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April 2020


donsutherland1
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1 hour ago, rclab said:

The sentiment could be reversed when, on a dog day in August, the sea breeze fails to reach Coney Island. As always .....

Yes, i do enjoy the sea breeze on those disgusting summer nights. 

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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.

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The next 8 days are averaging 54degs., or about 4degs. AN.

The next 17 days are averaging 52.5degs.(46/59), or just about Normal.

2020040500_054@007_E1_knyc_I_NAEFS@EPSGR

48* here at 6am.      56* by 2pm.       58* at 3pm.      54* at 4pm.

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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.

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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.

April52020500mb-1.jpg

April52020500mb-2.jpg

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.

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17 hours ago, donsutherland1 said:

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.

Yeah, the MJO supports a trough in the Great Lakes and Northeast around that time. 

9A35A3BC-49D5-44FC-9F08-56F6048661C0.gif.d21413d75d70c1f5cce1b6b48a4587c0.gif

 

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NAO is going positive soon, and the AO is barely even negative. I don't see much support for a trough in the east. If anything, maybe a trough in the west coast due to below normal SSTs:

cdas-sflux_ssta_global_1.png

Waters in much of the Atlantic are pretty warm, and that would support somewhat of a SE ridge.

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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.

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The next 8 days are averaging 53degs., or about 3degs. AN.

The next 17 days are averaging about 52degs.(48/59), or about  1deg. BN.

2020040612_054@007_E1_knyc_I_NAEFS@EPSGR

52* here at 6am.     54* by 10am.       58* by 1pm.      60* at 2pm.       64* by 4pm.     65* around 4:30pm.      Down to 53* then back up to 58* by 9pm.   60* at 10pm.

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4 minutes ago, Brian5671 said:

Too late in the year-would just be a cold rain for most.    Also have to question how cold it gets, there's been very little cold anywhere since late December

I wasn't implying there would be snow but the cold air show on the models in his video is impressive for April.

I could care less about April snow.

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1 minute ago, Rtd208 said:

I wasn't implying there would be snow but the cold air show on the models in his video is impressive for April.

I could care less about snow in April.

Let's see if modeling holds onto the cold-typically this winter/spring it has moderated significantly as it gets closer in time.

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2 hours ago, MJO812 said:

We have a block this time. Always in April. 

Smfh 

can't make it up....however looking at the Euro ensembles most of the cold air ends up in the moutain west/midwest-we end up a few degrees below normal but not the -10 that you're seeing out that way

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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.

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The next 8 days are averaging 52.5degs., or about 2degs. AN.

The next 17 days are averaging about -2.0[50.0](43/56}.

54* here at 6am.      53* at 7am.   57* by 10am.       61* by 2pm, but 56* at 3pm.

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