December 2018 General Discussion & Observations

[MJO812]

AO going negative around the 15th

PNA positive around the 15th

NAO going negative around the 15th

 

Possibly our next storm?

[LibertyBell]

3 hours ago, Mitchel Volk said:

Just look at Dec 1989

I have been thinking that for awhile too especially for the November-December couplet.

[LibertyBell]

15 hours ago, RU848789 said:

Looks like most of Atlantic County is getting hammered, including AC.  Decent snows for far SE Burlington and the southern tip of Ocean and radar trends make it look like the precip shield is trying to move north.  We'll see.  I don't recall being under an inverted trough ever or at least not in the last 25-30 years in Middlesex County.  Anyone in the NB/Edison area recall a decent IT event?  

I've never had one up here in SW Nassau County nor do I remember the city ever getting one either.  They just aren't favored here, they either happen well to our south like over Southern NJ or north of us in Southern New England.  I think the shape of the coastline may have something to do with that.

I remember a big one in Feb 2008 where SNJ and Philly got like 8 inches of snow.   This one also dumped 8 inches in SNJ

[LibertyBell]

14 hours ago, Gravity Wave said:

I remember the December 19-20 2009 storm, every model was consistently suppressing it up. DC was on the fringe and no one north of there was going to see anything significant. This was after 3 straight garbage winters for the MA so hope was low to begin with. Then the 18z NAM on the 17th showed a full fledged I-95 blizzard (it ended up being too generous with the northern extent of the heavy snow, much to my disappointment in Allentown) and every other model flipped on their next runs. It's up there with BDB as the most remarkable short term shift I've experienced for a major winter storm.

To be clear, I was too young to understand the 500mb setup for that storm and I'm not making any predictions.

That storm was best over Suffolk County, it was a bit of a disappointment west of there and since the whole storm occurred over a short time, mostly at night, I never saw a single flake lol.

[SnoSki14]

3 hours ago, Snow88 said:

AO going negative around the 15th

PNA positive around the 15th

NAO going negative around the 15th

 

Possibly our next storm?

Oh they'll probably be a storm, just not the one you're hoping for if the Euro is any indication. 

That's a very hostile to snow pattern that'll be setting up. It wouldn't surprise me if we didn't see snow till after the new year though last 10 days of December hold some promise. 

[LibertyBell]

5 minutes ago, SnoSki14 said:

Oh they'll probably be a storm, just not the one you're hoping for if the Euro is any indication. 

That's a very hostile to snow pattern that'll be setting up. It wouldn't surprise me if we didn't see snow till after the new year though last 10 days of December hold some promise. 

It might be more like December 2010 where it was cold but we just missed out on snow a few times before we got the big one in the last week of December.

[CIK62]

Next 8 days averaging 37degs., or about 2degs. BN.

Next 2 weeks not looking very interesting at the moment.     A lowly 20% chance of seeing at least 2" Snow by the 22nd.

300mb "hitman jet" 'taking system out' at Cape Hatteras, on current threat.

I am sure talk of how cold air will somehow get ingested into the mid-month low will start soon.   What a glorious storm it could be.

[tim]

...KFOK @ 14*..it was in the teens since 11pm last night.

eastport @ 21*..

alot of WASTED cold air..cold and dry is no beino.

[Dan76]

Bueno

[bluewave]

The pattern this week into early next is almost behaving more like a La Nina or neutral. We generally don't see the southern stream get suppressed so far south in an El Nino with a strong STJ pattern. There is a split flow pattern now with a strong disturbance over SE Canada forcing the southern stream far to the south. It's possible that this is related to the continuing +SOI pattern. BOM mentioned that the ocean and atmosphere are still not coupled which is odd for this late in the year with an El Nino.

http://www.bom.gov.au/climate/enso/

Sea surface temperatures in the tropical Pacific Ocean have now exceeded El Niño thresholds for more than a month. However atmospheric indicators—such as trade winds, cloud patterns, and the Southern Oscillation Index (SOI)—have not reached El Niño levels. This indicates that the tropical ocean and atmosphere are not reinforcing each other and remain 'uncoupled'. This coupling is required to establish and sustain any ENSO event, and is what drives widespread Australian and global impacts

SOI still positive

6 Dec 2018	1011.07	1006.20	5.97	2.34	-0.64
5 Dec 2018	1012.80	1007.45	8.46	2.15	-1.06
4 Dec 2018	1013.56	1009.35	2.54	1.78	-1.45
3 Dec 2018	1014.10	1008.80	8.20	1.52	-1.61
2 Dec 2018	1014.79	1008.40	13.86	0.95	-1.74
1 Dec 2018	1014.01	1009.05	6.43	0.49	-1.84
30 Nov 2018	1013.29	1009.45	6.11	0.56	-1.86
29 Nov 2018	1013.89	1009.05	12.47	0.75	-1.81
28 Nov 2018	1013.71	1008.40	15.46	0.84	-1.80

[frd]

1 hour ago, bluewave said:

The pattern this week into early next is almost behaving more like a La Nina or neutral. We generally don't see the southern stream get suppressed so far south in an El Nino with a strong STJ pattern. There is a split flow pattern now with a strong disturbance over SE Canada forcing the southern stream far to the south. It's possible that this is related to the continuing +SOI pattern. BOM mentioned that the ocean and atmosphere are still not coupled which is odd for this late in the year with an El Nino.

http://www.bom.gov.au/climate/enso/

Sea surface temperatures in the tropical Pacific Ocean have now exceeded El Niño thresholds for more than a month. However atmospheric indicators—such as trade winds, cloud patterns, and the Southern Oscillation Index (SOI)—have not reached El Niño levels. This indicates that the tropical ocean and atmosphere are not reinforcing each other and remain 'uncoupled'. This coupling is required to establish and sustain any ENSO event, and is what drives widespread Australian and global impacts

SOI still positive

6 Dec 2018	1011.07	1006.20	5.97	2.34	-0.64
5 Dec 2018	1012.80	1007.45	8.46	2.15	-1.06
4 Dec 2018	1013.56	1009.35	2.54	1.78	-1.45
3 Dec 2018	1014.10	1008.80	8.20	1.52	-1.61
2 Dec 2018	1014.79	1008.40	13.86	0.95	-1.74
1 Dec 2018	1014.01	1009.05	6.43	0.49	-1.84
30 Nov 2018	1013.29	1009.45	6.11	0.56	-1.86
29 Nov 2018	1013.89	1009.05	12.47	0.75	-1.81
28 Nov 2018	1013.71	1008.40	15.46	0.84	-1.80

Another great post ! Been watching the SOI myself and I am puzzled by its long streak of positives and how the atmosphere looks Nina vs Nino.

Do you think we will see them couple Ocean + atmosphere soon? 

I read that seemed liklely to happen early this month ( the coupling ) but I see no indications yet of that .

 

bluewave do you see any negative consequences regarding this  ( the  coupling )  when it comes to seasonal forecasts calling for snowier and colder than normal ? 

Thanks !  

[bluewave]

12 minutes ago, frd said:

Another great post ! Been watching the SOI myself and I am puzzled by its long streak of positives and how the atmosphere looks Nina vs Nino.

Do you think we will see them couple Ocean + atmosphere soon? 

I read that seemed liklely to happen early this month ( the coupling ) but I see no indications yet of that .

 

bluewave do you see any negative consequences regarding this  ( the  coupling )  when it comes to seasonal forecasts calling for snowier and colder than normal ? 

Thanks !  

 

Thanks, it looks like we'll see our driest stretch in a while with this current more suppressed pattern. But the ensembles are indicating a relaxation of this suppression around mid-December with a possible rain and wind maker. Cold and dry has been one of our rarest combinations recently. 

Longer term, we always seem to find a way to to end up with above normal snow during this decade. But the way we get there could be unusual like it often is each year.

[North and West]

34 minutes ago, bluewave said:

Thanks, it looks like we'll see our driest stretch in a while with this current more suppressed pattern. But the ensembles are indicating a relaxation of this suppression around mid-December with a possible rain and wind maker. Cold and dry has been one of our rarest combinations recently. 

Longer term, we always seem to find a way to to end up with above normal snow during this decade. But the way we get there could be unusual like it often is each year.

Honestly, not that I'm a fan of it from an excitement level, but it seems like we haven't had weather like this in a while; sustained cold and dry. I remember my dad mentioning that it was like this in 1976-1977; not sure if anyone can confirm those recollections.

I think it's good, too, from the aspect of allowing low-lying, flood-prone areas to dry out, and to help manage insect populations. 

Not exciting, but it's life.

[bluewave]

4 minutes ago, North and West said:

Honestly, not that I'm a fan of it from an excitement level, but it seems like we haven't had weather like this in a while; sustained cold and dry. I remember my dad mentioning that it was like this in 1976-1977; not sure if anyone can confirm those recollections.

I think it's good, too, from the aspect of allowing low-lying, flood-prone areas to dry out, and to help manage insect populations. 

Not exciting, but it's life.

Even missing out on the storm next week, NYC will still have one of the higher snowfall totals since 2009 by around the solstice.

NYC snowfall by 12-21 since 2009:

#1....10.9....2009

#2....8.6......2013

#3....7.0......2017

#4...6.4.......2018...so far

#5...4.7........2012

#6...3.2........2016

#7...2.9........2011

#8...1.2........2014

#9...0.1........2010

#10..0.0.......2015

 

 

[North and West]

1 minute ago, bluewave said:

Even missing out on the storm next week, NYC will still have one of the higher snowfall totals since 2009 by around the solstice.

NYC snowfall by 12-21 since 2009:

#1....10.9....2009

#2....8.6......2013

#3....7.0......2017

#4...6.4.......2018...so far

#5...4.7........2012

#6...3.2........2016

#7...2.9........2011

#8...1.2........2014

#9...0.1........2010

#10..0.0.......2015

 

 

Thanks, interesting stat! 2015 was warm, right? 

[bluewave]

2 minutes ago, North and West said:

Thanks, interesting stat! 2015 was warm, right? 

Yeah, that was our historic 50 degree +13 December. We still got one of my all-time favorite snowstorms a month later. Followed by the first below 0 in NYC since 1994 in February. 

[North and West]

16 minutes ago, bluewave said:

Yeah, that was our historic 50 degree +13 December. We still got one of my all-time favorite snowstorms a month later. Followed by the first below 0 in NYC since 1994 in February. 

That's how it goes sometimes. ¯\_(ツ)_/¯

[the_other_guy]

12 minutes ago, North and West said:

That's how it goes sometimes. ¯\_(ツ)_/¯

No, that was scary. And El Nino on steroids. If I never see a month like that again, it will be too soon.

[495weatherguy]

Just now, jfklganyc said:

No, that was scary. And El Nino on steroids. If I never see a month like that again, it will be too soon.

I wouldn't mind a few 50 degree days right about now

[Stormlover74]

4 minutes ago, 495weatherguy said:

I wouldn't mind a few 50 degree days right about now

Yeah the cold is pretty pointless if it's not going to snow

[North and West]

3 minutes ago, Stormlover74 said:

Yeah the cold is pretty pointless if it's not going to snow

It's good though to help control insect populations.

Other than that, it's boring.

[psv88]

6 hours ago, LibertyBell said:

That storm was best over Suffolk County, it was a bit of a disappointment west of there and since the whole storm occurred over a short time, mostly at night, I never saw a single flake lol.

Was in western suffolk for that storm and got 16", was incredible with the CCB sliding west to just about the N/S border. 

[donsutherland1]

Act 1 winter 2018-19 will conclude after this weekend's major Lower Middle Atlantic/Southeast snowstorm. The scenario painted by the return of a generally positive EPO and periodically positive Arctic Oscillation (AO) has shown up for some time on the ensembles.

A look at where we have been is helpful.

Scene 1 saw a historic November snowstorm in parts of the East. Cities such as Newark and New York had their biggest ever snowfall so early in the season.

Heavy snow blankets the New York City area (November 15)

Scene 2 featured an exceptional Arctic blast for Thanksgiving Day and the day after.

Central Park's 15° temperature was New York City's lowest November temperature since the mercury fell to 12° on November 27, 1932.

Select record-breaking and record-tying low temperatures for November 22:
Albany: 8° (old record: 9°, 1969)
Allentown: 14° (old record: 15°, 2014)
Bangor: 5° (old record: 11°, 1978)
Binghamton: 3° (old record: 10°, 1989) ***Tied November Record set on 11/30/1976***
Bridgeport: 16° (old record: 18°, 1987) ***Tied November Record set on 11/28/1951 and tied on 11/23/1972***
Hartford: 9° (old record: 14°, 1969)
Islip: 18° (old record: 20°, 1987)
Manchester: 9° (old record: 12°, 1969)
Mount Washington: -26° (old record: -11° set in 1969 and tied in 1987) ***Broke November Record (old monthly record: -20°, 11/30/1958)***
New York City-JFK: 18° (old record: 20°, 1987) ***Broke November Record (old monthly record: 19°, set on 11/30/1976 and tied on 11/21/1987)***
New York City-LGA: 19° (old record: 21°, 1987)
Newark: 17° (old record: 19°, 1987)
Portland: 6° (old record: 11°, 1888)
Poughkeepsie: 10° (old record: 14° set in 1972 and tied in 1984)
Providence: 15° (old record: 16° set in 1969 and tied in 1987)
Saranac Lake: -19° (old record: -2° set in 1972 and tied in 1987) ***Broke November Record (Old monthly record: -14°, set 11/26/1938 and tied on 11/28/1951)***
Scranton: 9° (old record: 15° set in 1969 and tied in 1987 and 2014)
Worcester: 7° (old record: 11°, 1987)

Record-breaking and record-tying low temperatures for November 23:
Albany: 4° (old record: 5°, 1972)
Allentown: 11° (old record: 16°, 1964 and 2000)
Binghamton: 0° (old record: 12°, 1989 and 2008) ***Broke November Record (old record: 3°, set on 11/30/1976 and tied on 11/22/2018)***
Bridgeport: 13° (old record: 16°, 1972) ***Broke November Record (old record: 16°, set on 11/28/1951 and tied on 11/23/1972 and 11/22/2018)***
Burlington: -1° (old record: 2°, 1888 and 1972)
Hartford: 5° (old record: 12°, 1972)
Mount Washington: -13° (tied record set in 1994)
New York City-JFK: 15° (old record: 25°, set in 1949 and tied in 1964, 1972, 2000, and 2008) ***Broke November Record (old record: 18°, 11/22/2018)***
New York City-LGA: 17° (old record: 23°, 1972) ***Tied November Record set on 11/29/1955***
Newark: 13° (old record: 21°, 1932)
Portland: 4° (old record: 7°, 1888 and 1978)
Poughkeepsie: 6° (old record: 9°, 1989)
Providence: 13° (old record: 14°, 1972)
Saranac Lake: -17° (old record: -11°, 1932)
Scranton: 5° (old record: 13°, 1972) ***Broke November Record (old record: 6°, set 11/29/1929 and tied on 11/26/1938)
Trenton: 13° (old record: 16°, 1880)
Westhampton: 6° (old record: 14°, 1964 and 2000) ***Broke November Record (old record: 9°, 11/24/2000)***
Worcester: 7° (old record: 9°, 1929, 1972, and 1989)

Scene 3 featured a blizzard on November 25-26 that brought heavy snow from Kansas to the Great Lakes Region. That storm dumped 8.4" snow at Chicago and 11.7" at Rockford.

Scene 4 saw an inverted trough bring a localized 3"-6" snowfall (with some higher amounts) to a portion of New Jersey, including Atlantic City where 4.8" fell.

Scene 5 will star a major early December Lower Mid-Atlantic/Southeast snowstorm.

There had been a window of opportunity during the first two weeks of December. By the time that period ends, Scenes 4 and 5 will have been put into the weather records books.

That the northern Mid-Atlantic and southern New England regions will very likely miss out given the 500 mb pattern (which, in this case provided above normal lead time for the area at greatest risk of significant snow) does not mean that the potential did not exist. It did.

Act 2, courtesy of the onset of a positive EPO, variable Arctic Oscillation (including positive values), and the MJO's move into milder phases will be defined by a pause. Typically, such pauses last 2 and sometimes 3 weeks. Unlike some recent Decembers, it does not appear that this pause will see exceptional warmth. It will likely see above normal readings in the means.

Act 2 is not the closing Act of December, much less winter. Unlike such "non-winters" as 2011-12, the SSTAs in the Pacific favor a negative EPO. Those SSTAs are remarkably similar to those that were present during winter 2002-03. During that winter, the EPO went positive and remained predominantly positive into the first week of January. Afterward, it went negative and was largely negative through the remainder of what proved to be a very snowy meteorological winter.

Already, some of the guidance suggests an end to the positive EPO that will likely develop in coming days. Whether the EPO will go negative toward the end of the December or start of January remains to be seen, as there remains uncertainty concerning the timing of such an evolution.

Nevertheless, my guess has been and remains that the last week of December could feature a growing risk of wintry weather. First, the trough will begin to redevelop. The weekly guidance strongly suggests the development of a sustained trough in the East in the longer-term. As that happens, colder air will return and opportunities for snow will increase. The last week of December could be volatile as the pattern evolves toward a stable colder pattern--the kind of pattern that defined such winters as 1977-78, 2002-03, and 2009-10.

During that last week of December, I believe it is more likely than not that New York City will see accumulating snow. Waiting might be challenging, but I believe the patience will be rewarded so to speak. At present, there remains no meaningful indication that the promising start to Winter 2018-19 will end in heartbreak.

Overall, things remain on track for a very widespread winter with cold anomalies and greater than normal snowfall. The coming pause does not change things. It is part of a larger transition that will see the winter increasingly gain the attributes one has seen in past Central Pacific-based El Niño winters during which both Atlantic and Pacific blocking predominated.

[frd]

1 hour ago, donsutherland1 said:

Act 1 winter 2018-19 will conclude after this weekend's major Lower Middle Atlantic/Southeast snowstorm. The scenario painted by the return of a generally positive EPO and periodically positive Arctic Oscillation (AO) has shown up for some time on the ensembles.

A look at where we have been is helpful.

Scene 1 saw a historic November snowstorm in parts of the East. Cities such as Newark and New York had their biggest ever snowfall so early in the season.

Heavy snow blankets the New York City area (November 15)

Scene 2 featured an exceptional Arctic blast for Thanksgiving Day and the day after.

Central Park's 15° temperature was New York City's lowest November temperature since the mercury fell to 12° on November 27, 1932.

Select record-breaking and record-tying low temperatures for November 22:
Albany: 8° (old record: 9°, 1969)
Allentown: 14° (old record: 15°, 2014)
Bangor: 5° (old record: 11°, 1978)
Binghamton: 3° (old record: 10°, 1989) ***Tied November Record set on 11/30/1976***
Bridgeport: 16° (old record: 18°, 1987) ***Tied November Record set on 11/28/1951 and tied on 11/23/1972***
Hartford: 9° (old record: 14°, 1969)
Islip: 18° (old record: 20°, 1987)
Manchester: 9° (old record: 12°, 1969)
Mount Washington: -26° (old record: -11° set in 1969 and tied in 1987) ***Broke November Record (old monthly record: -20°, 11/30/1958)***
New York City-JFK: 18° (old record: 20°, 1987) ***Broke November Record (old monthly record: 19°, set on 11/30/1976 and tied on 11/21/1987)***
New York City-LGA: 19° (old record: 21°, 1987)
Newark: 17° (old record: 19°, 1987)
Portland: 6° (old record: 11°, 1888)
Poughkeepsie: 10° (old record: 14° set in 1972 and tied in 1984)
Providence: 15° (old record: 16° set in 1969 and tied in 1987)
Saranac Lake: -19° (old record: -2° set in 1972 and tied in 1987) ***Broke November Record (Old monthly record: -14°, set 11/26/1938 and tied on 11/28/1951)***
Scranton: 9° (old record: 15° set in 1969 and tied in 1987 and 2014)
Worcester: 7° (old record: 11°, 1987)

Record-breaking and record-tying low temperatures for November 23:
Albany: 4° (old record: 5°, 1972)
Allentown: 11° (old record: 16°, 1964 and 2000)
Binghamton: 0° (old record: 12°, 1989 and 2008) ***Broke November Record (old record: 3°, set on 11/30/1976 and tied on 11/22/2018)***
Bridgeport: 13° (old record: 16°, 1972) ***Broke November Record (old record: 16°, set on 11/28/1951 and tied on 11/23/1972 and 11/22/2018)***
Burlington: -1° (old record: 2°, 1888 and 1972)
Hartford: 5° (old record: 12°, 1972)
Mount Washington: -13° (tied record set in 1994)
New York City-JFK: 15° (old record: 25°, set in 1949 and tied in 1964, 1972, 2000, and 2008) ***Broke November Record (old record: 18°, 11/22/2018)***
New York City-LGA: 17° (old record: 23°, 1972) ***Tied November Record set on 11/29/1955***
Newark: 13° (old record: 21°, 1932)
Portland: 4° (old record: 7°, 1888 and 1978)
Poughkeepsie: 6° (old record: 9°, 1989)
Providence: 13° (old record: 14°, 1972)
Saranac Lake: -17° (old record: -11°, 1932)
Scranton: 5° (old record: 13°, 1972) ***Broke November Record (old record: 6°, set 11/29/1929 and tied on 11/26/1938)
Trenton: 13° (old record: 16°, 1880)
Westhampton: 6° (old record: 14°, 1964 and 2000) ***Broke November Record (old record: 9°, 11/24/2000)***
Worcester: 7° (old record: 9°, 1929, 1972, and 1989)

Scene 3 featured a blizzard on November 25-26 that brought heavy snow from Kansas to the Great Lakes Region. That storm dumped 8.4" snow at Chicago and 11.7" at Rockford.

Scene 4 saw an inverted trough bring a localized 3"-6" snowfall (with some higher amounts) to a portion of New Jersey, including Atlantic City where 4.8" fell.

Scene 5 will star a major early December Lower Mid-Atlantic/Southeast snowstorm.

There had been a window of opportunity during the first two weeks of December. By the time that period ends, Scenes 4 and 5 will have been put into the weather records books.

That the northern Mid-Atlantic and southern New England regions will very likely miss out given the 500 mb pattern (which, in this case provided above normal lead time for the area at greatest risk of significant snow) does not mean that the potential did not exist. It did.

Act 2, courtesy of the onset of a positive EPO, variable Arctic Oscillation (including positive values), and the MJO's move into milder phases will be defined by a pause. Typically, such pauses last 2 and sometimes 3 weeks. Unlike some recent Decembers, it does not appear that this pause will see exceptional warmth. It will likely see above normal readings in the means.

Act 2 is not the closing Act of December, much less winter. Unlike such "non-winters" as 2011-12, the SSTAs in the Pacific favor a negative EPO. Those SSTAs are remarkably similar to those that were present during winter 2002-03. During that winter, the EPO went positive and remained predominantly positive into the first week of January. Afterward, it went negative and was largely negative through the remainder of what proved to be a very snowy meteorological winter.

Already, some of the guidance suggests an end to the positive EPO that will likely develop in coming days. Whether the EPO will go negative toward the end of the December or start of January remains to be seen, as there remains uncertainty concerning the timing of such an evolution.

Nevertheless, my guess has been and remains that the last week of December could feature a growing risk of wintry weather. First, the trough will begin to redevelop. The weekly guidance strongly suggests the development of a sustained trough in the East in the longer-term. As that happens, colder air will return and opportunities for snow will increase. The last week of December could be volatile as the pattern evolves toward a stable colder pattern--the kind of pattern that defined such winters as 1977-78, 2002-03, and 2009-10.

During that last week of December, I believe it is more likely than not that New York City will see accumulating snow. Waiting might be challenging, but I believe the patience will be rewarded so to speak. At present, there remains no meaningful indication that the promising start to Winter 2018-19 will end in heartbreak.

Overall, things remain on track for a very widespread winter with cold anomalies and greater than normal snowfall. The coming pause does not change things. It is part of a larger transition that will see the winter increasingly gain the attributes one has seen in past Central Pacific-based El Niño winters during which both Atlantic and Pacific blocking predominated.

Epic post Don, really enjoyed it.

If I may ask a question, with the global patterns you see ahead and the Central Pac based El Nino do you think we might be challenging any long standing cold records, either max but more so mins ? 

I ask this based on the fact that we could eventually experience cross polar flow combined with a loading background state and a severe -EPO, and -AO as well.

I have also noticed the expansive snow cover across NA., and the occurrence so far of some rather cold outbreaks early in the season, that set records.  

Hoping we do not go dry and cold, need some snow too Don :-)  Thanks and all the best with your forecast !!  

  

[donsutherland1]

It's difficult to say. Based on past years with extreme cold outbreaks during the November 20-December 10 period, the frequency of cases with single-digit or colder low temperatures in Philadelphia (selected due to its long record), is little different from climatology. Overall, 68% of those winters have 1 or more single-digit lows in January-March vs. 69% for climatology; 32% of those winters have 3 or more such days vs. 39% for climatology; 25% of such winters have 5 or more single-digit lows vs. 24% for climatology. The mean number of such occurrence is 2.6 days vs. 2.7 for climatology.

All things being equal, the probability is likely pretty similar to climatology. Should North American snow cover be deeper and more expansive than normal, that would increase the chances of such cold when cross-polar flow develops.

I'm more confident that this will be a snowy winter in the Middle Atlantic region than I am about the potential for record-challenging/setting cold.

 

 

[SnowGoose69]

9 hours ago, LibertyBell said:

I have been thinking that for awhile too especially for the November-December couplet.

December 2000 wasn’t much different.  Suppression and dry til the very end.  I don’t see this month resembling 89 or 2000 temp wise though or even 09.  It’ll probably be much closer to 2002 temp wise

[Brasiluvsnow]

Thanks for the writeup Sutherland very informative and I hope you are correct in your analysis 

[PB COLTS NECK NJ]

On 12/5/2018 at 12:24 PM, Snowfreak09 said:

What is your opinion for next weeks storm ?

 

I was wrong on it , I thought it would get as far N as Philly into CNJ.

 

Historic for NC/SC.

 

Good for them. 

[Monmouth_County_Jacpot]

Is that storm at the end of the euro warm can’t tell on my phone

[RU848789]

1 hour ago, donsutherland1 said:

It's difficult to say. Based on past years with extreme cold outbreaks during the November 20-December 10 period, the frequency of cases with single-digit or colder low temperatures in Philadelphia (selected due to its long record), is little different from climatology. Overall, 68% of those winters have 1 or more single-digit lows in January-March vs. 69% for climatology; 32% of those winters have 3 or more such days vs. 39% for climatology; 25% of such winters have 5 or more single-digit lows vs. 24% for climatology. The mean number of such occurrence is 2.6 days vs. 2.7 for climatology.

All things being equal, the probability is likely pretty similar to climatology. Should North American snow cover be deeper and more expansive than normal, that would increase the chances of such cold when cross-polar flow develops.

I'm more confident that this will be a snowy winter in the Middle Atlantic region than I am about the potential for record-challenging/setting cold.

 

 

Don - great write-up on the winter so far and the next couple of acts.  I hope you're right about it being a colder/snowier winter than normal - we've gotten used to that the last 10+ years, so I keep waiting for climo to kick back in and the fun to end, lol.  

Question for you: you answered frd's questions with very specific data on past climate in Philly and I've seen you do the same for many other locations, quite quickly - do you have proprietary data sources that you use or do you use public sources and, to do the statistical analyses that you do, do you have all these data in some relational database that allows simple queries or are you extracting raw data and then putting it into some simple spreadsheet or database that perhaps you've constructed that supports such queries?  I sometimes get asked questions on climate on other non-weather sites and I know it takes me a lot longer than ~30 minutes to find the relevant data and then do an analysis on that data, usually by hand.  I suspect you probably have access to reams of data and some sort of relational database that has built in queries to generate the kind of cool climo stats you share regularly or you're just way more efficient at it than I am, lol.  Anyway, love the stats you share.