January 2020 General Discussions & Observations Thread

[PB-99]

8 minutes ago, bluewave said:

The day 10 EPS still shows a strong -PNA pattern. That’s what people are concerned about. So anything too amped could easily cut. The difference between the old and new runs at that time is the weaker -EPO than a few days ago. 

New run

Old run

 

 

 

Run to Run Day 10 adjustment in the means / More trough in the east, more ridge out west.

 

 

 

 

The PNA goes pos later in the period. The trough splits and a piece heads east.

 

Let`s not start moving the goal posts and start talking about the PNA in here, the last few days we have been talking about the squashing of the SE ridge after day 12.

Today it`s after day 10. ( this fix began 2 days ago on the EPS ) 

If you want to have another convo about the PNA we can have one, that takes longer to develop.

 

But the SE ridge that you and I have been talking about over the last couple of days is doing exactly what I said it would do, feel the effects of the trough being ejected off the WC in the LR.

 

 

 

 

 

[Doorman]

Trenton NJ for the WIN!!!!  

      war-mis-ta uh huh

 

https://climate.cod.edu/data/forecast/GEFS/2020010712/MA/GEFSMA_prec_snens_384.png

 

[PB-99]

Yes everyone the PNA stays - through day 13/14. No one is denying that, but the focus has been on the SE ridge. The EPS ejects a piece of the TPV cutting across the CONUS in the 10 -15. 

The forcing heading away from p6 may allow that trough that split in the LR and head into the lakes.

All you need is a pos tilted trough to run under all the HP the EPS is seeing in Canada day 11 - 15 and winter returns ( or appears for the 1st time for some ) . 

If LP can be sat on and as long as the wave remains pos tilted the reduction of a SE ridge may allow you to be on the right side of the barroclinic zone.

My pushback is with the winters over idea as well, nothing until mid Feb crowd.

 

That is not what the EPS and GPS are telling you in the 10 - 15.

 

 

[bluewave]

14 minutes ago, PB-99 said:

 

 

Run to Run Day 10 adjustment in the means / More trough in the east, more ridge out west.

 

 

 

 

The PNA goes pos later in the period. The trough splits and a piece heads east.

 

Let`s not start moving the goal posts and start talking about the PNA in here, the last few days we have been talking about the squashing of the SE ridge after day 12.

Today it`s after day 10. ( this fix began 2 days ago on the EPS ) 

If you want to have another convo about the PNA we can have one, that takes longer to develop.

 

But the SE ridge that you and I have been talking about over the last couple of days is doing exactly what I said it would do, feel the effects of the trough being ejected off the WC in the LR.

 

I think most on here care more about what the SE ridge does when a storm is ejecting out of the Plains and Rockies. A flatter SE ridge in the means relative to the next week was expected post phase 4-5 peak. So you need to see improvements in the EPO and PNA before things get more interesting. But you will want to see those improvements make it to day 7-8 to have more confidence in the forecast. The 
day 10-15 range is always subject to change once within the 6-10. And the the 6-10 still changes once to within days 1-5.

[PB-99]

9 minutes ago, bluewave said:

I think most on here care more about what the SE ridge does when a storm is ejecting out of the Plains and Rockies. A flatter SE ridge in the means relative to the next week was expected post phase 4-5 peak. So you need to see improvements in the EPO and PNA before things get more interesting. But you will want to see those improvements make it to day 7-8 to have more confidence in the forecast. The 
day 10-15 range is always subject to change once within the 6-10. And the the 6-10 still changes once to within days 1-5.

 

I am not advocating for the abyss, in fact prob N 2m`s in the 11-15. But in late Jan that works.  But what I do like is how the 0 line is pushed down to NC and there are some height rises over H/B.

There`s a lot of HP showing up in Canada as the trough splits away. 

So I think things get interesting after we get past the 20th. 

[PB-99]

 

Comfy. 

[BxEngine]

47 minutes ago, Brian5671 said:

you have to look at more than the models.  Surely you know that by now.   They're a tool.   Part of a package.   Just b/c a day 10 prog says x or y, that's certainly not always the end result.

Like what? What other tools are you using to debate here? This back and forth isnt going to change anyone's minds to begin with, but lets at least try to go with something other than “cuz i think it will”.

[FPizz]

8 minutes ago, PB-99 said:

 

I am not advocating for the abyss, in fact prob N 2m`s in the 11-15. But in late Jan that works.  But what I do like is how the 0 line is pushed down to NC and there are some height rises over H/B.

There`s a lot of HP showing up in Canada as the trough splits away. 

So I think things get interesting after we get past the 20th. 

If the control has any clue, many would be happy.  But that is all in fantasy la la land. 

[BxEngine]

1 hour ago, SnoSki14 said:

This is the reality that some don't seem to understand. I think any significant change is still weeks away.

We'll see if the MJO will push through. My thoughts are that latter Feb and March probably end up colder than normal similar to past few years. 

There's a nice source region of cold building to our north that should impact us eventually. Marches, like Novembers, have also skewed colder over the past several years.

Can you explain using something remotely scientific, why you believe any significant pattern change is weeks away and why the models showing a trough in the east within 10 days or so are incorrect? 

[Brian5671]

2 minutes ago, BxEngine said:

Like what? What other tools are you using to debate here? This back and forth isnt going to change anyone's minds to begin with, but lets at least try to go with something other than “cuz i think it will”.

Polar vortex-strong

Atlantic blocking-nowhere to be found

Pacific blocking-neutral to slight

PNA-negative

MJO-warm phases

-

model runs are only part of the package-if they are getting something noted above wrong the error only gets worse as one heads further out...

what I see above is not exactly what I want to see for a prolonged wintry stretch (not just temps, but snow/ice) in our area

[Doorman]

because some love huggin,,, all things Euro,

https://www.americanwx.com/bb/topic/52736-the-panic-room-winter-2019-2020/?do=findComment&comment=5414407

really enjoy the pissn contests as always..... DM 

 

 

[BxEngine]

2 minutes ago, Brian5671 said:

Polar vortex-strong

Atlantic blocking-nowhere to be found

Pacific blocking-neutral to slight

PNA-negative

MJO-warm phases

-

model runs are only part of the package-if they are getting something noted above wrong the error only gets worse as one heads further out...

what I see above is not exactly what I want to see for a prolonged wintry stretch (not just temps, but snow/ice) in our area

Ok, so lets try this. Can you explain why the models manage to show a trough over us even with no atlantic blocking, no disturbed vortex, a bad pacific, and the mjo in the warm phases? If models are only part of it, shouldnt we try to break down how the models are wrong when saying theyre wrong? 

 

Dont take offense, this isnt directed at you specifically, but one only needs to read through the monthly pages of our snowiest months to find posts saying “winter over”. Everyone blasts tony and metsfan for their at times unbelievably idiotic optimism, but plenty here do the same shit from the other side, either in a rush to be correct, or in some cases, they play debbie downer to lower their own expectations so when snow does come they create a little bubble of happiness. Lets try to at least act like we’ve been doing this hobby for long enough to sound better than grandma looking at caterpillar stripes.

[donsutherland1]

Some quick thoughts on the long-range pattern evolution...

1. The GEFS remains stuck with essentially the western trough-eastern ridge pattern.

2. The EPS appears to have accelerated the onset of a colder pattern.

Both ideas are actually problematic.

First, the base case from historical data is that the MJO will likely progress  into Phases 7 and 8 in the extended range. The GEFS idea seems not to reflect that development. The shift in the MJO, even with lags, should start manifesting itself in some hemispheric changes.

Second, in past cases where strong AO+/PNA- regimes rapidly collapsed, the period of troughing in the East was often short-lived (late January 2000 followed by February 2000 provide an illustration). Also worrisome is that strong polar vortex that is shown on the extended range of the EPS. There would be a risk that its persistence would lead to a scenario where above normal 500 mb heights are elongated and eventually stretch across the CONUS with the coldest air being bottled up mainly in Canada (with only some transient shots).

Overall, I still think a slower pattern evolution still makes more sense, especially if the MJO progresses as typically is the case following very high amplitude passage through Phase 4 during the January 5-20 period. Colder shots would be transient until perhaps the closing week of January and then more sustained cold could develop. Interestingly enough, some of the recent CFSv2 weekly forecasts show such a situation.

 

[PB-99]

15 minutes ago, Brian5671 said:

Polar vortex-strong

Atlantic blocking-nowhere to be found

Pacific blocking-neutral to slight

PNA-negative

MJO-warm phases

-

model runs are only part of the package-if they are getting something noted above wrong the error only gets worse as one heads further out...

what I see above is not exactly what I want to see for a prolonged wintry stretch (not just temps, but snow/ice) in our area

Your concerns, 

1.

 

 

2. You don`t need a -NAO in late Jan to snow on the E/C

3. a +EPO may be 1 gripe, but does not usurp the pattern. 

4. The PNA can be NEG if there`s no SE ridge and a piece of the TPV comes across the CONUS. Canada is very cold and Pos tilted troughs can produce snow.

5. Compliments of Armando.

Heading into p8 sometime after the 20th and prob p1 in early Feb.

 

 

 

 

[PB-99]

11 minutes ago, donsutherland1 said:

Some quick thoughts on the long-range pattern evolution...

1. The GEFS remains stuck with essentially the western trough-eastern ridge pattern.

2. The EPS appears to have accelerated the onset of a colder pattern.

Both ideas are actually problematic.

First, the base case from historical data is that the MJO will likely progress  into Phases 7 and 8 in the extended range. The GEFS idea seems not to reflect that development. The shift in the MJO, even with lags, should start manifesting itself in some hemispheric changes.

Second, in past cases where strong AO+/PNA- regimes rapidly collapsed, the period of troughing in the East was often short-lived (late January 2000 followed by February 2000 provide an illustration). Also worrisome is that strong polar vortex that is shown on the extended range of the EPS. There would be a risk that its persistence would lead to a scenario where above normal 500 mb heights are elongated and eventually stretch across the CONUS with the coldest air being bottled up mainly in Canada (with only some transient shots).

Overall, I still think a slower pattern evolution still makes more sense, especially if the MJO progresses as typically is the case following very high amplitude passage through Phase 4 during the January 5-20 period. Colder shots would be transient until perhaps the closing week of January and then more sustained cold could develop. Interestingly enough, some of the recent CFSv2 weekly forecasts show such a situation.

 

 

Great post. 

[rclab]

42 minutes ago, BxEngine said:

Ok, so lets try this. Can you explain why the models manage to show a trough over us even with no atlantic blocking, no disturbed vortex, a bad pacific, and the mjo in the warm phases? If models are only part of it, shouldnt we try to break down how the models are wrong when saying theyre wrong? 

 

Dont take offense, this isnt directed at you specifically, but one only needs to read through the monthly pages of our snowiest months to find posts saying “winter over”. Everyone blasts tony and metsfan for their at times unbelievably idiotic optimism, but plenty here do the same shit from the other side, either in a rush to be correct, or in some cases, they play debbie downer to lower their own expectations so when snow does come they create a little bubble of happiness. Lets try to at least act like we’ve been doing this hobby for long enough to sound better than grandma looking at caterpillar stripes.

Aw damn, I was trying so hard to find those caterpillars in my postage stamp this fall, so I could finally try a winter forecast. Oh well at least I have Grandma. As always......

[Isotherm]

1 hour ago, BxEngine said:

Like what? What other tools are you using to debate here? This back and forth isnt going to change anyone's minds to begin with, but lets at least try to go with something other than “cuz i think it will”.

 

My presumption is that your inquiry was directed at the poster you quoted, rather than a general/non-specific inquiry. If the latter -- certainly (as I'm sure you know) -- there are a multitude of indicators to employ other than [in addition to] model guidance, including veridical atmospheric phenomenon(a), which produce scientifically known, pleiotropic effects hemispherically/globally. Speaking for myself, my starting point with any medium to long range forecast is observation of certain forcing mechanisms, i.e., the existence of deep tropical convection persisting over a certain spatial domain, i.e., westerly shear stress via +QBO in the stratosphere, i.e., atmospheric momentum deposits, torque and wind-flow patterns, etc., and then using that knowledge as a basis to form judgments regarding the likely resultant z500 outcome. Then, if model guidance in the medium-long term differs from my expected outcome based upon the totality of the circumstances analysis of indicators, it is prudent to dissent from those model projections. Note: I'm only speaking generally and not with reference to the specific pattern here. However, this was to respond to the inquiry you posed re tools available to employ.

[Rjay]

11 minutes ago, Isotherm said:

 

My presumption is that your inquiry was directed at the poster you quoted, rather than a general/non-specific inquiry. If the latter -- certainly (as I'm sure you know) -- there are a multitude of indicators to employ other than [in addition to] model guidance, including veridical atmospheric phenomenon(a), which produce scientifically known, pleiotropic effects hemispherically/globally. Speaking for myself, my starting point with any medium to long range forecast is observation of certain forcing mechanisms, i.e., the existence of deep tropical convection persisting over a certain spatial domain, i.e., westerly shear stress via +QBO in the stratosphere, i.e., atmospheric momentum deposits, torque and wind-flow patterns, etc., and then using that knowledge as a basis to form judgments regarding the likely resultant z500 outcome. Then, if model guidance in the medium-long term differs from my expected outcome based upon the totality of the circumstances analysis of indicators, it is prudent to dissent from those model projections. Note: I'm only speaking generally and not with reference to the specific pattern here. However, this was to respond the inquiry you posed re tools available to employ.

 

Correct.  

[bluewave]

This is the lowest snow cover extent across the Northern Hemisphere on January 6th since 2007.

 

[MJO812]

47 minutes ago, bluewave said:

This is the lowest snow cover extent across the Northern Hemisphere on January 6th since 2007.

 

Low snow cover doesnt mean anything 

2007

[Allsnow]

5 hours ago, bluewave said:

That’s actually one of the EPS biases. It tends to be too weak with MJO 6 after phase 5. Probably another reason that we could see plenty of model volatility after phase 5.

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0862.1

 

 

I always thought it was the RMM plots with the bias, thanks for the information. Nice call on the stronger wave in p6. Looks like we might slow down a bit in that phase and get to 7 by the end of the month. 

[BxEngine]

52 minutes ago, Snow88 said:

Low snow cover doesnt mean anything 

2007

It means we have the lowest amount of snow at this point since 2007. His post wasnt discussing the future. Relax.

[MJO812]

8 minutes ago, BxEngine said:

It means we have the lowest amount of snow at this point since 2007. His post wasnt discussing the future. Relax.

I'm relaxed 

You should be also 

[donsutherland1]

A storm responsible for bringing snow to parts of the Middle Atlantic region will bring some rain and wet snow to parts of the region overnight. Parts of New Jersey and Long Island could pick up 1"-3" snow in a few spots. Most of the region will likely see 0.5" or less.

Snowfall amounts included:

Baltimore: 1.5"; Harrisburg: 2.9"; Sterling: 2.0"; and, Washington, DC (DCA): Trace (0.5" was reported in Alexandria).

New York City will finish with a mean temperature near 41.0° during the first week of January once the daily low temperature is reached near midnight. Since 1869, there were 23 prior cases when the first week of January had a mean temperature of 40° or above in New York City. In 17 (74%), January wound up warmer than normal and in 12 (52%), January had a mean temperature of 35° or above. The average monthly temperature for January for all 23 cases was 36.0° (median temperature: 35.6°).

A short-duration fairly sharp cold shot is possible tomorrow and Thursday. The approach and passage of the Arctic front could trigger snow showers and even some heavier snow squalls tomorrow.

The light snowfall unfolding today and tonight is consistent with historic experience during very strong AO+ patterns during the first half of January. Based on the forecast strongly positive AO, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first 10 days of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables).

Following the brief cold shot, ridging with warmer than normal temperatures will develop and persist through at least mid-month. There is a growing possibility that temperatures could soar into the 60s this weekend even into southern New England.

Beyond that, there is the potential that the closing part of the month could see a colder pattern develop. The progression of the MJO and state of the teleconnections will determine the pattern evolution for the second half of the month.

The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was +0.7°C for the week centered around January 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.30°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions.

The SOI was +5.00 today.

Today, the preliminary Arctic Oscillation (AO) figure was +3.662. That was the highest AO figure since December 23, 2016 when the AO was +3.807.

No significant stratospheric warming event appears likely through January 15. Following some warming, the upper stratosphere will cool late in the period. Wave 2 activity will remain suppressed through mid-January. Overall, most of the stratosphere is forecast to remain cold on the EPS.

On January 6, the MJO was in Phase 4 at an amplitude of 1.591 (RMM). The January 5-adjusted amplitude was 0.904.

Based on sensitivity analysis applied to the latest guidance, New York City has an implied 84% probability of a warmer than normal January.

[Enigma]

I think we can write off the next 2 weeks. 

[MJO812]

2 minutes ago, Enigma said:

I think we can write off the next 2 weeks. 

Definitely  next week but winter is looking to return by MLK week.

[CIK62]

The next 8 days are averaging 43degs., or about 10egs. AN.

Month to date is +8.2[41.2].       Should be about +9.1[42.1] by the 16th.

33* here at 6am.      40* by Noon.     42* by 3pm(high)  Down quickly to 37* shortly after 3:45pm.

Nothing happening till the 17th. on any model.       Tomorrow should be the first BN day of the winter.

GFS is -2 for the period of the 17th-23rd, but still no real snow event due to continued lack of phasing with polar jet.  The only warm day is when it could snow.

 

[the_other_guy]

31F for our “cold” morning

Just killed a mosquito in my kitchen

If that doesnt sum up this winter...I dont know what does

[bluewave]

NYC already in the top 10 warmest January 1st to 15th periods before the warmest temperatures arrive.

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Mean Avg Temperature Jan 1 to Jan 15	Missing Count
1	2007-01-15	46.4	0
2	1932-01-15	44.0	0
3	1950-01-15	43.6	0
4	1907-01-15	43.5	0
5	1998-01-15	43.3	0
6	2005-01-15	42.2	0
7	1937-01-15	42.1	0
8	1930-01-15	41.7	0
9	1890-01-15	41.4	0
10	2020-01-15	41.2	8

[purduewx80]