February 2020 General Discussions & Observations Thread

[donsutherland1]

Afternoon thoughts...

1. There remains little indication that the Middle Atlantic region's growing snow drought (Washington, DC to New York City) will be dented by any significant snowfall for at least the next 7-10 days.

2. The guidance continues to differ concerning the MJO, but under most scenarios, whether the MJO will be in Phase 5 or 6 will make little difference. The AO+ should allow for warmer than normal conditions to prevail.

3. The extended range GFS idea of severe cold approaching the East and the GEFS idea of cold covering all of Canada and most of the CONUS are suspect.

4. The base case, which has support from the EPS and, to some extent the latest CFSv2 weekly guidance, is that the second half of February will wind up warmer to much warmer than normal in the Middle Atlantic and southern New England regions, even considering the short-lived shot of modified Arctic air to start that period.

 

[bluewave]

Last time that NYC dropped below 20 degrees was December 19th. Brief cool down with temperatures reaching 50 or warmer a few days before and after.

 

 

[LibertyBell]

18 hours ago, Isotherm said:

 

One essential reason is that the mean climatological pattern favors a +AO and +NAO. It's a physical, meteorological fact that it is more difficult to induce and maintain, for protracted duration, a -AO/-NAO. The prevailing polar jet flow is westerly, so the +NAO/AO is effectively an enhancement of the the prevailing, "normal" regime. A -AO/-NAO is an interruption of the mean flow. The frequency of positive AO/NAO winters is higher, actually by quite a bit, when one utilizes a large sample size. There are decadal predilections wherein a -NAO/AO can dominate -- see the late 1950s through the early 1970s, but over the long term, the frequency of +AO/NAO is higher. I just did a rough calculation, and circa 36% of winters since 1950 have been -NAO mean for DJF. So, that's a majority +NAO by a statistically significant margin. 

 

 

 

I posted this chart the other day, but it's worth a re-post now, as one bit of good news derived from this persistent +AO/NAO regime is that Arctic Sea Ice Extent has officially touched the 2000-2010 mean line -- quite impressive given how poorly we were faring sea ice wise.

 

Your measurements back my intuition.  Also it seems that positive NAO during negative NAO cycles are more likely than negative NAO during positive NAO cycles.

There's another factor that is tilted even more strongly towards less snow, which is that it isn't enough to have a negative NAO, you also need to have a west-based NAO.  That probably lowers a favorable NAO pattern for snow to even less than 36%!

We do have rare winters like 1960-61, 1993-94 and 2002-03 where you can get a lot of snow without the cooperation of a negative NAO though.  The Pacific needs to be great, which it isn't right this winter.

As per your sea ice data, is this the kind of extreme winter we're going to need to see normal sea ice coverage up north?  In other words, how do you get a pattern where it's very cold up there AND very cold down here also?  And when was the last time that happened, 1978-79?

Also how does the sunspot cycle factor into your calculations.  I am sure you are aware that we are going to reach the peak of the cycle next year, as we have extremely hot and dry summers every 11 years or so, going back to 1933, 1944, 1955, 1966, 1977, 1988, 1999, 2010, so the next one would be in 2021.  Do you think the SE Ridge flexing its muscles so strongly this winter is an early sign of the upcoming summer and especially Summer 2021 being extremely hot and dry (we get those 11 year peak heat summers with triple digit highs because the summers are dry as well as hot, a lot of rain would mute the highs.)

 

[Dan76]

One after another

[LibertyBell]

Just now, Dan76 said:

One after another

1000 trees down in the UK with Ciara (they officially name their major storms, which we should also be doing.)

Pressure down to 944 hpa there, it was 970 when it passed through here.

 

[LibertyBell]

1 hour ago, bluewave said:

More quick flights coming up.

 

whats the record for there, Chris?  This last one was 944 there!

 

[LibertyBell]

1 hour ago, bluewave said:

More quick flights coming up.

 

Even stronger on the latest run (918 hPA)

 

 

[forkyfork]

18 hours ago, Isotherm said:

I posted this chart the other day, but it's worth a re-post now, as one bit of good news derived from this persistent +AO/NAO regime is that Arctic Sea Ice Extent has officially touched the 2000-2010 mean line -- quite impressive given how poorly we were faring sea ice wise.

volume is still well below that line which means it's thin ice

[LibertyBell]

18 hours ago, weatherpruf said:

But we still found ways in the past to snow at times with the positive NAO, correct? I do not remember insects flying around outside, ever, before recent years, in mid winter. And grass wasn't green like it is now. And we never got anywhere near 80 in midwinter. We'd still get piddly 2-4 events from time to time, and the higher elevations of course had more. We really started to see bland winters in the 90's with warmer temps, outside of some notable anomalies ( 94 and 96 ). Then something happened in the 2000's and we started getting monster storms. That could be over for awhile. 

we got monster storms, but that was because we've been having wetter years, the winters haven't gotten colder.

But if you want to talk about insects and ticks in winter, remember Feb 2018 I think it was, when we hit 80?!  

[LibertyBell]

Just now, forkyfork said:

volume is still well below that line which means it's thin ice

so people are going to fall through the ice up there and die, just like they've been doing down here :-(

 

[LibertyBell]

18 hours ago, donsutherland1 said:

The growing snow drought continued in the Middle Atlantic region. Instead, above normal temperatures and periods of rain prevailed today.

Milder conditions will likely continue through Thursday. Afterward, a short-lived push of cold air could occur during the second half of the coming week into the weekend. Unlike with the prior Friday-Saturday cold shot, modified Arctic air will be involved, so minimum temperatures could fall into the teens in New York City and lower teens and perhaps single digits outside the City during the height of the cold.

Afterward, warmer air will quickly return. It is likely that the February 15-21 period will be warmer than normal overall.

Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first two weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm.

Winter 2019-2020 has become the 24th winter on record that has seen New York City receive less than 6" seasonal snowfall through February 10. Mean total snowfall for the 23 prior cases was 15.3" vs. the historic mean figure of 28.8". In addition, 30% of such winters wound up with less than 10" seasonal snowfall vs. 6% of winters in the historic record. 78% of such winters wound up with less than 20" seasonal snowfall vs. 31% of winters in the historic record. Just 13% of such winters wound up with 30" or more seasonal snowfall vs. 41% of winters in the historic record.

The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.8°C for the week centered around January 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.07°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions.

The SOI was +9.85 today.

Today, the preliminary Arctic Oscillation (AO) figure was +6.342. That figure exceeded the previous all-time record high figure of +5.911, which was set on February 26, 1990.

Near or just after mid-month, the guidance brings the MJO into Phase 6. There remains some uncertainty concerning its amplitude and duration in Phase 6. Its amplitude and the state of the teleconnections will determine the overall pattern during the start of the second half of February.

During the February 10-29 period, when the MJO is in Phase 6 at low amplitude, the state of the PNA has the largest impact on temperatures in the Middle Atlantic region. For example, in New York City, the mean temperature for PNA+ cases during the 1981-2019 period was 34.1°. For PNA- cases, it was 41.7°. In contrast, when the MJO has an amplitude of 1.000 or above, the state of the AO is more important. During such cases, the mean temperature for AO+ cases was 40.9° while the mean temperature for AO- cases was 35.5°. The mean temperature for the entire February 10-29, 1981-2019 period was 36.5°.

No significant stratospheric warming is likely through February 17, but the upper stratosphere above 5 mb will likely warm toward mid-February. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February.

On February 9, the MJO was in Phase 5 at an amplitude of 1.736 (RMM). The February 8-adjusted amplitude was 1.622.

Based on sensitivity analysis applied to the latest guidance, there is an implied 83% probability that New York City will have a warmer than normal February and an implied 54% probability that February 2020 will be among the 10 warmest such months on record.

Don, is there a list of seasons with less than 10" seasonal snowfall somewhere?  I want to see how they rank against each other.

 

[bluewave]

16 minutes ago, LibertyBell said:

Even stronger on the latest run (918 hPA)

 

 

Euro has twin 928 mb lows.

 

[LibertyBell]

3 hours ago, Juliancolton said:

That'll put the kibosh on all the leaf buds and flowering bulbs that sprouted during the last warm spell. Shame.

what will it take to put a permanent kibosh on the allergy season lol

[LibertyBell]

17 minutes ago, bluewave said:

Euro has twin 928 mb lows.

 

How will these storms impact us?  Will they be like what we had last week here?

 

[LibertyBell]

19 minutes ago, bluewave said:

Euro has twin 928 mb lows.

 

 

[LibertyBell]

rogue waves or a weather tsunami?

 

[donsutherland1]

34 minutes ago, LibertyBell said:

Don, is there a list of seasons with less than 10" seasonal snowfall somewhere?  I want to see how they rank against each other.

 

Allentown has had just 3 winters with less than 10" seasonal snowfall:

1972-73: 7.4"

1997-98: 7.7"

2001-02: 9.7"

[LibertyBell]

7 minutes ago, donsutherland1 said:

Allentown has had just 3 winters with less than 10" seasonal snowfall:

1972-73: 7.4"

1997-98: 7.7"

2001-02: 9.7"

Sorry I am on Long Island now lol.  Do you have the data for JFK and NYC, Don?

 

[Dan76]

LOL 918  

[bluewave]

That -560 meter 500 mb height anomaly on the EPS looks close to the record lowest for the North Atlantic.

 

 

[snowman19]

2 hours ago, donsutherland1 said:

Afternoon thoughts...

1. There remains little indication that the Middle Atlantic region's growing snow drought (Washington, DC to New York City) will be dented by any significant snowfall for at least the next 7-10 days.

2. The guidance continues to differ concerning the MJO, but under most scenarios, whether the MJO will be in Phase 5 or 6 will make little difference. The AO+ should allow for warmer than normal conditions to prevail.

3. The extended range GFS idea of severe cold approaching the East and the GEFS idea of cold covering all of Canada and most of the CONUS are suspect.

4. The base case, which has support from the EPS and, to some extent the latest CFSv2 weekly guidance, is that the second half of February will wind up warmer to much warmer than normal in the Middle Atlantic and southern New England regions, even considering the short-lived shot of modified Arctic air to start that period.

 

This tweet from John Homenuk (Earthlight) says it all, extremely strong stratospheric polar vortex the next 2+ weeks; as we turn the calendar to March, ++AO ++NAO -PNA/RNA +EPO. I think the fat lady is about to sing.....

 

[MJO812]

20 minutes ago, snowman19 said:

This tweet from John Homenuk (Earthlight) says it all, extremely strong stratospheric polar vortex the next 2+ weeks; as we turn the calendar to March, ++AO ++NAO -PNA/RNA +EPO. I think the fat lady is about to sing.....

 

Meanwhile areas to our north are seeing snow so this isnt a warm pattern for many.

[LibertyBell]

Just now, MJO812 said:

Meanwhile areas to our north are seeing snow so this isnt a warm pattern for many.

those places can see snow even with above normal temperatures

 

[bluewave]

33 minutes ago, LibertyBell said:

those places can see snow even with above normal temperatures

 

Imagine living an a place where you could have almost 100” of snow to date during your 4th warmest winter.

Time Series Summary for Caribou Area, ME (ThreadEx) - Dec through Feb
Click column heading to sort ascending, click again to sort descending.

Rank	Season	Mean Avg Temperature	Missing Count
1	2015-2016	21.6	0
2	2009-2010	21.0	0
3	2001-2002	19.3	0
4	2019-2020	18.2	19
5	1959-1960	17.7	0

 

Time Series Summary for Caribou Area, ME (ThreadEx) - Oct through Sep
Click column heading to sort ascending, click again to sort descending.

Season	Total Snowfall	Missing Count
2019-2020	92.8	233

[SnoSki14]

2 hours ago, Dan76 said:

LOL 918  

Latest GFS is 916

Incredible if it verifies.

[snowman19]

3 hours ago, MJO812 said:

Meanwhile areas to our north are seeing snow so this isnt a warm pattern for many.

It’s still a very warm pattern, just at that latitude and at this time of the winter, way above normal still means snow for them

[donsutherland1]

After another wet day, tomorrow will offer a brief reprieve from the precipitation. Nevertheless, more rain is likely tomorrow night into Thursday. A light accumulation of snow or sleet is possible in the far northern and western suburbs of New York City.

Milder conditions will likely continue through Thursday. Afterward, a short-lived push of cold air could occur during the second half of the coming week into the weekend. Unlike with the prior Friday-Saturday cold shot, modified Arctic air will be involved, so minimum temperatures could fall into the teens in New York City and lower teens and perhaps single digits outside the City during the height of the cold.

Afterward, warmer air will quickly return. It is likely that the February 15-21 period will be warmer than normal overall.

Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first two weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm.

The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was +0.8°C for the week centered around January 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.07°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions.

The SOI was +3.12 today.

Today, the preliminary Arctic Oscillation (AO) figure was +5.233. That figure exceeded the previous daily record high figure of +3.934, which was set in 1989.

Near or just after mid-month, the guidance brings the MJO into Phase 6. There remains some uncertainty concerning its amplitude and duration in Phase 6. Its amplitude and the state of the teleconnections will determine the overall pattern during the start of the second half of February.

During the February 10-29 period, when the MJO is in Phase 6 at low amplitude, the state of the PNA has the largest impact on temperatures in the Middle Atlantic region. For example, in New York City, the mean temperature for PNA+ cases during the 1981-2019 period was 34.1°. For PNA- cases, it was 41.7°. In contrast, when the MJO has an amplitude of 1.000 or above, the state of the AO is more important. During such cases, the mean temperature for AO+ cases was 40.9° while the mean temperature for AO- cases was 35.5°. The mean temperature for the entire February 10-29, 1981-2019 period was 36.5°.

No significant stratospheric warming is likely through February 19, but the upper stratosphere above 5 mb will likely warm toward mid-February. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February.

On February 10, the MJO was in Phase 5 at an amplitude of 1.533 (RMM). The February 9-adjusted amplitude was 1.736.

Based on sensitivity analysis applied to the latest guidance, there is an implied 87% probability that New York City will have a warmer than normal February and an implied 59% probability that February 2020 will be among the 10 warmest such months on record.

Finally, a sizable majority (>80%) of years in which the AO has been, on average, strongly positive during the first 15 days of February, as appears very likely this month, were followed by ridging in the means in part or all of the eastern CONUS during March. Therefore, a warmer than normal March appears to be a likely scenario.

[Jacob brooklyn]

9 hours ago, SnoSki14 said:

Very benign honestly. Most winters we'd see at least one single digit reading. 

And it has moderated considerably from what was shown a few days ago. I think it'll continue to moderate.

Probably mid to upper 30s Fri/Sat highs and upper teens to low 20s for lows. 

Yes. Too little too late. Of course 

[donsutherland1]

6 hours ago, LibertyBell said:

Sorry I am on Long Island now lol.  Do you have the data for JFK and NYC, Don?

 

JFK:
1972-73 1.6"
1997-98 3.6"
2011-12 3.7"
2001-02 4.5"
1994-95 7.9"
1988-89 8.2"
2006-07 8.5"
1989-90 9.6"
1996-97 9.8"

NYC:
1972-73 2.8"
2001-02 3.5"
1918-19 3.8"
1931-32 5.3"
1997-98 5.5"
2011-12 7.4"
1877-78 8.1"
1988-89 8.1"
1900-01 9.1"

[doncat]

Can't even get below 40°... 2 straight days.