bluewave

A waterspout to go with the hail today.

Getting pea size hail now on Staten Island.

If we can keep these record 700-500 mb lapse rates going into the summer, then it will be the case.

Heavier showers filling in more quickly just west of NYC than the models indicated yesterday. Impressive cold pool aloft with very steep mid-level lapse rates. So any stronger cells could produce some pea sized hail.

Models have pop up convection tomorrow under the deep upper low and cold pool. So it will be a hit or miss type affair during the day. Somebody could see the ground whitened with small hail under the steep mid-level lapse rates and low freezing level.

Unusual temperature pattern so far this May. Newark reached 86° during the first week of the month. Looks like our first time since 2010 with no May 8-15 follow up 80s in the forecast. Just goes to show how impressive a MJO event this was combined with lingering April blocking. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Ending Date Highest Max Temperature May 1 to May 7 May 8 to 15 2021-05-07 86 ? 2020-05-07 80 86 2019-05-07 78 79 2018-05-07 94 92 2017-05-07 76 71 2016-05-07 61 77 2015-05-07 87 88 2014-05-07 78 85 2013-05-07 72 81 2012-05-07 76 84 2011-05-07 73 76 2010-05-07 90 83

Our precipitation is increasing along with the temperatures. Rural, suburban, and urban sites are experiencing a faster minimum temperature rise than maximum. The maps below show the rate of change per decade. https://www.sciencedaily.com/releases/2020/09/200930194912.htm Days warmed more quickly in some locations, and nights did in others -- but the total area of disproportionately greater night-time warming was more than twice as large. The study shows this "warming asymmetry" has been driven primarily by changing levels of cloud cover. Increased cloud cover cools the surface during the day and retains the warmth during the night, leading to greater night-time warming. Whereas, decreasing cloud cover allows more warmth to reach the surface during the day, but that warmth is lost at night. https://www.ncdc.noaa.gov/temp-and-precip/us-trends/tmin/ann

I did a calculation of how much warmer the new 30 yr and 15yr climate normals are in NYC than 1981-2010. Month….30yr….15yr Dec.+1.6….+2.2 Jan..+1.1….+1.7 Feb…+0.6…+0.5 Mar..+0.3…+0.7 Apr…+0.7…+1.0 May…+0.8…+1.4 Jun….+0.5…+0.6 Jul….+1.0….+1.9 Aug….+0.9….+1.0 Sep….+1.2….+1.9 Oct….+1.0….+1.9 Nov…+0.3…+0.4

Same story in the Poconos. The summer minimums have been rising more quickly than the maximums. So this is a shared temperature pattern at rural, suburban, and urban stations.

The Euro has convection along the inverted trough with steep mid-level lapse rates on Saturday.

This will be our first cool stretch in a while. So it only took a record breaking MJO event to pull It off. Goes to the recent theme of needing something extreme to get cooler than average temperatures. KEWR GFSX MOS GUIDANCE 5/05/2021 0000 UTC FHR 24| 36 48| 60 72| 84 96|108 120|132 144|156 168|180 192 WED 05| THU 06| FRI 07| SAT 08| SUN 09| MON 10| TUE 11| WED 12 CLIMO X/N 65| 48 68| 47 63| 47 59| 45 62| 46 67| 47 66| 48 70 50 70 TMP 59| 51 61| 52 56| 51 53| 50 54| 50 60| 52 59| 53 63 DPT 45| 35 30| 35 37| 39 34| 37 36| 40 34| 35 32| 37 39 CLD OV| PC PC| CL OV| OV OV| PC OV| OV PC| CL PC| CL PC

The minimums are increasing faster than the maximums across the region. So the number of 70° minimums has doubled or tripled from 1981 to 2020. This is the case at urban,rural, and suburban stations. My guess is that this is related to the big increase in humidity and clouds at night as the climate warms. Since the Central Park station has become so overgrown with vegetation, POU to our north now has more 90° days than NYC. But the NYC nighttime minimums are increasing just as fast as other stations. So you can see it’s an artificial shading effect due to poor sensor sitting under the trees and bushes. Change in 90° highs and 70° lows ……….1981….90°…..70°…….2020…….90°……70° EWR…26/35….29/43 LGA….14/32….26/67 NYC….19/29…16/47 JFK…..11/29….11/40 ISP……..6/15……9/30 BDR……6/11……11/35 POU….12/3…..…19/9 BDL……14/6…….24/13 TTN…….18/17…..26/31

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