September 2025 OBS-Discussion centered NYC subforum

[donsutherland1]

8 hours ago, donsutherland1 said:

For the second time in less than a month, Bridgeport is not reporting its precipitation.

Yesterday's hourly data:

The lowered visibilities are consistent with falling rain:

Yesterday's NOWData:

In sum,Bridgeport had measurable rainfall yesterday. That data was not recorded. So far, today's rainfall has also not been measured. 

FYI, the NWS has added the rainfall amounts that were missing for both August and yesterday for Bridgeport. The region benefits from its high quality and responsive NWS office.

[psv88]

2.25” storm total here. Should keep the grass green into October 

[NorthShoreWx]

2 day rain total here was 1.83".  Today's maxT was 64.9⁰.

[Wxoutlooksblog]

8 hours ago, nycwinter said:

summer is over nyc will not hit 90 again until next year!

Probably but we do not yet know that for sure as a fact.

WX/PT

[donsutherland1]

The temperature dipped to 49° at White Plains this morning. Last year's first low in the 40s occurred on September 9. That is the earliest season low in the 40s since 2001 when the temperature fell to 49° on July 3. 

[IrishRob17]

32 minutes ago, donsutherland1 said:

The temperature dipped to 49° at White Plains this morning. Last year's first low in the 40s occurred on September 9. That is the earliest season low in the 40s since 2001 when the temperature fell to 49° on July 3. 

Is July 3 a typo?

[steve392]

46 degree's in Mahwah this morning, what a great feeling it was getting out of my truck feeling these cool temps.  

[donsutherland1]

13 minutes ago, IrishRob17 said:

Is July 3 a typo?

No. I checked.

[bluewave]

Top 5 coolest 8-25 to 9-7 period for the Great Lakes area. Similar theme to recent years with the coldest temperatures going to our west.

Will be interesting to see how big the temperature rebound is in the coming weeks as these cooldowns over the years have been tough to sustain for very long.

This was the coldest 8-25 to 9-7 period for Dayton, Ohio since record keeping began in 1935.

Time Series Summary for DAYTON INTERNATIONAL AIRPORT, OH top 5 coldest 8-25 to 9-7 periods 
Click column heading to sort ascending, click again to sort descending.

1	2025-09-07	63.3	0
2	2017-09-07	63.9	0
3	1988-09-07	64.7	0
-	1935-09-07	64.7	0
4	1986-09-07	64.9	0
-	1946-09-07	64.9	0
5	1968-09-07	65.3	0

[lee59]

52 degrees here this morning

[FPizz]

46.8, nice.  

[uofmiami]

49.1 in Muttontown & 51.4 in Syosset this morning. 

[wdrag]

CoCoRaHs summary late Fri, late Sat-Sun events... should help lower drought classification by one, that we will see Thursday. Note the whole NYC subforum did very well... max axis near I95, give or take. E Li you did aok.  Click for clarity the sunDAY leftovers, the Fri-Sun broad look (reds the heaviest), and then the detailed bulk NYC subforum.

[jm1220]

1 minute ago, wdrag said:

CoCoRaHs summary late Fri, late Sat-Sun events... should help lower drought classification by one, that we will see Thursday. Note the whole NYC subforum did very well... max axis near I95, give or take. E Li you did aok.  Click for clarity the sunDAY leftovers, the Fri-Sun broad look (reds the heaviest), and then the detailed bulk NYC subforum.

Much needed here for sure. Thanks as always for the analysis! 

[MANDA]

Just entered my CoCoRaHs obs.  My 9/5 to 9/8 total was 2.5".  Much needed.  Beautiful chilly morning with a low of 46. 

Lowest I've seen is Sandyston, NJ at 40.

 

[psv88]

51.0

[wdrag]

Regarding LR:  Complications for Wed-Fri, could result in some periodic rain for the coasts and at the least lots of clouds.

Overall:  I didnt check recent dryness, but already sw Canada seems to have been burning for a while and from what I can tell, excessive heat spreads eastward, north of the Great Lakes.  My guess is lots of smokey sky in our future next week when the pattern at mid levels seems to encourage sewd drift of sw Canada smoke.  That does not translate to near surface aerosol complications but visually, I 'think' we're headed to a return of smoky sky.

[TheClimateChanger]

1 hour ago, bluewave said:

Top 5 coolest 8-25 to 9-7 period for the Great Lakes area. Similar theme to recent years with the coldest temperatures going to our west.

Will be interesting to see how big the temperature rebound is in the coming weeks as these cooldowns over the years have been tough to sustain for very long.

This was the coldest 8-25 to 9-7 period for Dayton, Ohio since record keeping began in 1935.

Time Series Summary for DAYTON INTERNATIONAL AIRPORT, OH top 5 coldest 8-25 to 9-7 periods 
Click column heading to sort ascending, click again to sort descending.

1	2025-09-07	63.3	0
2	2017-09-07	63.9	0
3	1988-09-07	64.7	0
-	1935-09-07	64.7	0
4	1986-09-07	64.9	0
-	1946-09-07	64.9	0
5	1968-09-07	65.3	0

Do you think the new sensors are playing a role in the explosion of record lows? It's been wild to see these airports go from way warmer than everywhere to colder. 100% humidity observations went from basically non-existent to now I'm seeing some of these rural airports having eight hours a night at 100% with no weather (fog, precipitation).

 

 

[TheClimateChanger]

15 minutes ago, TheClimateChanger said:

Do you think the new sensors are playing a role in the explosion of record lows? It's been wild to see these airports go from way warmer than everywhere to colder. 100% humidity observations went from basically non-existent to now I'm seeing some of these rural airports having eight hours a night at 100% with no weather (fog, precipitation).

 

 

Looking at the observations from Pittsburgh (PIT), it appears to be about a 1F cooling offset. But YMMV by location - definitely something to keep an eye out for.

In June 2024, PIT was 72.8F, which was 3.9F above the Pennsylvania Southwest Plateau mean of 68.9F.

In June 2025, PIT was 73.1F, which was 2.9F above the Pennsylvania Southwest Plateau mean of 70.2F.

In July 2024, PIT was 76.5F, which was 3.3F above the Pennsylvania Southwest Plateau mean of 73.2F.

In July 2025, PIT was 77.0F, which was 2.3F above the Pennsylvania Southwest Plateau mean of 74.7F.

So it looks like relative to the Climate Division in which it is located, the new sensor shaved off 1F. Of course, the WBAN sites make up a decent proportion of the total stations in nClimDiv such that the offset may bias the divisional means unless it's been corrected by the pairwise homogenization algorithm. But if there is a residual bias in the divisional data, then the actual cooling offset may be a bit more than 1F.

This is a big reason why state and divisional rankings were higher this summer than the cities, as the cooperative sites [and other stations] had no change in equipment and thus had more continuity of record. This is a reversal of recent years/decades in which cities tended to rank higher than the corresponding state and divisional data.

[TheClimateChanger]

10 minutes ago, TheClimateChanger said:

Looking at the observations from Pittsburgh (PIT), it appears to be about a 1F cooling offset. But YMMV by location - definitely something to keep an eye out for.

In June 2024, PIT was 72.8F, which was 3.9F above the Pennsylvania Southwest Plateau mean of 68.9F.

In June 2025, PIT was 73.1F, which was 2.9F above the Pennsylvania Southwest Plateau mean of 70.2F.

In July 2024, PIT was 76.5F, which was 3.3F above the Pennsylvania Southwest Plateau mean of 73.2F.

In July 2025, PIT was 77.0F, which was 2.3F above the Pennsylvania Southwest Plateau mean of 74.7F.

So it looks like relative to the Climate Division in which it is located, the new sensor shaved off 1F. Of course, the WBAN sites make up a decent proportion of the total stations in nClimDiv such that the offset may bias the divisional means unless it's been corrected by the pairwise homogenization algorithm. But if there is a residual bias in the divisional data, then the actual cooling offset may be a bit more than 1F.

This is a big reason why state and divisional rankings were higher this summer than the cities, as the cooperative sites [and other stations] had no change in equipment and thus had more continuity of record. This is a reversal of recent years/decades in which cities tended to rank higher than the corresponding state and divisional data.

Looks like its going to vary widely from site to site. DTW has only cooled about 0.1F relative to its divisional mean, while CLE has cooled about 0.6-0.7F relative to its divisional mean compared to 2024.

[TheClimateChanger]

29 minutes ago, TheClimateChanger said:

Do you think the new sensors are playing a role in the explosion of record lows? It's been wild to see these airports go from way warmer than everywhere to colder. 100% humidity observations went from basically non-existent to now I'm seeing some of these rural airports having eight hours a night at 100% with no weather (fog, precipitation).

 

 

What is so funny about this comment? It's a legitimate question/concern.

Others have noticed this change as well on other weather forums:

New ASOS Temperature/Dewpoint System

This user noted that FFC, one of the original test sites, went from running warmer than ATL to colder:

This user noted that Valentine (NE) Airport went from quite a bit warmer than his readings to about the same, if not cooler. He also notes the sudden proliferation of 100% humidity which was pretty much non-existent on the traditional sensors.

[FPizz]

14 minutes ago, TheClimateChanger said:

What is so funny about this comment? It's a legitimate question/concern.

Others have noticed this change as well on other weather forums:

New ASOS Temperature/Dewpoint System

This user noted that FFC, one of the original test sites, went from running warmer than ATL to colder:

This user noted that Valentine (NE) Airport went from quite a bit warmer than his readings to about the same, if not cooler. He also notes the sudden proliferation of 100% humidity which was pretty much non-existent on the traditional sensors.

What does this have to do with this forum?  Go cry in theirs.

Also, all the bitching in the world doesn't matter, see NYC.  It never gets fixed.  If they don't care, why should we.

[TheClimateChanger]

24 minutes ago, TheClimateChanger said:

What is so funny about this comment? It's a legitimate question/concern.

Others have noticed this change as well on other weather forums:

New ASOS Temperature/Dewpoint System

This user noted that FFC, one of the original test sites, went from running warmer than ATL to colder:

This user noted that Valentine (NE) Airport went from quite a bit warmer than his readings to about the same, if not cooler. He also notes the sudden proliferation of 100% humidity which was pretty much non-existent on the traditional sensors.

Can definitely see that immediate, incredible impacts of that sensor change at FFC, which occurred on July 31, 2024. Based on this data, some locations may have cooled as much as 3.5 or 4F with the new sensors, but perhaps the aspiration was broken at the FFC site. They also changed (or are in the process of changing) the aspiration and solar radiation shields. Still even low temperatures dropped precipitously compared to ATL.

June 2024

FFC: 92.9/68.2

ATL: 91.1/71.8

July 2024

FFC: 92.4F/73.0

ATL: 90.7/74.0

August 2024

FFC: 90.2/67.3

ATL: 92.0/72.3

Wow! ATL was 2.0F above 1991-2020 in August 2024, while FFC was 1.1F below 1991-2020.

[bluewave]

1 hour ago, TheClimateChanger said:

Do you think the new sensors are playing a role in the explosion of record lows? It's been wild to see these airports go from way warmer than everywhere to colder. 100% humidity observations went from basically non-existent to now I'm seeing some of these rural airports having eight hours a night at 100% with no weather (fog, precipitation).

 

 

The record ridge and drought in Canada generated strong high pressure and low dewpoints. This was followed up by the record trough over the Western Great Lakes ago. These very cold early season temperatures are actually being driven by the minimums allowing ideal early fall radiational cooling. 

We should continue with the comfortable early fall temperatures here right into mid-September as Canadian high pressure dominates. 

But much the CONUS is experiencing expanding drought conditions. So we could see a drought feedback warm up beginning to west while we enjoy the great early fall weather here.

Unfortunately, the reliable models only go out 15 days. So the pattern from late September into October will depend on the pattern evolution.

If we start getting more high pressure to our SW, then that drought feedback warmth could arrive here later September into October.

Statistically we don’t see much 90° heat here at the warm spots like Newark that late in the season. We haven’t seen any 90° heat at these locations after September 20th since 2017 and 2019. 

But  you never know if this will be the first 2020s year to pull it off. Especially if the winds can turn more SW. 

The big theme here in recent years has been record 80s warmth right into late October and early November like last year. 
 

 

 

[TheClimateChanger]

27 minutes ago, bluewave said:

The record ridge and drought in Canada generated strong high pressure and low dewpoints. This was followed up by the record trough over the Western Great Lakes ago. These very cold early season temperatures are actually being driven by the minimums allowing ideal early fall radiational cooling. 

We should continue with the comfortable early fall temperatures here right into mid-September as Canadian high pressure dominates. 

But much the CONUS is experiencing expanding drought conditions. So we could see a drought feedback warm up beginning to west while we enjoy the great early fall weather here.

Unfortunately, the reliable models only go out 15 days. So the pattern from late September into October will depend on the pattern evolution.

If we start getting more high pressure to our SW, then that drought feedback warmth could arrive here later September into October.

Statistically we don’t see much 90° heat here at the warm spots like Newark that late in the season. We haven’t seen any 90° heat at these locations after September 20th since 2017 and 2019. 

But  you never know if this will be the first 2020s year to pull it off. Especially if the winds can turn more SW. 

The big theme here in recent years has been record 80s warmth right into late October and early November like last year. 
 

 

 

Yeah, this drought has been crazy. Looks like the Mississippi River will be seeing extremely low levels for a fourth consecutive fall: The Mississippi River is Set to Fall to Severe Levels for the Fourth Year in a Row

I know the gauge at Memphis had three of its 4 lowest gauge readings in the last 3 years. Last year reached at least -10.41 feet in early November, but this chart was never updated. Crazy to just be blowing out the 1988 & 2012 droughts ever single year with hardly a peep? I'm sure dredging/channel deepening is aiding these very low gauge heights (i.e., the same volume of water may pass with a lower river level) but still..

 

 

[Sundog]

4 hours ago, donsutherland1 said:

No. I checked.

I remember that cold blast. I was supposed to fly to Greece on the 2nd but there was engine trouble on my plane and I had to leave the next day instead.

Because of that I was able to catch that intense CAA and experience lows in the mid 50s the next morning when I would have otherwise missed them. 

[wdrag]

ASOS new temp sensors?  I'm out of touch... LINK for info?  Thanks, Walt

[FPizz]

20 minutes ago, wdrag said:

ASOS new temp sensors?  I'm out of touch... LINK for info?  Thanks, Walt

https://www.weather.gov/asos/CurrentEvents.html

Though I'm told from Tony Gigi when I asked about the qc process, that they only qc the instruments, not the environment around them.  Hence I guess why NYC is determined to be fine, since all the instruments are in correct working order.

[PhiEaglesfan712]

1988 was one that turned cold really quickly. The summer, particularly from June to the first half/two-thirds of August, was then a warmest on record. Then at the end of August, it just turned cold, and never really looked back. October 1988 was one of the coldest on record, and in some spots, beat out the cold standard of October 1976:

Come to think of it, the warm west makes this look like the October version of February (or JFM) 2015.

[steve392]

20 minutes ago, PhiEaglesfan712 said:

1988 was one that turned cold really quickly. The summer, particularly from June to the first half/two-thirds of August, was then a warmest on record. Then at the end of August, it just turned cold, and never really looked back. October 1988 was one of the coldest on record, and in some spots, beat out the cold standard of October 1976:

Come to think of it, the warm west makes this look like the October version of February (or JFM) 2015.

What kind of winter did that year have?