October 2025 Discussion and Obs

[donsutherland1]

A strong NAO blocking regime is in place and will persist into early November. As a result, an extended period of cooler than normal weather will prevail through the end of the month. 

Tomorrow will be a bit milder as temperatures rise into the upper 50s or lower 60s.

Rain will arrive late tonight or early tomorrow. A general 1"-3" rainfall is likely late Wednesday night through Friday. There remains some uncertainty about the area of heaviest rainfall. The storm will be followed by a continuation of cool weather.

In the long-range, the guidance suggests that an AO+/NAO+ regime could develop the first week in November. As has often happened with the loss of strong blocking, a milder regime could develop late in the first week of November or shortly afterward. 

The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.07°C and the ENSO Region 3.4 anomaly has averaged -0.48°C. La Niña conditions will likely continue through mid-winter.

The SOI was +18.18 today. 

The preliminary Arctic Oscillation (AO) was -0.392 today. The NAO was -1.634. 

Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.3° (0.4° above normal). 

Supplemental Information: The projected mean would be 1.4° above the 1981-2010 normal monthly value.

 

[SI Mailman]

2 hours ago, the_other_guy said:

if you had kids, you would understand. 

 

what you’re really mad at is shorter days… it’s like yelling at a cloud. Move south

 

People don't realize there's really only 9 hours of daylight in December, and they don't know how to allocate it.  

[bluewave]

19 hours ago, Sundog said:

 

1931-1960 average was 58.3 degrees

1941-1970 average was 58.7 degrees

 

Both easily warmer than the last two periods not affected by tree growth:

1961-1990: 57.5 degrees

1971-2000: 57.1 degrees

 

 

This period would be much warmer if it wasn’t for the tree growth. You can see how NYC is the only station which the high temperature has declined especially on the sunny days in October and other fully leafed out months. 

So in reality like all out other stations the actual high temperature if measured the old way prior to 1995 would have seen a steep rise instead of a slight decline. When we look at period since 1961 covering the 30 years prior to moving the ASOS under the trees in 1995 and the 30 years following we can see what is happening.

Notice the lows aren’t affected only the highs especially on the sunny days when the shade effect is greatest.

 

 

 

 

[Sundog]

22 minutes ago, bluewave said:

This period would be much warmer if it wasn’t for the tree growth. You can see how NYC is the only station which the high temperature has declined especially on the sunny days.

So in reality like all out other stations the actual high temperature if measured the old way prior to 1995 would have seen a steep rise instead of a slight decline. When we look at period since 1961 covering the 30 years prior to moving the ASOS under the trees in 1995 and the 30 years following we can see what is happening.

Notice the lows aren’t affected only the highs especially on the sunny days when the shade effect is greatest.

 

 

 

 

How could the 1961-1990 time period be affected by tree growth? Maybe the 1971-2000 a little but that would have been at the tail end of the period. 

Either way the 1931-1960 and 1941-1970 periods in Central Park were even warmer than Newark's current average, which is impressive.  

[bluewave]

30 minutes ago, Sundog said:

How could the 1961-1990 time period be affected by tree growth? Maybe the 1971-2000 a little but that would have been at the tail end of the period. 

Either way the 1931-1960 and 1941-1970 periods in Central Park were even warmer than Newark's current average, which is impressive.  

It wasn’t as much. But we need to see the 30 years prior to and after the ASOS getting put under the trees in 1995 for the full 60 year trend to emerge. Since 1995 was the year that NYC changed how they measure temperatures. This is why NYC is the only site with a decline in 90 days since the 1960s.

If NYC didn’t have the ASOS in the shade, then their current 15 year October average would be closer to LGA and not the artificially low 59.3°. 

That mid century period was a warm in October. Which declined later in the century. But the recent 15 year period is the warmest on record. 
 

Average October temperatures 

1941-1970

EWR…57.4°

NYC…58.7°

LGA…58.8°

1961-1990

EWR….57.2°

NYC….57.5°

LGA….57.4°

2010-2024

EWR…59.6°

NYC…59.3°

LGA….60.9°

[Sundog]

17 minutes ago, bluewave said:

It wasn’t as much. But we need to see the 30 years prior to and after the ASOS getting put under the trees in 1995 for the full 60 year trend to emerge. Since 1995 was the year that NYC changed how they measure temperatures. This is why NYC is the only site with a decline in 90 days since the 1960s.

If NYC didn’t have the ASOS in the shade, then their current 15 year October average would be closer to LGA and not the artificially low 59.3°. 

That mid century period was a warm in October. Which declined later in the century. But the recent 15 year period is the warmest on record. 
 

Average October temperatures 

1941-1970

EWR…57.4°

NYC…58.7°

LGA…58.8°

1961-1990

EWR….57.2°

NYC….57.5°

LGA….57.4°

2010-2024

EWR…59.6°

NYC…59.3°

LGA….60.9°

Can the tree growth really be making that much of a difference in October with the lower insolation if the park is basically the same as torchy Newark to its west?

59.3 vs 59.6, those are awfully close and Newark doesn't suffer from tree shade AND they are farther west. 

[bluewave]

Just now, Sundog said:

Can the tree growth really be making that much of a difference in October with the lower insolation if the park is basically the same as torchy Newark to its west?

59.3 vs 59.6, those are awfully close and Newark doesn't suffer from tree shade AND they are farther west. 

Yes since it’s the only station showing a high temperature decline especially on sunny days.

[Sundog]

11 minutes ago, bluewave said:

Yes since it’s the only station showing a high temperature decline especially on sunny days.

I have been complaining about the trees in Central Park for YEARS, trust me I am on board with this issue.

I just didn't think this problem stretched this deep into fall. I can understand May through mid September. 

So are you saying Central Park should have a HIGHER overall October average than Newark? 

[bluewave]

32 minutes ago, Sundog said:

I have been complaining about the trees in Central Park for YEARS, trust me I am on board with this issue.

I just didn't think this problem stretched this deep into fall. I can understand May through mid September. 

So are you saying Central Park should have a HIGHER overall October average than Newark? 

Yeah, without the tree growth NYC should be closer to LGA even in October. Notice how much of a difference there had been between when the trees are fully leafed out vs when the leaves drop. Since 90° days are sunny you see the artificial decline more on those days.

Fully leafed out

 

No leaves

 

[SACRUS]

 

58 / 57  - moderate rain with 0.40 already with 1 - 3 in totality.  Dries out later this evening and slowly clear out later Friday.  Nice dry / fall weekend coming up.  Overall near normal / slightly above through the first week.

 

[SACRUS]

Records:
 

Highs:

EWR: 82 (1946)
NYC: 82 (1961)
LGA: 81 (1946)
JFK: 79 (1961)


Lows:

EWR: 31 (1932)
NYC: 31 (1925)
LGA: 35 (2011)
JFK: 30 (1962)

 

Historical:


1844: 30 inches of snow fell during a three day storm at Buffalo Barracks, NY. (Ref. AccWeather Weather History)

1873L Lowest minimum temperature was 26° in DC and tied 10-31-1917 record. (Washington Weather Records - KDCA)

1925 - Nashville, TN, was blanketed with an inch of snow, their earliest measurable snow of record. (The Weather Channel)

 

1925:  Richmond, Virginia had a high temperature for the day of 44 °F making it the coolest October day on record (records since 1897). (Ref. Richmond Weather Records) 

 

1925: The earliest snow greater than one inch in Washington, DC, fell on October 30, 1925, (2.2") and October 20, 1940,(1.4"). The deepest Baltimore snowstorm ever recorded in October struck on this date in 1925, killing at least one person and blinding the rail birds at Laurel Park through all seven races. The storm dropped 1 to 3 inches of snow across the region, with an official 2.5 inches in Baltimore. That remains the deepest October snowfall on record for the city. In Baltimore, the snow began falling around 1 p.m. and continued into the evening, even as surface temperatures remained above freezing.

1947 - The Donora, PA, smog disaster finally came to an end. For five days an inversion trapped impurities in the lower atmosphere over the Monongahela Valley killing 20 persons, and leaving more than 2000 others sick. (26th-30th) (David Ludlum) (The Weather Channel)

1949: Haines Junction recorded The Yukon Canada’s greatest daily snowfall record as 26.5 inches fell. (Ref. Wilson Wx. History)

 

1987 - Severe thunderstorms in Oklahoma produced golf ball size hail and wind gusts to 74 mph near the town of Gould. Unseasonably warm weather prevailed across the central U.S. Temperatures warmed into the 80s form Texas to the Lower Missouri Valley. (Storm Data) (The National Weather Summary)

1988 - Ten cities in the Upper Midwest reported record low temperatures for the date. The morning low of 20 degrees at South Bend IND was a record for October, and lows of 18 degrees at Grand Rapids MI and 20 degrees at Fort Wayne IND equalled records for October. The low of 2 degrees at International Falls MN smashed their previous record for the date by 11 degrees. Syracuse NY received 2.9 inches of snow to establish a record for October with 5.7 inches for the month. (The National Weather Summary) (Storm Data)

1989 - Temperatures soared into the 70s in the northeastern U.S. The record high of 73 degrees at Alpena MI marked their sixth straight day of record warmth. In the western U.S., Klamath Falls OR reported a record low of 19 degrees. (The National Weather Summary)

 

1991: The Perfect Storm, also known as the No-Name Storm reached maximum strength on this day with a low pressure of 972 mb and sustained winds of 69 mph.

1991: After absorbing Hurricane Grace on the 29th, an intense ocean storm at 972 millibars or 28.70 inches of mercury, known as the Perfect Storm. The storm took a very unusual course and moved westward along 40°N and battered eastern New England with high winds and tides. Winds had already been gusting over 50 mph along the coast two days before. Major coastal flooding and beach erosion occurred all along the New England, New York, and New Jersey coastlines. Over 1,000 homes were damaged or destroyed from tides anywhere from 4 to 7 feet above normal. North Carolina's coast was lashed with occasional winds of 35 to 45 mph for five consecutive days. Other high wind gusts included: 78 mph at the Chatham NWS, 74 mph at Thatcher Island, 68 mph at Marblehead, 64 mph at Blue Hill Observatory (all in Massachusetts) and 63 mph at Newport, RI. Waves 10 to 30 feet high were common from North Carolina to Nova Scotia. In New Jersey, the greatest tidal departures of winter storms of record occurred during this event, with tide heights exceeded only by the Great Atlantic Hurricane of 1944. In Delaware, Maryland, and Virginia, the highest water levels were comparable to those of the nor'easter of March, 1962. A record high tide of 7.8 feet occurred at Ocean City, MD on the 30th, which eclipsed the old record of 7.5 feet recorded during the March 1962 storm. In Massachusetts, 25-foot waves reached the shoreline atop high tides already 4 feet above normal. At Boston, the tide reached 14.1 feet above mean low water or about 1 foot less than the tides associated with the "Blizzard of 1978. " One ship east of New England reported a 63 foot wave. Heavy rain continued into November 1st. Blue Hill Observatory in Milton, MA ended up with 5.76 inches of rain. Total damage from the storm exceeded $200 million dollars. (Ref. AccWeather Weather History)


1991: A strong winter storm brought southwest Kansas its first snowfall for the year, dumping up to 14 inches in Garden City. A large storage shed collapsed due to heavy snows in Johnson, and slippery roads caused a lot of havoc and claimed the life of a child in an automobile accident. Bitter cold temperatures also accompanied the heavy snows, and wind gusts to 45 mph brought wind chills down to -20°. The frigid conditions and blowing snow claimed the lives of two men, both of exposure in separate incidents, when they left their cars after they got stuck. Both men tried to make their way back home. (Ref. The Perfect Storm ) (Ref. Wilson Wx. History)

 1991: Billings, MT dipped to -7 °F which set a new record low for the month of October and it was the first time the station had even been below zero in October. Other October record lows included: Sheridan, WY: -9 °F and Miles City, MT: -8 °F, Scottsbluff, NE equaled their record for the earliest below zero temperature recorded with a low of -1 °F. (Ref. Wilson Wx. History)

1993: Record cold and snow occurred in the central and southern U.S. Cincinnati, OH recorded 5.9 inches of snow for its greatest October monthly snowfall ever. San Antonio, TX saw flakes for the first time ever in October. Laramie, WY plunged to 18° for its coldest reading on record for October. The 12° reading at Amarillo, TX set the same record. (Ref. AccWeather Weather History)

2004: Exceptionally heavy rains drenched the Manoa Valley near Waikiki in Hawaii. 10 inches of rain fell at the Manoa Arboretum in just 12 hours, causing flooding that rushed through the University of Hawaii's main research library. (Ref. Wilson Wx. History) (Ref. WxDoctor)

2012: Hurricane Sandy continues to loom ominously off the U.S. east coast, bringing very heavy rain and tropical storm to hurricane force winds to many millions of people well before the worst arrives. The coastal flooding is already terrible, as expected (even as far south as Miami and Fort Lauderdale!). Locations from North Carolina to Maine will continue to see incredible coastal flooding/erosion, with the worst near and north of where the center crosses land (approximately southern NJ into NYC, Long Island). Inland flooding will also be a large problem in the coastal states as well as the inland states throughout the northeast. Finally, the 50-90mph winds that many places will experience can easily damage roofs, break tree limbs, and uproot trees, bringing power lines down with them.
Superstorm Sandy. October 28-29. Category 1 Hurricane Sandy transitioned into a monstrous extratropical storm while making landfall along the New Jersey coast, resulting in one of the most intense and damaging East Coast storms of all time. Surging Atlantic waters (8-14 feet) inundated the Jersey shore and low-lying areas of NYC and Long Island, causing estimated damages of at least $60 billion. The storm caused 72 direct deaths (87 indirect) in the United States, the loss of power to 8.5 million homes and businesses, and the cancellation of more than 18,000 airline flights.

[psv88]

Remember when we used to get snow flurries by early November? Miss those days!

[Sundog]

1 minute ago, psv88 said:

Remember when we used to get snow flurries by early November? Miss those days!

I remember them closer to Thanksgiving, and it was usually mini snow squalls/flurries streaming in from the NW

[IrishRob17]

4 minutes ago, psv88 said:

Remember when we used to get snow flurries by early November? Miss those days!

My average first flakes date is 11/6 and average first measurable is 11/9...that said, the "Halloween" snowstorm in late October 2011 skews that average a bit. 

[psv88]

1 minute ago, IrishRob17 said:

My average first flakes date is 11/6 and average first measurable is 11/9...that said, the "Halloween" snowstorm in late October 2011 skews that average a bit. 

It did happen though…just like the years it didn’t snow until January 

[MJO812]

18 minutes ago, Sundog said:

I remember them closer to Thanksgiving, and it was usually mini snow squalls/flurries streaming in from the NW

Yep I remember flurries in middle November. 

[IrishRob17]

24 minutes ago, psv88 said:

It did happen though…just like the years it didn’t snow until January 

Good point. On that note, my latest first flakes was 12/4/06 with latest measurable 1/19/07. 

[psv88]

Happy Sandy Anniversary 

[FPizz]

42 minutes ago, psv88 said:

Remember when we used to get snow flurries by early November? Miss those days!

We had to put the leaves in those brown recycling bags growing up and I remember after a rainy day like today, having the standing water on those bags ice up.  

[MJO812]

Miserable day today 

[bluewave]

1 hour ago, IrishRob17 said:

My average first flakes date is 11/6 and average first measurable is 11/9...that said, the "Halloween" snowstorm in late October 2011 skews that average a bit. 

Yeah, we had accumulating snows around the area with the colder storm tracks and background temperatures at the end of October 2008 and 2011.

Then the big post Sandy snowstorm in November 2012 and SWFE in November 2018.

The best obviously for the whole season was the late November 1995 snow which carried through until early April 1996.

Before that the lack of snow following the November 1989 Thanksgiving snowstorm. Plus the earliest October 10, 1979  snows before the low seasonal snows that winter with the big suppression pattern when Virginia did so well. 

[psv88]

Winds are impressive out here. Nor’easter or not, the winds are howling. 

[SACRUS]

Very heavy rain up to 2 inches.