bluewave

The last two El Niños going over +2.0 had these La Niña-like tendencies overlapping with the El Niño. The SSTs have been so warm through the Indian Ocean into the Western Pacific, that the MJO 4-7 forcing has been very active. In the old days when cooler SSTs prevailed there, the MJO was quiet in these more Niña-like phases during such strong El Niños. Obviously, December 2015 was the most extreme example of this. That historic month actually had the strong MJO 5 combine with the El Niño to produce the record +13 month in the Northeast. None of the long range models had this in the forecast for December. The unusual Niña-like MJO 4-6 in January 2024 with a Southeast ridge wasn’t anticipated by the seasonal models. They had the classic El Niño stock composite and a deep trough in the Mid-Atlantic and Southeast. The record heat this week with the forcing coming out of the 4 region wasn’t well forecast back at the start of May. https://phys.org/news/2021-04-distinctive-mjo-super-el-nino.html A research group, led by Dr. Wenjun Zhang from the Nanjing University of Information Science and Technology analyzed MJO activity of the super El Niño event during the Northern Hemisphere winter of 2015/16. Observations show that the western Pacific MJO activity was strongly suppressed during the peak phase of the 1982/83 and 1997/98 super El Niño events. However, during the crest of the 2015/16 super El Niño event, western Pacific MJO-related convection was enhanced. "It is apparent that the enhanced western Pacific MJO is mainly related to its sea surface temperature (SST) anomaly distribution and the associated background thermodynamic conditions." said Dr. Zhang. His team's complete research and data are published in Advances in Atmospheric Sciences. When compared to the previous super El Niño events, the warm SST anomaly, or change from average, of the 2015/16 El Niño was located more westward than during the other two extreme seasons. Additionally, no significant cold SST anomaly was detected in the western Pacific. Accordingly, the moisture and air temperature tended to increase in the central-western Pacific during the winter of 2015/16 unlike the previous super El Niño events. This research highlights that climatologists should consider the SST anomaly distribution of super El Niño events for future MJO activity studies. https://journals.ametsoc.org/view/journals/clim/38/23/JCLI-D-24-0689.1.xml Easterly anomalies occurred in the equatorial central Pacific “unexpectedly” in January 2024, when an El Niño was at its peak. The cause of this “abnormal” zonal wind condition is investigated through the decomposition of multi-time-scale signals. The result indicates that the easterly anomalies arose from the combined effects of the Madden–Julian oscillation (MJO), the interdecadal variability–global warming trend (IDGT) signal and the “pure” interannual signal. It is found that a slowly moving active-phase MJO appeared over the Indo-Pacific warm pool during January 2024, and, as a result, there is a net positive precipitation anomaly over the warm pool, leading to easterly anomalies in the western-central equatorial Pacific. The IDGT signal since 1979 exhibits an enhanced zonal sea surface temperature (SST) gradient across the equatorial Pacific, which strengthens the trade wind at the equator. The summation of the MJO and IDGT signals surpassed the El Niño–induced westerly anomaly, leading to an unexpected equatorial easterly anomaly in January 2024. An assessment of observational data since 1979 shows a 10% chance of the occurrence of such an “uncoupling” during El Niño, during which the MJO and/or IDGT modes did play a role. https://pubmed.ncbi.nlm.nih.gov/31776488/ Here we show that rapid warming over the tropical oceans during 1981-2018 has warped the MJO life cycle, with its residence time decreasing over the Indian Ocean by 3-4 days, and increasing over the Indo-Pacific Maritime Continent by 5-6 days. We find that these changes in the MJO life cycle are associated with a twofold expansion of the Indo-Pacific warm pool, the largest expanse of the warmest ocean temperatures on Earth. The warm pool has been expanding on average by 2.3 × 105 km2 (the size of Washington State) per year during 1900-2018 and at an accelerated average rate of 4 × 105 km2 (the size of California) per year during 1981-2018. The changes in the Indo-Pacific warm pool and the MJO are related to increased rainfall over southeast Asia, northern Australia, Southwest Africa and the Amazon, and drying over the west coast of the United States and Ecuador.

Highs approaching the May monthly max in NJ today. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of May Highest Monthly Maximum Temperature Click column heading to sort ascending, click again to sort descending. 1 1996 99 0 2 2022 98 0 - 1992 98 0 - 1987 98 0 - 1962 98 0 3 1965 97 0 - 1895 97 0 4 2021 96 0 - 2016 96 0 - 1969 96 0 - 1964 96 0 - 1914 96 0 - 1880 96 0 5 2010 95 0 - 1994 95 0 - 1986 95 0 - 1941 95 0 - 1939 95 0 Monthly Data for May 1996 for New Jersey Click column heading to sort ascending, click again to sort descending. PENNSAUKEN 1N COOP 100 NEWARK LIBERTY INTL AP WBAN 99 Newark Area ThreadEx 99 TOMS RIVER COOP 99 PHILADELPHIA/MT. HOLLY WFO COOP 98 PEMBERTON COOP 98 PLAINFIELD COOP 97 INDIAN MILLS 2 W COOP 97 CRANFORD COOP 96 JERSEY CITY COOP 96 PHILLIPSBURG-EASTON BRIDGE COOP 96 TETERBORO AIRPORT WBAN 96 LITTLE FALLS COOP 96 WAYNE COOP 96 WANAQUE RAYMOND DAM COOP 96 HARRISON COOP 96 Atlantic City Area ThreadEx 96 BELLEPLAIN STA FOREST COOP 96 ATLANTIC CITY INTL AP WBAN 96 WOODSTOWN PITTSGROV 4E COOP 96 MOORESTOWN 4 E COOP 96 Monthly Data for May 2022 for New Jersey Click column heading to sort ascending, click again to sort descending. NEWARK LIBERTY INTL AP WBAN 98 TETERBORO AIRPORT WBAN 98 Newark Area ThreadEx 98 ESTELL MANOR COOP 96 HARRISON COOP 96 SOUTH JERSEY REGIONAL AIRPORT WBAN 96 ATLANTIC CITY INTL AP WBAN 95 INDIAN MILLS 2 W COOP 95 CALDWELL ESSEX COUNTY AP WBAN 95 AEROFLEX-ANDOVER AIRPORT WBAN 95 SOMERSET AIRPORT WBAN 95 EB FORSYTHE NEW JERSEY RAWS 95 Atlantic City Area ThreadEx 95

Yeah, that EC-AIFS frontal stall isn’t pretty. Let’s hope the front at least clears the area by Memorial Day. But the slow moving front and easterly winds signal is there for rain at least one day out of the three from Saturday to Monday.

Looks like we will keep the cooler with rain chances theme going again this year for the extended Memorial Day weekend.

While it would nice to pick up some soaking rains with the sharp cold front following the near to record heat this week, these fronts have had a tendency to dry out crossing the mountains before reaching the coast.

The developing El Niño isn’t the only thing going on now. The early month pattern with the more +PNA was closer to what we typically see with the May correlation. But this coming heatwave is more related to the MJO 4-6 convection pumping the Southeast ridge. The +30C wam pool extends all the way back to the IO.

You can see the general outline of the May El Niño 500 mb composite taking shape with alterations probably due to the competing marine heatwaves. The coming near to record May heatwave forecast for the East next week is much warmer than we typically see with such strong developing El Niños. Stronger Southeast ridge could be a function of the weaker RONI relative to ONI and more general subtropical ridging adding a more Niña-like flavor to the mix. The May Western North America El Niño ridge is located a little further SW than usual with the weaker Baja trough than they typically see. May 4th to 11th strong Nino ridge in SW Canada and Aleutian low north of Hawaii Forecast May 18th to 25th

Yeah, Islip is only ranked 13th warmest this spring for average high temperature due to the strong onshore flow influence. Areas to the west of the sea breeze are the top 5 for spring warmth. So next week looks like more of the same theme. Time Series Summary for ISLIP-LI MACARTHUR AP, NY Average Max Temp Mar 1 to May 14 Click column heading to sort ascending, click again to sort descending. 1 2010-05-14 60.5 0 2 2025-05-14 60.0 0 - 2012-05-14 60.0 0 3 2023-05-14 58.5 0 4 1991-05-14 58.1 0 5 2021-05-14 57.8 0 - 1999-05-14 57.8 0 6 2024-05-14 57.6 0 - 1977-05-14 57.6 0 - 1976-05-14 57.6 0 7 2002-05-14 57.5 0 8 2000-05-14 57.4 0 9 2016-05-14 57.1 0 10 1973-05-14 57.0 0 11 1985-05-14 56.9 0 12 2022-05-14 56.7 0 13 2026-05-14 56.4 0 14 2008-05-14 56.3 0 15 2006-05-14 56.2 0 - 1974-05-14 56.2 0 Time Series Summary for SUSSEX AIRPORT, NJ Click column heading to sort ascending, click again to sort descending. 1 2012-05-14 62.7 0 2 2025-05-14 62.4 0 3 2010-05-14 62.3 0 4 2026-05-14 61.5 0 5 2023-05-14 60.3 0 6 2024-05-14 60.2 0 7 2021-05-14 59.4 0 8 2016-05-14 59.3 0 9 2006-05-14 58.5 0 10 2004-05-14 58.1 0 Time Series Summary for PHILADELPHIA/MT. HOLLY WFO, NJ Click column heading to sort ascending, click again to sort descending. 1 2010-05-14 64.6 0 2 2025-05-14 64.5 0 3 2012-05-14 63.9 0 4 2026-05-14 63.8 0 5 2000-05-14 63.4 0 6 2002-05-14 62.5 0 7 2006-05-14 62.2 0 8 2024-05-14 62.1 0 9 2023-05-14 61.8 0 10 2021-05-14 61.6 0

Yeah, I can remember days like this living in Long Beach. Current forecast is for 40mph or higher SSW gusts along the South Shore Tuesday and Wednesday. So plenty of dangerous rip currents expected. People should stay out of the water especially before the lifeguard season starts.

The model mean is currently 94-99° for the usual NJ warm spots. So the drought both in the source region and locally should enhance. Since this is one of the worst droughts across the CONUS for the month of May. The record NJ high for the month of May is 99°. So some monthly maxes could be in jeopardy. Still around 5 days out so we can still refine. NJ made it to 98° in May back in 2022. In any event, we haven’t seen this type of May heat before leading into such a strong El Niño. May 2015 only made it to 91° in Newark. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Month of May Highest Maximum Temperature Click column heading to sort ascending, click again to sort descending. 1 1996 99 0 2 2022 98 0 - 1992 98 0 - 1987 98 0 - 1962 98 0 3 1965 97 0 - 1895 97 0 4 2021 96 0 - 2016 96 0 - 1969 96 0 - 1964 96 0 - 1914 96 0 - 1880 96 0 5 2010 95 0 - 1994 95 0 - 1986 95 0 - 1941 95 0 - 1939 95 0 The strongest developing El Niño May maxes 2023 90 0 2015 91 0 1997 86 1982 85 1972 82

It will be interesting to see if Philly can record their first 3 consecutive years under 40.00” since the early 1990s . Long range precipitation forecasting is very uncertain. The hope is that the STJ can come far enough north with the developing super El Niño to increase the rainfall enough in coming months to get over 40.00” by the end of December. Many spots have been running drier than average starting with the big dip in rainfall in September into October 2024. Monthly Total Precipitation for Philadelphia Area, PA (ThreadEx) Click column heading to sort ascending, click again to sort descending. 2026 2.84 2.24 1.90 2.11 0.37 M M M M M M M 9.46 2025 0.93 2.05 5.36 2.83 6.22 2.20 4.61 1.73 1.79 2.02 2.30 3.35 35.39 2024 5.91 1.49 7.19 4.16 1.72 4.68 2.44 5.07 0.77 T 2.52 3.45 39.40 2023 3.36 1.32 1.99 5.17 0.24 4.24 5.24 3.25 5.99 0.72 2.75 7.92 42.19 2022 3.35 2.87 2.09 4.51 4.16 5.03 2.20 2.70 2.06 5.80 2.89 4.85 42.51 2021 1.55 4.64 4.21 2.69 3.24 3.06 6.72 6.18 4.61 4.81 0.46 1.64 43.81 2020 2.64 2.46 3.94 3.75 2.20 3.21 5.54 8.53 4.23 4.09 4.79 4.38 49.76 2019 3.92 3.27 3.85 3.02 5.22 7.94 6.03 2.78 1.16 3.87 1.16 5.21 47.43 2018 2.85 6.02 4.74 3.94 5.21 3.34 3.06 4.11 9.76 3.08 9.03 6.38 61.52 2017 2.91 1.30 4.26 3.15 6.33 1.86 5.35 6.05 3.86 3.66 1.30 1.31 41.34 2016 2.63 4.36 2.01 1.75 6.65 1.87 3.88 1.70 3.52 2.06 2.17 2.72 35.32 2015 4.52 2.36 5.52 3.58 1.19 8.88 3.16 0.98 6.27 3.76 1.89 5.14 47.25 2014 3.55 5.12 4.23 6.69 2.91 5.46 4.30 3.55 1.69 2.53 4.07 3.27 47.37 2013 3.34 2.12 2.42 2.32 2.33 10.56 13.24 5.91 3.26 2.45 2.73 5.20 55.88 2012 2.59 1.84 0.79 2.55 3.35 2.94 1.48 5.37 5.48 4.08 1.05 4.42 35.94 2011 3.39 2.65 4.29 5.29 1.91 2.56 2.71 19.31 10.27 3.71 3.87 4.37 64.33 2010 2.19 5.75 7.33 2.65 2.53 2.05 6.28 2.19 3.48 5.01 1.76 3.24 44.46 2009 2.70 0.84 1.62 3.99 4.84 4.79 3.35 10.29 3.65 5.51 2.06 8.86 52.50 2008 1.74 3.93 3.67 2.19 4.55 2.87 3.45 2.44 4.31 1.59 4.02 5.57 40.33 2007 3.35 1.73 3.82 9.05 2.68 4.02 3.44 2.94 0.58 4.66 1.45 4.41 42.13 2006 4.34 1.51 0.91 3.71 2.16 7.95 4.27 3.93 5.97 6.42 4.88 2.15 48.20 2005 4.45 2.61 3.66 5.32 1.27 3.31 4.31 2.57 0.21 8.68 2.86 2.97 42.22 2004 1.70 2.50 3.54 6.02 3.62 4.57 7.91 4.17 5.19 2.24 4.55 3.17 49.18 2003 1.93 5.04 4.09 2.20 4.17 8.08 2.01 3.26 4.66 4.45 2.63 5.46 47.98 2002 2.43 0.55 4.03 2.17 3.57 3.73 2.12 2.47 3.67 5.90 4.65 4.05 39.34 2001 2.77 3.04 5.44 1.49 3.99 5.93 1.30 0.97 2.58 0.83 0.56 2.11 31.01 2000 3.22 2.02 6.32 3.05 3.03 3.82 5.54 2.90 8.28 1.51 2.21 2.82 44.72 1999 4.89 2.95 4.02 3.31 3.70 1.16 1.22 5.32 13.07 3.55 2.31 2.99 48.49 1998 4.24 3.25 3.93 2.70 3.87 4.91 1.79 1.26 1.86 1.84 1.18 0.82 31.65 1997 2.80 2.48 3.91 2.58 2.32 1.49 2.38 4.56 1.59 1.83 3.49 3.09 32.52 1996 4.39 2.12 4.27 4.48 3.25 4.73 8.17 4.29 4.95 4.30 3.03 8.47 56.45 1995 3.10 2.41 1.67 1.96 2.67 0.62 2.92 1.15 3.55 5.99 3.34 2.15 31.53 1994 4.27 3.27 6.44 2.86 3.66 1.74 10.42 4.54 1.64 0.94 3.03 2.11 44.92 1993 1.97 3.03 6.61 4.20 2.42 1.52 1.98 5.18 6.66 2.69 2.23 3.69 42.18 1992 0.88 1.31 3.19 1.26 2.74 1.84 5.05 2.00 3.04 1.23 3.26 4.61 30.41 1991 4.10 0.75 4.13 2.81 1.82 3.36 4.79 3.86 3.58 1.61 1.55 3.86 36.22 1990 4.09 1.44 2.59 3.16 6.08 3.39 2.62 4.07 1.71 1.68 1.17 3.79 35.79 1989 2.41 3.25 4.41 2.27 6.76 4.73 9.44 3.92 5.03 3.44 1.79 1.21 48.66 1988 2.72 4.11 2.24 2.92 3.67 0.57 8.07 3.16 2.62 2.16 5.17 1.00 38.41 1987 4.58 1.17 1.16 3.63 3.15 2.01 4.82 3.72 2.78 2.62 2.08 1.68 33.40 1986 4.13 3.38 1.25 4.46 0.70 1.99 4.10 3.70 2.33 2.22 6.27 5.89 40.42 1985 1.55 2.44 1.95 0.52 4.99 1.88 4.66 2.82 5.78 1.54 6.09 0.98 35.20 1984 2.22 2.81 6.14 4.25 6.87 2.85 6.99 3.28 1.96 2.56 1.56 2.17 43.66 1983 2.81 3.53 6.95 8.12 7.03 2.75 0.68 2.57 3.45 3.69 5.71 7.37 54.66 1982 4.45 3.16 2.66 6.06 4.47 5.76 1.94 2.20 2.32 1.94 3.67 1.80 40.43 1981 0.50 2.94 1.61 3.60 4.53 4.40 4.54 5.11 2.83 2.68 0.95 4.14 37.83 1980 2.27 0.96 7.01 4.79 3.22 1.73 6.58 0.80 2.79 5.03 2.85 0.77 38.80 1979 8.74 6.44 2.43 4.08 3.98 4.34 3.95 5.95 4.89 3.84 2.48 1.67 52.79 1978 8.86 1.35 4.31 1.76 6.01 1.75 5.27 6.04 1.59 1.20 2.20 5.61 45.95 1977 2.61 1.33 4.19 5.59 0.70 5.33 1.47 8.70 3.44 3.11 7.76 5.19 49.42 1976 4.50 1.66 2.38 2.06 4.35 3.42 4.04 2.17 2.44 4.30 0.32 1.63 33.27 1975 4.00 2.91 4.68 2.97 4.99 7.57 6.32 2.21 7.21 3.24 3.14 2.89 52.13 1974 2.95 2.14 4.91 2.77 3.21 4.43 2.08 3.83 4.68 1.93 0.81 4.04 37.78 1973 3.93 2.96 3.52 6.68 4.14 7.88 2.39 2.03 3.39 2.16 0.64 6.34 46.06 1972 2.34 5.09 2.69 4.08 4.11 5.79 2.62 3.76 1.12 3.77 9.06 5.20 49.63 1971 2.13 5.43 2.58 1.84 4.10 1.01 4.84 9.61 5.83 3.84 5.37 1.21 47.79 1970 0.74 2.08 3.83 6.12 2.57 4.60 2.75 3.99 0.82 3.66 4.71 3.27 39.14 1969 1.57 1.88 1.92 1.68 3.30 7.31 8.33 2.66 4.38 1.13 1.97 7.23 43.36 1968 2.90 1.40 4.98 1.57 5.17 5.89 2.00 1.24 0.44 3.15 4.17 2.54 35.45 1967 1.67 1.82 4.53 2.17 3.49 4.12 7.11 7.08 2.96 2.00 1.99 5.88 44.82 1966 2.82 4.30 0.68 4.35 2.95 0.41 2.35 1.63 8.70 5.12 2.36 4.33 40.00 1965 2.35 2.18 3.19 2.33 1.23 2.85 3.22 4.05 3.02 2.02 1.05 1.85 29.34 1964 3.92 2.83 1.94 5.27 0.47 0.21 3.83 0.49 2.42 1.73 1.64 5.13 29.88 1963 2.31 2.19 3.94 1.13 1.06 2.88 3.13 3.35 6.44 0.09 6.67 1.76 34.95

At least we are doing better than areas just to our south. Through May 14th Philly is having their 4th driest March 1st through May 13th. The drought should help boost the high temperatures in the usual warm spots next week. Pretty impressive to see the GFS, Euro, and CMC all showing 95+ potential for the usual warm spots. Time Series Summary for Philadelphia Area, PA (ThreadEx) Driest March 1 to May 13 Click column heading to sort ascending, click again to sort descending. 1 1926-05-13 3.79 0 2 1938-05-13 4.20 0 3 1930-05-13 4.32 0 4 2026-05-13 4.38 0 5 2012-05-13 4.42 0 6 1995-05-13 4.64 0 7 1985-05-13 4.71 0 8 1969-05-13 4.77 0 9 1887-05-13 4.91 0 10 1883-05-13 4.98 0

Yeah, we had the split forcing in the 2023-2024 El Niño with the record warm pool near the Dateline and another center off of Mexico like we are currently seeing. The 1997-1998 El Niño had very east based forcing since Nino 4 was so much cooler. 2023-2024 was more of a full basin event rather than an east based one like 1997-1998.

While the NAM often had unrealistic precipitation amounts especially since it wasn’t upgraded in almost 10 years, it did do much better than other models with the warm nose at 700mb to 800mb and snow to mix precipitation timing. So we may just have to compensate for this by manually speeding up the snow to mix precipitation timing in situations which the other models are too weak with the 700-800 MB WAA. The other story is that the SPC HREF was one of the best models showing snow banding and extreme heavy precipitation amounts. It did very well with the late February KU and several flash flooding events over the years.

I like focusing on where the +30C warm pools are. Since the actual forcing driving our sensible weather follows those areas. The current forecast is for split forcing centers near the Dateline and off of Mexico in late May.That Dateline forcing is closer to near record Nino 4 and MJO 7 and the forcing further east is with the record +PMM.