donsutherland1

Under bright sunshine, the temperature rose into the lower and middle 60s today. The weekend could start out quite mild with readings well into the 60s and perhaps the lower 70s. However, a storm passing to the south of the region could bring some rain to parts of the region on Sunday. April will likely close with much above normal temperatures. The guidance has now moved into good agreement that the month will close with highs generally in the 70s. The potential for an 80° reading as far north as New York City exists. Tuesday and Wednesday could be the warmest days in a region stretching from the Great Lakes area to the Northeast. This outcome would be consistent with the MJO's having moved through Phase 6 at a very high amplitude during the April 1-15 period. Since 1974, there were 7 cases where the MJO reached Phase 6 at an amplitude of 1.500 or above during April 5-15, as was the case this year. Only 1981 had an April 20-30 maximum temperature below 80° (75°). The average highest figure for such cases was 81.3°. The MJO's ongoing passage through Phase 7 at a very high amplitude is consistent with an outcome that typically yields 1-2 80° days. Both the dynamical guidance and statistical measures that incorporate ENSO and the forecast teleconnections are in agreement that the first half of May will likely be warmer than normal in the region. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.4°C for the week centered around April 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.33°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral-cool ENSO conditions are now developing. Neutral ENSO conditions will likely be in place by the end of spring. The SOI was +12.40 today. The preliminary Arctic Oscillation (AO) figure was -0.181 today. On April 21 the MJO was in Phase 7 at an amplitude of 2.048 (RMM). The April 20-adjusted amplitude was 2.096 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 92% probability that New York City will have a warmer than normal April. April will likely finish with a mean temperature near 54.6° (1.6° above normal).

I hope that when COP26 is held in November, China and India will provide more specifics and more ambitious targets. I also hope that the U.S. will come forth with a detailed action plan on how it would achieve its committed reduction and what enforcement mechanism e.g., carbon pricing, would be deployed to assure that it can meet its long-term goal. Shorter-term benchmarks along the way would also be helpful in adding credibility.

Morning thoughts... At 7 am, the temperature was 39° in New York City’s Central Park. That will very likely be the last temperature in the 30s there until some time next fall. Today will be partly to mostly sunny and noticeably milder than yesterday. High temperatures will likely reach the lower 60s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 62° Newark: 65° Philadelphia: 63° Tomorrow will be partly cloudy and even warmer. There are growing indications on the guidance that the closing days of April could feature much above normal temperatures.

Yes, there were two different times when it snowed on May 9. None of the NYC area sites reported measurable snow.

The summit was a start. It was useful in that it demonstrated that the U.S. is returning to the global effort to address climate change and that it will be working with other countries in that process. At COP26, it will be important that the U.S. and others provide concrete commitments. Even today's U.S. goal is lacking specifics on how it will arrive there, what measures will be used to assess progress, and what enforcement mechanisms might be used to ensure that the goal is attained.

The temperature could fall into the 30s for one more day tomorrow morning. If so, that will likely be the last time(s) the temperature falls into the 30s in Central Park until next fall. The afternoon will be fair and noticeably milder. The weekend could start out quite mild with readings well into the 60s and perhaps the lower 70s. April will likely close with much above normal temperatures. The guidance has now moved into good agreement that the month will close with highs generally in the 70s. The potential for an 80° reading as far north as New York City exists. This outcome would be consistent with the MJO's having moved through Phase 6 at a very high amplitude during the April 1-15 period. Since 1974, there were 7 cases where the MJO reached Phase 6 at an amplitude of 1.500 or above during April 5-15, as was the case this year. Only 1981 had an April 20-30 maximum temperature below 80° (75°). The average highest figure for such cases was 81.3°. The MJO's ongoing passage through Phase 7 at a very high amplitude is consistent with an outcome that typically yields 1-2 80° days. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.4°C for the week centered around April 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.33°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral-cool ENSO conditions are now developing. Neutral ENSO conditions will likely be in place by the end of spring. The SOI was +7.21 today. The preliminary Arctic Oscillation (AO) figure was -0.181 today. On April 20 the MJO was in Phase 7 at an amplitude of 2.096 (RMM). The April 19-adjusted amplitude was 2.119 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 90% probability that New York City will have a warmer than normal April. April will likely finish with a mean temperature near 54.5° (1.5° above normal).

This summit is another welcome step demonstrating that the United States has begun to re-engage with the world. The U.S. strategic position was weakened badly from four years of chaotic and demoralizing disengagement. When it comes to addressing the great challenge of climate change, global cooperation is imperative. Climate change and its consequences are not confined within national boundaries.

2020’s last 30s occurred on May 10 at JFK and NYC and May 9 at LGA. There was a trace of snow at all three sites on May 9 (the changeover of the rain occurred after 1 am; the afternoon saw additional snow showers and a minor snow squall in parts of the region).

Morning thoughts... Through 8 am, the low temperature in New York City’s Central Park was 36°. Since 1990, New York City has had a low temperature in the 30s on or after April 22 on just four prior occasions: 2000 (April 27), 2012 (April 28), 2015 (April 25), and 2020 (May 9). The mean date for the last temperature in the 30s during the 1990-2020 timeframe was April 14. Today will be variably cloudy, blustery, and cool. An afternoon shower cannot be ruled out. High temperatures will likely reach the upper 40s and lower 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 51° Newark: 52° Philadelphia: 52° Tomorrow will be partly cloudy and milder. There are growing indications on the guidance that the closing days of April could feature much above normal temperatures.

Yesterday into today, a storm brought daily record snowfall to parts of the Midwest into upstate New York. Accumulations included: Buffalo: 4.8" Detroit: 3.5" Hambden, OH: 8.0" Indianapolis: 2.0" (biggest April 20th or later snowstorm since May 2, 1897 and 2nd biggest overall) Kansas City: 3.5" (biggest snowstorm April 9th or later) Louisville: 1.8" (only the 3rd measurable snowfall on record on or after April 20th and biggest snowstorm April 9th or later) Toledo: 5.2" Wyandotte, MI: 4.4" Ohio's Cuyahoga and Geauga Counties saw numerous locations pick up 6" or more of snow. That storm was responsible for bringing a strong cold front across the region this afternoon. In its wake, temperatures have fallen rapidly. The temperature will fall well into the 30s in New York City tomorrow morning and may again fall into the upper 30s on Friday morning. This will likely be the last time(s) the temperature falls into the 30s in Central Park until next fall. April will likely close with much above normal temperatures. The guidance has now moved into good agreement that the month will close with highs generally in the 70s. The potential for an 80° reading as far north as New York City exists. This outcome would be consistent with the MJO's having moved through Phase 6 at a very high amplitude during the April 1-15 period. Since 1974, there were 7 cases where the MJO reached Phase 6 at an amplitude of 1.500 or above during April 5-15, as was the case this year. Only 1981 had an April 20-30 maximum temperature below 80° (75°). The average highest figure for such cases was 81.3°. The MJO's ongoing passage through Phase 7 at a very high amplitude is consistent with an outcome that typically yields 1-2 80° days. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.4°C for the week centered around April 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.33°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral-cool ENSO conditions are now developing. Neutral ENSO conditions will likely be in place by the end of spring. The SOI was +8.29 today. The preliminary Arctic Oscillation (AO) figure was +0.256 today. On April 19 the MJO was in Phase 7 at an amplitude of 2.119 (RMM). The April 18-adjusted amplitude was 1.932 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 80% probability that New York City will have a warmer than normal April. April will likely finish with a mean temperature near 54.2° (1.2° above normal).

New York City’s proximity to the Atlantic Ocean moderates its temperatures, but provides additional moisture for snowfall. As a result, even as New York City has slightly fewer measurable snow events each year than Kansas City does, its events are bigger and its snowfall average is greater. On account of the larger temperature extremes, Kansas City can see earlier or later snowfalls than New York City. Frequency of First Measurable Snowfall before November 1 (1991-2020): Kansas City: 6 cases New York City: 1 case Frequency of Last Measurable Snowfall on or after April 1 (1991-2020): Kansas City: 9 cases New York City: 5 cases Days per Year for Select Snowfall Amounts (1991-2020): Kansas City: Measurable: 13.8; 2” or more: 2.8; 4” or more: 1.0; 6” or more: 0.5 New York City: Measurable: 11.4; 2” or more: 4.7; 4” or more: 2.8; 6” or more: 1.4 Total Days with 10” or More Snowfall (1991-2020): Kansas City: 1 New York City: 11

The temperature at Philadelphia has fallen from 72 degrees at 1 pm to 58 degrees at 2 pm during a thunderstorm. The temperature will likely fall sharply in New York City once the cold front moves through.

Incredible scenes.

Hambden, OH: 8.0”

That’s impressive. It’s a special event.

How much snow have you had?

Ottawa Hills (2 NE), OH: 7.0”

Louisville picked up 0.4” of snow yesterday. That broke the daily record of a Trace, which was set in 1953. It was only the 3rd measurable snowfall on record on April 20th or later.

Typo on my part. Yes, it’s Ohio.

Morning thoughts... At 7:40 am, the late-season storm that brought daily record snowfall to many parts of the Midwest was bringing snow to Buffalo. Already, amounts in excess were being reported in the greater Buffalo area. As that storm tracks into Quebec, it will drag a strong cold front across the region. Passage of that front could be marked by a squall line with strong thunderstorms, damaging winds, and even some hail. Today will be partly sunny and unseasonably warm. Showers and thunderstorms are likely this afternoon. High temperatures will likely reach the middle and upper 60s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 68° Newark: 68° Philadelphia: 65° Tomorrow will be variably cloudy and blustery. The temperature will struggle to reach the lower 50s.

Gorgeous photos.

Point Place (1 W), OH: 6.0”

It was borderline. I don’t have issues with the choice. I suspect that if the heaviest accumulations were likely near rush hour, then there would have been an advisory. Either way, this is a really special event.

I have no issues with the call. I just posted the criteria.

IND’s advisory criteria can be found here: https://www.weather.gov/ind/criteria Although 3”-5” is the threshold, there is an optional 2”-4” threshold. So, it was an event for which the NWS could have gone either way.