December 2024

[donsutherland1]

Milder air surged back into the region to close the weekend. High temperatures included 55° in New York City and 59° in Philadelphia. Tomorrow and Tuesday will be somewhat cooler, but still on the mild side of normal. Temperatures could peak in the upper 50s and lower 60s into southern New England on Wednesday.

A series of two storms will bring rain to accompany the return of milder temperatures. Tomorrow will likely see periods of rain with a general 0.25"-0.75" storm total. A larger storm will affect the region Wednesday into Thursday. At present, this storm could be capable of bringing widespread 1"-2" rainfall. Some places could see locally higher amounts of up to 3" of rain. Following two storms, it will turn briefly noticeably colder late in the week before milder air starts to return during the weekend.

The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025.

The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 27. 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 -0.23°C. Neutral ENSO conditions may still evolve into a La Niña event during the winter. Uncertainty as to whether a La Niña will actually develop continues to increase. Currently, 47% of dynamical models and 22% of the statistical models forecast the development of a La Niña.

The SOI was +17.07 yesterday.

The preliminary Arctic Oscillation (AO) was -1.286 today.

Based on sensitivity analysis applied to the latest guidance, there is an implied 64% probability that New York City will have a colder than normal December (1991-2020 normal). December will likely finish with a mean temperature near 37.8° (1.3° below normal).

 

[JustinRP37]

Man I gotta say since moving to Putnam county we haven’t had a great winter. Still go to Vermont and Catskills for most of my skiing. I’m ready to move back to southern Westchester. Miss it down there just so expensive. 

[bluewave]

6 hours ago, NEG NAO said:

This is why you can't trust any model past Day 5- 10 Verified -Dec 2 12Z Run Vs. Dec 8th 12Z Run concentrated on Dec 12 12Z

GFS Model – 850mb Temp Anomaly for CONUS | Tropical Tidbits

CMC Model – 850mb Temp Anomaly for CONUS | Tropical Tidbits

Also IMO anybody who knows what the weather will be like Christmas week today is kidding themselves........

The one constant is that the Pacific Jet has been verifying stronger than forecast leading to cutter and hugger storm tracks. So we get warm ups ahead of the lows with mostly rain at the coast. The cold comes in behind the storms instead of being in place ahead of the lows. The LES areas and higher elevations get the bulk of the snows. What you want to see is cold in place ahead of the storms with a clean BM storm track. But the fast Pacific flow has been working against the BM track for years. When we do get BM tracks there is usually a primary low running to the Lakes forcing the baroclinic zone too far north. 

[MJO812]

30 minutes ago, bluewave said:

The one constant is that the Pacific Jet has been verifying stronger than forecast leading to cutter and hugger storm tracks. So we get warm ups ahead of the lows with mostly rain at the coast. The cold comes in behind the storms instead of being in place ahead of the lows. The LES areas and higher elevations get the bulk of the snows. What you want to see is cold in place ahead of the storms with a clean BM storm track. But the fast Pacific flow has been working against the BM track for years. When we do get BM tracks there is usually a primary low running to the Lakes forcing the baroclinic zone too far north. 

The neutral enso might help us out this winter. I think we are in finally in for a good winter.

[MJO812]

Wow

[wdrag]

I'm in agreement on EPS weeklies etc... grain of salt at best.   Our long range models just can't pick up on the extremes that occur week 3 and beyond and they're not outstanding week two.  Example of EPS large shifts below for temps the period Dec 9-16.  NAEFS closes it out from Dec 2... with a much better solution--OVERALL near normal where the EPS has chilled greatly compared to Dec 3.  Wish it were true that our modeling can reveal the abnormal departures beyond week 2... I dont think so. 

[donsutherland1]

On 12/1/2024 at 8:49 AM, donsutherland1 said:

The week ahead looks cold and mainly dry. A clipper system could bring some light snow or flurries, especially from eastern Pennsylvania into New England late Tuesday night into Wednesday.

Final Outcomes:

The period was colder than normal but warmer than the guidance had implied.

[GaWx]

1 hour ago, donsutherland1 said:

Final Outcomes:

The period was colder than normal but warmer than the guidance had implied.

Agreed. Per the map, these cities in the -3 to -6C shading were closer to the -6C than the -3C based on the location of the small areas of the next colder shading over NC and a small area in New England being significantly closer than the nearest locations of the next warmer shading. This implies to me that this Euro run was predicting ~-5C or -9F anomaly for these 4 cities, which is nearly twice as large an anomaly as what verified.

Edit: Aside: However, down in my area (KSAV), it verified at -9.6F or about right fwiw.

[bluewave]

12 hours ago, MJO812 said:

The neutral enso might help us out this winter. I think we are in finally in for a good winter.

Going to need to slow the Pacific Jet down in order to see decent snows near the coast. Notice how even in the short term we warm up ahead of the storms and the cold comes in behind the lows. This is a great pattern for the lakes and higher elevations. 

Fast Pacifc flow features alternating ridges and troughs

 

 

[SnoSki14]

12 hours ago, MJO812 said:

The neutral enso might help us out this winter. I think we are in finally in for a good winter.

Yeah right I'll believe it when I see it. The only thing I'm seeing is a likely end to dry conditions with fast pacific flow dominating. 

[jm1220]

13 hours ago, bluewave said:

The one constant is that the Pacific Jet has been verifying stronger than forecast leading to cutter and hugger storm tracks. So we get warm ups ahead of the lows with mostly rain at the coast. The cold comes in behind the storms instead of being in place ahead of the lows. The LES areas and higher elevations get the bulk of the snows. What you want to see is cold in place ahead of the storms with a clean BM storm track. But the fast Pacific flow has been working against the BM track for years. When we do get BM tracks there is usually a primary low running to the Lakes forcing the baroclinic zone too far north. 

If we’re using the 3” metric for Dec snow and hope for a good Nina winter for NYC, hopefully we can get some kind of opportunity before the month ends. Right now it looks like crap at best. At least the rain is coming back. Long term droughts aren’t a thing here. 

[Brian5671]

28 minutes ago, SnoSki14 said:

Yeah right I'll believe it when I see it. The only thing I'm seeing is a likely end to dry conditions with fast pacific flow dominating. 

We are starting the annual punt the good pattern out-we are now out to January....

[MJO812]

28 minutes ago, SnoSki14 said:

Yeah right I'll believe it when I see it. The only thing I'm seeing is a likely end to dry conditions with fast pacific flow dominating. 

It's only December for crying out loud

 

[EastonSN+]

I don't know if the information is available, however the mid to late 80s and early 90s featured the dreaded cold/warm up ahead of storm and rain/cold for years. 

Was the fast Paced jet the same issue then or was another factor driving the bus? The information may not be around however may provide insight as to why this is happening and perhaps how long (was about 8 years before).

I remember one storm in January 1993 I believe that was in the lower teens in the morning, received about 1 inch of slop and then 50s and heavy rain then everything froze on the backend.

[Brian5671]

6 minutes ago, EastonSN+ said:

I don't know if the information is available, however the mid to late 80s and early 90s featured the dreaded cold/warm up ahead of storm and rain/cold for years. 

Was the fast Paced jet the same issue then or was another factor driving the bus? The information may not be around however may provide insight as to why this is happening and perhaps how long (was about 8 years before).

I remember one storm in January 1993 I believe that was in the lower teens in the morning, received about 1 inch of slop and then 50s and heavy rain then everything froze on the backend.

Alot of out to sea storms back then too--the NAO was in a dominate + state

[EastonSN+]

Just now, Brian5671 said:

Alot of out to sea storms back then too--the NAO was in a dominate + state

Yeah just like the last few years where Norfolk, Tennessee, the Delmarva (Ocean City Maryland) have see good snowstorms. We have had strong negative NAOs like the past month and years with not much to show. This is really a parallel of the 80s and early 90s.

[the_other_guy]

45 minutes ago, Brian5671 said:

We are starting the annual punt the good pattern out-we are now out to January....

Just to check your ridiculousness it’s December 9

[rclab]

13 hours ago, MJO812 said:

The neutral enso might help us out this winter. I think we are in finally in for a good winter.

 

1 hour ago, bluewave said:

Going to need to slow the Pacific Jet down in order to see decent snows near the coast. Notice how even in the short term we warm up ahead of the storms and the cold comes in behind the lows. This is a great pattern for the lakes and higher elevations. 

Fast Pacifc flow features alternating ridges and troughs

 

 

 

1 hour ago, SnoSki14 said:

Yeah right I'll believe it when I see it. The only thing I'm seeing is a likely end to dry conditions with fast pacific flow dominating. 

 

55 minutes ago, Brian5671 said:

We are starting the annual punt the good pattern out-we are now out to January....

 

55 minutes ago, MJO812 said:

It's only December for crying out loud

 

It is ….. as always …..

[SACRUS]

 

38 / 34 mostly cloudy with rain closing in on EPA.  Rain today around 0.25 for most.  Next heavy rain Tue PM - Wed  up to 2 inches of rain with more north and east.   Colder Thu - Sat  ahead of an overall near to warmer than normal Sun and into and beyond mid month.

 

[SACRUS]

Records:

Highs:

EWR: 68 (1966)
NYC: 66 (1966)
LGA: 66 (1966)
JFK: 64 (1991)


Lows:

EWR: 12 (1934)
NYC: 7 (1876)
LGA: 13 (1968)
JFK: 14 (1968)


Historical:

 

1786 - A second great snowstorm in just five days brought another 15 inches of snow to Morristown NJ, on top of the eight inches which fell on the 7th and 8th, and the 18 inches which fell on the 4th and 5th. The total snowfall for the week was thus 41 inches. New Haven CT received 17 inches of new snow in the storm. Up to four four feet of snow covered the ground in eastern Massachusetts following the storms. (9th-10th) (David Ludlum) (The Weather Channel)

1917 - A severe winter storm struck the Ohio Valley and the Great Lakes Region. It produced 25 inches of snow and wind gusts to 78 mph at Buffalo NY. The storm produced 26 inches of snow at Vevay IND, with drifts fourteen feet high. By the 16th of the month people could walk across the frozen Ohio River from Vavey into Kentucky. (8th-9th) (David Ludlum) (The Weather Channel)

 

1987 - The fifth storm in nine days kept the northwestern U.S. wet and windy. Winds along the coast of Washington gusted to 75 mph at Oceans Shores and at Hoquiam, and the northern and central coastal mountains of Oregon were drenched with three inches of rain in ten hours, flooding some rivers. Snowfall totals in the Cascade Mountains of Washington State ranged up to 36 inches in the Methow Valley. High winds in Oregon blew a tree onto a moving automobile killing three persons and injuring two others at Mill City. (The National Weather Summary) (Storm Data)

1988 - A winter storm blanketed the Southern and Central Appalachians with up to ten inches of snow. Arctic air invaded the north central U.S. bringing subzero cold to Minnesota and North Dakota. (The National Weather Summary) (Storm Data)

1989 - A strong storm produced wind gusts of 40 to 65 mph from the Alaska Peninsula to the North Gulf Coast of Alaska. Southeasterly winds gusted to 75 mph in the Anchorage hillside. Gusty winds associated with a strong cold front caused a power outage across much of the island of Hawaii. (The National Weather Summary) (Storm Data)

[SACRUS]

 

NYC  Dec 9 2005 : 5.8 inches snow (7.5 for the week)

[Stormlover74]

Euro still driest around an inch for Wednesday. A bit more east. Nam 2.5+

[SACRUS]

 

[North and West]

We are starting the annual punt the good pattern out-we are now out to January....

.

[cleetussnow]

I think we have a shot at something end of December pattern-wise.  We’ll have a better idea if we punt on that early next week.  Nothing screams good pattern though at this point. 

[Stormlover74]

Euro Sunday night. Not enough cold air near the coast but interior could do well

[SnowGoose69]

GFS BUFKIT does not really mix winds down, even at JFK but I'm always suspect, even in winter on SSE flow about that

[jm1220]

5 hours ago, SACRUS said:

 

NYC  Dec 9 2005 : 5.8 inches snow (7.5 for the week)

I was living in PA at the time-8" or so there. South shore in that one had zilch. 

[SnowGoose69]

1 minute ago, jm1220 said:

I was living in PA at the time-8" or so there. South shore in that one had zilch. 

That was the most insane gradient I ever saw.  Closest comparisons were 1/23/98 and 1/7/94 where in the first case NYC/N Queens had a massive ice storm and were 28-30 while the central and S parts of the borough and LI had rain.  1/7/94 some of the very far northern parts of LI like Lloyd Neck had 8 inches of snow while the south shore was entirely ZR with some sleet at times

[NorthShoreWx]

7 minutes ago, jm1220 said:

I was living in PA at the time-8" or so there. South shore in that one had zilch. 

East sucked in that one.  Had about a half inch of snow over to rain here.  Eastern Massachusetts was the place to be.