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January 2018 Discussions & Observations Thread

Rtd208

By Rtd208,
in New York City Metro

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Paragon

Paragon

Posted
Posted
4 hours ago, nzucker said:

There may be one more coastal snow attempt after the Thursday one around Day 10. Looks like a potential second trough coming into the TN/MS Valley...some of the GFS runs show this cyclogenesis potential.

I heard about another big arctic shot coming down the middle of next week after a brief warm up.

 

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Paragon

Paragon

Posted
Posted
18 hours ago, bluewave said:

Pretty wild that it's 100 years to the day of the last single digit low in NYC for New Years day. Happy New Year everyone and try to stay warm. 

Nice comparison between winter 1917-18 and 2017-18.

If it wasn't for our changing climate, this winter might have been just as cold as that one.

If that holds, we can expect winter 2033-34 to be like 1933-34 ;-)

 

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Paragon

Paragon

Posted
Posted
6 hours ago, Isotherm said:

 

Thanks! Appreciate the kinds words. 1) Partially Nina driven, a combination of worsening tropical forcing, GWO/AAM cycling, and other internal mechanisms such as the brewer-dobson circulation which governs ozone transport, among others; 2) It's not as much about the magnitude of SSTA's as much as it is the cycling and orientation of tropical forcing which can often resemble ENSO events stronger than the current. In the pre-season, I thought this winter's tropical forcing pattern would more closely resemble a moderate or stronger La Nina, even though SSTA's weren't reflective of that. The NPAC ridging is classic Nina pattern. The December pattern was expected to be the major aberration month, with a gradual retrogression thereafter; 3) Not a real gradient pattern (in the sense of latitudinal thermal gradients); the cold should try to pool in the mid-west / rockies eastward to the appalachains, and the one constant this winter has been a predominately +NAO, which will continue to resist the eastward expansion of cold in the means. MJO cycling will act contemporaneously to force SE-ridging in the means as well. We'll have arctic shots, but the pattern doesn't look great for coastal snow potential after the 10th.

You can get a big snowstorm even in a milder pattern, a la Feb 2006.  If this is the best the winter is likely to be and we end up with less than 12" before the pattern changes, then we're likely to end up with a below seasonal snowfall total by the end of the season unless the season turns around like it did in Feb in the 2005-06 winter which was a much milder winter than this one is likely to be even with a pattern change.

 

Another winter with some similarities was 1993-94 with all the arctic shots but not  a lot of snow timed with those arctic shots, but we still managed to get ours in February.  That one also had a +NAO.  I remember many of the events that were forecast to changeover didn't because the waters were so cold.

This winter looks like a cross between 1993-94 and 2005-06.

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Paragon

Paragon

Posted
Posted
20 hours ago, nzucker said:

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.

Nate I think our biggest snowfall will actually come in February- in some ways this winter is like a colder version of 2005-06, which had small but frequent snowfalls in December, a mild January, and a big snowstorm in February in spite of the fact that it never got very cold again.  You can still get a blockbuster in a mild pattern, it just needs proper timing like that one was.  That winter was much milder than this one is likely to be even if the pattern changes.  Historically, we haven't had a big March snowstorm in a long time (last year's was big inland not for us), so I think that February is the month to look for our biggest snowstorm.

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tim

tim

Posted
Posted
4 minutes ago, donsutherland1 said:

Westhampton's low temperature yesterday was -3°. That smashed the old record of 4°, which was set in 2002.

...and then it bounced back up to 14* by 4am..pretty extreme temperature fluctuations.

..i'm currently @ 10* up from my low of +1*..

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bluewave

bluewave

Posted
Posted
23 minutes ago, North and West said:


Recency (and childhood) bias: 1994 isn’t on there! Also, good lord, just how brutal was 1918?


.

94 is just outside the top 10. 1917-1918 was the coldest winter on record for NYC. It took a continuation of the record NEPAC blocking regime since 2013 to reach these extreme levels of Arctic cold. Looks like the coldest is yet to come for this weekend before the pattern gradually begins to relax during the 2nd into 3rd weeks of January. January thaw will probably become a big internet buzzword after this impressive run of Arctic cold. People will have forgotten what it feels like to have high temperatures above freezing again.;)

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North and West

North and West

Posted
Posted
94 is just outside the top 10. 1917-1918 was the coldest winter on record for NYC. It took a continuation of the record NEPAC blocking regime since 2013 to reach these extreme levels of Arctic cold. Looks like the coldest is yet to come for this weekend before the pattern gradually begins to relax during the 2nd into 3rd weeks of January. January thaw will probably become a big internet buzzword after this impressive run of Arctic cold. People will have forgotten what it feels like to have high temperatures above freezing again.

I’m in the Caribbean that week, so I’m cool with that.


.
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donsutherland1

donsutherland1

Posted
Posted

This morning’s low temperature in New York City was 13°. That makes today the 7th consecutive day on which the low temperature was below 20°. The last time the temperature fell below 20° for at least 7 days was February 12-21, 2015 (10 consecutive days). In addition, the 7-day average temperature for New York City (12/26/2017-1/1/2018) is 17.9°. That’s the coldest 7-day average since 2/15-21/2015 when the temperature averaged 17.6°.
NYC’s Average Temperature Through:

1/1 13.0° (20.0° below normal)
1/10 20.4°-25.2° (1/1 estimate: 19.0°-24.4°)
1/15 23.3°-28.5° (1/1 estimate: 22.1°-27.7°)

Per aggressive sensitivity analysis, the estimated probability of a below normal monthly anomaly: 59% (1/1 estimate: 59%)

My baseline thinking from 12/31 remains little changed concerning the possible snowstorm for January 4-5 except for parts of New England. Most of Long Island should 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).

Previously, I had suggested that eastern New England could also pick up a significant snowfall, but that if the dual-center solution is accurate, the consolidation of systems could occur too far to the east to bring a significant snowfall to that area except for Cape Cod south and east. Given the possible emerging consensus on the mesoscale models, I have growing confidence that parts of New England will pick up a significant snowfall (6” or more). That area could include the Providence, Boston, and Portland. All said, there is a growing probability that parts of Long Island into New England could receive 6” or more snow and possibly 10” or more snow.

Caution remains warranted, as the global models are still in considerable disagreement among themselves and with the mesoscale models. Eastern Maine into New Brunswick will likely experience a crippling blizzard.

Overall, my confidence is low to moderate. The guidance typically can't resolve such complex setups at an extended range and it might not be until the 1/3 0z runs before there is decent agreement.

It is possible that the higher-resolution mesoscale models might have a somewhat better handle on the complex interaction of short waves that will lead to the development of the exceptionally powerful storm that will bring the snowfall to parts of the region.

If I had to guess some probabilities for NYC:

No snow: Around 20%; Measurable snowfall: 80%; 1" or more: 45%; 2" or more: 35%; 4" or more: 25%; 6" or more: 10%.

The probabilities for 1” or more, 2” or more are 5% higher than yesterday’s thinking. The probability for 4” or more is 10% higher and the probability for 6” or more is 5% higher than yesterday’s thinking.

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donsutherland1

donsutherland1

Posted
Posted

From the NWS Upton: 

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
1143 AM EST Tue Jan 2 2018

CTZ008-011-012-NYZ078>081-030045-
/O.NEW.KOKX.WS.A.0001.180104T0500Z-180105T0500Z/
Northern New London-Southern Middlesex-Southern New London-
Northwestern Suffolk-Northeastern Suffolk-Southwestern Suffolk-
Southeastern Suffolk-
1143 AM EST Tue Jan 2 2018

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING...

* WHAT...Heavy snow possible. Plan on difficult travel conditions,
  including the morning and evening commute on Thursday. Total
  snow accumulations of 6 or more inches are possible.

* WHERE...Portions of southeast Connecticut and Suffolk County on
  Long Island.

* WHEN...From late Wednesday night through Thursday evening.

* ADDITIONAL DETAILS...Wind gusts between 30 to 40 mph are
  possible. This may result in blowing and drifting of snow.
  Significant reductions in visibility are possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch means there is potential for significant
snow, sleet or ice accumulations that may impact travel. Continue
to monitor the latest forecasts.

$$
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donsutherland1

donsutherland1

Posted
Posted

Today was New York City’s 8th consecutive subfreezing day. That’s the longest such stretch since a 9-day period running from January 16-24, 2005. Further, the 12/27/2017-1/2/2017 period has had a 7-day mean temperature of just 17.0°. That’s NYC’s coldest 7-day period since January 16-22, 1994 when the temperature averaged just 15.3°.

At this time, given the slow convergence of the guidance (mesoscale models shifting somewhat eastward with the precipitation shield and global models. With the 18z GFS now moving into somewhat better agreement with the other guidance, my confidence concerning the storm has increased to moderate.

My thinking is that eastern Long Island across eastern New England will likely experience a high-impact snowstorm. Blizzard conditions are likely. Across this area, 6” or more snow is very likely. 10” or more is likely. The high winds will produce near zero visibility and considerable blowing and drifting. For those areas, this is not a storm to be minimized. If everything comes together, it could be among the area’s most ferocious blizzards in the last decade, even as it might not produce the highest snowfall amounts.

In terms of ratios, my guess is that near NYC and westward could see 12:1 ratios. Suffolk County could see 9:1-10:1 ratios due to very high winds.

It should be noted that there remains above normal uncertainty. Larger than usual revisions could still be needed.

Preliminary snowfall estimates:

Atlantic City: 2”-4”
Bangor: 8:”-16”
Bridgeport: 2”-4”
Boston: 8”-14”
Concord: 4”-8”
Hartford: 2”-4”
Islip: 4”-8”
Morristown: 1”-3”
New York City: 2”-4”
Newark: 2”-4”
Philadelphia: 1”-3”
Portland: 8”-16”
Poughkeepsie: 1”-3”
Providence: 6”-12”
Westhampton: 6”-12”
White Plains: 1”-3”
Worcester: 6”-12”

In my opinion, there remains about a 25% probability that NYC will receive 4” or more snow and a 10% probability that the City will pick up 6” or more snow.

Behind the storm, and extremely cold air mass will blast into the region. Most locations, and possibly Central Park, could experience at least one subzero low temperature. Warming is likely to occur

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MJO812

MJO812

Posted
Posted
1 hour ago, donsutherland1 said:

Today was New York City’s 8th consecutive subfreezing day. That’s the longest such stretch since a 9-day period running from January 16-24, 2005. Further, the 12/27/2017-1/2/2017 period has had a 7-day mean temperature of just 17.0°. That’s NYC’s coldest 7-day period since January 16-22, 1994 when the temperature averaged just 15.3°.

At this time, given the slow convergence of the guidance (mesoscale models shifting somewhat eastward with the precipitation shield and global models. With the 18z GFS now moving into somewhat better agreement with the other guidance, my confidence concerning the storm has increased to moderate.

My thinking is that eastern Long Island across eastern New England will likely experience a high-impact snowstorm. Blizzard conditions are likely. Across this area, 6” or more snow is very likely. 10” or more is likely. The high winds will produce near zero visibility and considerable blowing and drifting. For those areas, this is not a storm to be minimized. If everything comes together, it could be among the area’s most ferocious blizzards in the last decade, even as it might not produce the highest snowfall amounts.

In terms of ratios, my guess is that near NYC and westward could see 12:1 ratios. Suffolk County could see 9:1-10:1 ratios due to very high winds.

It should be noted that there remains above normal uncertainty. Larger than usual revisions could still be needed.

Preliminary snowfall estimates:

Atlantic City: 2”-4”
Bangor: 8:”-16”
Bridgeport: 2”-4”
Boston: 8”-14”
Concord: 4”-8”
Hartford: 2”-4”
Islip: 4”-8”
Morristown: 1”-3”
New York City: 2”-4”
Newark: 2”-4”
Philadelphia: 1”-3”
Portland: 8”-16”
Poughkeepsie: 1”-3”
Providence: 6”-12”
Westhampton: 6”-12”
White Plains: 1”-3”
Worcester: 6”-12”

In my opinion, there remains about a 25% probability that NYC will receive 4” or more snow and a 10% probability that the City will pick up 6” or more snow.

Behind the storm, and extremely cold air mass will blast into the region. Most locations, and possibly Central Park, could experience at least one subzero low temperature. Warming is likely to occur

Nice forecast but I hope those numbers for NYC go up .

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CPcantmeasuresnow

CPcantmeasuresnow

Posted
Posted
11 minutes ago, donsutherland1 said:

I do, too. There's probably more upside potential than downside potential.

That's really what it's come down to for many of us. You can't be too disappointed when you're only expecting 1-3 from a sub 960 January storm off shore. All we have is an upside, even it's slim.

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gravitylover

gravitylover

Posted
Posted
23 hours ago, donsutherland1 said:

Both sites are currently -1°. It certainly feels like deep winter outside.

Just for reference - If you haven't seen the DXR site it sits right at the base of a few large hills to its east and south with a gradual rise to the north. There is an open corridor running basically E/W so if there is a breeze oriented from those directions it scours the valley out and a NW breeze will moderate the temp at the site pretty easily. On still or nearly still nights the hollow the airport sits in does get really cold compared to much of the rest of the area.

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