/mjo/science/mjo-atmospheric-angular-momentum-length-of-day#:~:text=MJO and Torques,Ocean (Madden%2C 1988). MJO and Torques Frictional and mountain torques induced by the MJO circulation anomalies are responsible for the angular momentum exchange between the atmosphere and the solid earth. Positive frictional torques start the upward trend in AAM when convection increases over the central Indian Ocean (Madden, 1988). As convection moves to the west Pacific, positive mountain torques from east Asian and South American topography provide for a continued increase in AAM. AAM reaches a maximum as convection weakens near the dateline. The relative roles of a direct forcing by the convection versus eddy transport processes induced by the convection remain to be determined. Real time monitoring of the zonal and global AAM budget provides a convenient monitoring and diagnostic tool of the MJO.

The Arctic region shifts with the anomalous +3 AO following the SSW will probably take further research. It is also a very warm signal for us while working in concert with the tropical convection pattern. Several years back there were papers showing a possible link between the Indian Ocean convection and +AO. So it will be interesting to see if such a strong +AO following this SSW is in any related to the recent record Indian Ocean forcing. We usually don’t see such strong forcing there at the time of SSWs. Would probably be a great project for a research paper.

It’s a combination of the record SSTs in the WPAC for such a strong El Niño and the El Niño itself. So we get MJO action which when combined with El Niño is very warm. As these MJOs progress eastward they excite the +EAMT leading to the Pacific Jet extensions. So just looking at one specific MJO phase composite probably won’t be adequate. This most recent Jet extension will take a few weeks to play out. Hoping we can see some improvements by mid-February relative to the start.

Even in this new era of warmth extremes, what is showing up to start February is way beyond what we have ever seen during an El Niño February. The highly amplified MJO over the WPAC is flipping the script. This would be extreme for December let alone in February when El Niño’s are supposed to be cold. Ridiculous how far into Canada the above freezing line gets pushed.

These Pacific Jet extensions through the highly amplified MJO and +EAMT will continue to run the table at least into early February. So this pretty much guarantees that we’ll see a record breaking 9 warm to record warm winters in a row since the 15-16 super El Niño.

We’ll consider it a January thaw even through the colder period was short.