donsutherland1

Morning thoughts... 1. Snow fell in parts of the Great Lakes region yesterday. Snowfall amounts included 1.7" in Chicago (old daily record: 1.5", 1980) and 1.3" in Detroit. 2. Following the system, temperatures were in the 20s across that region this morning. Low temperatures included: Chicago: 28; Detroit: 25; Indianapolis: 24; Milwaukee: 26; and, Rockford: 23. 3. Another storm will move eastward out of the Plains States tomorrow and then off the East Coast on Saturday. It will likely bring a swath of snow across parts of the Great Lakes region, across northeastern Pennsylvania and then into New England. Initial snowfall ideas: Albany: 3”-6” Binghamton: 4”-8” Boston: 2” or less Chicago: 1"-3" Detroit: 1"-3" Scranton: 2”-4” No accumulations are likely in New York City, Newark, and Philadelphia where a cold rain is likely.

Probably not. Some sleet pellets are possible.

Cooler weather covered the region today. Late this week into the weekend, a storm will come out of the Plains States bringing a cold rain to the coastal region of the Middle Atlantic States, including Philadelphia, Newark, and New York City. An area stretching from northeastern Pennsylvania across central New York State and into central New England could pick up at least some snow. Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Support on the extended guidance for a return of warmer than normal conditions for the closing days of April has increased. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. In addition, two-thirds of cases that saw the MJO reach Phase 8 at an amplitude of 2.000 or above during the April 5-20 period, as happened this month, saw a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.72°C and the ENSO Region 3.4 anomaly has averaged +0.58°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was -5.41 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.278. On April 14, the MJO was in Phase 1 at an amplitude of 1.413 (RMM). The April 13-adjusted amplitude was 1.592. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 58% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

Morning thoughts... 1. A dense area of clouds that stretches from eastern North Carolina to southeastern New Hampshire will shift eastward this morning leading to sunshine in the New York Metro Area and later Long Island. 2. The region is now in a period where readings will generally average somewhat below normal to near normal with perhaps a few milder days. 3. Late this week and early this weekend, a storm coming out of the Plains States will likely spread a cold rain to coastal areas. Interior parts of Pennsylvania, northwestern New Jersey, along with central New York State, and central New England could see at least some snow. 4. There continues to be growing support in the long-range for a warmer pattern to develop in the closing days of April.

I tend to doubt it, at least as far as the coastal areas or nearby regions are concerned.

Following yesterday's fierce storm, more tranquil weather returned. The temperature topped out in the upper 50s and lower 60s across the region. Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Some of the extended guidance shows the return of warmer conditions for the closing days of April. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. In addition, two-thirds of cases that saw the MJO reach Phase 8 at an amplitude of 2.000 or above during the April 5-20 period, as happened this month, saw a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.72°C and the ENSO Region 3.4 anomaly has averaged +0.58°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +7.21 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.658. On April 13, the MJO was in Phase 1 at an amplitude of 1.589 (RMM). The April 12-adjusted amplitude was 1.911. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 56% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

Morning thoughts... 1. Following yesterday's daily record 1.92" precipitation in Central Park (old record: 1.26", 1920), sunshine has returned. The high temperature will likely top out in the middle and upper 50s in contrast to yesterday's late day high of 67. 2. This morning record cold covered parts of the Plains States. Records included: Colorado Springs: 7 (old record: 8, 1933); Denver: 11 (old record: 15, 1933); Grand Forks, ND: 4 (old record: 8, 1950); Lincoln, NE: 16 (tied record set in 1950); North Platte, NE: 15 (tied record set in 1928); Rapid City: 5 (old record: 13, 2018); and, Rochester, MN: 14 (old record: 18, 1962). 3. Through the next 7-10 days, a generally cooler than normal pattern with much below normal temperatures centered over the Plains States will likely prevail. In the Middle Atlantic and southern New England regions, readings will generally be somewhat below normal to near normal with a few milder days. 4. A warmer pattern could begin to develop during the closing days of April.

A rapidly deepening storm brought high winds and heavy rain to the region today. With 1.92", New York City had its largest precipitation amount since September 25, 2019 when 1.95" precipitation was recorded. In the wake of the intense storm, somewhat cooler air will return to the region. Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. In addition, two-thirds of cases that saw the MJO reach Phase 8 at an amplitude of 2.000 or above during the April 5-20 period, as happened this month, saw a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.72°C and the ENSO Region 3.4 anomaly has averaged +0.58°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +16.65 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.178. On April 12, the MJO was in Phase 8 at an amplitude of 1.917 (RMM). The April 11-adjusted amplitude was 2.179. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 56% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

Thanks Maureen.

At 2 pm, the temperature was 59° with strong southeasterly winds.

As of 10 am, New York City had received 1.17” rain. This is the biggest precipitation amount this year. The last time with at least as much precipitation was December 9, 2019 when 1.57” fell.

Today saw partly cloudy skies with high temperatures reaching the upper 50s and lower 60s. Clouds will increase tonight. Overnight, a rapidly deepening storm will track toward the Great Lakes. By tomorrow night, the storm could have a central pressure under 970 mb as it pushes through Quebec. Before then, this storm will spread periods of moderate to heavy rain into the region tonight into tomorrow. Rainfall amounts will likely total 0.75"-1.75" with some locally higher amounts in excess of 2.00". Strong winds with gusts past 65 mph are likely tomorrow. The potential also exists for some strong to possibly severe thunderstorms. Colder air should return for Tuesday. This is a genuinely cold air mass. Earlier today, the temperature fell to -3° in Great Falls. The only other times the temperature fell below zero this late in the season was April 20 (-1°) and April 22 (-8°) in 2008. Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Sunday and Monday are among the days that could see temperatures reach above normal levels. The Plains States will likely experience much colder than normal readings. The potential exists for warming after April 24. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. In addition, two-thirds of cases that saw the MJO reach Phase 8 at an amplitude of 2.000 or above during the April 5-20 period, as happened this month, saw a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +15.50 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.695. On April 11, the MJO was in Phase 8 at an amplitude of 2.179 (RMM). The April 10-adjusted amplitude was 2.066. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 55% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

Under bright sunshine, temperatures rose into the 50s across the region today. Record warmth prevailed in parts of the United Kingdom, Ireland and France. In parts of the United Kingdom and Ireland, temperatures approached all-time April records. Daily records included: Birmingham, UK: 75°; Brest, France: 75°; Cork, Ireland: 66°; Cranwell, UK: 75°; Dublin: 66°; East Midlands, UK: 72°; Humberside, UK: 75°; Jersey, UK: 75°; London-Gatwick: 75°; London-Heathrow: 75°; Manchester, UK: 66°; Paris-Charles de Gaulle: 77°; Paris-Le Bourget: 77°; Saint-Yan, France: 77°; Scampton, UK: 73°; Troyes, France: 77°; and, Yeovilton, UK: 77°. Tomorrow will be partly sunny and noticeably milder. Temperatures will likely rise into the 60s. Overnight, a rapidly deepening storm will track toward the Great Lakes. By Monday night, the storm could have a central pressure under 970 mb as it pushes through Quebec. Before then, this storm will spread periods of moderate to heavy rain into the region tomorrow night and Monday. Rainfall amounts will likely total 0.75"-1.75" with some locally higher amounts in excess of 2.00". Strong winds with gusts past 50 mph are likely on Monday. The potential also exists for some strong to possibly severe thunderstorms. Colder air should return for Tuesday. Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Sunday and Monday are among the days that could see temperatures reach above normal levels. The Plains States will likely experience much colder than normal readings. The potential exists for warming after April 24. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. In addition, two-thirds of cases that saw the MJO reach Phase 8 at an amplitude of 2.000 or above during the April 5-20 period, as happened this month, saw a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +5.19 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.895. On April 10, the MJO was in Phase 8 at an amplitude of 2.068 (RMM). The April 9-adjusted amplitude was 1.613. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 54% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

This afternoon, the temperature rose into the middle 50s under bright sunshine. As a result, people came outdoors to enjoy the fine spring day.

In the wake of yesterday's cold front, today was blustery with changeable skies and even some snow flurries. Snowfall amounts included: Albany: Trace; Binghamton: 0.5"; New York City: Trace; Newark: Trace; and, Scranton: 0.2". Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. Sunday and Monday are among the days that could see temperatures reach above normal levels. The Plains States will likely experience much colder than normal readings. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. The 4/6 0z run of the EPS weeklies supports such a scenario. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was -1.88 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.907. On April 9, the MJO was in Phase 7 at an amplitude of 1.614 (RMM). The April 8-adjusted amplitude was 1.226. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely. Based on sensitivity analysis applied to the latest guidance, there is an implied 55% probability that New York City will have a cooler than normal April. April will likely finish with a mean temperature near 52.5°.

Very nice job, Isotherm. I hope you’re well.

A few snow flurries fell in southern Westchester County.

A strong cold front moved across the region with a thin squall line. In its wake, the sky cleared and a gusty wind prevailed. Parts of the south again saw record warmth. High temperatures included: Jacksonville: 92° (tied record set in 2011); Miami: 94° (old record: 93°, 1982); Mobile: 90° (old record: 89°, 1965); New Orleans: 89° (old record: 86°, 1999); Pensacola: 88° (old record: 85°, 1945, 1946, and 1965); Tallahassee: 92° (tied record set in 2011); and, West Palm Beach: 93° (old record: 92°, 1965). Through at least April 24, readings could average generally below normal to near normal with a few warmer than normal days across the Middle Atlantic and southern New England regions. The Plains States will likely experience much colder than normal readings. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. The 4/6 0z run of the EPS weeklies supports such a scenario. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +1.44 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.821. On April 8, the MJO was in Phase 7 at an amplitude of 1.225 (RMM). The April 7-adjusted amplitude was 1.155. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely.

This afternoon a strong cold front pushed through the region with a thin squall line accompanied by high winds, thunder, and a downpour. Afterward, the clouds pushed rapidly eastward, and the remainder of the day was a fine April day with readings in the 50s. The wind remained gusty.

Clouds broke in parts of the region this afternoon sending temperatures into the 60s and even the 70s. High temperatures included: Allentown: 72°; Bridgeport: 54°; Harrisburg: 73°; Islip: 60°; New York City: 64°; Newark: 69°; Philadelphia: 75°; and, Poughkeepsie: 60°. Parts of the southern United States again saw record heat. Highs included: Kansas City: 88° (old record: 84°, 1905 and 2001); Miami: 92° (old record: 90°, 1953 and 2014); New Orleans: 88° (tied record set in 1948); St. Louis: 90° (old record: 89°, 1890); and, Topeka: 88° (tied record set in 1905). Across the Atlantic Ocean, record warmth again prevailed in many parts of Europe. Daily record highs included: Berlin: 73°; Capo Mele, Italy: 75°; Culdrose, UK: 64°; De Kooy, Netherlands: 66°; Diepholz, Germany: 72°; Dresden: 72°; Evreaux, France: 75°; Geilenkirchen, Germany: 77°; Genova, Italy: 77°; Goeree, Netherlands: 57°; Lille, France: 77°; London-Gatwick: 73°; Paris-Charles de Gaulle: 77°; Rotterdam: 73°; Rouen, France: 77°; and, Trieste, Italy: 75°. Cooler air will likely return just after April 10. Afterward, the next 1-2 weeks could see readings average generally below normal to near normal with a few warmer than normal days. The Plains States could experience much colder than normal readings. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. The 4/6 0z run of the EPS weeklies supports such a scenario. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +6.63 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.298. On April 7, the MJO was in Phase 6 at an amplitude of 1.158 (RMM). The April 6-adjusted amplitude was 1.119. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely.

Today featured ample sunshine and more above normal readings. High temperatures included: Allentown: 70°; Bridgeport: 63°; Harrisburg: 68°; Islip: 64°; New York City: 68°; Newark: 68°; Philadelphia 65°; and, Poughkeepsie: 68°. Parts of the central and southern U.S. saw near record to record warmth. At St. Louis, the temperature reached 87°. At New Orleans, the temperature topped out at 88°, which surpassed the previous daily record of 86°, which was set in 1978 and tied in 1986. Across the Atlantic, record warmth pushed north and eastward into parts of Scandinavia and Russia. Record high temperatures included: Halli, Finland: 59°; Helsinki: 57°; Mikkeli, Finland: 59°; St. Petersburg: 66°; Tallinn, Estonia: 64°; Tampere, Finland: 61°; and, Vilnius, Lithuania: 68°. Cooler air will likely return just after April 10. Afterward, the next 1-2 weeks could see readings average generally below normal to near normal with a few warmer than normal days. The Plains States could experience much colder than normal readings. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. The 4/6 0z run of the EPS weeklies supports such a scenario. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was -8.22 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.719. On April 6, the MJO was in Phase 6 at an amplitude of 1.122 (RMM). The April 5-adjusted amplitude was 1.034. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely.

On this date in 1982, a historic April blizzard was raging. Today, under bright sunshine, temperatures rose into the middle 60s in much of the region. High temperatures included: Allentown: 67°; Bridgeport: 66°; Harrisburg: 66°; Islip: 64°; New York City: 66°; Newark: 68°; Philadelphia: 66°; and, Poughkeepsie: 64°. Record warmth again prevailed in parts of western Europe. Record high temperatures included: Amsterdam: 72°; Bergen, Norway: 61°; De Kooy, Netherlands: 66°; Deelen, Netherlands: 73°; Floro, Norway: 59°; Orsta-Volda, Norway: 63°; Visby Flygplats, Sweden: 59°; Vlieland, Netherlands: 64°; and, Wittmundhaven, Germany: 73°. Cooler air will likely return just after April 10. Afterward, the next 1-2 weeks could see readings average generally below normal to near normal with a few warmer than normal days. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East, as occurred this month, saw the development of a trough in the East after April 10. That trough typically persisted in the means for 1-2 weeks. The 4/6 0z run of the EPS weeklies supports such a scenario. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.6°C for the week centered around April 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.75°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was -10.10 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.277. On April 5, the MJO was in Phase 5 at an amplitude of 1.035 (RMM). The April 4-adjusted amplitude was 1.118. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely.

This afternoon, drier air pushed eastward from Pennsylvania leading to a period where it was partly to mostly sunny in the New York City Metro Area. As a result, the temperature topped out in the 60s there and in much of the region. High temperatures included: Allentown: 69°; Bridgeport: 53°; Harrisburg: 67°; Islip: 53°; New York City: 65°; Newark: 64°; Philadelphpia: 67°; and, Poughkeepsie: 64°. Despite a preliminary daily record negative NAO value of -1.813 (old -1.739, 1975), daily record high temperatures were toppled in parts of western Europe. Daily records included: Cherbourg, France: 70°; East Midlands, UK: 66°; Goeree, Netherlands: 66°; La Heve, France: 72° (old record: 62°); Orleans, France: 73°; Paris-Charles de Gaulle: 72°; Paris-Le Bourget: 72°; Paris-Orly: 73°; Shawbury, UK: 68°; and, Tours, France: 73°. Cooler air will likely return near or just after April 10. Afterward, there is uncertainty as to the longer-term pattern evolution. Past cases that saw the NAO average -0.750 or below during April 1-5 with warmth in the East saw troughing develop after April 10 and persist for 1-2 weeks. This pattern evolution is the base case for the April 11-20 period. As a result, readings should generally average below normal to near normal during that 10-day timeframe. Looking ahead to May, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019, as was the case this April, wound up with a warmer than normal May. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.5°C for the week centered around March 25. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.67°C and the ENSO Region 3.4 anomaly has averaged +0.57°C. Neutral and occasionally warm ENSO conditions will likely prevail through at least the end of April. The SOI was +0.72 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.082. On April 4, the MJO was in Phase 5 at an amplitude of 1.120 (RMM). The April 3-adjusted amplitude was 1.260. February 2020 saw the ENSO Region 1+2 anomaly increase by more than 0.50°C. Such a development has typically occurred before a warmer than normal summer. In all such cases, a warmer than normal spring was followed by a warmer than normal summer. Therefore, a warmer than normal summer is currently more likely than not. Should Spring wind up warmer than normal, a warm or even hot summer will be very likely.

During April 1-5, the NAO has averaged a preliminary -1.520. That is the second lowest average on record for this timeframe. Only April 1-5, 1975 with an average of -1.564 had a lower figure. Records go back to 1950. Since 1950, there were five cases where the NAO averaged -0.750 or below during April 1-5. Two (1958 and 1975) were colder than normal. Three (1953, 1998, and 1999) were warmer than normal. Below are 500 mb height anomalies for the warmer cases and then the 5-day average anomalies for April 11-15 and April 16-20. These historic cases, both individually and as a composite, suggest that a 1-2 week period where a trough predominates in the means in the East could develop near or after April 10. This suggests that the April 11-20 period could see generally below normal to near normal readings if the pattern evolves in similar fashion. Both the CFSv2 and EPS weeklies have supported such an outcome for that timeframe.

Early afternoon thoughts... 1. At 12 pm, temperatures in the area included: Allentown: 64° (sunny); Bridgeport: 51°; Islip: 50°; New York City: 56°; Newark: 55°; Philadelphia: 60°; and, Poughkeepsie: 59°. 2. An area of clear skies was moving through eastern Pennsylvania and western New Jersey at noon. As this area heads eastward, a period of at least partly sunny skies should develop this afternoon in New York City and its nearby suburbs. This period of sunshine should lead to temperatures rising into the lower 60s in many parts of the region. 3. The preliminary daily NAO value was -1.813. That surpassed the daily record of -1.739, which was set in 1975. Nevertheless western Europe, particularly France and the United Kingdom experienced record high daily temperatures.