bluewave

This looks like one of those rare times when the warmest temperature between March 1st and 20th is higher than March 21st to April 4th. All the guidance shifted to more blocking from late March into early April. So the early spring much above to record warmth pattern will be on hiatus for a while. EPS March 21 to 28 March 28 to April 4th

The 0z EPS shifted to more blocking in early April from the warmer look it had a few days ago. The Scandinavian Ridge just set a new record for both March and April. So we may have to be patient for spring to make a return following the colder end of March.

Looks like an active storm pattern to close out the month as closed lows roll underneath the blocking.

Large increase in Northeast rainfall and snowfall extremes as the SSTs rapidly warm and water vapor rises. https://phys.org/news/2018-07-extreme-precipitation-northeast.html From Maine to West Virginia, the Northeast has seen a larger increase in extreme precipitation than anywhere else in the U.S. Prior research found that these heavy rain and snow events, defined as a day with about two inches of precipitation or more, have been 53 percent higher in the Northeast since 1996. A Dartmouth study finds that hurricanes and tropical storms are the primary cause of this increase, followed by thunderstorms along fronts and extratropical cyclones like Nor'easters. The findings are published in the Journal of Geophysical Research. Our study provides insight into what types of extreme storms are changing and why. We found that hurricanes were responsible for nearly half of the increase in extreme rainfall across the Northeast. A warmer Atlantic Ocean and more water vapor in the atmosphere are fueling these storms, causing them to drop more rain over the Northeast," explains Jonathan M. Winter, an assistant professor of geography at Dartmouth and co-author of the study. "Other research has demonstrated that these two conditions have been enhanced in our warmer world," added Huanping Huang, a graduate student in earth sciences at Dartmouth and the study's lead author. The findings demonstrate that 88 percent of the extreme precipitation increase after 1996 was caused by large storms in Feb., March, June, July, Sept. and Oct. Hurricanes and tropical storms, also known as "tropical cyclones," accounted for nearly half, or 48 percent, of the increase in extreme rainfall. After 1996, the Northeast experienced almost four times more extreme rainfall events from hurricanes and tropical storms than from 1979-1995. Severe thunderstorms along "fronts," especially intense downpours along cold fronts, accounted for 25 percent of the increase in extreme precipitation. Nor'easters and other "extratropical cyclones," which are storms that form outside of the tropics, accounted for 15 percent of the increase in extreme precipitation. Other research has found that the causes of more frequent extreme precipitation events in this study—increased ocean temperatures, more water vapor in the atmosphere, and a wavier jet stream—are associated with a warmer world. These results build on the team's earlier research by examining what caused the increase in heavier or extreme precipitation beginning in 1996. The researchers analyzed precipitationdata from 1979 to 2016 across the Northeast— Maine, New Hampshire, Vermont, Mass., Conn., R.I., N.J., N.Y., Pa., Md., DC, Del., and W.Va. in conjunction with data pertaining to daily weather maps and oceanic and atmospheric fields. https://journals.ametsoc.org/view/journals/wefo/29/6/waf-d-14-00056_1.xml Abstract On 8–9 February 2013, the northeastern United States experienced a historic winter weather event ranking among the top five worst blizzards in the region. Heavy snowfall and blizzard conditions occurred from northern New Jersey, inland to New York, and northward through Maine. Storm-total snow accumulations of 30–61 cm were common, with maximum accumulations up to 102 cm and snowfall rates exceeding 15 cm h−1. Dual-polarization radar measurements collected for this winter event provide valuable insights into storm microphysical processes. In this study, polarimetric data from the Weather Surveillance Radar-1988 Doppler (WSR-88D) in Upton, New York (KOKX), are investigated alongside thermodynamic analyses from the 13-km Rapid Refresh model and surface precipitation type observations from both Meteorological Phenomena Identification Near the Ground (mPING) and the National Weather Service (NWS) Forecast Office in Upton, New York, for interpretation of polarimetric signatures. The storm exhibited unique polarimetric signatures, some of which have never before been documented for a winter system. Reflectivity values were unusually large, reaching magnitudes >50 dBZ in shallow regions of heavy wet snow near the surface. The 0°C transition line was exceptionally distinct in the polarimetric imagery, providing detail that was often unmatched by the numerical model output. Other features include differential attenuation of magnitudes typical of melting hail, depolarization streaks that provide evidence of electrification, nonuniform beamfilling, a “snow flare” signature, and localized downward excursions of the melting-layer bright band collocated with observed transitions in surface precipitation types. In agreement with previous studies, widespread elevated depositional growth layers, located at temperatures near the model-predicted −15°C isotherm, appear to be correlated with increased snowfall and large reflectivity factors ZH near the surface.

We need a SW to W flow for our local area to reach 100°. This usually requires the ridge axis to build westward toward the Great Lakes. But the ridge axis during recent summers has been elongated to the east of New England. So we get more onshore flow and higher humidity instead of more 100° days. Our most extreme daily heat record in recent years occurred during February 2018. The SE Ridge built to record heights over the region for the entire cold season. This was associated with the 500 mb heights increase as outlined in the presentation at the start of the thread. It was the first time that our area experienced 80° record heat in February. https://www.wunderground.com/cat6/summer-february-80-massachusetts-78-nyc Astonishing summer-like heat cooked the Eastern U.S. on Wednesday, smashing all-time records for February warmth in cities in at least ten states, from Georgia to Maine. At least 24 cities recorded their hottest February temperature on record on Wednesday, including New York City (78°), Hartford, CT (74°) and Concord, NH (74°). According to Weather Underground weather historian Christopher C. Burt, February 20 - 21 marked the most extraordinary heat event to ever affect the Northeastern quadrant of the U.S. during the month of February, since official records began in the late 1800s. He catalogued the following eight states that tied or beat all-time February state heat records over the past two days, noting that in the case of Maine and Vermont, “It is simply amazing to beat a state temperature record by some 8°F!”:Pennsylvania: 83° at Capitol City (ties old record for the state)New York: 79° at La Guardia Airport (old state record 78°)Vermont: 77° at Bennington (old state record 68°)New Hampshire: 77° at Manchester and Danbury (old state record 72°)Maine: 77° at Wells (old state record 69°)New Jersey: 83° at Teterboro (old state record 80°)Massachusetts: 80° at Fitchburg (old state record 73°)Ohio: 80° at Cincinnati Lunken Airport (ties old record for the state)

During recent summers, the high has set up east of New England instead of near Bermuda like in the old days. So this allowed Hartford to record more 90° days than around NYC in 2020. Burlington, Vermont was also able to record their first 80° minimum temperature in 2018. Time Series Summary for Hartford Area, CT (ThreadEx) - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 90 Missing Count 1 2020 39 0 2 1983 38 0 3 2002 35 0 4 2010 34 0 - 1965 34 0 5 2018 32 0 - 1966 32 0 6 2016 31 0 - 1991 31 0 7 1988 30 0 - 1973 30 0 Time Series Summary for LAGUARDIA AIRPORT, NY - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 90 Missing Count 1 2010 48 0 2 2018 38 0 3 2002 35 0 4 2020 34 0 - 1991 34 0 5 2016 32 0 6 1983 31 0 7 2005 30 0 - 1953 30 0 Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 90 Missing Count 1 2010 54 0 2 1993 49 0 3 1988 43 0 4 2021 41 0 - 2002 41 0 - 1991 41 0 5 2016 40 0 - 1983 40 0 - 1959 40 0 6 1994 39 0 - 1944 39 0 7 2005 37 0 - 1987 37 0 8 2018 36 0 - 1949 36 0 9 2015 35 0

As the subtropical ridge expanded northward to the Canadian Maritimes, the flow became more S to SSE. So this has allowed the record high dew points to move into the region during recent summers. At times the result was higher actual temperatures into New England than around NYC Metro. This was due to a more SW flow into those areas. But both our area and New England have experienced the warmest and most humid summers on record summers since 2010.

The EPS has our next big warm up during the first week of April.

The best we have done during the last week of March since the snowier era began in 2003 has been a trace. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Ending Date Total Snowfall Mar 25 to Mar 31 Missing Count 2021-03-31 0.0 0 2020-03-31 0.0 0 2019-03-31 0.0 0 2018-03-31 T 0 2017-03-31 0.0 0 2016-03-31 0.0 0 2015-03-31 T 0 2014-03-31 T 0 2013-03-31 T 0 2012-03-31 0.0 0 2011-03-31 0.0 0 2010-03-31 0.0 0 2009-03-31 0.0 0 2008-03-31 0.0 0 2007-03-31 0.0 0 2006-03-31 0.0 0 2005-03-31 0.0 0 2004-03-31 0.0 0 2003-03-31 T 0

Doesn’t look like there will be any 80° days this March. So we won’t be able to make it 3 in a row. This will only be the 2nd March since 2010 to have the monthly maximum temperature during the first week. Warmest March temperatures and date since 2010 Newark 3-7-22…...76° 3-26-21….84° 3-20-20…80° 3-15-19….77° 3-30-18...62° 3-1-17…….73° 3-9-16……82° 3-26-15….64° 3-11-14…..67° 3-30-13….61° 3-22-12….79° 3-18-11…..80° 3-20-10….75°

While the blocking pattern coming up doesn’t look like the strongest we have seen this time of year, it’s enough for the backdoor boundary to stall near our area in late March. Less warm temperatures after today than we have been experiencing. Then a slow moving storm system next week under the block. We’ll have to see if NYC can get the last freeze of the season around the 29th which has been the 15 year average. 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. Year Last Value First Value Season Length Minimum 03-01 (2020) 10-31 (2020) 215 Mean 03-29 11-19 235 Maximum 04-16 (2014) 12-10 (2011) 257 2021 04-03 (2021) 32 11-23 (2021) 32 233 2020 03-01 (2020) 25 10-31 (2020) 32 243 2019 03-18 (2019) 32 11-08 (2019) 29 234 2018 04-09 (2018) 32 11-14 (2018) 32 218 2017 03-23 (2017) 23 11-10 (2017) 25 231 2016 04-10 (2016) 31 12-09 (2016) 29 242 2015 04-01 (2015) 32 11-24 (2015) 32 236 2014 04-16 (2014) 31 11-18 (2014) 24 215 2013 03-23 (2013) 32 11-12 (2013) 31 233 2012 03-27 (2012) 30 11-06 (2012) 31 223 2011 03-29 (2011) 31 12-10 (2011) 32 255 2010 03-27 (2010) 29 12-04 (2010) 32 251 2009 03-24 (2009) 27 12-07 (2009) 32 257 2008 03-30 (2008) 28 11-18 (2008) 29 232 2007 04-09 (2007) 32 11-11 (2007) 31 215

Westchester is currently at the 10th warmest March through the 18th. NYC and other areas are just outside the top 10. Plenty of competition for even warmer recent years. Time Series Summary for WESTCHESTER CO AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Mar 1 to Mar 18 Missing Count 1 2016-03-18 45.2 0 2 2012-03-18 45.0 0 3 1973-03-18 44.4 0 4 2020-03-18 43.9 1 5 1983-03-18 43.5 0 6 2010-03-18 43.1 0 7 1990-03-18 42.5 1 8 1977-03-18 41.6 0 9 2000-03-18 41.1 7 10 2022-03-18 40.8 0 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 Mar 1 to Mar 18 Missing Count 1 2016-03-18 49.0 0 2 2012-03-18 48.3 0 3 2020-03-18 48.2 0 4 1977-03-18 47.7 0 5 1973-03-18 47.3 0 - 1921-03-18 47.3 0 6 1946-03-18 46.7 0 7 2010-03-18 46.3 0 8 1990-03-18 46.2 0 9 2000-03-18 46.0 0 10 1903-03-18 45.6 0 11 1945-03-18 45.5 0 12 1878-03-18 45.4 0 13 2022-03-18 45.1 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Mar 1 to Mar 18 Missing Count 1 1973-03-18 46.3 0 2 2016-03-18 45.3 0 3 2012-03-18 44.2 0 4 2020-03-18 43.9 0 5 2010-03-18 43.6 0 6 1977-03-18 43.4 0 7 2000-03-18 42.5 0 8 1983-03-18 41.9 0 - 1974-03-18 41.9 0 9 2011-03-18 41.6 0 10 1990-03-18 41.4 0 11 2022-03-18 41.3 0

Today could be our last shot at 70s this month. Models have a wetter pattern by next week with more blocking. Then maybe our last freeze potential in late March.

Record highs to our north today.

It kept the beach traffic out of Long Beach that summer. While the residents loved it, the merchants that depended on beach crowds weren’t too happy. But it was nice having the bike lane on the Boardwalk less crowded.

2009 was the last cool summer around the area.

Last summer was the first time in years that Newark lead the area in 90° days. So it’s all about where the warmest temperatures set up. But one of the stations in the NE NJ urban corridor usually has the most 90° days. Data for April 1, 2021 through October 31, 2021 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 NJ NEWARK LIBERTY INTL AP WBAN 41 NJ HARRISON COOP 38 NJ CALDWELL ESSEX COUNTY AP WBAN 37 NJ CANOE BROOK COOP 32 NY LAGUARDIA AIRPORT WBAN 25 Data for April 1, 2020 through October 31, 2020 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 NJ HARRISON COOP 39 NJ CANOE BROOK COOP 37 NJ CALDWELL ESSEX COUNTY AP WBAN 37 NY LAGUARDIA AIRPORT WBAN 34 NJ NEWARK LIBERTY INTL AP WBAN 31 Data for April 1, 2019 through October 31, 2019 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 NJ HARRISON COOP 39 NJ TETERBORO AIRPORT WBAN 37 NJ CALDWELL ESSEX COUNTY AP WBAN 36 NJ CANOE BROOK COOP 31 NJ NEWARK LIBERTY INTL AP WBAN 27 NY LAGUARDIA AIRPORT WBAN 26 Data for April 1, 2018 through October 31, 2018 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 NJ HARRISON COOP 47 NJ TETERBORO AIRPORT WBAN 46 NJ CANOE BROOK COOP 38 NY LAGUARDIA AIRPORT WBAN 38 NJ NEWARK LIBERTY INTL AP WBAN 36

3 days reaching 70° or warmer used to be a rarity before the start of astronomical spring.

It was always forecast to be a final dynamic warming with a transient -NAO -AO block. Looks like we could see a slow moving closed low. So there is the chance of some heavier rains with a slow moving system under the block.

Taste of spring next few days. Widespread 70s today. Some spots may reach 70° again tomorrow. Then a chance of thunderstorms on Saturday which could be locally strong to severe.

https://www.nature.com/articles/s41558-021-01159-7.epdf?sharing_token=_FVaOVyABkcD2Hudkuy4HdRgN0jAjWel9jnR3ZoTv0O_gxR6rgaJtPXjMaI-B_Efht4SyFms8mqqnoqmB-1adVBLGM5Ox8NTZgYnk58C8f_MqmRXlgMUKAvhPoz3ntaVpIMcZZ9PrSyXcXowWePIeqVtKWaAjhHN6qpaUvjsKJPMu2-ItgHqBkpP-ekBm2TbTkyKT4Ld921Svm7C1wJQmod5-Am_0W6rnLf3GjdTJ9U%3D&tracking_referrer=www.theguardian.com Abstract The northeastern United States (NEUS) and the adjacent Northwest Atlantic Shelf (NWS) have emerged as warming hotspots, but the connection between them remains unexplored. Here we use gridded observational and reanalysis datasets to show that the twentieth-century surface air temperature increase along the coastal NEUS is exceptional on the continental and hemispheric scale and is induced by a combination of two factors: the sea surface temperature (SST) increase in the NWS associated with a weakening Atlantic Meridional Overturning Circulation (AMOC), and atmospheric circulation changes associated with a more persistent positive North Atlantic Oscillation. These connections are important because AMOC slowdown and NWS warming are projected to continue. A survey of climate model simulations indicates that realistic SST representation at high spatial resolution might be a minimum requirement to capture the observed pattern of coastal warming, suggesting that prior projection-based assessments may not have captured key features in this populous region.

Models going for the final dynamic warming around March 25th. So we get a brief interruption of the spring pattern with some blocking and cooler temperatures. The persistent La Niña background state returns to start April with a warmer -PNA SE Ridge pattern .

JFK can hit 70° on Friday if the winds stay westerly for long enough. If we keep the offshore flow long enough, then it will be possible. The models have a wind shift in the afternoon. So it may be a race to see how warm we get before the SE flow and clouds arrive.

The warm spots away from the shore in NJ make another run on 70° today. Friday looks like it will be the warmest day of the week. Widespread readings in the 70-75 range.