May 2021

[Rjay]

55 minutes ago, nycwinter said:

no montauk is cooler then the park how many days it was in the 80;s or 70;s in the city and montauk was in the 50;s

[psv88]

Just popped to 90 here in nw Suffolk. 

[Shades]

I would bet higher maxes in JFK in late Srping/early summer on a NW/N flow than LGA, and even some days well into the summer depending on the dry adiabatic. That flow is coming off the mainland of Queens and the Van Wyck - I count expressways as a type of topography in these parts.

[Shades]

Someone could pickup a grant on seasonal micro-climates in the five boroughs, if someone hasn't already. It's not all about the ASOS, IJS.

[SnowGoose69]

A fairly strong shift today in all the 12Z models to keep the rain south 5/28-/5/30...probably too early yet to spike the football but the pattern did scream suppression to a degree there.

[winterwx21]

We don't know if next weekend's rain will stay south, but it does appear that we have a decent chance of some strong storms in the heat/humidity wednesday evening. Hopefully that will work out, because the soil is really dry right now. Really need some rain.

[LibertyBell]

1 hour ago, psv88 said:

Just popped to 90 here in nw Suffolk. 

also has hit 90 here in SW Nassau, 91 to be exact, with completely overcast skies, which is interesting

[LibertyBell]

2 hours ago, SACRUS said:

Some late afternoon maxes today with some more clearing and peak 850.   Clouds definitely ate into early afternoon heating. 

it just hit 91 here under overcast skies this is pretty late for a daily max lol

 

[LibertyBell]

2 hours ago, donsutherland1 said:

The tree issue was much smaller back in 1993 than it is today.

JFK has reached a high of 90° so far. 

yess  good to see, 91 here right now cloudy but not humid.....this is some weird weather.  How can it be cloudy but not humid lol?

 

[LibertyBell]

3 hours ago, psv88 said:

The winds were from the nw and LGA is on the LI sound. JFK usually hotter than LGA with a nw wind

this also happens to be the kind of wind that keeps the allergies away for me.  I love low humidity heat.

 

[Rtd208]

Current temp 90/DP 64

[psv88]

91

[crossbowftw3]

Front/windshift beginning to creep in, 79/64 while Binghamton has fallen to 68.

[Cfa]

90/66 split today, currently 85.

[doncat]

91/69 today.

[uofmiami]

88 in Muttontown (88.3) & Syosset (87.5) for the high. 

[donsutherland1]

The temperature rose to 90° or above in numerous locations for a second consecutive day. Areas reporting 90° temperatures included:

Allentown: 90°
Atlantic City: 94° (tied record set in 1964)
Baltimore: 95°
Bridgeport: 90° (old record: 89°, 1992)
Boston: 90°
Georgetown: 93° (tied record set in 1964)
Harrisburg: 93°
New York City-JFK: 92° (old record: 89°, 1964 and 1980)
Newark: 94°
Philadelphia: 92°
Providence: 90°
Sterling, VA: 92° (tied record set in 1964)
Trenton: 90°
Washington, DC: 94°
Wilmington, DE: 94° (tied record set in 1925)

Yesterday was the first day on record in May when Islip reached 90° or above while New York City's Central Park did not reach 90°. Today became the first day on record when Bridgeport reached 90° or above, but Central Park did not reach 90°.

90° Days for Select Cities (through May 23):

Albany: 0 (2020: 13 days; 5-Year Average: 13.6 days)
Allentown: 1 (2020: 24 days; 5-Year Average: 27.6 days)
Baltimore: 2 (2020: 46 days; 5-Year Average: 44.6 days)
Boston: 1 (2020: 14 days; 5-Year Average: 17.2 days)
Bridgeport: 1 (2020: 11 days; 5-Year Average: 13.4 days)
Burlington: 2 (2020: 20 days; 5-Year Average: 13.0 days)
Harrisburg: 1 (2020: 35 days; 5-Year Average: 30.6 days)
Hartford: 1 (2020: 39 days; 5-Year Average: 29.0 days)
Islip: 1 (2020: 8 days; 5-Year Average: 9.4 days)
New York City-JFK: 2 (2020: 12 days; 5-Year Average: 10.2 days)
New York City-LGA: 0 (2020: 34 days; 5-Year Average: 29.4 days)
New York City-NYC: 0 (2020: 20 days; 5-Year Average: 18.2 days)
Newark: 3 (2020: 31 days; 5-Year Average: 31.2 days)
Philadelphia: 2 (2020: 36 days; 5-Year Average: 34.6 days)
Scranton: 1 (2020: 25 days; 5-Year Average: 16.4 days)
Washington, DC: 3 (2020: 46 days; 5-Year Average: 50.8 days)

New York City-Newark Average: 1 (2020: 22 days)
...Expected: 2 (based on regression equation tied to JFK-LGA-EWR data)

To date, JFK Airport has recorded more 90° temperatures than both Central Park and LaGuardia Airport. Only 1978 and 1984 saw JFK report more 90° than both Central Park and LaGuardia Airport.

Tomorrow and Tuesday will see a return of noticeably cooler air before another big push of warm air takes place.

The dominant weather story into the closing week of May will be the synoptic impact 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. There will likely be at least one more day on which the temperature will make a run at 90° in parts of the region this week.

Today, the preliminary value of the PNA was -1.121. The PNA will likely rise above -1.000 tomorrow. During the May 16-31, 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 May 16-23 period, the likely mean temperatures will be 71.3° at New York City and Philadelphia 70.6° at 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. During the May 16-23 period, the temperature reached 80° or above on 50% of days and 85° or above on 38% of days in New York City. The temperature reached 80° or above on 75% of days and 85° or above on 38% of days in Philadelphia. In both cities, the warmth overperformed somewhat.

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.

Nevertheless, the Memorial Day weekend will likely be unsettled and cooler. Periods of rain are possible, though there is large uncertainty about the amount of precipitation. A light to perhaps moderate rainfall appears more likely than a heavy rainfall based on the ensembles.

The first 7-10 days of June could also start off warmer than normal. The MJO's passage through Phase 4 at an amplitude of 1.500 or above during the May 15-25 period coupled with ENSO Region 1+2 temperature anomalies above -1.0°C and below +1.0°C, as has been the case this year, has typically seen warmth in the East during the first 10 days of June. Cooler conditions typically prevailed when the ENSO Region 1+2 anomalies were outside that range.

Neutral ENSO conditions have now developed. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.3°C for the week centered around May 12. 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 -0.38°C. Neutral ENSO conditions will likely prevail into at least mid-summer.

The SOI was +6.68 today.

The preliminary Arctic Oscillation (AO) figure was +1.261 today.

On May 21 the MJO was in Phase 4 at an amplitude of 1.644 (RMM). The May 20-adjusted amplitude was 1.863 (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 80% probability that New York City will have a warmer than normal May (1991-2020 normal). May will likely finish with a mean temperature near 64.5° (1.3° above normal).

 

[crossbowftw3]

Temperatures tumbling. 73/61

[psv88]

Beautiful evening! 80 and light breeze

[SACRUS]

5/23

ACY: 94
EWR: 94
JFK: 92
PHL: 92
BLM: 92
TTN: 90
New Brnswck: 90
TEB: 89
ISP: 89
LGA: 88
NYC: 88

[psv88]

3 minutes ago, SACRUS said:

5/23

ACY: 94
EWR: 94
PHL: 92
BLM: 92
TTN: 90
New Brnswck: 90
TEB: 89
ISP: 89
LGA: 88
NYC: 88

BLM replaced JFK? I think NJ plenty well represented on that list already with 7 lol, spread the wealth

[SACRUS]

9 minutes ago, psv88 said:

BLM replaced JFK? I think NJ plenty well represented on that list already with 7 lol, spread the wealth

JFK: 92

missed the paste.

[tmagan]

Central Park has not been above 96 degrees since September 8, 2015. That is tied for the second longest streak of all time with January 1, 1869 [beginning of record] to June 29, 1874. The all time record is ten years and one day from July 2, 1901 to July 3, 1911.

[psv88]

6 minutes ago, tmagan said:

Central Park has not been above 96 degrees since September 8, 2015. That is tied for the second longest streak of all time with January 1, 1869 [beginning of record] to June 29, 1874. The all time record is ten years and one day from July 2, 1901 to July 3, 1911.

More accurately stated, the Central Park thermometer has not recorded a reading above 96 degrees since that date...

[donsutherland1]

16 minutes ago, psv88 said:

More accurately stated, the Central Park thermometer has not recorded a reading above 96 degrees since that date...

IMO, the statistical evidence (slight cooling in summer high temperatures at Central Park while the remainder of the region has warmed approximately one degree F) demonstrates that the summer records are inaccurate. One of three measures should be taken to preserve or restore data integrity:

1. Trees should be trimmed so that the ASOS is in compliance with customary practice

2. The ASOS should be moved to an alternative location in the Park that would be in compliance and also have limited risk of falling out of compliance anytime soon

3. Homogenization of the Central Park temperatures to bring them into line where they should be (some degree of error would exist)

All three of these approaches are preferable to increasingly flawed summer data. I'd prefer the first two, but the third would be a useful resort were the first two not pursued.

[lee59]

If Central Park temperatures are a little to low in the day, it doesn't make up for the heat island affect at night. Another thing is the temperature readings at airports are in many cases surrounded by those hot tarmacs. I wonder if the open space of the airport lets the wind pick up that hot tarmac temperature and just make the entire airport temperature higher on those very hot sunny days.

[Intensewind002]

Disgustingly hot in my house, me and my dad haven't put the air conditioners in yet 

[lee59]

89 degree high here for the second day in a row. 65 degrees for tomorrow and still not a drop of rain.

[LibertyBell]

2 hours ago, lee59 said:

If Central Park temperatures are a little to low in the day, it doesn't make up for the heat island affect at night. Another thing is the temperature readings at airports are in many cases surrounded by those hot tarmacs. I wonder if the open space of the airport lets the wind pick up that hot tarmac temperature and just make the entire airport temperature higher on those very hot sunny days.

JFK temps are matched here in SW Nassau

[LibertyBell]

2 hours ago, donsutherland1 said:

IMO, the statistical evidence (slight cooling in summer high temperatures at Central Park while the remainder of the region has warmed approximately one degree F) demonstrates that the summer records are inaccurate. One of three measures should be taken to preserve or restore data integrity:

1. Trees should be trimmed so that the ASOS is in compliance with customary practice

2. The ASOS should be moved to an alternative location in the Park that would be in compliance and also have limited risk of falling out of compliance anytime soon

3. Homogenization of the Central Park temperatures to bring them into line where they should be (some degree of error would exist)

All three of these approaches are preferable to increasingly flawed summer data. I'd prefer the first two, but the third would be a useful resort were the first two not pursued.

we've repeatedly changed snowfall measurements after the fact, I dont get the hesitation here.