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January 2018 Discussions & Observations Thread


Rtd208

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1 minute ago, bluewave said:

Just wait until the NAM gets to within range since it really excels with these CAD set ups. This could be a high impact ice/snow event for the interior regions. Some frozen may make it to the coast at the very end if the dry slot doesn't cut off the precip first. 

Yup. You’ve been all over this . Some winters the cold just wins. While we def will mild up at times this month, folks need to be very careful about extended warmth and even moreso the Euro weeklies torching thru first week of Feb. As soon as EPO trends +, the AO goes negative. Interesting times ahead 

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Weeklies are ugly/blowtorch from Jan 18th through the second week of February. Starts transitioning late second week of February. The low height signal persists near the West Coast until that time; the EPO rebuilds for mid February onward, and the NAO is positive.

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5 minutes ago, Isotherm said:

Weeklies are ugly/blowtorch from Jan 18th through the second week of February. Starts transitioning late second week of February. The low height signal persists near the West Coast until that time; the EPO rebuilds for mid February onward, and the NAO is positive.

That's why I'm a bit surprised as to why so many people think we're going to have a rocking February. Statistically February is the warmest month in a La Nina, I'm pretty sure the monthlies had us torching in February after a BN Dec-Jan. 

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2 hours ago, bluewave said:

More traditional La Nina pattern developing next few weeks. Looks like the Euro tries to bring the forcing back closer to W oft he DL later in the month.  With a lag, that should probably produce a post thaw more favorable winter period in February.

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Other guidance isn't as bullish w/ the eastward propagation and keeps the MJO circulating 4-6; one also must consider the lower frequency forcing which will remain further west for awhile. There will be changes down the road, but we'll have to see how quickly w2 can perturb the vortex as well as GWO/AAM budget changes.

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10 minutes ago, Isotherm said:

 

 

Other guidance isn't as bullish w/ the eastward propagation and keeps the MJO circulating 4-6; one also must consider the lower frequency forcing which will remain further west for awhile. There will be changes down the road, but we'll have to see how quickly w2 can perturb the vortex as well as GWO/AAM budget changes.

It would be nice if the CPC MJO site updated again. It hasn't updated since January 1st. I just saw the weeklies and they imply holding onto a more Maritime Continent La Nina forcing pattern a little longer into February like you just said. That would fit with a slower progression through 4-6. 

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23 minutes ago, bluewave said:

It would be nice if the CPC MJO site updated again. It hasn't updated since January 1st. I just saw the weeklies and they imply holding onto a more Maritime Continent La Nina forcing pattern a little longer into February like you just said. That would fit with a slower progression through 4-6. 

Yeah, agreed. Not saying I'd totally buy into them. That possibility is on the table if GWO/AAM alterations as well as w2 perturbation of the vortex is slower. They're about a week later than I've been thinking with respect to the transition. 

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1 hour ago, SnoSki14 said:

That's why I'm a bit surprised as to why so many people think we're going to have a rocking February. Statistically February is the warmest month in a La Nina, I'm pretty sure the monthlies had us torching in February after a BN Dec-Jan. 

One has to be careful about automatically assuming the composite La Niña climatology will prevail. Such climatology would have indicated a warmer than normal January across much of the CONUS. It appears likely that January will finish colder than normal in the eastern third to perhaps half of the CONUS. Since 1950, the longest stretch of subfreezing days in NYC during a La Niña winter occurred in 1996 (9). No other La Niña winter had a stretch within 5 days of what has just taken place. In addition, winter 2017-18 has already seen more snowfall than 10 of the 21 La Niña winters did in their entirety since 1950.

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1 hour ago, bluewave said:

It would be nice if the CPC MJO site updated again. It hasn't updated since January 1st. I just saw the weeklies and they imply holding onto a more Maritime Continent La Nina forcing pattern a little longer into February like you just said. That would fit with a slower progression through 4-6. 

MJO is updated through yesterday here: http://www.bom.gov.au/climate/mjo/

 

I personally expect a slow pattern due to ridging feedbacks from low Arctic sea ice extent around the Bering Sea.

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1 hour ago, donsutherland1 said:

One has to be careful about automatically assuming the composite La Niña climatology will prevail. Such climatology would have indicated a warmer than normal January across much of the CONUS. It appears likely that January will finish colder than normal in the eastern third to perhaps half of the CONUS. Since 1950, the longest stretch of subfreezing days in NYC during a La Niña winter occurred in 1996 (9). No other La Niña winter had a stretch within 5 days of what has just taken place. In addition, winter 2017-18 has already seen more snowfall than 10 of the 21 La Niña winters did in their entirety since 1950.

La ninas are too variable with enough outliers to just broad brush them like many do. There is also a difference between east and west based. I doubt this suddenly becomes a "typical nina" when it hasn't been so far. That said for those of us southwest of your area who are still waiting for any meaningful snow I'm torn between being hopeful that this seems to be a year cold wins and more chances will come or feeling worried that we wasted a long cold stretch with no snow to show for it and maybe that was our best chance. 

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26 minutes ago, psuhoffman said:

La ninas are too variable with enough outliers to just broad brush them like many do. There is also a difference between east and west based. I doubt this suddenly becomes a "typical nina" when it hasn't been so far. That said for those of us southwest of your area who are still waiting for any meaningful snow I'm torn between being hopeful that this seems to be a year cold wins and more chances will come or feeling worried that we wasted a long cold stretch with no snow to show for it and maybe that was our best chance. 

I suspect that there will be more opportunities. It is plausible that the coming storminess may mark the early stages of a transition away from the generally drier than normal conditions that have prevailed since autumn. If so, once we get through the thaw, there should be opportunities even for parts of the Middle Atlantic region that have yet to experience much snowfall.

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While December was colder than normal in the Northeast, on a nationwide scale, 2017 was less impressive (as far as geographic coverage and magnitude) than all colder than normal La Nina winters since 1980. 2005, which was a warmer than normal winter, had more expansive nationwide cold in December.

This post is not meant to be misconstrued as forecast, it's merely an observation. However, it suggests that December's pattern was reflective of countervailing mechanisms to an extent greater than that of other years favoring cold.

 

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Yesterday was the 14th consecutive day on which the temperature remained below freezing in New York City, marking the longest such period since the 16-day period from January 19 through February 3, 1961. At 4 am this morning, the mercury slipped above freezing in Central Park, ending a 346-hour period during which it stayed below 32°.

The region is now moving into a January thaw that will occasinally be interrupted by transient cold shots courtesy of a frequently negative AO.

On Thursday, the temperature could reach 50° for the first time since December 22. Some of the guidance takes the temperature to 60° or above on Friday, which would be the first such reading since December 5. Further, the 1/9 0z GFS MOS forecasts a low temperature of 52° on Friday. The record high minimum temperature for January 12 is 47°, which was set just last year.

NYC’s Average Temperature Through:

1/8: 17.3° (15.7° below normal)
1/10: 20.8°-21.4° (1/8 estimate: 20.4°-21.6°)
1/15: 25.7°-28.1° (1/8 estimate: 25.6°-28.4°)
1/20: 26.7°-30.0° (1/8 estimate: 26.4°-30.0°)

Per aggressive sensitivity analysis, the estimated probability of a below normal monthly anomaly: 55% (1/8 estimate: 58%)

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8 hours ago, Isotherm said:

While December was colder than normal in the Northeast, on a nationwide scale, 2017 was less impressive (as far as geographic coverage and magnitude) than all colder than normal La Nina winters since 1980. 2005, which was a warmer than normal winter, had more expansive nationwide cold in December.

This post is not meant to be misconstrued as forecast, it's merely an observation. However, it suggests that December's pattern was reflective of countervailing mechanisms to an extent greater than that of other years favoring cold.

 

Yeah, I was pointing this out in the December discussion thread. Recent years have featured a prominent mild period around the solstice. The mild week this year at that time prevented colder monthly departures than you would expect for the magnitude of cold that followed after Christmas. December 2013 would have featured a cold departure for the month if it wasn't for the 70 degree record warmth around the solstice.

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12 hours ago, SnoSki14 said:

That's why I'm a bit surprised as to why so many people think we're going to have a rocking February. Statistically February is the warmest month in a La Nina, I'm pretty sure the monthlies had us torching in February after a BN Dec-Jan. 

 

Because the weeklies are horrible ver wise after week 3.

Here is the upcoming 5 to 10 missed by the last 3 weekly runs.

A total miss.

Again,  someone yells torch and you bite without peeling back even 1 layer.

The trough will back by Feb 5th.

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Because the weeklies are horrible ver wise after week 3.

Here is the upcoming 5 to 10 missed by the last 3 weekly runs.

A total miss.

Again,  someone yells torch and you bite without peeling back even 1 layer.

The trough will back by Feb 5th.

I wont debate temp anomalies in the LR. Most stuff 10 days+ is a challenge enough.....getting temp anomalies to verify in that range is quite the task. Often we see muted verification or even, as you posted, almost total opposite. What concerns me is the ens locking in on a trof or lp anchoring in off the NW US/W Canada Coast. That is not a great look for us downstream. Doesnt necessarily = torch but if we dont get help, real help, on the ATL side, we are going to pass by our best climo period with limited chances imo. Again, doesnt mean a shutout by any means BUT if that look holds I could definitely see several AN days, sandwich a few transient BN days, several AN days cycle irt temps. We could score on the transitions but who knows.....LR is such a crapshoot. Im personally not a huge fan of what is setting up in the PAC even with hopes of a -AO. We need the ATL to work with that look.
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12 minutes ago, Ralph Wiggum said:
1 hour ago, PB COLTS NECK NJ said:
 

Because the weeklies are horrible ver wise after week 3.

Here is the upcoming 5 to 10 missed by the last 3 weekly runs.

A total miss.

Again,  someone yells torch and you bite without peeling back even 1 layer.

The trough will back by Feb 5th.

 

I wont debate temp anomalies in the LR. Most stuff 10 days+ is a challenge enough.....getting temp anomalies to verify in that range is quite the task. Often we see muted verification or even, as you posted, almost total opposite. What concerns me is the ens locking in on a trof or lp anchoring in off the NW US/W Canada Coast. That is not a great look for us downstream. Doesnt necessarily = torch but if we dont get help, real help, on the ATL side, we are going to pass by our best climo period with limited chances imo. Again, doesnt mean a shutout by any means BUT if that look holds I could definitely see several AN days, sandwich a few transient BN days, several AN days cycle irt temps. We could score on the transitions but who knows.....LR is such a crapshoot. Im personally not a huge fan of what is setting up in the PAC even with hopes of a -AO. We need the ATL to work with that look.

Very realistic assessment and fully agree.  I think the snow chances will continue, but won't be optimal until perhaps February.  

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52 minutes ago, Ralph Wiggum said:
1 hour ago, PB COLTS NECK NJ said:
 

Because the weeklies are horrible ver wise after week 3.

Here is the upcoming 5 to 10 missed by the last 3 weekly runs.

A total miss.

Again,  someone yells torch and you bite without peeling back even 1 layer.

The trough will back by Feb 5th.

 

I wont debate temp anomalies in the LR. Most stuff 10 days+ is a challenge enough.....getting temp anomalies to verify in that range is quite the task. Often we see muted verification or even, as you posted, almost total opposite. What concerns me is the ens locking in on a trof or lp anchoring in off the NW US/W Canada Coast. That is not a great look for us downstream. Doesnt necessarily = torch but if we dont get help, real help, on the ATL side, we are going to pass by our best climo period with limited chances imo. Again, doesnt mean a shutout by any means BUT if that look holds I could definitely see several AN days, sandwich a few transient BN days, several AN days cycle irt temps. We could score on the transitions but who knows.....LR is such a crapshoot. Im personally not a huge fan of what is setting up in the PAC even with hopes of a -AO. We need the ATL to work with that look.

I think the 18 th thru 4th is AN , I was responding to thinking Feb would be warm.

Look at those 500s , they look warm right? 

They will not be a 2 weeks ongoing torch  , that's all HP extending down from a region that never warms to it`s full potential.

so even the warm period will threaten.

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