bluewave

The -30C 850 mb temperature near James Bay is close to the record for late April. It looks like the TPV splits in a few days and a piece heads for Maine. So NYC has a shot at dipping under 40° with the interior northeast having a hard freeze potential.

Any system based on polarities like ours always runs the risk of falling out of balance. I would like to think that we can eventually shift our consciousness to a higher level which recognizes that we are part of nature rather than separate from it. But it may take until sea level rise begins to inundate our coastal cities or major crop failures occur due to extreme weather and climate events. Climate warming is still too much of an abstraction for society at large to begin to contemplate. The best we can do right now is for like minded individuals to take this information and make any adaptations we can for a much more extreme climate in the future. It’s a bit of a paradox that the very nature of our evolution on this planet has selected more short term gains rather than long term sustainability. That’s how we have wound up with so many environmental degradation issues which are facing us. At some point we need to use our inherent creativity to override these outdated modes of existence which may have served prehistoric societies short term survival needs but have to be modernized for our current situation. Short term thinking served our ancestors coming out of the caves who had to be on guard in order to quickly get away from dangerous animals. Now we need to use our higher nature to shift toward an existence more in alignment with nature and fellow humans.

Models back to a stronger cold front this week with a piece of the TPV heading for Maine. So interior sections need to watch for a hard freeze. NYC may dip below 40° which will feel very chilly for late April. The low pressure will become the new 50/50 low which has been so persistent since late March. So more continuing backdoor potential.

Mostly driven by the warm minimums due to all the clouds, showers, and onshore flow keeping the high temperatures in check. The average high temperature is nearly 10° colder than last April. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Max Temperature Apr 1 to Apr 19 Missing Count 1 2023-04-19 70.6 0 2 2010-04-19 69.7 0 3 2002-04-19 69.1 0 4 1945-04-19 67.5 0 5 2012-04-19 67.0 0 6 1981-04-19 66.7 0 7 1941-04-19 66.2 0 8 2006-04-19 65.9 0 9 1968-04-19 65.5 0 10 2017-04-19 65.4 0 11 1976-04-19 65.0 0 12 1994-04-19 64.6 0 13 1955-04-19 64.3 0 14 1959-04-19 64.2 0 15 1991-04-19 63.8 0 16 2019-04-19 63.6 0 - 2005-04-19 63.6 0 17 1969-04-19 63.4 0 18 2015-04-19 62.9 0 - 1999-04-19 62.9 0 19 1974-04-19 62.8 0 20 1963-04-19 62.7 0 21 2014-04-19 62.5 0 - 1977-04-19 62.5 0 22 1985-04-19 62.4 0 23 2013-04-19 62.3 0 24 2008-04-19 61.9 0 25 1998-04-19 61.6 0 26 2024-04-19 61.5 0

No, the Greenland block is still going strong plus we have a -EPO. That MJO 8 back in late March reset the whole pattern to more blocking with a stronger 50/50 low. This pattern maintains a backdoor nearby with only brief warm ups between plenty of onshore flow, clouds, and showers. Canada is starting to get cold after so much record winter warmth. Figures the relaxation from MJO 4-7 would wait until the spring.

Nice improvements today on the 12z Euro. While there will still be a near record polar vortex near James Bay next week, the cold goes more to the east rather than the south. So the lowest NYC may get next week is the 40s rather than the 30s which were shown yesterday. But we’ll continue to watch further runs since these forecasts involving a PV nearby in Canada can jump around a lot from run to run. This is more something we see in the winter rather than in late April. New run Old run

You should probably invest in a set up like this.

They were a few degrees warmer for the high temperatures. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Max Temperature Jun 1 to Jul 31 Missing Count 1 2009-07-31 79.8 0 2 1969-07-31 80.8 0 3 1972-07-31 80.9 0 4 1985-07-31 81.0 0 - 1979-07-31 81.0 0 - 1958-07-31 81.0 0 5 1996-07-31 81.3 0 - 1947-07-31 81.3 0 6 2000-07-31 81.4 0 - 1945-07-31 81.4 0 7 2003-07-31 81.5 0 - 1936-07-31 81.5 0 8 1956-07-31 81.6 0 9 1967-07-31 81.7 0 10 1982-07-31 81.8 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Highest Max Temperature Jun 1 to Jul 31 Missing Count 1 2009-07-31 91 0 2 1996-07-31 92 0 - 1979-07-31 92 0 - 1960-07-31 92 0 3 1976-07-31 93 0 - 1970-07-31 93 0 4 1985-07-31 94 0 - 1975-07-31 94 0 - 1939-07-31 94 0 - 1938-07-31 94 0 5 2003-07-31 95 0 - 1973-07-31 95 0 - 1967-07-31 95 0 - 1946-07-31 95 0

It was the only June and July on record with the average high under 80° at Newark. Very unusual summer for the modern era. As soon as the pattern began to warm in August Central Park got that big microburst.

I really enjoyed the 2009 summer since it was still warm enough to go to the beach and boardwalk and it kept the beach crowds down in Long Beach. I was willing to put up with extra rainfall especially early on in June. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Jun 1 to Jul 31 Missing Count 1 1940-07-31 71.5 0 2 2009-07-31 71.6 0 3 1947-07-31 71.7 0 4 1936-07-31 72.0 0 5 1932-07-31 72.1 0

You continue to mix apples and oranges in your comparisons. First, NYC is the only site in the region that is situated under shade trees and every other site gets direct sunlight. It’s well known that you don’t take temperatures under trees. Second, that Franklin institute rooftop site can run cooler than the street level sites as has been the case with the NYC micronet rooftop sites. Third, PHI runs cool since it’s situated in a swamp on the Delaware River at one of the widest points. Your argument about Newark holds no water since it’s actually been shown to run cooler than surrounding sites on days where it’s subject to sea breezes since it’s in a swampy area near the bay. Plus none of the sites other than NYC shows a summer high temperature cooling pattern while the minimums have been rising. So blocking solar radiation to any site with trees is going to taint your observations. Numerous sites have hit 100° around the region since 2012. The area approaching NE NJ is naturally warmer even if there was no urbanization due to a downsloping effect on a SW to W flow. While the temperature measurements from the 1930s were less reliable, the NJ state record was set in Runyon during the 1930s and is located in this warmer corridor. So no urbanization was needed. It’s naturally a warmer part of the region than areas further to the SW due to typography alone.

They already have the record for not getting above 98° due to how thick the tree growth has become over the sensor. Number of Consecutive Days Max Temperature <= 98 for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Run Length Ending Date Period of record: 1869-01-01 to 2024-04-17 1 4291 2024-04-17 2 4022 1977-07-17 3 3260 1894-06-24 4 2844 1911-07-02 5 2212 1917-07-30 6 1786 2010-07-04 7 1763 1988-07-09 8 1761 1962-05-18 9 1476 1923-07-19 10 1475 1948-08-25 Data for January 1, 2013 through April 18, 2024 Click column heading to sort ascending, click again to sort descending. State Name Station Type Highest Max Temperature NJ NEWARK LIBERTY INTL AP WBAN 103 NJ HARRISON COOP 102 NJ CANOE BROOK COOP 101 NY LAGUARDIA AIRPORT WBAN 101 CT NORWICH PUBLIC UTILITY PLANT COOP 101 NJ CRANFORD COOP 100 NJ TETERBORO AIRPORT WBAN 100 NJ CALDWELL ESSEX COUNTY AP WBAN 100 NJ TETERBORO AIRPORT COOP 100 NY JFK INTERNATIONAL AIRPORT WBAN 100 NY SETAUKET STRONG COOP 100 NJ RINGWOOD COOP 99 NY WEST POINT COOP 99 NY WORLD TRADE CENTER WBAN 99 NY ISLIP-LI MACARTHUR AP WBAN 99 CT STAMFORD 5 N COOP 99 CT PUTNAM LAKE COOP 99 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 99 NY NY CITY CENTRAL PARK WBAN 98 Data for January 1, 2013 through April 18, 2024 Click column heading to sort ascending, click again to sort descending. State Name Station Type Highest Max Temperature PA MARCUS HOOK COOP 103 PA NORRISTOWN COOP 102 PA PHOENIXVILLE 1 E COOP 101 NJ SOMERSET AIRPORT WBAN 101 NJ HIGHTSTOWN 2 W COOP 101 NJ FREEHOLD-MARLBORO COOP 101 NJ MANASQUAN 1 NW COOP 101 PA PHILADELPHIA FRANKLIN INSTITUTE COOP 101 NJ ATSION COOP 101 NJ SOUTH JERSEY REGIONAL AIRPORT WBAN 101 MD STEVENSVILLE 2SW COOP 100 DE GEORGETOWN-DELAWARE COASTAL AIRPORT WBAN 100 NJ WRIGHTSTOWN COOP 100 PA NORTHEAST PHILADELPHIA AIRPORT WBAN 100 NJ MARGATE COOP 100 NJ LONG BRANCH-OAKHURST COOP 100 NJ NEW BRUNSWICK 3 SE COOP 100 NJ ATLANTIC CITY INTL AP WBAN 100 MD ROYAL OAK 2 SSW COOP 99 PA READING REGIONAL AIRPORT WBAN 99 NJ CAPE MAY 2 NW COOP 99 NJ PENNSAUKEN 1N COOP 99 NJ POTTERSVILLE 2 NNW COOP 99 NJ FLEMINGTON 5 NNW COOP 99 NJ EB FORSYTHE NEW JERSEY RAWS 99 PA PHILADELPHIA INTL AP WBAN 99 NJ HAMMONTON 1 NE COOP 99 NJ ESTELL MANOR COOP 99 NJ PHILADELPHIA/MT. HOLLY WFO COOP 99 Data for January 1, 2013 through April 18, 2024 Click column heading to sort ascending, click again to sort descending. State Name Station Type Highest Max Temperature CT COLEBROOK RIVER LAKE COOP 102 NY SARA NEW YORK RAWS 100 NY MELROSE 1 NE COOP 100 NY POUGHKEEPSIE AIRPORT WBAN 99 NY STONYKILL NEW YORK RAWS 99 NY ROSENDALE 2 E COOP 99 NY SCHOHARIE COOP 99 CT FALLS VILLAGE COOP 99 NY CAMBRIDGE COOP 99 CT THOMASTON DAM COOP 99 NY ALBANY INTERNATIONAL AIRPORT WBAN 99

It’s really impressive how persistent the Canadian blocking has been since last spring. Figures it would mainly wait until the winter to link up the Southest ridge. The degree to which the blocking holds on will probably help to refine some of our summer weather details. While we usually have been very warm during El Niño to La Niña summer transitions, a continued wet pattern and more high pressure to the north could work to temper the heat potential somewhat.

The forecast beyond day 10 will probably come down to how strong the 50/50 low remains. The OP Euro maintains a stronger 50/50 with continued backdoor potential. We would want something closer to EPS to have a shot at more than a day or two warm up before getting backdoored again. The original day 10+ EPS underestimated the backdoor influence this week. So would want to see improvement show up under 168 hrs to have confidence that this pattern was going to relax.

Looks we have a shot at near the coldest 850mb temperatures on record near James Bay next week for late April. A -28C cold core at 850mb is pretty ridiculous this late in the season. Will be interesting to see how close this gets to the Northeast day 6-10. It’s possible that interior regions could see a hard freeze with 30s all the way to the coast. We probably won’t know for sure until we get under 120 hrs since pinning down exact polar vortex positions day 6-10 can be tricky.

Where was this pattern during the winter?

It’s based on hourly reports which is what it was designed to do.

There is no underrepresentation since it all depends on what time interval you use. Set it to 24 hrs and the April 2003 drop is the top one. Anytime you have an afternoon within 24-72 hours with a 30°+ difference it’s noteworthy.

That one was in May 2020 but the one last May was equally as extreme for some locations. https://www.nrcc.cornell.edu/regional/narrative/narrative.html Northeast Overview - May 2023 Notable Weather EventsAn upper-level low pressure system that had stalled near the region in late April finally meandered away during the first few days of May but continued to bring persistent below-normal temperatures and rounds of precipitation during that time. In fact, a rare May snow event occurred in some higher-elevation locations of West Virginia and southwestern Pennsylvania. The greatest storm snow total reached 20.3 inches in Davis, West Virginia, ranking as West Virginia’s largest May snowstorm and the snowiest May for any West Virginia site on record. Davis saw 10.1 inches of snow on May 3, ranking as the greatest daily snowfall for May for any West Virginia site. Meanwhile, Snowshoe, West Virginia, had its snowiest May since records began in 1975 with 16.0 inches and its snowiest May day with 7.0 inches on May 3. The site’s snow depth of 15 inches on May 4 was the greatest May snow depth on record for any West Virginia site. The event was also notable even at sites that saw less snowfall, such as Donegal, Pennsylvania, which had its snowiest May since records began in 1945 with 0.7 inches of snow. In addition, on May 1, a storm system associated with the upper-level low set record-low sea level pressures for May at least eight sites including Boston, Massachusetts; Williamsport, Pennsylvania; and New York City. Low temperatures on May 18 bottomed out in the 20s and 30s in multiple parts of the Northeast, running as much as 22 degrees F colder than normal. For instance, lows of 30 degrees F in Scranton, Pennsylvania, and 33 degrees F in Providence, Rhode Island, ranked among the 10 coldest low temperatures for May at those sites. After a mild April, some crops were ahead of schedule, leaving them particularly susceptible to the unusually cold temperatures. There was widespread frost/freeze damage to grape vines, particularly in central and eastern New York where early estimated losses of 70 to 100 percent of some grape varietals were reported at some vineyards. Early estimates indicate around a third of Massachusetts’ apple crop was damaged, while preliminary estimates from New Hampshire indicate damages to the state’s apple crop could exceed $1 million. Vermont officials reported severe damage to thousands of acres of crops, while Connecticut officials also have reported significant crop losses. The full extent of damage will take more time to assess.

The TPV looks even stronger this time near Hudson Bay maxing out near -5 SD. It’s forecast to weaken as it heads to Maine. But there will still be a late season possible hard freeze for interior regions. Both events followed a late season -EPO pattern after record warmth prevailed during the winter.

Something unusual is going on with the the TPV. It’s becoming consolidated and very strong for late April. The forecast is for it to approach record low 500mb heights for late April levels near Hudson Bay next week. All the guidance splits a piece off and it heads for Maine day 6-10. If this scenario verifies, interior portions of the Northeast could face a hard freeze.

It will be interesting to see if Newark can maintain a high only in the 40s tomorrow. It would be one of the more impressive 48-72 hr afternoon temperature drops during the month of April if they can pull it off. The last 80s to 40s in the afternoon in April over a few days was back in 2018. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&v=tmpf&hours=72&month=apr&dir=cool&how=exact&_r=t&dpi=100&_fmt=png

You can see the artificial warm season daytime cooling at Central Park when the ASOS was installed under the trees around 1995. That’s when the decrease in 90° days began to occur. So these charts show the previous 30 years vs the 30 years since the deep shade became a factor under the trees.

Probably related to the big changes in the Pacific SSTs since 2014 along with the more frequent and amplified MJO 4-7s during the winter. A recent paper was just published on this remarkable warming in the North Pacific SST patterns since the 2014 marine heatwave. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101078 The fundamental result of this study is that the first EOF of SST in the North Pacific has changed starting in 2014. For more than 20 years, the PDO has been used to describe the state of the North Pacific. However, since the marine heatwave of 2014, there have been remarkable changes to the dominant mode of SST in the North Pacific. The spatial pattern of the first EOF of SST from 1950 to 2021 is notably different from the PDO, suggesting that though the PDO served as a useful metric of SST variations until 2014 (Johnstone &Mantua, 2014), it may no longer be as effective a climate index for the North Pacific. From 1950 until the 2014 MHW, the first EOF remained consistent in its proportion of positive and negative regions with both taking up roughly half the area of the North Pacific (and with the positive region taken to be the eastern Pacific). When EOFs are calculated from 1950 to endpoints after 2014, the first EOF has a maximum positive region covering 77% of the North Pacific, with a PC indicating the largest anomalies on record. These changes to the first EOF/PC of North Pacific SST are nothing short of remarkable. In concert with these changes, the second EOF/PC of SST has also undergone profound evolutionsince 2014. This second EOF now accounts for approximately 18% of the variability, growing from 13% during the 1950–2013 period. The spatial structure of the second EOF now is positive over almost the entire basin, with a PC that has grown strongly positive in the last several years. Thus, the second EOF/PC describes warming over much of the Pacific not in the positive lobe of the first EOF.

The interesting thing is that we had those 2 cold winters just before the record 9 winters of record warmth since 15-16. Almost like our last really cool summer in 2009 was followed by all the record summer warmth since 2010. The lone top 10 coldest February 2015 month got answered by a record amount of top 10 warmest winter months since then including the +13.3 December 2015 and 80° in February 2018 not to mention all the 40° winters in recent years. Then our lone top 10 coldest June into July 2009 was answered by the warmest summer on record in 2010 and a record number of top 10 warmest summer months since then.