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Tomorrow will be mainly cloudy with readings in the lower and middle 60s. The probability of a wet week has diminished markedly in the region, as Arthur will very likely turn out to sea. Thus, moderate to significant rainfall will likely be confined to the Southeast coast and lower Middle Atlantic region. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +11.51 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.018. On May 16, the MJO was in Phase 2 at an amplitude of 1.465 (RMM). The May 15-adjusted amplitude was 1.055. Since 1950, there were two cases where the April AO averaged +0.500 or above while the May AO averaged -0.500 or below: 1952 and 1954. Both cases featured a warmer than normal June. The flip to a warm June was particularly notable in 1954. Such an outcome suggests that the prevailing pattern could change toward one that would favor a warm June and perhaps warm summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 78% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 60.6°.

Temperatures rose well into the 60s even as sunshine was dimmed by high clouds and advancing mid-level clouds. In one community, the fun was back… In another, the litter was back…

The increasing greenhouse gas forcing is overwhelming the modest dip in solar irradiance.

Early clouds gave way to abundant sunshine. In response, temperatures rose into the 70s across the region. Tomorrow will likely be cooler with readings mainly in the middle 60s. The potential exists for a very wet week next week though differences exist among the guidance. Much will depend on the track what will likely become Tropical Storm Arthur will take and how it interacts with a system coming out of the Ohio Valley. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +12.66 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.070. On May 15, the MJO was in Phase 2 at an amplitude of 1.052 (RMM). The May 14-adjusted amplitude was 1.076. Based on sensitivity analysis applied to the latest guidance, there is an implied 73% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 60.8°.

This afternoon, the temperature soared to 84° in New York City. Despite today's warmth, the first 15 days of May saw readings average 4.0° to 6.0° below normal in the northern Middle Atlantic and southern New England regions. In New York City, the temperature was 4.5° below normal. In parts of Greece, Bulgaria, and Serbia & Montenegro, May record high temperatures were set today. The ingredients are coming together for a very wet week next week. The potential exists for tropical moisture to get involved. If that happens, some parts of the region could see excessive amounts of rain. The second half of May could wind up warmer than normal overall. There is some model and ensemble support for at least one bout of much above normal readings. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was -0.90 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.254. On May 14, the MJO was in Phase 2 at an amplitude of 1.073 (RMM). The May 13-adjusted amplitude was 0.959. Based on sensitivity analysis applied to the latest guidance, there is an implied 70% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 60.8°.

This afternoon and early evening was mostly sunny and very warm. The temperature soared into the 80s. Spring was in full bloom. People came out to the park to enjoy the refreshing sea breeze that had developed during the afternoon.

The exceptional cold pattern that led to parts of the region experiencing a rare May snowfall is now behind us. Moderation is underway. Ahead of an approaching front, temperatures could surge into the upper 70s and even lower 80s across the region. Showers and thunderstorms are likely late in the day. A few could be strong. Despite tomorrow's warmth, the first 15 days of May will see readings average 4.0° to as much as 6.0° below normal in the northern Middle Atlantic and southern New England regions. The second half of May could wind up warmer than normal overall. There is some model and ensemble support for at least one bout of much above normal readings. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +8.90 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.230. On May 13, the MJO was in Phase 2 at an amplitude of 0.959 (RMM). The May 12-adjusted amplitude was 0.927. Based on sensitivity analysis applied to the latest guidance, there is an implied 74% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 60.8°.

Temperatures again ran below normal today, but slow moderation should commence in coming days. Nevertheless, the first 15 days of May could see readings average 4.0° to as much as 6.0° below normal in the northern Middle Atlantic and southern New England regions. Just before mid-month, the pattern will likely change bringing about warmer weather, including more frequent days where the temperature is above normal. The second half of May could wind up warmer than normal. There is model and ensemble support for at least one bout of much above normal readings. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +15.26 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.546. On May 12, the MJO was in Phase 2 at an amplitude of 0.933 (RMM). The May 11-adjusted amplitude was 0.650. The MJO was recently in Phase 1 at an amplitude in excess of 1.500 for two days. During the 1981-2019 period, the MJO was in Phase 1 at an amplitude of 1.500 or above for two or more years in six cases: 1988, 1990, 1995, 1997, 2005, and 2010. During May, three (50%) were cooler than normal; two (33%) were near normal; and, one (17%) was warmer than normal. Ultimately, two-thirds of those cases went on to have a warmer to much warmer than normal summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 71% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 60.8°.

The wind will diminish tonight. Under mainly clear skies readings will drop into the 30s outside New York City. Some frost is possible in some of the distant suburbs. Afterward, slow moderation should commence. Nevertheless, generally cooler than normal to much cooler than normal conditions will likely predominate until toward mid-month. Overall, the first 15 days of May could see readings average 4.0° to as much as 6.0° below normal in the northern Middle Atlantic and southern New England regions. However, just before mid-month, the pattern will likely change bringing about warmer weather, including more frequent days where the temperature is above normal. The second half of May could wind up warmer than normal. There is growing model and ensemble support for at least one bout of much above normal readings. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +3.62 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.324. On May 11, the MJO was in Phase 1 at an amplitude of 0.653 (RMM). The May 10-adjusted amplitude was 0.675. The MJO was recently in Phase 1 at an amplitude in excess of 1.500 for two days. During the 1981-2019 period, the MJO was in Phase 1 at an amplitude of 1.500 or above for two or more years in six cases: 1988, 1990, 1995, 1997, 2005, and 2010. During May, three (50%) were cooler than normal; two (33%) were near normal; and, one (17%) was warmer than normal. Ultimately, two-thirds of those cases went on to have a warmer to much warmer than normal summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 61.0°.

Another strong cold front moved through the region today, bringing showers, thundershowers, and even some hail to parts of the region. The air mass behind the front was sufficiently cold to bring 0.5" snow to Detroit last night. Tomorrow morning could witness more low temperature records challenged or broken across parts of the region. Daily record low temperatures for May 12 include: Allentown: 34°, 1963 Binghamton: 31°, 1988 and 1996 Bridgeport: 40°, 1990 Harrisburg: 36°, 1907 New York City-JFK: 43°, 1963 and 2019 New York City-LGA: 43°, 1940 New York City-NYC: 40°, 1874 and 1907 Newark: 40°, 1938 Philadelphia: 37°, 1962 White Plains: 38°, 1969 and 1990 There is a chance that New York City's low temperature could drop below 40°. Currently, May 2020, which has had 3 such days, is tied with 1874, 1891, 1923, 1947, and 1963 for the most such days in May. Generally cooler than normal to much cooler than normal conditions will likely predominate until toward mid-month. Overall, the first 15 days of May could see readings average 4.0° to as much as 6.0° below normal in the northern Middle Atlantic and southern New England regions. However, just before mid-month, the pattern will likely change bringing about warmer weather, including more frequent days where the temperature is above normal. The second half of May could wind up warmer than normal. There is growing model and ensemble support for at least one bout of much above normal readings. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.2°C for the week centered around May 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.37°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +1.70 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.261. On May 10, the MJO was in Phase 1 at an amplitude of 0.683 (RMM). The May 9-adjusted amplitude was 0.523. The MJO was recently in Phase 1 at an amplitude in excess of 1.500 for two days. During the 1981-2019 period, the MJO was in Phase 1 at an amplitude of 1.500 or above for two or more years in six cases: 1988, 1990, 1995, 1997, 2005, and 2010. During May, three (50%) were cooler than normal; two (33%) were near normal; and, one (17%) was warmer than normal. Ultimately, two-thirds of those cases went on to have a warmer to much warmer than normal summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 65% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 61.0°.

Today, the temperature rebounded into the 60s after a brisk start. Nevertheless, the first 10 days of May were much cooler than normal in the Northeast. At New York City, the temperature averaged 4.5° below normal. Another cold front will move across the region tomorrow bringing showers and just a chance of a thundershower. Clouds will likely break during the afternoon. Generally cooler than normal to much cooler than normal conditions will likely predominate until toward mid-month. Overall, the first 15 days of May could see readings average 4.0° to as much as 6.0° below normal in the northern Middle Atlantic and southern New England regions. However, near mid-month, the pattern will likely change bringing about warmer weather, including more frequent days where the temperature is above normal. The second half of May could wind up warmer than normal. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was +0.4°C for the week centered around April 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.46°C and the ENSO Region 3.4 anomaly has averaged +0.56°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +2.55 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.303. On May 9, the MJO was in Phase 8 at an amplitude of 0.517 (RMM). The May 8-adjusted amplitude was 0.406. The MJO was recently in Phase 1 at an amplitude in excess of 1.500 for two days. During the 1981-2019 period, the MJO was in Phase 1 at an amplitude of 1.500 or above for two or more years in six cases: 1988, 1990, 1995, 1997, 2005, and 2010. During May, three (50%) were cooler than normal; two (33%) were near normal; and, one (17%) was warmer than normal. Ultimately, two-thirds of those cases went on to have a warmer to much warmer than normal summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a cooler than normal May. May will likely finish with a mean temperature near 61.0°.

The return of sunshine vanquished the early morning chill. As a result, a fairly large number of people came out to the local park. Three photos:

Morning thoughts... 1. The current generally cold pattern will likely conclude near mid-month. Afterward, a warmer regime with more frequent above normal readings will develop. 2. This morning, the low temperature in New York City was 39 degrees. The last time New York City had 3 consecutive low temperatures in the 30s during May was in 1947. 3. Caribou picked up a daily record 5.5" snow yesterday. The old record was 1.4", which was set in 1967. As a result, seasonal snowfall increased to 151.6", which makes winter 2019-2020 Caribou's 6th snowiest winter on record. The two-winter total is 317.0", which exceeds the previous two-winter record of 313.5", which had been set during winters 2007-08 and 2008-09. Caribou has also received 150" or more snow in two consecutive winters for the first time on record.

Final short clip from this memorable May 9th:

A record-shattering cold air mass accompanied by rain changing to snow briefly transformed May into what should have been February. At New York City, the temperature fell to the lowest level in May since 1891. The afternoon saw wild skirmishes between approaching summer and retreating winter as they fought it out on the battlefield of May. The afternoon featured strong winds, unseasonable wind chill, sunshine, clouds, snow showers, and snow squalls. Record low temperatures this morning included: Baltimore: 34° (old record: 36°, 1966 and 2017) Binghamton: 24° (old record: 27°, 1966) Bridgeport: 35° (old record: 37°, 1966, 1976, and 1977) Islip: 34° (old record: 36°, 1977, 1985, and 1987) New York City-JFK: 34° (old record: 38°, 1977) New York City-LGA: 36° (old record: 37°, 1947) New York City-NYC: 34° (old record: 35°, 1947) Scranton: 29° (old record: 31°, 1966) White Plains: 32° (old record: 33°, 1977) Tonight, as the wind slackens, some additional record temperatures are likely. Generally cooler than normal to much cooler than normal conditions will now likely predominate until toward mid-month. Overall, the first 10 days of May could see readings average 2.5° to as much as 5.0° below normal in the northern Middle Atlantic and southern New England regions. Moderation will likely commence near mid-month. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was +0.4°C for the week centered around April 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.46°C and the ENSO Region 3.4 anomaly has averaged +0.56°C. Neutral and occasionally warm ENSO conditions will likely prevail through mid-May. ENSO Region anomalies, which cooled slightly during the last week of April, could continue a steady cooling during May. The SOI had an increased tendency for positive values during April. During this month, the SOI was positive on 17 (57%) days. During the February-March period, the SOI was positive on 38% days. This shift in tendencies may further reinforce or reflect the idea that ENSO region anomalies could begin to cool. The SOI was +10.44 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.267. On May 8, the MJO was in Phase 8 at an amplitude of 0.401 (RMM). The May 7-adjusted amplitude was 0.325. The MJO was recently in Phase 1 at an amplitude in excess of 1.500 for two days. During the 1981-2019 period, the MJO was in Phase 1 at an amplitude of 1.500 or above for two or more years in six cases: 1988, 1990, 1995, 1997, 2005, and 2010. During May, three (50%) were cooler than normal; two (33%) were near normal; and, one (17%) was warmer than normal. Ultimately, two-thirds of those cases went on to have a warmer to much warmer than normal summer. Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a cooler than normal May. That probability will increase markedly through mid-month as the coldest anomalies of the month take hold. May will likely finish with a mean temperature near 61.0°.

Today saw dramatic changes in the weather, as snow flurries, showers, and squalls moved through the region. Offshore snow squall Approaching snow squall During a snow squall Departing snow squall Departing snow squall

Short video clip from late this afternoon:

More snow flurries. Across the Long Island Sound there looked to be an impressive snow shower on the North Shore.

We just had a passing flurry in Larchmont.

44 in 1977 for today. Lowest ever: 43, 5/3/1873 and 5/5/1891

Central Park reached 34 degrees at 6 am. That set a new daily record and is the coldest May temperature since May 6, 1891.

A quick video from earlier:

That’s also NYC’s coldest May temperature since 5/9/1947.

May 6, 1891.

Snow is falling in Larchmont, NY.