bluewave

We just shifted to a humid subtropical climate with the new 1991-2020 climate normals.

Yeah, December 2015 going +13 was the big reset month. Each El Niño since 2002-2003 has added new changes to our climate. You can look back and see new patterns of extremes following the 2002-2003, 2004-2005, 2009-2010, and 2015-2016 events. So each global temperature jump creates a new type of baseline for us.

Continuation of our new subtropical climate theme. The dew point at JFK reached 70° again today. This was the 64th day so far this year. All the top years for 70° or higher dew points have occurred since 2016. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=70&month=all&year=2021&dpi=100&_fmt=js #1…..89 days….2018 #2….77 days…..2019 #3….68 days…..2016 #4….64 days…..2021…2020

Islip made it to 78° today. So this was the 21st day in September to reach 75° or warmer. It’s only 4 days behind the September all-time record. Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Sep Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 75 Missing Count 1 2005 25 0 2 2015 24 0 - 1980 24 0 3 2019 23 0 - 1998 23 0 4 2017 22 0 - 2007 22 0 5 2020 21 0 - 1968 21 0 2021 21 9

The potential for a few more 80° degree days showing up over the next week. KEWR GFSX MOS GUIDANCE 9/21/2021 1200 UTC FHR 24 36| 48 60| 72 84| 96 108|120 132|144 156|168 180|192 WED 22| THU 23| FRI 24| SAT 25| SUN 26| MON 27| TUE 28|WED CLIMO N/X 67 81| 69 76| 61 75| 59 74| 59 81| 59 77| 59 75| 61 54 72

Another 80° day at Newark as the endless summer pattern continues. Time Series Summary for NEWARK LIBERTY INTL AP, NJ - Jan through Dec Click column heading to sort ascending, click again to sort descending. Rank Year Number of Days Max Temperature >= 80 Missing Count 1 2015 118 0 2 1994 114 0 3 2016 113 0 - 1993 113 0 - 1991 113 0 4 2011 111 0 - 2010 111 0 5 1959 108 0 2021 108 102

The 592 dm height at Caribou today was one of the highest on record for so late in the season.

Congratulations. The 12z UKMET joined the CMC. Heaviest convection later Thursday into early Friday. The front keeps moving enough that both models are now dry for Saturday.

The next big WAR amplification is in early October with the potential for a hurricane to be somewhere underneath.

The 12z NAM joins the slower models with cutoff and cold front later in the week as the WAR builds to record levels for late September over Newfoundland on Tuesday.

Following the briefly lower dew points, 70° dew points will return ahead of the cutoff low this week.

High temperatures beat guidance again as Newark adds another 80° day to the list.

We’ll see if the JMA is correct about that pattern locking in for October.

Record Newfoundland blocking ahead of the big cutoff this week. So the front stalls out for several days. More very heavy training convection potential coming up.

Several stations just had the 2nd warmest 09-12 to 09-18 on record. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 12 to Sep 18 Missing Count 1 2005-09-18 78.4 0 2 2021-09-18 77.1 0 3 1957-09-18 75.4 0 4 1931-09-18 74.9 0 5 1994-09-18 74.5 0 Time Series Summary for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 12 to Sep 18 Missing Count 1 2005-09-18 75.6 0 2 2021-09-18 74.4 0 3 2018-09-18 72.3 0 4 1998-09-18 72.2 0 5 1971-09-18 72.1 0 Time Series Summary for WESTCHESTER CO AP, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 12 to Sep 18 Missing Count 1 2005-09-18 73.7 0 2 2021-09-18 72.2 0 3 1957-09-18 72.0 0 4 2018-09-18 71.6 0 5 1971-09-18 71.5 0

They just missed the record high of 90° by a few degrees.

It will make 3 months in a row with several local stations going 10”+ Monthly Data for September 2021 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Total Precipitation NY STATEN ISLAND 4.5 SSE CoCoRaHS 9.92 CT NORWICH 2.5 NNE CoCoRaHS 9.26 NJ HARRISON COOP 9.25 NJ NORTH ARLINGTON 0.7 WNW CoCoRaHS 9.23 NJ NEWARK LIBERTY INTL AP WBAN 8.79 Monthly Data for August 2021 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Total Precipitation NY BROOKLYN 3.1 NW CoCoRaHS 12.41 NJ RINGWOOD 3.0 SSE CoCoRaHS 11.57 NJ WEST MILFORD TWP 2.5 SSE CoCoRaHS 11.29 NJ CHARLOTTEBURG RESERVOIR COOP 10.73 NY WANTAGH 0.3 ESE CoCoRaHS 10.54 NY HOWARD BEACH 0.4 NNW CoCoRaHS 10.34 NY NY CITY CENTRAL PARK WBAN 10.32 NJ HARRISON COOP 10.24 Monthly Data for July 2021 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. State Name Station Type Total Precipitation NY PORT WASHINGTON 0.8 N CoCoRaHS 14.76 CT NORTHFORD 0.8 SW CoCoRaHS 12.54 CT DARIEN 3.6 N CoCoRaHS 12.06 CT DARIEN 2.4 NW CoCoRaHS 11.43 NY NY CITY CENTRAL PARK WBAN 11.09 CT STRATFORD 0.9 W CoCoRaHS 11.04 CT WESTPORT 2.5 ENE CoCoRaHS 11.01 CT NORWALK 2.9 NNW CoCoRaHS 10.98 CT NORWALK 1.4 ENE CoCoRaHS 10.75 CT DARIEN 1.8 ENE CoCoRaHS 10.71 NY ALBERTSON 0.2 SSE CoCoRaHS 10.68 CT STAMFORD 4.2 S CoCoRaHS 10.62 CT DURHAM 2.2 SSW CoCoRaHS 10.58 NY QUEENS 3.7 N CoCoRaHS 10.54 CT NEW CANAAN 1.9 ENE CoCoRaHS 10.48 NJ LINDEN 2.2 NW CoCoRaHS 10.32 CT WEST HAVEN 0.8 W CoCoRaHS 10.29 CT REDDING 1.4 E CoCoRaHS 10.25 CT MIDDLEFIELD 0.6 SE CoCoRaHS 10.24 NY LOCUST VALLEY 0.3 E CoCoRaHS 10.13

Models really slowing down the cold front later in the week due to the UL closing off over the Great Lakes. So heavy convection potential where the front stalls out. Probably several days of closer to normal temperatures behind the front. New run Old run

Since September has warmed so much, LGA only has a +1.4 departure through the 17th. So the departures don’t tell the whole story. In our warmer climate, +1.4 is all that is needed for a top 10 warmest first 17 days of September. Time Series Summary for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 1 to Sep 17 Missing Count 1 1961-09-17 77.4 0 2 2015-09-17 77.2 0 3 2005-09-17 77.1 0 4 1947-09-17 76.7 0 5 2016-09-17 76.0 0 6 2018-09-17 75.3 0 7 1983-09-17 74.9 0 8 1971-09-17 74.7 0 9 2021-09-17 74.4 0 10 1957-09-17 74.3 0

The Euro has highs in the 70s and lows in the 50s behind the cold front near the coast later next week. Still has a piece of the WAR hanging on. So the coldest departures remain to our west with the blocking.

It’s always interesting to see how the EPS weeklies compare with the SEAS5 seasonal forecast. The Euro seasonal was picking up on the October blocking potential from the forecast issued back in July. South based blocks can still have above normal temperatures in the Northeast like we saw last winter. So the latitude of the block is important. Early July forecast for October

The EPS ends September with higher latitude blocking that becomes more south based over time. 9-27 to 10-4 10-04 to 10-11 10-11 to 10-18

Continuation of the warm pattern for this time of year. More 80s this weekend. But models have now shifted to more blocking for later in September. Old run New run

You know it’s a warm pattern when Islip reaches 81° on a NE wind in mid-September.

Yeah, we needed the strong SE ridge to boost the SSTs for heavier snows. Luckily, the years that the SE Ridge ran the table without blocking like 2012 and 2020 were in the minority. Some of our best snowfalls have occurred a month after the record SE Ridge was replaced by blocking. The historic January 30” blizzard followed the historic +13.3 SE Ridge December 2015. The historic February 2018 SE Ridge and 80° at Newark was followed by the March historic 30” snows on Long Island.