bluewave

The cool down for late September continues to look less impressive following the record near 600dm ridge this week. EPS new forecast September 21st-28th Old forecast September 21st-28th

More flash flooding here at Tweed following the event back in late July.

This El Niño continues to feature the ridge axis much further south than usual like we saw during the summer. There have been dual ridges near Hudson Bay and the Southeast U.S this September. Perhaps the Southeast ridge maxing out at a record 600dm for September this week is signaling more of a shift north for late September. The trough along the West Coast and record rains in Southern California have been closer to past El Niño expectations during September. Overpowering 500mb ridges have been a common recent theme regardless of ENSO state.

We’ll see if we can make it to 20 days reaching 80° at the warm spots like Newark by later in the fall which has become more common in recent years.

During the 1970s my worst warm season flooding occurred during Agnes and Belle. The 1980s and 1990s warm season flooding was also mostly tropical storms or hurricanes. We could probably say the same about the 2000s although some non tropical events began to register. But the 2010s and 2020s are more of a mix between tropical systems and weak lows. My most extreme rainfall in Long Beach was he weak low in mid-August 2011 that produced 10” during the morning and closed the barrier island to traffic since the areas around the bridges were flooded.

More and more we are seeing these major warm season flash flooding events occur without defined tropical systems. The warmer atmosphere holds more moisture so tropical systems aren’t required. These days all that is required is a weak low or stalled out front. Public Information Statement National Weather Service New York NY 157 PM EDT Sun Sep 13 2026 ...PRECIPITATION REPORTS... Location Amount Time/Date Provider ...Connecticut... ...Fairfield County... Stamford 7.45 in 1220 PM 09/13 AWS Fairfield County... Stamford 7.45 in 1220 PM 09/13 AWS Essex County... MONTCLAIR 8.51 in 1210 PM 09/13 CWOP

July 1911 was a weaker version of what we got this July 2026 closer to our area. Also note that the cooler weather in mid to late July 1911 didn’t occur this year. Those old time heat waves were often followed by much cooler conditions than we get these days. On September 14th, 1911 an observer near the MPO area recorded a low of 26°. So you can see how much colder the climate was back then.

The lows in NYC run cooler than the surrounding urban sites like LGA and EWR. So the tree growth is probably lowering the minimum temperatures also to some extent. In the old days the NYC minimums would average closer to or warmer than those sites before the excessive tree growth. Data for June 1, 2026 through September 13, 2026 Average Minimum Temperature Click column heading to sort ascending, click again to sort descending. NY PORT AUTH DOWNTN MANHATTAN WALL ST HEL ICAO 70.2 NY LAGUARDIA AIRPORT WBAN 70.0 NJ NEWARK LIBERTY INTL AP WBAN 68.0 NY NY CITY CENTRAL PARK WBAN 67.6 NY JFK INTERNATIONAL AIRPORT WBAN 67.5 NJ HARRISON COOP 67.3 NJ TETERBORO AIRPORT COOP 66.7 NJ TETERBORO AIRPORT WBAN 66.6 NY FARMINGDALE REPUBLIC AP WBAN 66.3 NJ CANOE BROOK COOP 66.3 NY MONTAUK AIRPORT WBAN 65.7 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN 65.3 NY ORIENT POINT STATE PARK COOP 65.2 NY ISLIP-LI MACARTHUR AP WBAN 65.1 Data for June 1, 1977 through September 13, 1977 Average Minimum Temperature Click column heading to sort ascending, click again to sort descending. NY NEW YORK LAUREL HILL COOP 67.6 NY NEW YORK AVE V BROOKLYN COOP 67.4 NY NY CITY CENTRAL PARK WBAN 66.8 NY LAGUARDIA AIRPORT WBAN 66.2 NJ NEWARK LIBERTY INTL AP WBAN 66.1

Yeah, this is the heaviest downpour since the summer with plenty of street and parking lot flooding in my area. Southern CT has really been the focus of the heaviest rains. The complete opposite of last summer when we had record low rainfall.

Looks like we’ll get an early sample of the super El Nino ridge north of the Great Lakes in late September.

NYC isn’t considered one of the local warm spots these days due to the artificial cooling from the trees. So the mid 80s will likely be from around Philly to perhaps Newark. This record breaking 600 dm ridge really moderated the cool down which was expected to follow for late September. New run Old run

It’s tough to find the exact locations of where the Mt Pocono observations were taken before the airport opened. So it’s possible some of those warmer readings further back in time were taken at lower elevations where it’s warmer than the current airport location. That may be why some of the earlier warm records haven’t been matched at the current airport location. Station Thread for Mount Pocono Area, PA Name Period in Thread 1 Pocono Mountains Municipal Airport 10/01/1999 to 12/31/2025 2 Tonyhanna Pocono Mountain Airport 12/01/1961 to 09/30/1999 3 Mt. Pocono 09/12/1901 to 11/30/1961 Before official automated airport observations began at the Pocono Mountains Regional Airport (KMPO) in 1999, weather observations in Mount Pocono were recorded by volunteer citizens through the National Weather Service Cooperative Observer Program (COOP). [1, 2, 3] These historical records for Mount Pocono date back to 1901. Under this cooperative network, dedicated local residents, meteorologists, and property owners used equipment provided by the weather bureau to manually record daily maximum and minimum temperatures, snowfall, and rainfall from their own properties or local stations within the community. This long-standing cooperative network is what established Mount Pocono's foundational climate archive

The definition we use for endless summer in the fall is highs of 80° or warmer. This year got off an early start for 80s back in March. So many locations across the region are in the top 5 for 80° days this year. The number Sep to Nov 80° days have more than tripled at the usual warm spots like Newark over their period of record. So now we just take a higher 80°+ days for granted in the fall. 2009 was the last time we had under 10 days reaching 80° during the fall at the locally warmer spots like Newark.

Probably more mid 80s to perhaps around 90° by later next week at the usual warm spots. So a continuation of the endless summer pattern. Really impressive to see a near 600 dm ridge in September. Very difficult to get any sustained fall cooldowns beyond 3-4 days with such strong ridges.

Northern California has been the place to be so far for cool fall weather.

The U.S. was fortunate that none of our regions experienced an extreme as high as France did. The Southwest finished their warmest summer at +3.5° and Colorado +3.4 against the warmest 1991-2020 normals. France finished at +6.4 and was their warmest summer. So they nearly doubled the departures experienced in our warmest regions. This is why they had such a large disruption to their agriculture industry. The warmest extremes relative to historic averages over the last decade in the CONUS have been focused in the winter and early spring rather than the summers.

Cooler summers in general have been missing since 2010. Most of the region finished around the 10th warmest summer this year using dense rank sorting. The Poconos weren’t quite as warm coming in around 19th warmest. So the higher elevations were the place to be.

Significantly stronger vertical wind shear than 2015 and 1997.

This was our warmest developing super El Niño summer relative to the long term averages. These used to be reliably cooler summers. 2015 was the first one that was warmer but not as warm as this year was.

This has been our pattern since March. Ridge out West builds east from time to time. With the warm ups being stronger than the cool downs which followed.

Both the Euro and GFS are hinting at a record Southeast ridge next week.

One of the most impressive features has been the record breaking ridge in the Southwest since last November. The Southwest has been setting records for warmth month after month. The record warmth has spread to the East Coast at times since March as the ridge has shifted back and forth.

When we see some wunderground stations with much higher readings than surrounding sites, it’s often unshielded or poorly shielded sensors.

Really impressive how much stronger this event is than 1997-1998. The August upper ocean heat value of +3.23 was a new all-time record. August 1997 was only +1.79. It didn’t peak until October at +2.56.