bluewave

The biggest issue for the Philly airport is it consistently is subject to cooling breezes off the Delaware River. This makes it an unrealistic proxy for the actual warm season temperatures in downtown Philadelphia which runs several degrees warmer. So residents in the densest population zones in the Philadelphia urban centers are experiencing warmer conditions than the airport. Same goes for the airport at Newark. The ASOS is very close to the bay and experiences cooling sea breezes which keep the temperatures lower than the urban areas just inland from the sea breeze influence. So where the residents actually live they experience warmer conditions than the airport. NYC has a different twist to underreporting the actual urban temperatures. When the NWS left NYC in the early 1990s the Central Park observing site fell into disrepair. They installed an ASOS under a tree canopy placing it in the deep shade in 1995. The old ASOS was in an open sitting not under a cooler canopy. So this created an artificial cooling in the NYC temperature record around 1995 since the measurements before then were taken out in the open. This is why the NYC readings started running cooler than surrounding sites when it had been warmer or as warm as the surrounding sites in the years prior to the 1990s. LaGuardia airport also has issues with cooler warm season readings than the surrounding sites since the ASOS is right on the water and gets cooling breezes. So its temperatures in the warm season run cooler than the surrounding sites. The good news is that NYC established a micronet and placed sensors in the densest urban city neighborhoods where the people actually live. These readings have shown that the neighborhoods where the people actually live have consistently run warmer than the airport. There have been numerous 100° readings just inland from the airport to the south when the airport only maxed out in the 90s. So the moral of the story is that we need more thermometers in the warmer neighborhoods since they aren’t subject to the cooling breezes that the airports often get. This does a disservice to the residents in these urban environments that have to experience higher levels of heat than the cooler local airports.

The strong winds will continue to be the common denominator.

Saturday looks like or next run on 80° for the warm spots.

Good question. Today should see a drop off in the winds. But tomorrow will have very steep low level lapse rates. So we could see 45-50 mph westerly gusts especially if the downslope warming beats guidance by a few degrees like we haven been regularly experiencing.

Yeah, they made to 93° on 4-14-23 and had to wait until July 3rd to get that warm again.

Big improvement from yesterday. MAXIMUM 60 254 PM 92 2023 62 -2 MAXIMUM 43 1205 AM 90 1977 61 -18

Philly is in a much different multiyear snow drought this time around. The 7 year snowfall average dipped to 10.5” for the first time on record after 24-25 snowfall season just ended. Marking an unprecedented reversal from the 7 year record high of 36.8” in 15-16. Lowest 7 year snowfall averages in Philly 2025….10.5” 1992….14.9” 1977…..14.4” 1955….13.4” 1933….12.5”

Record breaking 61 days with wind gusts over 30 mph since January 1st. Newark/Liberty PTSUNNY 58 37 45 NW20G37 https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=140&network=NJ_ASOS&station=EWR&syear=1900&sday=0101&eday=0412&varname=avg_wind_gust&w=aoa&thres=30&year=2025&_r=t&dpi=100&_fmt=png

Looks like the Euro is capturing the warmer downslope conditions today better than some of the other guidance.

The main correlation with storm tracks since 18-19 has been the Pacific Jet. We got a relaxation during 20-21 which allowed the -NAO -AO to produce a KU BM track on 2-1-21 and another smaller BM event about a week later. Also a brief window in January 22 with the MJO 8 +PNA which favored areas from ACY to ISP to BOS. Just a little wide of the BM for areas a little further west to cash in. But most other times the Pacific Jet has had an overpowering influence leading to cutters, huggers, and suppressed Southern Stream storm tracks. Plus the stronger Southeast Ridge influence even at times of strong -NAO and -AO intervals which was absent before this decade at times of such strong blocking. So this adds a new conditionality to those older correlations. So you need to take more of bigger picture view rather than just looking at the NAO in isolation. If you noticed we finally got something close to a BM track the last few days. The reason the lagged -NAO correlation finally worked now and not over the winter was due to the Pacific Jet backing off a bit from recent months. My guess is that the record warmth in Siberia weakened the gradient between the record SST warmth east of Japan allowing the jet to back off.

Yeah. 1983-04-19 45 35 40.0 -12.1 25 0 0.87 1.5 T

It was the latest in NYC since 1980. Frost/Freeze Summary for NY CITY CENTRAL PARK, NY Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. 1891 05-06 (1891) 32 11-04 (1891) 30 181 1874 04-30 (1874) 32 11-12 (1874) 32 195 1919 04-26 (1919) 31 11-14 (1919) 30 201 1892 04-25 (1892) 32 11-11 (1892) 32 199 1888 04-25 (1888) 31 11-17 (1888) 30 205 1930 04-24 (1930) 31 11-06 (1930) 31 195 1872 04-23 (1872) 29 11-16 (1872) 30 206 1875 04-22 (1875) 28 11-02 (1875) 31 193 1925 04-21 (1925) 32 10-29 (1925) 31 190 1922 04-21 (1922) 32 11-21 (1922) 32 213 1926 04-20 (1926) 28 11-04 (1926) 31 197 1904 04-20 (1904) 27 10-31 (1904) 32 193 1897 04-20 (1897) 24 11-18 (1897) 32 211 1890 04-19 (1890) 30 11-21 (1890) 31 215 1887 04-19 (1887) 29 10-30 (1887) 32 193 1980 04-17 (1980) 32 11-16 (1980) 32 212 2014 04-16 (2014) 31 11-18 (2014) 24 215

February 2015 was a one-off type event that we won’t see again absent some massive volcanic eruption dramatically cooling the earths climate.

April 1875 was very cold and snowy which would be a -10 by today’s much warmer climate normals. April 16th through the 22nd was close to what our average January temperstures are these days at only 34.1°. So not something we can experience anymore in the much warmer climate. Climatological Data for NY CITY CENTRAL PARK, NY - April 1875 Click column heading to sort ascending, click again to sort descending. Sum 1500 1031 - - 590 0 3.08 13.5 Average 51.7 35.6 43.7 -10.0 - - - - Normal 61.8 45.5 53.7 - 354 14 4.09 0.4 1875-04-01 61 39 50.0 1.9 15 0 0.00 0.0 1875-04-02 65 48 56.5 8.1 8 0 0.06 0.0 1875-04-03 55 41 48.0 -0.8 17 0 0.34 0.0 1875-04-04 46 37 41.5 -7.7 23 0 0.31 0.0 1875-04-05 58 37 47.5 -2.1 17 0 0.00 0.0 1875-04-06 54 M M M M M 0.00 0.0 1875-04-07 M 31 M M M M 0.06 0.5 1875-04-08 51 33 42.0 -8.8 23 0 0.00 0.0 1875-04-09 47 37 42.0 -9.2 23 0 0.02 0.0 1875-04-10 61 39 50.0 -1.6 15 0 0.00 0.0 1875-04-11 66 47 56.5 4.5 8 0 0.00 0.0 1875-04-12 48 35 41.5 -10.9 23 0 0.10 T 1875-04-13 35 30 32.5 -20.3 32 0 0.87 8.7 1875-04-14 52 30 41.0 -12.2 24 0 0.14 1.3 1875-04-15 57 41 49.0 -4.6 16 0 0.00 0.0 1875-04-16 48 33 40.5 -13.5 24 0 0.10 T 1875-04-17 33 27 30.0 -24.3 35 0 T T 1875-04-18 32 25 28.5 -26.2 36 0 T T 1875-04-19 40 22 31.0 -24.1 34 0 0.00 0.0 1875-04-20 41 29 35.0 -20.5 30 0 0.00 0.0 1875-04-21 43 26 34.5 -21.3 30 0 0.00 0.0 1875-04-22 51 28 39.5 -16.7 25 0 0.00 0.0 1875-04-23 60 35 47.5 -9.0 17 0 0.00 0.0 1875-04-24 59 35 47.0 -9.9 18 0 0.37 0.0 1875-04-25 51 34 42.5 -14.7 22 0 0.44 3.0 1875-04-26 61 41 51.0 -6.6 14 0 0.00 0.0 1875-04-27 58 45 51.5 -6.4 13 0 0.00 0.0 1875-04-28 46 42 44.0 -14.2 21 0 0.21 0.0 1875-04-29 54 40 47.0 -11.5 18 0 0.06 0.0 1875-04-30 67 44 55.5 -3.4 9 0 0.00 0.0 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending 4-16 to 4-22 1 1875-04-22 34.1 0

It just happened a few years ago several times at even later dates. The big change we have seen is that these April snow events are struggling to accumulate near the coast as it gets warmer. So we wind up with just a trace rather than an accumulation.

This wasn’t that big of a deal. Since LGA had accumulating snow and not just a T a few days later back in 2014. Then a T on 5-9-20. Maybe if the low temperatures were really cold like the maxes were yesterday they could have had a light accumulation. 2014-04-16 47 32 39.5 -14.4 25 0 0.05 0.2 2020-05-09 49 36 42.5 -19.2 22 0 0.03 T

Correlations or associations shift over time with the climate. From the 1950s to early 1970s -PNA -NAO -AO was associated with a trough in the East. But in recent times this has featured a strong Southeast Ridge. Even the -NAOs and -AOs have been occurring with a strong Southeast Ridge. My guess as to why this has been the case is due to the rapid warming of the Atlantic Ocean leading to a stronger subtropical ridge. So when we used to get more of a trough in the East the tendency has become more of a Southeast Ridge. This is the weakness's of just relying on the older teleconnections like NAO, AO, PNA, and EPO and not recognizing changes in the ridge structures and orientations further south. Plus the much stronger Pacific Jet is playing a role in the ridge strength also.

That was in 2020 leading up to the record May snowfall. April 2002 was only a little warmer than average by modern standards. But the warmth from the 13th to 19th was very impressive. Climatological Data for NEWARK LIBERTY INTL AP, NJ - April 2002 Click column heading to sort ascending, click again to sort descending. Sum 1963 1396 - - 330 68 3.76 T - Average 65.4 46.5 56.0 2.7 - - - - 0.0 Normal 62.6 44.1 53.3 - 363 14 3.87 0.5 2002-04-01 62 45 53.5 5.7 11 0 0.07 0.0 0 2002-04-02 58 39 48.5 0.3 16 0 0.00 0.0 0 2002-04-03 77 41 59.0 10.4 6 0 0.05 0.0 0 2002-04-04 52 37 44.5 -4.4 20 0 0.00 0.0 0 2002-04-05 44 33 38.5 -10.8 26 0 T T 0 2002-04-06 49 32 40.5 -9.2 24 0 T T 0 2002-04-07 49 28 38.5 -11.6 26 0 0.00 0.0 0 2002-04-08 62 40 51.0 0.5 14 0 T 0.0 0 2002-04-09 77 55 66.0 15.1 0 1 0.07 0.0 0 2002-04-10 67 48 57.5 6.2 7 0 0.01 0.0 0 2002-04-11 57 47 52.0 0.3 13 0 0.00 0.0 0 2002-04-12 55 43 49.0 -3.1 16 0 0.06 0.0 0 2002-04-13 74 54 64.0 11.5 1 0 0.07 0.0 0 2002-04-14 74 55 64.5 11.6 0 0 0.09 0.0 0 2002-04-15 82 58 70.0 16.8 0 5 0.02 0.0 0 2002-04-16 92 64 78.0 24.4 0 13 0.00 0.0 0 2002-04-17 97 68 82.5 28.5 0 18 0.00 0.0 0 2002-04-18 93 74 83.5 29.1 0 19 0.00 0.0 0 2002-04-19 91 63 77.0 22.2 0 12 0.59 0.0 0 2002-04-20 69 54 61.5 6.4 3 0 0.23 0.0 0 2002-04-21 56 48 52.0 -3.5 13 0 0.01 0.0 0 2002-04-22 58 42 50.0 -5.9 15 0 0.29 0.0 0 2002-04-23 56 39 47.5 -8.7 17 0 0.00 0.0 0 2002-04-24 61 37 49.0 -7.6 16 0 0.00 0.0 0 2002-04-25 52 43 47.5 -9.4 17 0 0.50 0.0 0 2002-04-26 61 40 50.5 -6.8 14 0 0.00 0.0 0 2002-04-27 65 38 51.5 -6.1 13 0 0.03 0.0 0 2002-04-28 57 48 52.5 -5.5 12 0 1.54 0.0 0 2002-04-29 57 43 50.0 -8.3 15 0 T 0.0 0 2002-04-30 59 40 49.5 -9.1 15 0 0.13 0.0 0

The NAO was much more positive from 11-12 to 17-18 than it has been from 18-19 to 24-25. Yet there was a record number of BM tracks from 11-12 to 17-18 with the strong +NAO over those winters. But very few BM tracks in the last 7 seasons vs the previous 7 seasons. Which has been reflected in the steep snowfall decrease in places like NYC Metro region. So as I have said, it’s the Pacific Jet driving the decline in BM tracks and snowfall much more than the Atlantic side and teleconnections like the NAO. Trying to use correlations from a different climate era isn’t going to work out.

While 90s have always been rare in April, the highest maxes for the month have been steadily increasing.

That’s a function of the all or nothing snowfall regime which began in the 1990s as the winters have warmed. To reach normal to above normal snowfall has fallen squarely on the shoulders of BM storm tracks which most times were NESIS ranked KU events. The years without BM tracks and KU events were duds since the 1990s and the years with BM tracks were great. Since we lost the BM storm track in 18-19, nearly all the seasons with the exception of 20-21 around NYC were well below average. This is the risk of relying exclusively on one type of storm track to reach normal seasonal snowfall. When it was much colder from the 1960s to early 1990s we had a wider variety of storm tracks to reach average. So plenty of very cold winters without benchmark KU events broke even. These were the moderate storms with took BM tracks but didn’t rank on the KU scale. So in a colder climate we were able to nickel and dime our way to close to normal. These days nickel and dime events which were frequent this past winter just couldn’t get the job done since the storm tracks were so warm on the days with precipitation over .25 around NYC.

Those correlation composites are outdated since they were before we began to see the climate shifts in recent years. So newly emergent patterns will always have smaller sample sizes to draw from than from a colder stable era over decades and decades. January 2025 was one of the strongest -NAO winter months of the 2020s with very little snow to show for it. Same went for March 2023 with a strong -NAO.

We had great snows during the +NAO winters in 04-05, 13-14, 14-15, 15-16, 16-17 and 17-18. So the Pacific Jet has had more influence than the teleconnections in determining the BM storm tracks and snowfall in this area. The -NAO only helps snowfall when the Pacific Jet relaxes and the -NAO doesn’t link up with the Southeast Ridge.

It would be cool if you knew someone in one of these towers that would let you come over during high wind events.While I wouldn’t want to experience it all the time, it would be interesting to see what it was like at least once. Almost reminds me of one of those theme park attractions. I actually had a fiend who lived in the West End of Long Beach in a 2nd story unit which was built on lally columns. His ceiling lamp would sway and he had creaking noises when the winds went over 50mph. https://www.dezeen.com/2021/02/05/floods-and-high-winds-plague-residents-of-rafael-vinolys-432-park-avenue/

Yeah, the record SST warmth to the east of Japan when coupled with the Siberian air masses to the west over Northeast Asia really increase the gradient and Jet Stream across the Pacific. This leads to storm tracks cutting through the Great Lakes, hugging the I-78 to I-84 corridor, or getting suppressed to our south.This is why Philly to Boston experienced the lowest 7 year snowfall totals since 18-19 since the BM tracks have been missing. In the much warmer climate since the 1990s, we haven’t had an average to above an average snowfall season without an active 40/70 BM storm track. Prior to the 1990s we could get to closer to average snowfall without the BM tracks since the air masses were cold enough for more significant front end snows with the hugger tracks before the changeover occurred. We also used to get more snowy clippers in those days dropping to our south. But this storm track has shifted closer to the Great Lakes. Perhaps in the coming years we can find a way to shift the warm pool east of Japan a bit and allow that Jet to back off a bit. But it’s really a big unknown with the way the subtropical oceans have seen record warming in recent years. There was a record BM storm track from 09-10 to 17-18. This shifted to the opposite extreme since 18-19. We are reminded what happened with the storm track shift west of the APPS for State College. They had a record snowfall regime from the 60s to 90s with many historic inside runners just east of the APPS. That track had pretty much become dormant since 03-04. So there snowfall has been in steep decline since then as more storms are cutting west of the mountains now. We just don’t know enough about forecasting very long range storm track patterns to determine if the BM storm track goes the way of the inside runner east of the APPS or we can see at least some intermittent BM tracks in the coming years.