January 2020 General Discussions & Observations Thread

[SnoSki14]

Going off a day 11-15 ensemble is not something I'd depend on. 

The only thing that's been verifying is a stronger than progged SE ridge and I don't see that changing with the highly unfavorable Pacific & MJO. 

Any colder than normal weather won't happen until Feb assuming the MJO doesn't get stuck. Feb will likely be much colder than Jan (not difficult if January is +6 or better) though it could still be AN.

I like raindancewx's analysis about how the months are mimicking what we saw in late summer and fall. 

[MJO812]

11 minutes ago, SnoSki14 said:

Going off a day 11-15 ensemble is not something I'd depend on. 

The only thing that's been verifying is a stronger than progged SE ridge and I don't see that changing with the highly unfavorable Pacific & MJO. 

Any colder than normal weather won't happen until Feb assuming the MJO doesn't get stuck. Feb will likely be much colder than Jan (not difficult if January is +6 or better) though it could still be AN.

I like raindancewx's analysis about how the months are mimicking what we saw in late summer and fall. 

What?

[Zelocita Weather]

18z GFS, wow! Someone in NJ going to be pleasantly surprised Tom night/Wed

 

[HVSnowLover]

20 minutes ago, Zelocita Weather said:

18z GFS, wow! Someone in NJ going to be pleasantly surprised Tom night/Wed

 

GFS keeps flirting with making this interesting up to NYC but I feel like it's a tease

[bluewave]

We definitely liked the SSW that produced the record snows in March 2018 better.

 

[HVSnowLover]

There's definitely cold air around, this weekends storm is showing that, we are just a bit too far south to access it in this pattern. 

[Allsnow]

Snowfall this morning.

Knyc 0.2

Lga 0.7

Jfk 0.3

Ewr 0.9 

 

[David-LI]

What are these models WRF-ARW? No idea how good they are but this ARW 2 has a nice snow event for everyone.

[donsutherland1]

A weak disturbance coated parts of the region with snow earlier today. Snowfall amounts included: Basking Ridge, NJ: 0.8"; Bridgeport: Trace; Islip: Trace; New York City: 0.2"; and, Newark: 0.9".

Following the light snowfall, temperatures rose into the middle 40s.

It is now all but certain that New York City will have a mean temperature of 40° or above during the first week of the month. Since 1869, there were 23 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 Wednesday and Thursday. Ahead of the cold shot, a system will likely bring precipitation to the region from tomorrow into Wednesday. Parts of the area could pick up a light snowfall, though most of the region will likely see little or no accumulation. A greater chance for 2" or more snow exists for parts of Virginia, Maryland, Delaware, and southern New Jersey.

The light snowfall scenario 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. 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.

Despite continuing 500 mb differences in the extended range, there remains strong consensus between the EPS and GEFS that the PNA will remain negative to strongly negative past mid-month. Such a scenario would lead to a continuation of a generally mild pattern beyond mid-month. Transient cold shots would be possible.

A PNA- typically translates in warm anomalies in the Middle Atlantic region. For the January 16-31, 1981-2019 period, the mean temperature for New York City and Philadelphia was 32.2° and 32.1° respectively. When the PNA was negative, those values were 34.2° and 34.1° respectively. The coldest mean temperatures for PNA- periods occurred when the EPO and AO were both negative (New York City: 29.1° and Philadelphia: 28.9°). The warmest occurred when the EPO and AO were both positive (New York City: 37.9° and Philadelphia: 37.5°).

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 +18.61 today. That is the highest SOI figure since August 10, 2019 when the SOI was +20.15.

Today, the preliminary Arctic Oscillation (AO) figure was +3.126.

No significant stratospheric warming event appears likely through January 14, several short periods of warming appear likely to develop in the upper stratosphere and then to approach or reach 5 mb over the next 10 days before fading. Wave 2 activity will remain relatively muted following the first week of the month except in the upper stratosphere where it will trigger the warming principally above 5 mb. Overall, most of the stratosphere is forecast to remain cold on the EPS.

On January 5, the MJO was in Phase 3 at an amplitude of 0.904 (RMM). The January 4-adjusted amplitude was 0.405.

Based on sensitivity analysis applied to the latest guidance, New York City has an implied 81% probability of a warmer than normal January.

[MJO812]

21z ARW have most of the members really amped up. 

 

Weird

[NYCweatherNOW]

Rap looks really north of every model at the end of its run

[NYCweatherNOW]

SREF spread

 

 

[purduewx80]

Will Wednesday's squalls be more impressive than tomorrow night's snow? Stay tuned...

[Rjay]

Thread for the 8th is open

[CIK_62]

Anyone care to verify if the CFS mean  for the 30-Day Period Jan.18-Feb.17 is a actually predicting the coldest ever such period at 17degs.BN!?    That would roughly be tantamount to 30 days starting at  10* and going up to 23*.

[CIK62]

Seems my phone has a different account/profile as indicated above.

At any rate courtesy of WxBell:

[doncat]

Already the first 6 days of the month with a +7.4° departure...that will decrease some the next few days, then well you know.

[CIK62]

The next 8 days are averaging 43degs., or about 11degs. AN.

Month to date is +8.3[41.3].       Should be about +9.9[42.3] by the 15th.

39* here at 6am.      45* by Noon.

EURO/GFS are a Trace of Snow, CMC is Zippo.       Most importantly, GFS is all BN T's starting near the 17th.      But we need a total snow cover for 10's of thousand of square miles around us to do that -17 for a 30-Day Period.

 

[bluewave]

12 hours ago, HVSnowLover said:

There's definitely cold air around, this weekends storm is showing that, we are just a bit too far south to access it in this pattern. 

Near record jet streak to our north with such an extreme temperature gradient.

 

[snowman19]

5 minutes ago, bluewave said:

Near record jet streak to our north with such an extreme temperature gradient.

 

It would appear the people who said the the models were too quick with the change to colder yesterday, were correct, they have backed down from what they were showing yesterday. Looks like a slower, post 1/21 change now..

[MJO812]

3 minutes ago, snowman19 said:

It would appear the people who said the the models were too quick with the change to colder yesterday, were correct, they have backed down from what they were showing yesterday. Looks like a slower, post 1/21 change now..

Post 1/20 has always been the change and no one backed down.

[LongBeachSurfFreak]

14 minutes ago, Snow88 said:

Post 1/20 has always been the change and no one backed down.

Just follow the trends of the last few years, even  decade. Post 1/20 has been the sweet spot. Starting with Jan 15

[bluewave]

22 minutes ago, snowman19 said:

It would appear the people who said the the models were too quick with the change to colder yesterday, were correct, they have backed down from what they were showing yesterday. Looks like a slower, post 1/21 change now..

The Jan 20-31 period will come down to the MJO and how it interacts with the pattern. Models seem to agree that we into phase 6 by the 20th. It’s always tricky trying to time out any 500 mb changes past day 10. Since model errors in the day 8-10 time frame just seem to get compounded further out in time. You can see how the SE ridge is a little stronger day 8 than the previous day 10 forecast indicated. 

New run
 

Old run

[PB-99]

1 hour ago, snowman19 said:

It would appear the people who said the the models were too quick with the change to colder yesterday, were correct, they have backed down from what they were showing yesterday. Looks like a slower, post 1/21 change now..

 

This is incorrect, Bluewave posted the difference between day 8 and day 10 ( 2 days ago ) . The EPS began to correct yesterday in the L/R

 

The LR CORRECTED TO MORE TROUGH  in the N/E in the L/R 

 

 

[PB-99]

1 hour ago, bluewave said:

The Jan 20-31 period will come down to the MJO and how it interacts with the pattern. Models seem to agree that we into phase 6 by the 20th. It’s always tricky trying to time out any 500 mb changes past day 10. Since model errors in the day 8-10 time frame just seem to get compounded further out in time. You can see how the SE ridge is a little stronger day 8 than the previous day 10 forecast indicated. 

New run
 

Old run

 

This is from 2 days ago , the LR got colder in means overnight from day 12 on The correction started yesterday. 

[LibertyBell]

On 1/5/2020 at 8:36 AM, bluewave said:

Temperatures at least reaching 60+ look like a good bet on the warmest days. But the location of the front will be critical for the exact temperatures. This is going to be an unusually wet January warm up. So the exact temperatures will probably have to wait to within 120 hrs.

Unusually wet January warm up

So yesterday was the day when we hit 72 back in 2007, which was also the anniversary of the great Jan 96 blizzard!  Is 72 the all-time monthly record for Jan, Chris?

 

[LibertyBell]

1 hour ago, bluewave said:

The Jan 20-31 period will come down to the MJO and how it interacts with the pattern. Models seem to agree that we into phase 6 by the 20th. It’s always tricky trying to time out any 500 mb changes past day 10. Since model errors in the day 8-10 time frame just seem to get compounded further out in time. You can see how the SE ridge is a little stronger day 8 than the previous day 10 forecast indicated. 

New run
 

Old run

A good thing about late Jan is that you dont need temps to be abnormally cold to get a significant snowfall event.  Storm track is essential though.

 

[LibertyBell]

1 hour ago, LongBeachSurfFreak said:

Just follow the trends of the last few years, even  decade. Post 1/20 has been the sweet spot. Starting with Jan 15

14-15 and 15-16 being cases in point.  What I find concerning though is that the mild pattern started later this time, so it might be more like 05-06 or 06-07.

 

[PB-99]

For those who love the GFS, it wants to speed towards 7 

 

[LibertyBell]

On 1/5/2020 at 8:11 AM, donsutherland1 said:

Overnight, the EPS and GEFS moved farther apart in the extended range with their 500 mb forecasts. For the GEFS, it is "Groundhog Day." Nothing more needs to be said about its forecast. The EPS begins to elongate the Aleutian High, until it reaches the Pacific Northwest. As a result, the trough over the west gets pushed eastward and the ridge in the East gets pushed eastward, as well.

For now, I continue to suspect that the pattern change will be more gradual than what is shown on the 0z EPS, especially as the EPS continues to forecast a negative PNA (perhaps a measure of some discontinuity with its 500 mb maps). The last week of January could turn colder. The progression of the MJO and state of the teleconnections will be important.

Twin "nightmare" scenarios for consideration:

1. The GEFS scores a "win." Efforts to knock down the ridge are quickly followed by a recovery of the ridge and the ridge remains resilient through the remainder of the month.

2. The pattern abruptly changes as the above normal height anomalies are rapidly elongated. However. the pattern change is short-lived as a fast Pacific jet leads to the above normal height anomalies eventually stretching across the CONUS leaving the below normal height anomalies over Canada and perhaps northern New England.

The underlying assumption is the continued strength of the polar vortex with a persistent AO+.

Interestingly enough, at 500 mb, both the EPS and GEFS remain in agreement over the fate of Europe. There, the unwelcome above-to-much above normal height anomalies will persist through the end of their forecast.

I wasn't aware of what was going in Europe, Don!  How bad is it over there?  Is there a global temp map for December?  I also heard that Australia just had its hottest and driest year on record, and it's not even close.