donsutherland1

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.

During the day, some drier air worked into parts of the region from the north, promoting partly sunny conditions. Temperatures topped out in the upper 50s and lower 60s. High temperatures included: Allentown: 62°; Bridgeport: 58°; Islip: 58°; New York City: 62°; Newark: 60°; and, Philadelphia: 57° More clouds and slightly cooler conditions are likely tomorrow. Readings will likely return to the 60s early next week. Cooler air could return near April 10. Afterward, there is uncertainty about the longer-term pattern evolution, especially as the NAO could remain predominantly negative through mid-month. There is some ensemble support for the NAO to go positive after mid-month. Even as there is uncertainty about the outlook beyond April 10, 73% of cases that saw one or more days where the NAO fell to -1.000 or below during April 1-10, 1950-2019 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 -11.32 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.153. On April 3, the MJO was in Phase 5 at an amplitude of 1.257 (RMM). The April 2-adjusted amplitude was 1.329. 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.

As noted on February 17: None of the guidance shows cold of the expanse and magnitude shown during the second half of February, much less over a two week period. At this point, especially with the current pattern and forecast ensembles, calls for extreme cold on a scale of March 1960 should be viewed with a great deal of skepticism. Extremes, by definition, are low probability events. When no clear variables for producing them are currently visible or available in the guidance, their absence should raise significant "red flags." Here is the final outcome:

As the a strong ocean storm responsible for today's overcast and occasionally rainy conditions begins to move away from the region, milder conditions will develop tomorrow. Temperatures will likely return to the 60s early next week. Cooler air could return near April 10. Afterward, there is uncertainty about the longer-term pattern evolution, especially as the NAO could remain predominantly negative through mid-month. There is some ensemble support for the NAO to go positive after mid-month. 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 -16.08 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.098. On April 2, the MJO was in Phase 5 at an amplitude of 1.331 (RMM). The April 1-adjusted amplitude was 1.185. 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.

A strong offshore storm will spread clouds into the region tonight into tomorrow. A period of steady rain and gusty winds is possible into tomorrow, especially on parts of Long Island. Showers could extend into and just west of the New York City Metro Area. The first five days of April will see somewhat below normal to near normal temperatures with the NAO below -1.000. Today's preliminary value was -1.541. That surpasses the previous daily record of -1.356, which was set in 1975. During the April 1-7, 1981-2019 period, the mean temperature was 49.3° for New York City and 50.5° for Philadelphia. During cases when the NAO was -0.75 or below, the respective mean temperatures for New York City and Philadelphia were 47.9° and 49.4°. However, the limited pool of cold air available to be tapped this year could result in a shorter-duration period of cool readings than is typically associated with such patterns. Cooler air could return near April 10. Afterward, there is uncertainty about the longer-term pattern evolution, especially as the NAO could remain predominantly negative through mid-month. 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 -10.67 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.399. On April 1, the MJO was in Phase 4 at an amplitude of 1.181 (RMM). The March 31-adjusted amplitude was 1.578. 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.

After a cool start, the temperature rose into the middle 50s across much of the region today. A strong offshore storm will spread clouds into the region late tomorrow and tomorrow night. A period of steady rain and gusty winds is possible into Friday, especially on parts of Long Island. Parts of Alaska, British Columbia, and Alberta saw near record to record low temperatures earlier today. Hoonah AK had a low temperature of 13°, which smashed the daily record low figure of 22° from 1996. Juneau had a minimum temperature of 14°, which tied the record set in 1920 and tied in 1948. The first five days of April will see somewhat below normal to near normal temperatures as the NAO heads below -1.000. During the April 1-7, 1981-2019 period, the mean temperature was 49.3° for New York City and 50.5° for Philadelphia. During cases when the NAO was -0.75 or below--today's preliminary figure was -1.056--the respective mean temperatures for New York City and Philadelphia were 47.9° and 49.4°. However, the limited pool of cold air available to be tapped this year could result in a short-duration period of cool readings. Afterward, there is uncertainty about the longer-term pattern evolution. Some of the guidance suggests that cooler air could return near April 10. 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 +5.33 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.895. On March 31, the MJO was in Phase 4 at an amplitude of 1.583 (RMM). The March 30-adjusted amplitude was 2.010. 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.

Morning thoughts... 1. The NAO has now dropped below -1.000 with a preliminary daily value of -1.056. 2. The temperature in New York City had risen to 47 degrees after a morning low of 38 degrees. March 1 was very likely New York City's last freeze. 3. Near record to record cold covered parts of Alaska, British Columbia, and Alberta this morning. At Hoonah, AK, the temperature had fallen to 13 degrees at 7 am local time. That smashed the old record low figure of 22 degrees, which was set in 1996.

For purposes of looking at the GFS (FV3) cold bias, the model blend I use for my sensitivity analysis has a departure of +1.5° for the April 1-17 period vs. the GFS's -2.0°. It will be interesting to see the actual number.

March 2020 will finish with a mean temperature of 48.0° in New York City. That made March 2020 New York City's 7th warmest March on record. In the South, New Orleans will likely finish with a mean temperature of 73.1°, easily making March 2020 the warmest March on record there. The old record was 70.7°, which was set in 2012. The first week of April will see somewhat below normal to near normal temperatures, as the NAO, now at a preliminary value of -0.297, heads below -1.000. During the April 1-7, 1981-2019 period, the mean temperature was 49.3° for New York City and 50.5° for Philadelphia. During cases when the NAO was -0.75 or below, the respective mean temperatures for New York City and Philadelphia were 47.9° and 49.4°. Afterward, there is uncertainty about the longer-term pattern evolution. 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 -1.48 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.653. On March 30, the MJO was in Phase 4 at an amplitude of 2.012 (RMM). The March 29-adjusted amplitude was 2.002. 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. April will likely be somewhat warmer to warmer than normal in the East. Based on sensitivity analysis applied to the latest guidance, there is an implied 53% probability that New York City will have a warmer than normal April.

Clouds broke late this afternoon. Readings topped out in the upper 40s.

Morning thoughts... Recently, the MJO moved through Phase 3 at a very high amplitude. There have been two distinct clusters of outcomes for April following such passages during the March 20-31 period. Despite the most recent CFSv2 forecast, Cluster 1 (warmer outcome in the East) is the more likely one. First, the closing 10 days of March have seen the presence of much less cold air than the colder cluster. Second, some of the large-scale hemispheric changes that have been evolving in response to ENSO conditions also favor a milder outcome in the East. Third, the 3/30 run of the EPS weeklies were warmer than the 3/27 run. Fourth, the core of the cold on the CFSv2 is more consistent with the warmer cluster with the primary difference being its showing modest cold anomalies that extend to the East Coast. Overall, even as much of the East Coast will likely be on the mild side of normal, warm anomalies very likely won't rival those of February or March.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA 0.5 0.5 0.2 -1.0 0.7 0.5 -0.5 0.2 -1.5

An exceptionally warm March is now concluding on a cool note. The first week of April will likely be somewhat cooler than normal to near normal, as the NAO heads toward or even below -1.000. During the April 1-7, 1981-2019 period, the mean temperature was 49.3° for New York City and 50.5° for Philadelphia. During cases when the NAO was -0.75 or below, the respective mean temperatures for New York City and Philadelphia were 47.9° and 49.4°. Afterward, there is uncertainty about the longer-term pattern evolution. New Orleans will likely record a monthly average temperature near 73.1°. That would smash the March record of 70.7°, which was set in 2012. It is very likely that Baltimore, New York City, Newark, Philadelphia, and Washington, DC have seen their last measurable snowfall of winter 2019-2020. New York City's last measurable snowfall this winter was January 18. That would mark the earliest such occurrence of the last measurable snowfall. The existing record is January 19, 2002. New York City is all but certain to finish winter 2019-2020 with less than 10" snow for the first time since winter 2011-2012 and for only the 10th time on record. Snowfall records go back to winter 1868-1869 (when 25.5" fell from January-March 1869). It is increasingly likely that New York City has seen its last freeze of the winter, which occurred on March 1. That would be the second earliest such occurrence. The record is February 28, 1942. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.8°C for the week centered around March 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.55°C and the ENSO Region 3.4 anomaly has averaged +0.50°C. Neutral ENSO conditions will likely prevail through at least the end of April. The SOI was -6.61 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.189. On March 29, the MJO was in Phase 4 at an amplitude of 2.007 (RMM). The March 28-adjusted amplitude was 1.931. A sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-15 AO average was +2.758. Only 1989 (+3.336) and 1990 (+2.948) had higher AO averages during this period. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region. A warmer than normal March and spring remain the base case. 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 near 100% probability that New York City will have a warmer than normal March and that March 2020 will rank among the 10 warmest March cases on record. March will likely finish with a monthly mean temperature near 48.0°, which would rank as the 7th warmest March on record. Finally, in most cases following strong AO+ February and March periods, ridging is present in the East during April. As a result, April will likely be at least somewhat warmer than normal in the East. Although recent runs of the CFSv2 have grown cooler, the latest run of the EPS weeklies was warmer.

An exceptionally warm March is now concluding. The first week of April will likely be somewhat cooler than normal to near normal, as the NAO heads toward or even below -1.000. During the April 1-7, 1981-2019 period, the mean temperature was 49.3° for New York City and 50.5° for Philadelphia. During cases when the NAO was -0.75 or below, the respective mean temperatures for New York City and Philadelphia were 47.9° and 49.4°. In parts of the southeastern United States, temperatures reached record high levels earlier today. Daily records included: Charleston, SC: 87° (tied record set in 1985 and tied in 2012); Jacksonville: 91° (old record: 89°, 1907 and 1991) ***Record 5th March day with a high temperature of 90° or above (old record: 4, March 1907)***; Mobile: 87° (old record: 85°, 1879); New Bern, NC: 89° (old record: 88°, 1985); New Orleans: 84° (old record: 83°, 2000, 2007, 2011, 2012, and 2017); Pensacola: 87° (old record: 83°, 1884 and 1974); and, Savannah: 90° (tied record set in 1907) New Orleans is on track to record a monthly average temperature near 72.8°. That would smash the March record of 70.7°, which was set in 2012. It is very likely that Baltimore, New York City, Newark, Philadelphia, and Washington, DC have seen their last measurable snowfall of winter 2019-2020. New York City's last measurable snowfall this winter was January 18. That would mark the earliest such occurrence of the last measurable snowfall. The existing record is January 19, 2002. New York City is all but certain to finish winter 2019-2020 with less than 10" snow for the first time since winter 2011-2012 and for only the 10th time on record. Snowfall records go back to winter 1868-1869 (when 25.5" fell from January-March 1869). It is increasingly likely that New York City has seen its last freeze of the winter, which occurred on March 1. That would be the second earliest such occurrence. The record is February 28, 1942. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.8°C for the week centered around March 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.55°C and the ENSO Region 3.4 anomaly has averaged +0.50°C. Neutral ENSO conditions will likely prevail through at least the end of April. The SOI was -11.35 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.024. On March 28, the MJO was in Phase 4 at an amplitude of 1.875 (RMM). The March 27-adjusted amplitude was 1.786. A sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-15 AO average was +2.758. Only 1989 (+3.336) and 1990 (+2.948) had higher AO averages during this period. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region. A warmer than normal March and spring remain the base case. 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 near 100% probability that New York City will have a warmer than normal March and that March 2020 will rank among the 10 warmest March cases on record. March will likely finish with a monthly mean temperature near 48.3°, which would rank as the 6th warmest March on record. Finally, in most cases following strong AO+ February and March periods, ridging is present in the East during April. As a result, April will likely be warmer than normal in the East.