May 2021

[thunderbolt]

1 hour ago, Rjay said:

Temp went from 76 to 70 when winds shifted from north to south.  

Tell me about it  Brother I just went from 78 to 70

[donsutherland1]

Under partly to mostly sunny skies, the temperature soared into the upper 70s early this afternoon in the New York City area. Peonies and ornamental onions are now in full bloom in the New York Botanical Garden.

[uncle W]

1962 and 1996 had the hottest temperature of the year on May 19th-20th...May 1964 and 1965 had early heat...I remember both years had back to back 90 degree days the second half of the month...both years hit 94...

[doncat]

17 minutes ago, uncle W said:

1962 and 1996 had the hottest temperature of the year on May 19th-20th...May 1964 and 1965 had early heat...I remember both years had back to back 90 degree days the second half of the month...both years hit 94...

Had a 99° on the 20th 1996.

[uncle W]

3 minutes ago, doncat said:

Had a 99° on the 20th 1996.

it was 99 on May 19th 1962...I had baseball practice that day and remember it well...

[donsutherland1]

The dominant weather story over the 7-10 days will be the development of a strongly to occasionally severely negative PNA. That development will lead to a warmer to perhaps much warmer than normal second half of May.

The PNA is currently forecast by most ensemble members to fall to -1.000 or below during the second half of May and remain there for perhaps a week or more. During the 1991-2020 period, the mean temperature was 65.2° in New York City and 67.0° in Philadelphia. When the PNA was -1.000 or below, the average temperature was 67.7° in New York City and 69.3° in Philadelphia.

During the 1991-2020 period, 30% of days in New York City and 41% of days in Philadelphia had high temperatures of 80° or above. During the 1991-2020 period, 15% of days in New York City and 23% of days in Philadelphia had high temperatures of 85° or above. When the PNA was -1.000 or below during that period, 41% of days in New York City and 50% of days in Philadelphia had high temperatures of 80° or above. When the PNA was -1.000 or below during that period, 24% of days in New York City and 35% of days in Philadelphia had high temperatures of 85° or above.

For the first time, the guidance has "noticed" the big change in the PNA and has swung toward a dramatically warmer outcome. The implied probability of a cooler than normal May was 55% yesterday. Today, there is an implied 65% probability of a warmer than normal May.

More immediately, temperatures will likely top out in the 70s in much of the region through the weekend. A minor push of slightly cooler air is possible early next week before a more impressive warmup unfolds.

As had been the case with April, the closing week of May could wind up warmer to much warmer than normal. In the four cases where the MJO reached Phase 1 at an amplitude of 2.000 or above in combination with a cool ENSO Region 3.4 anomaly during the May 1-10 period, as occurred this year, three wound up with warmer to much warmer than normal conditions. At New York City, the mean temperature during the closing 7 days of May was 72.7° during those three cases while it was 72.0° at Philadelphia. The 1991-2020 means were 67.9° and 69.7° respectively. Only May 25-31, 2013 (monthly ENSO Region 1+2 anomaly of -1.38°C) was cooler than normal. However, 90° heat arrived on May 29 in Philadelphia and May 30 in New York City during 2013.

Neutral ENSO conditions have now developed. The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.4°C for the week centered around May 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.83°C and the ENSO Region 3.4 anomaly has averaged -0.42°C. Neutral ENSO conditions will likely prevail into at least mid-summer.

The SOI was +25.83 today.

The preliminary Arctic Oscillation (AO) figure was -0.201 today.

On May 13 the MJO was in Phase 2 at an amplitude of 0.909 (RMM). The May 12-adjusted amplitude was 0.885 (RMM).

In late April, the MJO moved through Phase 8 at an extreme amplitude (+3.000 or above). Only February 25, 1988 and March 18-19, 2015 had a higher amplitude at Phase 8. Both 1988 and 2015 went on to have an exceptionally warm July-August period. July-August 1988 had a mean temperature of 79.1°, which ranked 4th highest for that two-month period. July-August 2015 had a mean temperature of 78.9°, which ranked 5th highest for that two-month period. September 2015 was also the warmest September on record. The MJO's extreme passage through Phase 8 could provide the first hint of a hot summer.

Based on sensitivity analysis applied to the latest guidance, there is an implied 65% probability that New York City will have a warmer than normal May (1991-2020 normal). May will likely finish with a mean temperature near 64.0° (0.8° above normal).

 

[Santa Claus]

sun shower in pway

[uncle W]

May warm spells with at least three consecutive days 85 or higher in NYC...

dates.................days 90+ max

5/25-27/1880.....3.......3.....96

5/09-11/1896.....3.......3.....91

5/05-09/1930.....5.......2.....91

5/28-30/1931.....3.......3.....93

5/27-29/1935.....3.......0.....89

5/28-31/1939.....4.......3.....96

5/27-30/1959.....4.......1.....94

5/20-22/1959.....3.......2.....91

5/18-21/1962.....4.......2.....99

5/29-31/1969.....3.......2.....97

5/09-13/1970.....5.......2.....93

5/22-24/1980.....3.......1.....90

5/24-27/1981.....4.......0.....87

5/28-31/1986.....4.......2.....94

5/28-31/1987.....4.......3.....97

5/29-31/1988.....3.......1.....91

5/27-31/1991.....5.......3.....91

5/21-23/1992.....3.......2.....93

5/19-21/1996.....3.......2.....96

5/29-31/1999.....3.......0.....89

5/05-09/2000.....5.......3.....93

5/01-04/2001.....4.......3.....92

5/11-13/2004.....3.......0.....86

5/25-31/2015.....7.......0.....88

5/25-29/2016.....5.......2.....92

5/17-19/2017.....3.......3.....91

[TriPol]

8 hours ago, doncat said:

These early in the season heat events always seem to sneak up on us.

From what I recall, whenever we get 90s in May, we rarely get 90s in June. 

[psv88]

27 minutes ago, TriPol said:

From what I recall, whenever we get 90s in May, we rarely get 90s in June. 

That doesnt seem right

[CIK62]

The next 8 days are averaging 70degs.(61/79) or about +6.0.       This was a cooler GFS run.        The other two main models still have 90's+ during May 20-24.   Little rain continues as a theme for the next 10.  Last week of May BN and wet?

Month to date is  58.9[-2.2].        Should be 62.7[+0.7] by the 24th.

58*(57%RH) by 6am., scattered overcast.         60* by 9am.       62* at 10am.        Reached 68* at 7pm.          Overcast, boring weather day.           59* by 10pm.

[donsutherland1]

Morning thoughts...

Today will be variably cloudy and somewhat cooler. Temperatures will likely reach the lower to perhaps middle 70s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 74°

Newark: 76°

Philadelphia: 73°

Tomorrow will be partly cloudy with high temperatures again reaching the lower 70s in most places. As the PNA plunges to abnormally low levels for May, an impressive warmup could develop later this week.

[donsutherland1]

9 hours ago, TriPol said:

From what I recall, whenever we get 90s in May, we rarely get 90s in June. 

No. There is almost no correlation for New York City (Central Park: 1980-2020). The coefficient determination between whether May had a 90° day and the number of June 90° days is approximately 0.03. The coefficient of determination between the number of 90°  days in May and number of 90° days in June is about 0.04.

Since 1980, New York City has averaged 1.0 90° day in May and 2.9 90°  days in June. When May had no 90°  days, the June average was 2.5 days (minimum: 0 days; maximum: 6 days). When May had 1 or more 90°  days, the June average was 3.4 days (minimum: 0 days; maximum: 9 days).

[Rtd208]

Temp going up quickly once again this morning.

Current temp is 66 here.

[SACRUS]

That transition to warm happened sooner than the 2016 shift but still feel 2016 offers good benchmark this summer .  Made it up to 80 yesterday, clouds will likely get in the way at matching that but as the ridge shifted east on  guidance and now chance at 90s (barring clouds) Wed (5/19) - Sat (5/22).  Models push 850 temps to >16C by Thu and near 18c Fri and Sat before storms arrive.  Beyond there looks like a cool down 5/23 - 5/26 then some more warmth to end the month.  We'll see if we turn noticeably wetter from this dry period  come June.

[SACRUS]

 

[SnoSki14]

Multiple 90+ temps looking likely later next week. Could be another latter month hot spell that turns cooler once June starts. 

Seems to be a theme where the first half to 2/3 of the month is normal to BN and then it goes very warm last third or so. 

[forkyfork]

23 hours ago, nycwinter said:

felt warm this morning cant wait for fall...

haha

[SnoSki14]

Just now, forkyfork said:

haha

That screams record highs.

[gravitylover]

13 hours ago, forkyfork said:

haha

Don't go gloating now

 

I've got really dark skies and long rolling thunder just to my north. I can see the rain column and the hair on my arms is standing up. Temp is down at least 5° in the last few minutes too.

[Rtd208]

Current temp is 75 here.

[bluewave]

12z Euro has something for everyone. The warm spots could see their first 90° of the season on Thursday. Then it has a backdoor for Friday. It’s a compromise between the warmer CMC and cooler GFS. Models struggling with where too place the ridge axis and offshore low. 

 

[uncle W]

hows this for a reversal...

May 23th 1925 the temperature hit 91 in the afternoon...by midnight it was 59 and that was the next days high...the 25th had a high of 53 and a low of 41...

[LoboLeader1]

Just had a thundershower move through the area a short time ago. Temp is now down to 63.

[donsutherland1]

A minor push of slightly cooler air is possible early this week before an impressive warmup unfolds. At the height of the warmth, the 90° isotherm could reach parts of the Middle Atlantic region.

The dominant weather story into at least the closing week of May will be the development of a strongly to occasionally severely negative PNA. That development will lead to a warmer to perhaps much warmer than normal second half of May.

The PNA is currently forecast by most ensemble members to fall to -1.000 or below during the second half of May and remain there for perhaps a week or more. During the 1991-2020 period, the mean temperature was 65.2° in New York City and 67.0° in Philadelphia. When the PNA was -1.000 or below, the average temperature was 67.7° in New York City and 69.3° in Philadelphia.

During the 1991-2020 period, 30% of days in New York City and 41% of days in Philadelphia had high temperatures of 80° or above. During the 1991-2020 period, 15% of days in New York City and 23% of days in Philadelphia had high temperatures of 85° or above. When the PNA was -1.000 or below during that period, 41% of days in New York City and 50% of days in Philadelphia had high temperatures of 80° or above. When the PNA was -1.000 or below during that period, 24% of days in New York City and 35% of days in Philadelphia had high temperatures of 85° or above.

As had been the case with April, the closing week of May could wind up warmer to much warmer than normal. In the four cases where the MJO reached Phase 1 at an amplitude of 2.000 or above in combination with a cool ENSO Region 3.4 anomaly during the May 1-10 period, as occurred this year, three wound up with warmer to much warmer than normal conditions. At New York City, the mean temperature during the closing 7 days of May was 72.7° during those three cases while it was 72.0° at Philadelphia. The 1991-2020 means were 67.9° and 69.7° respectively. Only May 25-31, 2013 (monthly ENSO Region 1+2 anomaly of -1.38°C) was cooler than normal. However, 90° heat arrived on May 29 in Philadelphia and May 30 in New York City during 2013.

Neutral ENSO conditions have now developed. The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.4°C for the week centered around May 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.83°C and the ENSO Region 3.4 anomaly has averaged -0.42°C. Neutral ENSO conditions will likely prevail into at least mid-summer.

The SOI was +22.23 today.

The preliminary Arctic Oscillation (AO) figure was -0.061 today.

On May 14 the MJO was in Phase 2 at an amplitude of 0.924 (RMM). The May 13-adjusted amplitude was 0.910 (RMM).

In late April, the MJO moved through Phase 8 at an extreme amplitude (+3.000 or above). Only February 25, 1988 and March 18-19, 2015 had a higher amplitude at Phase 8. Both 1988 and 2015 went on to have an exceptionally warm July-August period. July-August 1988 had a mean temperature of 79.1°, which ranked 4th highest for that two-month period. July-August 2015 had a mean temperature of 78.9°, which ranked 5th highest for that two-month period. September 2015 was also the warmest September on record. The MJO's extreme passage through Phase 8 could provide the first hint of a hot summer.

Based on sensitivity analysis applied to the latest guidance, there is an implied 73% probability that New York City will have a warmer than normal May (1991-2020 normal). May will likely finish with a mean temperature near 64.3° (1.1° above normal).

 

[LibertyBell]

On 5/15/2021 at 6:50 AM, bluewave said:

That was the famous sensor calibration error when the temperature at Newark stopped recording. While the temperature was missing at Newark, Harrison reached 106°. But they went with the last reading at 12:38 at Newark of 103° before the outage.  Central Park made it to 103° just after 3pm with all the foliage blocking the sensor. So the actual high at Newark was probably around 106°.

Data for July 6 - HARRISON, NJ
Click column heading to sort ascending, click again to sort descending.

Date	Max Temperature	Min Temperature	Precipitation	Snowfall	Snow Depth
2010-07-06	106	80	0.00	0.0	0

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE NEW YORK NY
509 PM EDT TUE JUL 6 2010

...HIGH TEMPERATURE RECORDS FOR JULY 6TH BROKEN OR TIED AT ALL SIX 
WFO NEW YORK NY CLIMATE SITES.

               .....TEMPERATURE.....TIME (LDT).....PREVIOUS RECORD       
CENTRAL PARK NY........103............311 PM...........101 1999...
LA GUARDIA NY..........103............342 PM...........101 1999...
JFK ARPT NY............101...........1240 PM............99 1999...
ISLIP NY...............101............255 PM............99 1999...
BRIDGEPORT CT...........98...........1252 PM............98 1999...
NEWARK NJ..............103*..........1234 PM...........102 1999...

*NOTE: SENSOR CALIBRATION ERROR OCCURRED AT NEWARK NJ. OFFICIAL
       TEMPERATURE OF 103 WAS MEASURED BY FAA CONTRACT OBSERVER.

wow were all those adjusted later?  I thought NYC reached 104 and JFK hit 103.  Why dont we have back up thermometers at all these places (like, regular ones, not this ASOS stuff.)

all the records for that day were from 1999? I remember JFK hit 102 on one of those days....was that the day before?

 

 

[LibertyBell]

5 hours ago, uncle W said:

hows this for a reversal...

May 23th 1925 the temperature hit 91 in the afternoon...by midnight it was 59 and that was the next days high...the 25th had a high of 53 and a low of 41...

east wind?

 

[LibertyBell]

6 hours ago, bluewave said:

12z Euro has something for everyone. The warm spots could see their first 90° of the season on Thursday. Then it has a backdoor for Friday. It’s a compromise between the warmer CMC and cooler GFS. Models struggling with where too place the ridge axis and offshore low. 

 

90 degrees predicted for next Saturday, is that when the backdoor goes away again?

 

[LibertyBell]

On 5/15/2021 at 7:29 PM, uncle W said:

May warm spells with at least three consecutive days 85 or higher in NYC...

dates.................days 90+ max

5/25-27/1880.....3.......3.....96

5/09-11/1896.....3.......3.....91

5/05-09/1930.....5.......2.....91

5/28-30/1931.....3.......3.....93

5/27-29/1935.....3.......0.....89

5/28-31/1939.....4.......3.....96

5/27-30/1959.....4.......1.....94

5/20-22/1959.....3.......2.....91

5/18-21/1962.....4.......2.....99

5/29-31/1969.....3.......2.....97

5/09-13/1970.....5.......2.....93

5/22-24/1980.....3.......1.....90

5/24-27/1981.....4.......0.....87

5/28-31/1986.....4.......2.....94

5/28-31/1987.....4.......3.....97

5/29-31/1988.....3.......1.....91

5/27-31/1991.....5.......3.....91

5/21-23/1992.....3.......2.....93

5/19-21/1996.....3.......2.....96

5/29-31/1999.....3.......0.....89

5/05-09/2000.....5.......3.....93

5/01-04/2001.....4.......3.....92

5/11-13/2004.....3.......0.....86

5/25-31/2015.....7.......0.....88

5/25-29/2016.....5.......2.....92

5/17-19/2017.....3.......3.....91

1991 had a classic and very underrated summer....people forget how hot that summer truly was and all the records that were set.

 

[forkyfork]

7 hours ago, bluewave said:

12z Euro has something for everyone. The warm spots could see their first 90° of the season on Thursday. Then it has a backdoor for Friday. It’s a compromise between the warmer CMC and cooler GFS. Models struggling with where too place the ridge axis and offshore low. 

hopefully the front nearby can give us convection