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I don't want to sound dismissive of tropical forcing, it's got a role to play and a crucial piece of forecasting in the extended range.  But the correlations are often overvalued by forecasts at the mid and high lats, especially in recent times.

 

In my opinion the guys who use it as the foundational/principal basis for the majority of their forecasts tend to overvalue it's usefulness.  More pieces to the puzzle.  It's not the answer to all weather and it gets that reputation sometimes.

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6 minutes ago, NittanyWx said:

I don't want to sound dismissive of tropical forcing, it's got a role to play and a crucial piece of forecasting in the extended range.  But the correlations are often overvalued by forecasts at the mid and high lats, especially in recent times.

 

In my opinion the guys who use it as the foundational/principal basis for the majority of their forecasts tend to overvalue it's usefulness.  More pieces to the puzzle.  It's not the answer to all weather and it gets that reputation sometimes.

PSU in the MA forum has said he's noticed when the wave moves fast it has less impact...might be something to that

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5 minutes ago, SnowGoose69 said:

PSU in the MA forum has said he's noticed when the wave moves fast it has less impact...might be something to that

Yeah we can test that via historical ERA5 data, would be interesting to see the difference in h5 response with 30-40 day cycles vs slightly longer.

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26 minutes ago, NittanyWx said:

I don't want to sound dismissive of tropical forcing, it's got a role to play and a crucial piece of forecasting in the extended range.  But the correlations are often overvalued by forecasts at the mid and high lats, especially in recent times.

 

In my opinion the guys who use it as the foundational/principal basis for the majority of their forecasts tend to overvalue it's usefulness.  More pieces to the puzzle.  It's not the answer to all weather and it gets that reputation sometimes.

This isn’t to challenge you in any way, I’m just very curious and trying to learn.

If it’s not just in MJO activity, what caused / contributed to all the record warmth and consistent back to back warm winters since 2016? What do you think is driving that outside the obvious?

Anomalous MJO activity at least sort of gives a partial explanation, you know? But I’m curious if you have any other thoughts. 

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11 minutes ago, Volcanic Winter said:

This isn’t to challenge you in any way, I’m just very curious and trying to learn.

If it’s not just in MJO activity, what caused / contributed to all the record warmth and consistent back to back warm winters since 2016? What do you think is driving that outside the obvious?

Anomalous MJO activity at least sort of gives a partial explanation, you know? But I’m curious if you have any other thoughts. 

Without giving too much away, there's actually quite a strong correlation to USA temperatures/degree days and stratospheric temps in the preceding month(s) for December, and that correlation strengthened significantly this year.

 

When I bang on about source region and questioning cold displacement this is certainly something I look at closely.

 

This is one example of about 3-4 others that I think have a physical role to play in development of the PV and displacement/location thereof.  There does seem to be a tropo connection to it (wave breaking another crucial one).

 

Indian Ocean Dipole/ENSO modulation of tropical forcing has a role to play in contributing to those warm winters too.    What I look for are multiple signals pointing in the same direction for higher conviction forecasting.

 

What I'm saying is GSDM/RMM based forecasting as the sole basis for a view has, historically, had a high bust rate...particularly in regards to timing which is often smoothed over as 'was right, just wrong on timing'.   Not to burst anyone's bubble, but if you're wrong on timing, you're wrong...

 

There are sub-seasonal influences all over the place.  But generally speaking strong ENSO winters tend to be higher conviction forecasting because of the known correlations globally as well.  There's always sub seasonal variables that modulate it though, and the key is to pick out what's a legitimate signal vs noise that can fuck up a forecast.

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I hope everyone is at least enjoying a frigid week with some light snows. It feels cold and miserable and much more wintry than the past two years. My driveway and street aren’t melting well, I feel like I’ll fall on the ice, and it’s disgusting outside to look at. I can’t wait for spring.


.

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There's also the ever sneaky bg global warming which is occurring too.  Even the guys who don't believe in it are using trendline forecasts when making seasonal HDD forecasts which is their tacit acknowledgement that they can't ignore that contribution anymore...

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even with the jet extension, this doesn't have the same feel as December, as you still have polar flow with ridging into AK and Siberia

like this isn't really torchy as the source region is still intact, it's different from Dec where you have a straight up vortex over those regions

is it great, no, but it would still provide opportunities before the jet retracts. I can see this trending worse, but it's fine for now. then, when the jet retracts, which it will, that's when the door opens for something bigger

gfs-ensemble-all-avg-nhemi-z500_anom_1day-6940000.thumb.png.3270d06aa12a8332c55685ce1703a27a.pngcmc-ensemble-all-avg-nhemi-z500_anom_1day-6940000.thumb.png.b7f7a5d2748912b369e8440ab0263aab.pngcompday.G11Ajgj2K3.gif.15c2e5125402be2cc308be56409c52e2.gif

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14 minutes ago, Allsnow said:

Their is a lag effect 

OK, so how many days is the lag?  It's totally dependent on the pattern, speed of forcing, amplitude and interference/noise from ERW/KW  right?

 

This is the issue I have with some of this stuff because when we look at phase diagrams and h5 analogs we are often looking at 'same time' in the analog cases.  Yet, when the analog fails, there's a lag, how much is in the eye of the beholder.

 

For operational forecasting purposes, how are you supposed to beat the model with this form of forecasting?

 

Like I think we are very kind at explaining away failures with this methodology and there's no real hard and fast rule, and that's how you get into timing is wrong, which means a forecast bust.  Like this ventures into the 'oh I'm right, but wrong on timing'.  'Cold is coming eventually' and being off by 6 days isnt a good forecast...

 

How many times this winter have folks used the MJO and just flat out whiffed on the temperatures associated with the given pattern?  I think in terms of operational mid to longer range forecasting and I'm not convinced the methodology leads to more accurate results.  I've been doing this for a long time too so I have a pretty big sample size.

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2 hours ago, NittanyWx said:

There's also the ever sneaky bg global warming which is occurring too.  Even the guys who don't believe in it are using trendline forecasts when making seasonal HDD forecasts which is their tacit acknowledgement that they can't ignore that contribution anymore...

The global warming link has several components. First warmer temperatures lead to record highs across the year greatly exceeding record lows. This has been evident at numerous stations. Places like BHO have had 50 top 10 warmest months and only 1 coldest since 2010. This very high ratio is also evident across our local area. 

Next, the rapid warming of the WPAC has lead to the MJO slowing down and amplifying in phases 4-7. This is very important implications on a global scale. December 2015 marked the first time such extreme MJO 4-7 behavior was noted during such a strong El Niño. We saw a repeat during this El Niño leading to record VP anomaly amplitude in 7. During both El Niño’s double digit warm departures were noted in parts of North America. So now these competing marine heatwaves act to modulate the expression of the El Niño’s and La Ninas. We saw a similar extreme MJO interaction during the 21-22 La Niña when double digit warm departures were noted in Texas during that December. 

So the extra heat observed by the oceans has lead to non linear type changes. Where SST temperature thresholds in those regions have been surpassed leading to these standing waves getting stuck in place.

They have lead to easily recognizable model errors which great aided in the early realization that the December temperatures would greatly exceed the original long range model forecasts. 
 

There have been numerous papers published on all these topics in addition to the lagged effects of these MJO waves. The tropical marine heatwaves have had an outsized influence on our day to day weather. This research has been more fruitful so far than inquiries of this being a result of Arctic amplification and reduced sea ice. 

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This is not a shot at Paul because I understand what he's trying to do, but according to this methodology, I should've expected a ton of ridging in Alaska and Greenland next week, a big trough Aleutians into Japan and the models today have the exact opposite sign in these very important polar areas, which are of key use for how we forecast the synoptic patternImage

ECMWF-EPS_500mbHgtanom_nhemflat_f156.png?v=s7gjic

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6 minutes ago, bluewave said:

The global warming link has several components. First warmer temperatures lead to record highs across the year greatly exceeding record lows. This has been evident at numerous stations. Places like BHO have had 50 top 10 warmest months and only 1 coldest since 2010. This very high ratio is also evident across our local area. 

Next, the rapid warming of the WPAC has lead to the MJO slowing down and amplifying in phases 4-7. This is very important implications on a global scale. December 2015 marked the first time such extreme MJO 4-7 behavior was noted during such a strong El Niño. We saw a repeat during this El Niño leading to record VP anomaly amplitude in 7. During both El Niño’s double digit warm departures were noted in parts of North America. So now these competing marine heatwaves act to modulate the expression of the El Niño’s and La Ninas. We saw a similar extreme MJO interaction during the 21-22 La Niña when double digit warm departures were noted in Texas during that December. 

So the extra heat observed by the oceans has lead to non linear type changes. Where SST temperature thresholds in those regions have been surpassed leading to these standing waves getting stuck in place.

They have lead to easily recognizable model errors which great aided in the early realization that the December temperatures would greatly exceed the original long range model forecasts. 
 

There have been numerous papers published on all these topics in addition to the lagged effects of these MJO waves. The tropical marine heatwaves have had an outsized influence on our day to day weather. This research has been more fruitful so far than inquiries of this being a result of Arctic amplification and reduced sea ice. 

 

Not sure I'm really seeing that signature here for Dec, do see a Nino standing wave though and some hints of 30 day MJO cycle...

image.png.ad2cc6dcee18b2e17adc44e6dea58c67.png

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1 minute ago, NittanyWx said:

 

Not sure I'm really seeing that signature here for Dec, do see a Nino standing wave though...

image.png.ad2cc6dcee18b2e17adc44e6dea58c67.png

The standing was was a result of the El Niño interaction with the record WPAC warm pool as the VP anomalies were located further to the west than is typical for an El Niño. 

 

 

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Again, I'm not dismissing the science behind these ideas, my question is as an operational forecaster, is it actually helping you if you're wrong on key synoptic features and timing and using that as the primary basis for your forecast.

 

How you decide to forecast is your own decision and I'm up to the individual forecaster.  What I'm seeing myself is throwing into question the efficacy of it's usage for operational purposes when benchmarked as THE primary forecasting basis.

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4 minutes ago, bluewave said:

The standing was was a result of the El Niño interaction with the record WPAC warm pool as the VP anomalies were located further to the west than is typical for an El Niño. 

 

 

This is fairly similar to the 02 Nino forcing.  02 definitely didn't have the W Pac warm pool assist to the level of this year, and wasn't as warm in the east, but thought it's interesting.

2002.png

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49 minutes ago, NittanyWx said:

 

This is fairly similar to the 02 Nino forcing.  02 definitely didn't have the W Pac warm pool assist to the level of this year, and wasn't as warm in the east, but thought it's interesting.

2002.png

The typical El Niño standing wave in December is just east of the Dateline. This year it was to the west with the wave effectively becoming established in the MJO 7 region. This lead to the warmest December on record for much of North America. The pattern was more similar to the El Niño phase 7 composite than the  standard  El Niño one which isn’t as warm. The inability of seasonal models like the Euro see the MJO effect beyond a week or two lead to the significant underestimation of the December temperature anomalies in North America. This was why I began pointing out the risks to the warm side for the December forecasts back in the fall. I finally upped my December forecast to +2.5 to 5.0 around the start of December for NYC when I had positive conformation of my earlier thoughts. Also outlined the +10 or more regions in the upper Midwest to Canada. Most forecasts at this time were still much cooler and didn’t really come around to the warmer risks until later in the month. 

07F3F965-C76B-4440-BF1A-D0571D190B2E.gif.9bbb9e0ec4813faf31e3d830b915c7ec.gif

038C0E1F-8265-46D2-8118-0417C5B960C9.jpeg.ab4a39ad81476bc8827a6aa4326ec5be.jpeg

 

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A storm could impact the region Friday or Saturday. New York City, Newark, and nearby areas will pick up 1"-3" of snow. Philadelphia and a swath of central New Jersey will likely see 3"-5" with some locally higher amounts of up to 6". The central and northern Hudson Valley's will see a coating to an inch of snow.

Following the storm, the temperature will likely fall into the teens in New York City during the weekend. This weekend will likely see this winter's coldest readings so far.

Beyond that, a noticeable warming trend that could send temperatures well into the 40s across the region and even into the 50s in parts of the region will likely commence. This warm period will very likely assure that January will wind up as a warmer than normal month and Winter 2023-24 will become yet another warmer than normal winter in the New York City and Philadelphia areas.

The ENSO Region 1+2 anomaly was +0.9°C and the Region 3.4 anomaly was +1.9°C for the week centered around January 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +1.18°C and the ENSO Region 3.4 anomaly has averaged +1.95°C. A basinwide El Niño event is ongoing. The ongoing El Niño event has recently peaked.

The SOI was +19.70 today.

The preliminary Arctic Oscillation (AO) was -2.226 today. Strong blocking in the final week of November, as occurred this year, has often been followed by frequent blocking in December and January.

On January 16 the MJO was in Phase 4 at an amplitude of 2.667 (RMM). The January 15-adjusted amplitude was 2.277 (RMM).

Based on sensitivity analysis applied to the latest guidance, there is an implied 82% probability that New York City will have a warmer than normal January (1991-2020 normal). January will likely finish with a mean temperature near 35.7° (2.0° above normal).

 

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6 hours ago, rclab said:

 

 

Good morning Liberty, Allsnow. I’ve read that the oceans absorb much of the carbon output. If the oceans are sentient perhaps what is being experienced could be called justice. If they are not then the effects may be more in the realm of self fulfilling prophecy. Stay well, as always …..

Theoretically there should be a way to pump the heat out of the oceans.

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3 minutes ago, North and West said:


Wouldn’t algae theoretically do this, in the same way reforestation sequesters carbon on land?


.

A double edged sword because algae blooms can be toxic also (see red tide).

And fertilizers are also draining into the waterways resulting in more of these toxic algae blooms and causing die offs (and are also toxic to us and our pets.)

 

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Phase 4 at high amplitude during January 18 +/- 3 days for NYC:

image.png.2bf70c726b080cb458c7e04c2e59fecc.png

In this case, it appears that a strong EPO-/AO- pattern has more than offset the impact of the MJO during January 15-18, 2024. With the AO forecast to rise rapidly to strongly positive values, the cold will quickly depart (as is currently modeled beyond the coming weekend).

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