September 2025 OBS-Discussion centered NYC subforum

[psv88]

Water levels are high on the north shore. Probably a 1.5 feet above normal. Stiff breeze as well 

[wdrag]

2 hours ago, FPizz said:

Sundays forecast seems subject to change if Walt is correct with more rain.

I'll need to wait this out...  one thing I didnt see was EC AI was almost nothing.

It could be the EC suite (non AI) is too strong and too far southwest with the 5H vort plunging sdwd from south center Canada with the resultant sfc response too robust here. Would make this a period of waa showers Sunday afternoon and maybe cool frontal showers Monday.

I do think its best to play temps conservatively and cooler in this pattern for another 10 days and wait this out a bit but I plan on showers Sunday afternoon and possibly right into Monday night.  

Patience... at least for me til a I reconsider later on.  12z WPC D4-6 guidance has boosted qpf a bit and I think that right... dont plunge into the unusual heavy solution till we have more confidence. Lets not say its a nice end to the weekend beginning of next week. 

[Brian5671]

Euro wet for next Monday

[FPizz]

5 minutes ago, Brian5671 said:

Euro wet for next Monday

CMC wet east of NYC, drier west, but other models have nothing

[Brian5671]

3 minutes ago, FPizz said:

CMC wet east of NYC, drier west, but other models have nothing

Cutoff lows notoriously difficult with precip placement.  But would be nice to get another dump of rain and on a Monday-that would be great

[jm1220]

1 hour ago, FPizz said:

CMC wet east of NYC, drier west, but other models have nothing

If the low can close off and dig west of us, we’ll get a moist fetch off the ocean. If not, probably cloudy and nasty. 

[Stormlover74]

10 minutes ago, jm1220 said:

If the low can close off and dig west of us, we’ll get a moist fetch off the ocean. If not, probably cloudy and nasty. 

euro did this last month and busted badly. could still happen but right now if its alone its probably off

[donsutherland1]

Today, Islip recorded its third consecutive high of 74° and Central Park saw its third consecutive high of 73°. The last time both locations had three consecutive days with the same high simultaneously was during July 6-8, 2000 when both locations had three consecutive highs of 79°.

Tomorrow will be briefly warmer with highs in the upper 70s to perhaps lower 80s. A few locations could see a shower or thundershower tomorrow night into Friday as a cold front pushes through.

The next round of showers or rainfall could be Monday.

September 1-15 is on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024.

The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn.

The SOI was -5.70 today. 

The preliminary Arctic Oscillation (AO) was +0.415 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 59% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 68.4° (0.8° below normal). 

Supplemental Information: The projected mean would be 0.4° above the 1981-2010 normal monthly value.

 

[bluewave]

The Euro lost the cutoff low for early next week. It’s replaced by a 591 dm ridge to our west. So it has mid 80s from Sunday right into next week. 
 

New run

Old run

[wdrag]

Yes... and it was my mistake not checking EC AI... it never had this EPS/CMCE solution.  Drier GEFS was right. Now warmer pattern and I suspect smokey eventually next week from Canada. 

[SACRUS]

 

60 / 58 clear.  Warmer stretch upper 70s - low 80s perhaps a few of the hotter areas get into the mid 80s today and Sunday.  Overall warmer period coming up - cut off ull now into the SE but persistent onshore flow will keep any stronger warmth west of the area.  The period Mon - Thu still need be watched for rain with wetter forecasts still appearing, otherwise riding a dry stretch with near 80 and warmer lows vs normal.

 

[SACRUS]

 

Records (9/11)

Highs:

EWR: 99 (1983)
NYC: 99 (1983)
LGA: 96 (1983)
JFK: 96 (1983)


Lows:

EWR: 47 (1932)
NYC: 43 (1917)
LGA: 51 (1967)
JFK: 49 (1967)

Historical:

 

1900: The remnants of the Great Galveston Hurricane were located over central Iowa on this day. Eastern Nebraska, northwest Iowa, and southern Minnesota show four-plus inches of rain from this storm.

 

1942: A line of thunderstorms raced across Minnesota at 70 mph, destroying 651 barns in a 30 mile wide, 180 mile long path. (Ref. AccWeather Weather History).
 

1949 - An early snowstorm brought 7.5 inches to Helena MT. In Maine, a storm drenched New Brunswick with 8.05 inches of rain in 24 hours, a state record. (The Weather Channel)

1954: On September 10th and 11th Hurricane Edna crosses Cape Cod and give the Boston area a record 5.64 inches of rain in 24 hours. (Ref. NOAA Boston Weather Events)

1960: Hurricane Donna made landfall during the evening on the North Carolina coast near Wilmington. Winds gusted to 115 mph and the lowest pressure reported with this landfall was 958 mb. Donna would move offshore once again the next morning and regain strength as it stayed just offshore until hitting Long Island shortly afternoon on September 12 with winds of near 100 mph. (Ref. AccWeather Weather History)

1961 - Very large and slow moving Hurricane Carla made landfall near Port Lavaca TX. Carla battered the central Texas coast with wind gusts to 175 mph, and up to 16 inches of rain, and spawned a vicious tornado which swept across Galveston Island killing eight persons. The hurricane claimed 45 lives, and caused 300 million dollars damage. The remnants of Carla produced heavy rain in the Lower Missouri Valley and southern sections of the Upper Great Lakes Region. (David Ludlum) (Storm Data)

1976 - Up to five inches of rain brought walls of water and millions of tons of debris into Bullhead City AZ via washes from elevations above 3000 feet. Flooding caused more than three million dollars damage. Chasms up to forty feet deep were cut across some roads. (The Weather Channel)

1984: (Not to be confused with Diane 1955 Mid Atlantic U.S) Hurricane Diana finally strikes North Carolina coast near Bald Head Island after drifting around the Cape Fear, NC area for two days. Diana made landfall as a category two hurricane, but just the day before, the hurricane had been a category four storm with a central pressure of 28.02 inches of mercury and maximum sustained winds of 135 mph. There were dire predictions of disaster from nervous emergency management officials. Fortunately, Diana stalled and wobbled away from land as it neared the Cape Fear area. Diana was the first significant hurricane to strike the North Carolina coast since Donna of 1960. As the eye passed over Southport, NC residents noted hearing crickets chirping in the calm. Three people died in North Carolina as a result of Diana, but damage was minimal. (Ref. AccWeather Weather History)
 

1986 - Thunderstorms caused flash flooding and subsequent river flooding in central Lower Michigan. Up to 14 inches of rain fell in a 72 hour period, and flooding caused 400 million dollars damage. (Storm Data)

1987 - Late afternoon and evening thunderstorms produced large hail and damaging winds in Texas, and spawned three tornadoes. Thunderstorm winds gusted to 70 mph at Goodnight TX. (The National Weather Summary) (Storm Data)

1988 - Snow blanketed parts of the Central Rocky Mountain Region and the Central Plateau, with ten inches reported at Mount Evans in Colorado. Smoke from forest fires in the northwestern U.S. reached Pennsylvania and New York State. Hurricane Gilbert, moving westward over the Carribean, was packing winds of 100 mph by the end of the day. (National Weather Summary) (Storm Data)

1989 - Nine cities in the north central U.S. reported record low temperatures for the date, including Havre MT with a reading of 23 degrees. Livingston MT and West Yellowstone MT tied for honors as the cold spot in the nation with morning lows of 17 degrees. Thunderstorms produced hail over the Sierra Nevada Range of California, with two inches reported on the ground near Donner Summit. The hail made roads very slick, resulting in a twenty car accident. (The National Weather Summary) (Storm Data)

1998: An outbreak of 8 tornadoes occurred across southern Louisiana in conjunction with landfalling Tropical Storm Frances that was looping along the upper Texas coast. The only known fatality directly attributable to Frances was in Lafourche Parish, LA, where a man was killed when his trailer home was destroyed by a tornado. Six others were injured. (Ref. Wilson Wx. History)

 

2001: Hurricane Erin was off the coast of New Jersey and New York on this day. 

 

2002
Tropical Storm Gustav strengthened to a hurricane over the open waters south of New England. This is the latest date for the first hurricane of the season to develop for the Atlantic on record.
(Ref. Wilson Wx. History)

2008: Hurricane Ike continued its march towards the upper Texas coast with 100 mph winds and a minimum central pressure of 945 millibars or 27.91 inches of mercury. Hurricane watches and warnings went up along the upper Texas coast into Louisiana. (Ref. Wilson Wx. History)


2017: In the days leading up to the storm, more than 6.5 million Floridians were told to evacuate. In a calamitous northward sweep from the Everglades to the Florida Panhandle, a weakening but still monstrously powerful Hurricane Irma battered a string of cities on the state’s palm-fringed west coast Sunday before advancing toward Georgia and the Carolinas.Irma hits Florida on Sunday night the 10th.
Irma data

2017: On Monday, a day after visiting lashing rains, surging tides and terrifying winds on nearly every corner of Florida, Irma unleashed flash flooding in three states and left a sweaty, disruptive legacy: no power for about 7 million people. Confronting a panorama of destruction stretching from coast to coast, with rescue efforts still in progress and a massive cleanup only beginning to gather pace, Florida and federal officials opted for frankness: It might take weeks for electricity to be fully restored. The storm’s direct death toll, mercifully, was not commensurate with Irma’s wrath. Authorities in Georgia on Monday reported three storm-related deaths, without providing details, and one person died in South Carolina. An electrocution was reported in central Florida — a grim hazard in flooding’s aftermath. Irma is being blamed for 34 deaths in the Caribbean before it hit Florida, according to the Associated Press.


2018: Hurricane Florence was a powerful and long-lived Cape Verde hurricane, as well as the wettest tropical cyclone on record in the Carolinas and the ninth-wettest tropical cyclone to affect the contiguous United States. The sixth named storm, third hurricane, and the first major hurricane of the 2018 Atlantic hurricane season, Florence originated from a strong tropical wave that emerged off the west coast of Africa on August 30, 2018. Steady organization resulted in the formation of a tropical depression on the next day near Cape Verde. Progressing along a steady west-northwest trajectory, the system acquired tropical storm strength on September 1, and fluctuated in strength for several days over open ocean. An unexpected bout of rapid intensification ensued on September 4– 5, culminating with Florence becoming a Category 4 major hurricane on the Saffir–Simpson scale with estimated maximum sustained winds of 130 mph.

[SACRUS]

 

Through the first 10 days Sep

 

Dep

LGA: -4.1
NYC: -3.4
JFK: -3.5
ISP: -2.3
EWR: -2.2  

[SACRUS]

1 hour ago, wdrag said:

Yes... and it was my mistake not checking EC AI... it never had this EPS/CMCE solution.  Drier GEFS was right. Now warmer pattern and I suspect smokey eventually next week from Canada. 

 

Still wouldnt rule out a trend wetter/cloudier.  The ridge looks poised to have a cutoff underneath in that period, seems to have some what closed off near the SE overnight forecasting.

[SACRUS]

 

 

Quickly up to 72 here

[wdrag]

2 hours ago, SACRUS said:

 

Still wouldnt rule out a trend wetter/cloudier.  The ridge looks poised to have a cutoff underneath in that period, seems to have some what closed off near the SE overnight forecasting.

I agree with you but overall, the EC AI did not buy into the initial Sunday-Monday EC EPS  closed low aloft scenario...admittedly as we mentioned... highly unusual pattern evolution.

I am curious as to the multiple ensembles with sct showers Saturday (FOUS has LGA 90% RH at 60 hours 00z Sun) and it still looks like sct or widespread  showers ahead of the seed moving short wave Sunday. 

Middle of next week might also have closed low feature in mid ATLC.  For now will monitor what might transpire. 

[psv88]

14 minutes ago, wdrag said:

I agree with you but overall, the EC AI did not buy into the initial Sunday-Monday EC EPS  closed low aloft scenario...admittedly as we mentioned... highly unusual pattern evolution.

I am curious as to the multiple ensembles with sct showers Saturday (FOUS has LGA 90% RH at 60 hours 00z Sun) and it still looks like sct or widespread  showers ahead of the seed moving short wave Sunday. 

Middle of next week might also have closed low feature in mid ATLC.  For now will monitor what might transpire. 

Upton has a dry weekend east of the city. 

[winterwx21]

Looks like nice extended summer next week. Still no real heat coming, but highs probably in the low 80s here all next week. 

[winterwarlock]

Looks summery weekend and next week...all forecasts low 80s at least

[MANDA]

38 minutes ago, winterwx21 said:

Looks like nice extended summer next week. Still no real heat coming, but highs probably in the low 80s here all next week. 

Not my favorite but manageable.  This cool run has been great though.

[MANDA]

No changes to the Drought Monitor this sub forum.  With the rain last week, cool temperatures and lowering sun angle not as critical as it would have been back in July and August.  Drought intensified / expanded over New England.

[PhiEaglesfan712]

16 hours ago, donsutherland1 said:

The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001.

I'm pretty sure 2006 had a colder than normal first half and second half of September. It also had a colder than normal first half and second half of October. Then, things really flipped and we had record warmth from November through the first of January 2007 (before the bottom fell out of the thermometer in February 2007).

[Brian5671]

A couple fall noreasters would wipe out that drought map...

[psv88]

80 and sunny. Absolutely perfect weather 

[donsutherland1]

23 minutes ago, PhiEaglesfan712 said:

I'm pretty sure 2006 had a colder than normal first half and second half of September. It also had a colder than normal first half and second half of October. Then, things really flipped and we had record warmth from November through the first of January 2007 (before the bottom fell out of the thermometer in February 2007).

September 16-30, 2006 had a mean temperature of 66.6, which was slightly above even the 1991-2020 baseline for this period.

[Sundog]

1 hour ago, PhiEaglesfan712 said:

I'm pretty sure 2006 had a colder than normal first half and second half of September. It also had a colder than normal first half and second half of October. Then, things really flipped and we had record warmth from November through the first of January 2007 (before the bottom fell out of the thermometer in February 2007).

"Warmest winter on record" really looked like it was going to happen until that record PNA ridge unleashed the Arctic. 

[SACRUS]

 

83 / 49 here - a gorgeous day.

[donsutherland1]

Tomorrow will be partly sunny with temperatures reaching the middle and upper 70s. The weekend will see a continuation of partly sunny skies with highs mainly in the middle and upper 70s. A few of the warmer spots could reach or exceed 80°.

The next round of showers could be Monday. Temperatures will top out in the upper 70s to perhaps lower 80s on Monday and Tuesday.

September 1-15 is on track to achieve a solid cool anomaly. Since 2000, there have been nine years that saw a cooler than normal first half of September. Two-thirds of those years went on to record a warmer than normal second half of September. Only two of those years (2017 and 2019) wound up with a monthly mean temperature of 70.0° or above. Overall, for two-thirds of those years, the cool start was sufficiently cool to produce a cooler than normal monthly anomaly. The last year that saw both a cooler than normal first half and second half of September was 2009. Prior to that, it was 2001. The last year to record a cooler than normal first half of September followed by a warmer than normal September was 2024.

The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.4°C for the week centered around August 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.33°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. La Niña conditions will likely develop during mid- or late-autumn.

The SOI was -6.30 today. 

The preliminary Arctic Oscillation (AO) was +0.370 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 55% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 68.7° (0.5° below normal). 

Supplemental Information: The projected mean would be 0.7° above the 1981-2010 normal monthly value.