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January 2018 Discussions & Observations Thread


Rtd208

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1 hour ago, jfklganyc said:

Flew into JFK tonight. Interior waterways (bays inside barrier islands) in Jersey and south shore of LI totally frozen. Really gleamed with the snow.

One exception was the Great South Bay closest to the Freeport area...but that will freeze shortly.

That hasnt happened in 3 years or so. I imagine Flushing Bay around LGA will start to freeze over the weekend but I havent been flying in there and can not verify.

 

The very southern end of Little Neck Bay was iced over Thursday when I drove past it.  It was just starting, but I imagine that has expanded a good bit since then.

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4 hours ago, donsutherland1 said:

January 21, 1985 when the high temperature was 9.

The coldest day I have ever experienced :)

Frosted over windows, I still remember it to this day, couldn't see a thing outside in the early morning hours lol.

I'd like to see a single digit high again and that would basically guarantee a low below 0.

 

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NYC has a chance to join the rare under 20 degrees over 13 days since 1970 club. NYC is currently at 19.8 since Dec 26th with even colder temperatures forecast through Jan 7th. The ice on the local waterways will be very impressive by next weekend.

 

5a48ed5951cec_Screenshot2017-12-31at8_51_36AM.png.81817a4b58d6027255ce06a01a101d80.png

 

 

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10 hours ago, Paragon said:

What an odd winter.  And I thought most of the cold was confined to December 1917 lol.

What exactly happened that winter to cause it to be so anomalously cold?

 

Much of the Northern Hemisphere was filled with much colder than normal air. Today's coverage is far smaller. Some of that cold air periodically pushed deep into the CONUS.

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It has not reached -3 in NYC officially for 74 years.   Besides, I am certain the EURO Meteorgram a few days ago showed a -13, which quickly disappeared.

On the other hand, the last 22 years have been all about breaking every snow record there is---it could be the time to mess with the low end of temperature scale has come.   New highs beat new lows about 4 to 1 for the last 30 years+.

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The preeminent, highly capricious hemispheric pattern will continue over the coming weeks; however, background forcing mechanisms will increasingly countermand the propitious signals for colder than normal in East. The BDC is beginning to weaken, reflective of warming temperatures in the tropical stratosphere, and decreasing ozone concentrations in the Arctic domain. Wave-2 activity will see a spike over the coming week, though well within typical standard deviations. Wave activity flux will largely decrease over the week 1-2 period as tropospheric-stratospheric energy transfer declines, and the PNJ intensifies. One can see the tightening / consolidation on latest data, although the w2 activity will aid in maintaining a somewhat northward displaced surf zone.

 

Nonetheless, the majority of January will feature a stronger than normal SPV and thus a predilection to downwell these anomalies into the troposphere, preferentially the eastern AO and NAO domains. This will tighten the jet, tending to enhance the West Atlantic Ridge signature. 

 

Conversely, one of the more propitious signals is the development of a mean chi 200 signature not too dissimilar from the structure in 2013-14 which induced poleward ridging in the NE PAC. The MJO will circulate into the IO/Maritime Continent w/ probable maintenance in these regions for the balance of January. However, there will be sufficient off-equator forcing to extend the jet eastward w/ induction of rossby wave breaks (sound familiar?) into the NPAC. Heightened WAF in the NPAC will continue to force the regeneration / pulsing of mid/upper level ridging near/south of AK. 

 

What will be the resultant atmospheric circulation structure? In my opinion, it will be one which largely favors the Lakes/Mid-west and interior Northeast for snowfall, with warm-up / rain / cold -- a very spasmodic roller coaster of temperatures but biased warmer than normal on the East Coast. The NHEM circulation will attempt to force the trough in the Central US, and there will be resistance of the +NAO induced West Atlantic Ridge.

 

In other words, I'm not seeing a blowtorch, but it still looks biased warmer than normal for the East Coast with a largely unfavorable pattern for snowfall. It should be warmer than nromal on the West Coast with colder than normal from the Rockies to the Lakes. AAM tendency will be negative, but with poleward propagation of +AAM anomalies which will maintain a +NAO. Arctic outbreaks will continue; however, with the poleward EPO predilection. We are entering mid winter, so snowfall is certainly possible even in less than favorable patterns. But it will be a step-back from the early winter favorability which would be harmonious with my thoughts on this winter's progression.

 

2ryn0o1.png

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Looking at the guidance for the past several days and giving greater weight to the EPS and, to a lesser extent the GEFS, than any of the operational models through today's 18z runs, my initial thinking is that the potential storm for January 4-5 will likely pass a bit too far to the east to bring the immediate NYC area a significant snowfall (6" or more).

Typically, dual low pressure systems consolidate into the single system that lies to the east of the other center. My early premise is that the large number of modeled solutions showing dual systems is probably reasonable. Where the consolidation ultimately takes place and how quickly remain highly uncertain.

My baseline thinking is that most of Long Island would pick up an accumulating snowfall with eastern Suffolk County having the best chance of seeing 6" or more. NYC and its immediate suburbs would pick up a light snowfall with a small accumulation (up to a few inches possible). Eastern New England could also pick up a significant snowfall, but if the dual-center solution is accurate, the consolidation of systems could occur too far to the east except to bring a significant snowfall to Cape Cod south and east. Nothing is assured right now.

My confidence in such thinking is low. The guidance typically can't resolve such complex setups at an extended range and it might not be until the 1/2 0z or 1/2 12z runs before there is decent agreement.

Therefore, a bigger impact for the greater NYC area remains on the table, even if it does not appear to be the most likely outcome right now. The 12z EPS had about a third of the members showing 4" or more snow and about a quarter with 6" or more snow. Just over a quarter had none.

Further, some of the guidance has shifted the precipitation shield a little farther west and the 500 mb pattern has generally improved for a more westward impact. It bears watching to see if there is a continuation in such developments. For now, my guess is that the 18z GFS is the easternmost outlier. The 12z CMC is the westernmost one.

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10 hours ago, donsutherland1 said:

Much of the Northern Hemisphere was filled with much colder than normal air. Today's coverage is far smaller. Some of that cold air periodically pushed deep into the CONUS.

I think we have a shot of at least tying that 16 consec day record, looks like we'll go below zero at the end of the week  and next weekend will be the coldest of the year.  It's going to take a lot to dislodge this historically cold airmass.

 

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6 hours ago, donsutherland1 said:

Looking at the guidance for the past several days and giving greater weight to the EPS and, to a lesser extent the GEFS, than any of the operational models through today's 18z runs, my initial thinking is that the potential storm for January 4-5 will likely pass a bit too far to the east to bring the immediate NYC area a significant snowfall (6" or more).

Typically, dual low pressure systems consolidate into the single system that lies to the east of the other center. My early premise is that the large number of modeled solutions showing dual systems is probably reasonable. Where the consolidation ultimately takes place and how quickly remain highly uncertain.

My baseline thinking is that most of Long Island would pick up an accumulating snowfall with eastern Suffolk County having the best chance of seeing 6" or more. NYC and its immediate suburbs would pick up a light snowfall with a small accumulation (up to a few inches possible). Eastern New England could also pick up a significant snowfall, but if the dual-center solution is accurate, the consolidation of systems could occur too far to the east except to bring a significant snowfall to Cape Cod south and east. Nothing is assured right now.

My confidence in such thinking is low. The guidance typically can't resolve such complex setups at an extended range and it might not be until the 1/2 0z or 1/2 12z runs before there is decent agreement.

Therefore, a bigger impact for the greater NYC area remains on the table, even if it does not appear to be the most likely outcome right now. The 12z EPS had about a third of the members showing 4" or more snow and about a quarter with 6" or more snow. Just over a quarter had none.

Further, some of the guidance has shifted the precipitation shield a little farther west and the 500 mb pattern has generally improved for a more westward impact. It bears watching to see if there is a continuation in such developments. For now, my guess is that the 18z GFS is the easternmost outlier. The 12z CMC is the westernmost one.

And regardless of the snow impact, the storm is going to bring down historically cold air on gusty winds! That may be the main impact of this storm.

 

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8 hours ago, Isotherm said:

The preeminent, highly capricious hemispheric pattern will continue over the coming weeks; however, background forcing mechanisms will increasingly countermand the propitious signals for colder than normal in East. The BDC is beginning to weaken, reflective of warming temperatures in the tropical stratosphere, and decreasing ozone concentrations in the Arctic domain. Wave-2 activity will see a spike over the coming week, though well within typical standard deviations. Wave activity flux will largely decrease over the week 1-2 period as tropospheric-stratospheric energy transfer declines, and the PNJ intensifies. One can see the tightening / consolidation on latest data, although the w2 activity will aid in maintaining a somewhat northward displaced surf zone.

 

Nonetheless, the majority of January will feature a stronger than normal SPV and thus a predilection to downwell these anomalies into the troposphere, preferentially the eastern AO and NAO domains. This will tighten the jet, tending to enhance the West Atlantic Ridge signature. 

 

Conversely, one of the more propitious signals is the development of a mean chi 200 signature not too dissimilar from the structure in 2013-14 which induced poleward ridging in the NE PAC. The MJO will circulate into the IO/Maritime Continent w/ probable maintenance in these regions for the balance of January. However, there will be sufficient off-equator forcing to extend the jet eastward w/ induction of rossby wave breaks (sound familiar?) into the NPAC. Heightened WAF in the NPAC will continue to force the regeneration / pulsing of mid/upper level ridging near/south of AK. 

 

What will be the resultant atmospheric circulation structure? In my opinion, it will be one which largely favors the Lakes/Mid-west and interior Northeast for snowfall, with warm-up / rain / cold -- a very spasmodic roller coaster of temperatures but biased warmer than normal on the East Coast. The NHEM circulation will attempt to force the trough in the Central US, and there will be resistance of the +NAO induced West Atlantic Ridge.

 

In other words, I'm not seeing a blowtorch, but it still looks biased warmer than normal for the East Coast with a largely unfavorable pattern for snowfall. It should be warmer than nromal on the West Coast with colder than normal from the Rockies to the Lakes. AAM tendency will be negative, but with poleward propagation of +AAM anomalies which will maintain a +NAO. Arctic outbreaks will continue; however, with the poleward EPO predilection. We are entering mid winter, so snowfall is certainly possible even in less than favorable patterns. But it will be a step-back from the early winter favorability which would be harmonious with my thoughts on this winter's progression.

 

2ryn0o1.png

But it's this back and forth pattern that is best for big blockbuster storms.  The earlier pattern was good only for small/minor events.

Also, our SSTs are so much colder now, that any changeover scenarios would likely be delayed.  This might be more like 1993-94.

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10 hours ago, JerseyWx said:

I think that's overdone for the city, as usual, but for areas north and West it certainly isn't out of the question.

I think the city can easily get to below 0 with the kind of airmass that is coming, but -10 no lol.

 

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13 hours ago, Isotherm said:

The preeminent, highly capricious hemispheric pattern will continue over the coming weeks; however, background forcing mechanisms will increasingly countermand the propitious signals for colder than normal in East. The BDC is beginning to weaken, reflective of warming temperatures in the tropical stratosphere, and decreasing ozone concentrations in the Arctic domain. Wave-2 activity will see a spike over the coming week, though well within typical standard deviations. Wave activity flux will largely decrease over the week 1-2 period as tropospheric-stratospheric energy transfer declines, and the PNJ intensifies. One can see the tightening / consolidation on latest data, although the w2 activity will aid in maintaining a somewhat northward displaced surf zone.

 

Nonetheless, the majority of January will feature a stronger than normal SPV and thus a predilection to downwell these anomalies into the troposphere, preferentially the eastern AO and NAO domains. This will tighten the jet, tending to enhance the West Atlantic Ridge signature. 

 

Conversely, one of the more propitious signals is the development of a mean chi 200 signature not too dissimilar from the structure in 2013-14 which induced poleward ridging in the NE PAC. The MJO will circulate into the IO/Maritime Continent w/ probable maintenance in these regions for the balance of January. However, there will be sufficient off-equator forcing to extend the jet eastward w/ induction of rossby wave breaks (sound familiar?) into the NPAC. Heightened WAF in the NPAC will continue to force the regeneration / pulsing of mid/upper level ridging near/south of AK. 

 

What will be the resultant atmospheric circulation structure? In my opinion, it will be one which largely favors the Lakes/Mid-west and interior Northeast for snowfall, with warm-up / rain / cold -- a very spasmodic roller coaster of temperatures but biased warmer than normal on the East Coast. The NHEM circulation will attempt to force the trough in the Central US, and there will be resistance of the +NAO induced West Atlantic Ridge.

 

In other words, I'm not seeing a blowtorch, but it still looks biased warmer than normal for the East Coast with a largely unfavorable pattern for snowfall. It should be warmer than nromal on the West Coast with colder than normal from the Rockies to the Lakes. AAM tendency will be negative, but with poleward propagation of +AAM anomalies which will maintain a +NAO. Arctic outbreaks will continue; however, with the poleward EPO predilection. We are entering mid winter, so snowfall is certainly possible even in less than favorable patterns. But it will be a step-back from the early winter favorability which would be harmonious with my thoughts on this winter's progression.

 

2ryn0o1.png

Great post..I think we will be colder than normal thru about Jan 10-15, then have a rapid warm-up with several cutters. 

This has been typical of La Ninas winters with the cold December through mid January, a warmer February, and then a cold March.

The intensification of the PNJ has been synonymous with the fact that the polar vortex was never fully disturbed, and that overall background conditions of -ENSO and low solar/-QBO send mixed signals as to the structure and intensity of the stratospheric vortex. 

As you say, however, I do expect some north Pacific blocking to continue which will continue to make each blast behind a cutter meaningful cold. The current displacement of the polar vortex into the eastern United States may be the most significant since Jan 1994 or Jan 1977, and that is synonymous with the -EPO block.

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This morning’s low temperature in New York City was 7°. That is the coldest minimum temperature since February 14, 2016 when the temperature fell to -1°. NYC has now had 2 consecutive days with low temperatures below 10° and 6 consecutive days with low temperatures below 20°. Those are the longest such stretches since February 13-14, 2016 with single-digit low temperatures and February 12-21, 2015 when 10 consecutive minimum temperatures below 20° were registered.

Estimated NYC Average Temperature Through:

1/10 19.0°-24.4°
1/15 22.1°-27.7°

Per aggressive sensitivity analysis, the estimated probability of a below normal monthly anomaly: 59%

All said, a colder than normal January appears likely. The January cold anomaly could approach or exceed the December one.

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