bluewave

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.

Not much outside of the Great Lakes this spring. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=24&which=cd&csector=conus&var=precip&w=rank&p=day&year=2026&month=4&sdate=2026%2F03%2F01&edate=2026%2F05%2F13&cmap=RdYlBu&cmap_r=on&_r=t&dpi=100&_fmt=png

JMA has the current velocity potential and an archive with 5 day to 3 month means. https://www.data.jma.go.jp/tcc/tcc/products/clisys/figures/db_hist_mon_tcc.html