December 2017 Discussions & Observations Thread

[donsutherland1]

With respect to the pattern I expect to evolve near or just after January 7 (and likely last 1-2 weeks), below is a snapshot (500 mb pattern, temperature anomalies, and select NYC statistics):

[White Gorilla]

8 minutes ago, donsutherland1 said:

With respect to the pattern I expect to evolve near or just after January 7 (and likely last 1-2 weeks), below is a snapshot (500 mb pattern, temperature anomalies, and select NYC statistics):

January thaws are anyway quite common even in the coldest and snowiest winters, correct? 

[donsutherland1]

1 minute ago, White Gorilla said:

January thaws are anyway quite common even in the coldest and snowiest winters, correct? 

Yes they are. I’m not too worried about such a thaw.

[bluewave]

NYC is on track for its first 7 day or greater run of highs below 32 since Jan 2005.

NYC 7 day or longer streaks below 32 since 1970 and ending date:

1-23-00...7

1-15-82...8

1-19-77...1-11-96...1-31-04...1-24-05...9

2-19-79...11

2-7-78....12

 

[SnoSki14]

2 hours ago, bluewave said:

NYC is on track for its first 7 day or greater run of highs below 32 since Jan 2005.

NYC 7 day or longer streaks below 32 since 1970 and ending date:

1-23-00...7

1-15-82...8

1-19-77...1-11-96...1-31-04...1-24-05...9

2-19-79...11

2-7-78....12

 

The cold could be the story this winter, very impressive stretch with several chances of single digits lows outside the city.

[ForestHillWx]

I'm at 16. Low temp is projected to be 12. 

Winds are light, if any. Skies are clear. Might get into the single digits tonight. 

[White Gorilla]

1 hour ago, bluewave said:

This will probably be our coldest stretch of the whole winter.

 

 

 

 

 

Hoping our snowiest stretch is yet to come.  

[JerseyWx]

7 hours ago, bluewave said:

NYC is on track for its first 7 day or greater run of highs below 32 since Jan 2005.

NYC 7 day or longer streaks below 32 since 1970 and ending date:

1-23-00...7

1-15-82...8

1-19-77...1-11-96...1-31-04...1-24-05...9

2-19-79...11

2-7-78....12

 

Wow, we didn't get 7 days+ of below 32° in Feb. 2015?

[Stormlover74]

2 minutes ago, JerseyWx said:

Wow, we didn't get 7 days+ of below 32° in Feb. 2015?

There was a 9 day stretch with all 32 or below except for 1 day at 33 

[CPcantmeasuresnow]

8.1

We may make an unexpected run to 0 tonight.

[sferic]

Liberty NY 5.9 as of 12:10AM

[JerseyWx]

44 minutes ago, Stormlover74 said:

There was a 9 day stretch with all 32 or below except for 1 day at 33 

Oh okay, thanks.  Just missed it.

[Rtd208]

Cold night, current temp is 21 here.

[Paragon]

15 hours ago, donsutherland1 said:

Yes they are. I’m not too worried about such a thaw.

1996 Prime example

Also 1966-67

 

 

[Paragon]

12 hours ago, bluewave said:

NYC is on track for its first 7 day or greater run of highs below 32 since Jan 2005.

NYC 7 day or longer streaks below 32 since 1970 and ending date:

1-23-00...7

1-15-82...8

1-19-77...1-11-96...1-31-04...1-24-05...9

2-19-79...11

2-7-78....12

 

Interesting not to see Dec 1989 in this list!

That was consist below freezing weather that month.

Also interesting that 1978 never went below zero yet has a longer streak than 1977 which was much colder (and also much less snowier than 1978).

 

[CIK62]

Next 8 days down to averaging 19degs, or 15degs. BN.

DEC. is nearly NORMAL as of today and should end @ about 2.5degs. BN.

[LongBeachSurfFreak]

Even if we miss out on big snows we should see the best ice on area water ways since feb 15. If the cold ends up being as long lasting as the gfs says we could see ice rivaling January 77. 

[tim]

17 minutes ago, LongBeachSurfFreak said:

Even if we miss out on big snows we should see the best ice on area water ways since feb 15. If the cold ends up being as long lasting as the gfs says we could see ice rivaling January 77. 

...i know most of us don't want a 'brown winter'..but this cold spell should set up some fine

skating conditions..it will be interesting to see our south shore bays freeze up..the only thing

that would mess up some pond hockey would be some snowfall..but thats ok!

[SnoSki14]

45 minutes ago, LongBeachSurfFreak said:

Even if we miss out on big snows we should see the best ice on area water ways since feb 15. If the cold ends up being as long lasting as the gfs says we could see ice rivaling January 77. 

That will be interesting to see, with temps well below freezing through at least the next 8 days they'll definitely be some icing. 

[Rtd208]

Current temp is 20 here.

[CIK62]

GFS keeps us in the snow totals donunt hole for the next 10 days, while CMC has a foot of the white stuff here.  They seem to be exchanging roles as we move along.

[ForestHillWx]

Was at 13 at 6:00 am. Currently, 15. Tonight's projected low is 5. 

Duration of the cold versus the strength of the cold shot seems to be the theme so far. 

[bluewave]

7 hours ago, JerseyWx said:

Wow, we didn't get 7 days+ of below 32° in Feb. 2015?

Only 3 days in Feb 2015. The longest streak since 2010 has been 5 days in Jan 14, Feb 14, and Jan 13. So we should have a decent ice build up on local waterways by the first week of the New Year.

[PB COLTS NECK NJ]

And so it begins 

Keep in mind this is 15 to as much as 20 to 1.

The EPS has come west and with 96 hours left expect this to come west to a point.

If an IVT to the controls extent occurs on LI it would a great event.

 

Right now it's . 2 to .3 is the mean from NYC on East ,  I think . 5 has a chance to get very close to the coast , but we will have to wait until 12z tomorrow to see if that trend is real 

This matches the Canadian. the GFS was discounted by us as well as Upton as late as last night.

[North and West]

And so it begins 
Keep in mind this is 15 to as much as 20 to 1.
The EPS has come west and with 96 hours left expect this to come west to a point.
If an IVT to the controls extent occurs on LI it would a great event.
 
Right now it's . 2 to .3 is the mean from NYC on East ,  I think . 5 has a chance to get very close to the coast , but we will have to wait until 12z tomorrow to see if that trend is real 
This matches the Canadian. the GFS was discounted by us as well as Upton as late as last night.

What’s IVT? I need an acronym guide.


.

[Dan76]

inverted trough

[PB COLTS NECK NJ]

2 minutes ago, North and West said:

What’s IVT? I need an acronym guide.


.

It's an inverted trough . They are common in New England but the reason why this one is believable is because you have the negative coming through just south of us.

Where / if  that set up are just a guess. But all you need is .4 and at 20 to 1 you get a snowstorm.

We are 4 days out so theres time to see how real it is.

[The Plowsman]

What’s IVT? I need an acronym guide.


.

InVertedTrough

[donsutherland1]

Yesterday’s high temperature of 28° was the coldest December maximum temperature in NYC since December 15, 2017 when the temperature also topped out at 28°. This morning’s 19° low temperature (as of 8 am) was the coldest December temperature since December 16, 2016 when the mercury fell to 17°. Both figures are very likely to be surpassed in coming days. If the 12/27 0z ECMWF is accurate, the thermometer could slip toward 10° just before the ball drops at Times Square.

Monthly Mean Temperature for NYC Through:
12/26 38.4°
12/31 35.0°-35.8° (12/26 estimate: 35.1°-36.1°)

Per aggressive sensitivity analysis, the estimated probability of a below normal monthly anomaly: 84% (12/26 estimate: 76%)

Despite the bone dry GFS runs through December, I believe it still remains likely that an area running from Philadelphia to Boston will see monthly total snowfall of 8" or more.
Snowfall totals are as follows through December 26:

Boston: 9.1” (0.8” above normal)
Bridgeport: 6.8” (2.2” above normal)
New York City: 7.0” (3.0” above normal)
Newark: 7.2” (2.7” above normal)
Philadelphia: 7.7” (4.8” above normal)

At present, my model preference is for a blend between the 0z EPS and 0z ECMWF for the possible 12/30-31 event. The pattern is complex and small errors in the placement of the polar vortex can lead to the difference between no snow for the greater NYC area and a moderate snowfall. The higher resolution guidance should, in theory, have a better handle on the pattern.

Currently, 60% of EPS members show 1” or more snow and just over 30% show 2” or more. The statistical top 10% figure is 4.3”. Therefore, I maintain reasonable confidence that the greater NYC area will likely experience a light to potentially moderate snowfall. The highest amounts are likely to be north and east of New York City.

Finally, the latest run of the ECMWF was a bit less aggressive with the forecast EPO+/AO+ pattern following the first week in January. Such a pattern, should it develop, will likely be temporary. As a result, there is a growing probability that January could also wind up colder than normal in the eastern third of the United States, even assuming a 1-2 week relaxation of the cold pattern.

[frd]

7 minutes ago, donsutherland1 said:

Yesterday’s high temperature of 28° was the coldest December maximum temperature in NYC since December 15, 2017 when the temperature also topped out at 28°. This morning’s 19° low temperature (as of 8 am) was the coldest December temperature since December 16, 2016 when the mercury fell to 17°. Both figures are very likely to be surpassed in coming days. If the 12/27 0z ECMWF is accurate, the thermometer could slip toward 10° just before the ball drops at Times Square.

Monthly Mean Temperature for NYC Through:
12/26 38.4°
12/31 35.0°-35.8° (12/26 estimate: 35.1°-36.1°)

Per aggressive sensitivity analysis, the estimated probability of a below normal monthly anomaly: 84% (12/26 estimate: 76%)

Despite the bone dry GFS runs through December, I believe it still remains likely that an area running from Philadelphia to Boston will see monthly total snowfall of 8" or more.
Snowfall totals are as follows through December 26:

Boston: 9.1” (0.8” above normal)
Bridgeport: 6.8” (2.2” above normal)
New York City: 7.0” (3.0” above normal)
Newark: 7.2” (2.7” above normal)
Philadelphia: 7.7” (4.8” above normal)

At present, my model preference is for a blend between the 0z EPS and 0z ECMWF for the possible 12/30-31 event. The pattern is complex and small errors in the placement of the polar vortex can lead to the difference between no snow for the greater NYC area and a moderate snowfall. The higher resolution guidance should, in theory, have a better handle on the pattern.

Currently, 60% of EPS members show 1” or more snow and just over 30% show 2” or more. The statistical top 10% figure is 4.3”. Therefore, I maintain reasonable confidence that the greater NYC area will likely experience a light to potentially moderate snowfall. The highest amounts are likely to be north and east of New York City.

Finally, the latest run of the ECMWF was a bit less aggressive with the forecast EPO+/AO+ pattern following the first week in January. Such a pattern, should it develop, will likely be temporary. As a result, there is a growing probability that January could also wind up colder than normal in the eastern third of the United States, even assuming a 1-2 week relaxation of the cold pattern.

I love reading your posts as always. If I may ask a question, do you see any indications that later in Jan and Feb of a wetter pattern developing, or do you forsee below normal precip?

At one point with the MJO it appeared we were going to get more STJ action, but that has faded the last away the last four days. Thanks Don.