bluewave

The fewest MJO winter phase 8-1 days followed by a new May phase 1 amplitude record. It’s tough to keep up with all these new weather extremes and swings. Back in February it was the historic AO/NAO reversal.

Classic spring backdoor day. Highs BDR…64° ISP…..65° LGA…69° JFK….71° EWR…75°

It’s good to see that we now have supplemental 15 year climate normals for the first time. The 15 year snowfall average at Islip of 36.3 is now similar to the old 1981-2010 normals for portions of New England. The December 15 year average temperature is now close to 40° in NYC. A 40° December is similar to the old 1981-2010 normals around Washington DC. The new 15 year July temperature around 80° at LGA and EWR is similar to the 1981-2010 average around DC. ISLIP LI MACARTHUR AP, NY Get this data as .csv | .pdf Season MAX TEMP (°F) MIN TEMP (°F) AVG TEMP (°F) PRECIP (IN) SNOW (IN) Annual 61.8 45.8 53.8 47.42 36.3 NEW YORK CNTRL PK TWR, NY Dec 45.0 34.4 39.7 4.88 4.6 NEW YORK LAGUARDIA AP, NY Jul 87.4 72.8 80.1 4.47 0.0 NEWARK INTL AP, NJ Jul 88.0 70.3 79.2 5.05 0.0 https://www.ncei.noaa.gov/access/us-climate-normals/ https://www.washingtonpost.com/weather/2021/05/04/noaa-new-climate-normals/ It used to be that the normals would give a great idea of what the climate has been like for someone’s 30-year career, so new resource managers could get up to speed quickly on how and why a more senior manager made the choices they did based on past climate,” McPherson said in an email. “Now we’re seeing enough change from one decade to the next that we need to prepare managers differently. They need to understand these are not static, so the direction of change is as important, or more important, as the values of the normals themselves.” NOAA has been experimenting with supplemental climate normals that may better reflect what to expect in the 2020s. Some researchers have argued that climatological periods shorter than 30 years could be more accurate for monthly temperature averages used in the near future. Thus, the new NOAA climate normals include a supplemental set of 15-year data for the period 2006-2020, a first for any climate-norms update.

Interesting how the first 90° date at Newark remains unchanged around May 20th since 1971. But the date of the first 80° has moved up from April 27 to March 31. So a late month warm up would match the MJO progression and the longer term trends.

Looks like some heavy downpours tonight with the elevated convection.

Yesterday could be the warmest for a while. Models have switched to a classic May backdoor pattern next few days. Tough to get mid 80s for more than a day at a time with a record 3.6 SD MJO 8-1 pattern. 2021 5 1 -3.6043048 -0.29759625 1 3.6165698

Classic spring warm day temperature distribution around the area. Jones Beach N/A 59 N/A N/A S10G16 N/A Wantagh N/A 66 50 55 S12 N/A Kennedy Intl PTSUNNY 77 48 35 SW15 29.72S LaGuardia Arpt MOSUNNY 82 44 26 W12G21 29.68F Newark/Liberty PTSUNNY 83 45 26 SW24 29.70S

The Euro had the morning showers with warm front moving through. Should see a big temperature jump this afternoon. So 80+ for the areas in NJ that get warm sectored is still on track.

The MJO was less robust at this time last year. But the blocking north of Alaska was pretty extreme. Just a month earlier we had the record 1068 mb high over the Arctic. So the pattern was primed for a record May Arctic outbreak here. The daily record low of 34° in NYC was the 3rd coldest on record for April. To put that in perspective, the last time NYC had a top 3 coldest monthly low temperature was way back in April and August 1982 and 1986. So I guess that it’s fitting the April 1982 blizzard set the standard for April blizzards and cold. The trace last May was a record shared with 1977 for latest in the season. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of May Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1891 32 0 2 1874 33 0 3 2020 34 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Apr Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1923 12 0 2 1874 20 0 3 1982 21 0 Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Aug Click column heading to sort ascending, click again to sort descending. Rank Year Lowest Min Temperature Missing Count 1 1986 50 0 - 1982 50 0 - 1976 50 0 - 1965 50 0 - 1885 50 0

You had to figure that a cooler trough would find a way to develop by later next week with a record MJO 8-1 for early May. The big question is how the individual storm details will work out with so much model spread. The models may not be much help beyond 3-5 days with such an amplified pattern. Big warm up next several days MJO 8-1 cool down by later in the week

Yeah, I have noticed this also. It seems to happen when the top of the mixed layer gets near 700mb. The peak wind gusts often run about 5 to 10 KT higher than strongest surface to 700mb level forecast sounding winds. The afternoon peak gusts around NYC occurred near the time of the convection moving through. The Manhattan Mesonet rooftop sensor gusted to 60 mph at 2:20 then had .01 of rain at 2:35. http://www.nysmesonet.org/weather/meteogram#network=nysm&stid=manh

8th warmest spring so far in NYC. So it’s no surprise to see the models indicating 80° potential for the warm spots on Sunday. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Mar 1 to Apr 30 Missing Count 1 1945-04-30 53.3 0 2 2010-04-30 53.0 0 3 2012-04-30 52.8 0 4 1921-04-30 52.2 0 5 2016-04-30 51.1 0 6 1985-04-30 50.5 0 7 1903-04-30 50.3 0 8 2021-04-30 50.1 0 - 1977-04-30 50.1 0 - 1946-04-30 50.1 0 9 2002-04-30 50.0 0 - 1991-04-30 50.0 0 10 1973-04-30 49.8 0

A +2.5 to +3.5 March followed by a +1 to +2 April.

Jones Beach already gusting to 46 mph. Jones Beach N/A 61 N/A N/A NW35G46

NYC is currently at the 9th warmest March and April average temperature of 50.0°. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Mar 1 to Apr 30 Missing Count 1 1945-04-30 53.3 0 2 2010-04-30 53.0 0 3 2012-04-30 52.8 0 4 1921-04-30 52.2 0 5 2016-04-30 51.1 0 6 1985-04-30 50.5 0 7 1903-04-30 50.3 0 8 1977-04-30 50.1 0 - 1946-04-30 50.1 0 9 2021-04-30 50.0 1 - 2002-04-30 50.0 0 - 1991-04-30 50.0 0 10 1973-04-30 49.8 0

Lapse rates really steepen next few hours. 45KT in the mixed layer should produce gusts to 50 mph + by later this afternoon. Then a 50KT LLJ arrives this evening with the potential for some peak gusts to around 60 mph.

I started a May 2021 thread.

Looks like some briefly cooler temperatures on May 1st with morning low 40s around NYC. Then a quick rebound in temperatures back to the 70s on Sunday.

While the forecast soundings are indicating only modest CAPE, the seasonally high PWATS signal the chance for some much needed rainfall. Maybe some locally strong to severe storms if we can destabilize more than forecast with the decent shear. But most will be happy to get a soaking downpour.

Looks like our first +3 SD MJO phase 8 since February 2017. That one was preceded by the blizzard of 2017. But much warmer conditions and a spring wavelength response didn’t allow for a similar wintery outcome. 2021 4 27 -2.8350327 1.1143280 8 3.0461676 2017 2 15 -3.0841775 0.94387865 8 3.2253771 https://www.weather.gov/okx/Blizzard_Feb92017

Just looking at the teleconnections, it appears like this should have been a cold April. But the warmer south based blocking continued like we saw during the winter. So it was a rare warmer than average -EPO, -AO, -NAO April.

This is one of the less common months when the high temperatures are driving the departures. NYC was +1.5 on the max and +0.3 on the min through yesterday. Frequent cold fronts and drier conditions have allowed the minimum temperatures to remain near normal while the high temperatures have been above average. CLIMATE REPORT NATIONAL WEATHER SERVICE NEW YORK, NY 435 PM EDT WED APR 28 2021 ................................... ...THE NEWARK NJ CLIMATE SUMMARY FOR APRIL 28 2021... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1893 TO 2021 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 89 157 PM 90 1990 67 22 68 2009 MINIMUM 50 502 AM 33 1934 48 2 40 AVERAGE 70 57 13 54

Yeah, now the temperature is back down to 71° at LGA. Very impressive hourly and daily temperature jumps since late March on the wind shifts. The temperature on the South Shore back in late March rose from 57° to 80° in an hour.

Today was the 7th highest April diurnal temperature range for Newark at 38°.