Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

February 2020 General Discussions & Observations Thread


Rtd208
 Share

Recommended Posts

1 hour ago, bluewave said:

This +EPO /+AO pattern looks stuck in place until further notice. Just a brief Arctic shot this weekend within a continuing warm pattern. Last March saw some improvement due to the big -EPO. But who knows this year with the way things have been going.

 

why are these mild patterns so stable and last for months while cold snowy patterns only last a few weeks at most? 2010-11 is celebrated as a prolonged cold and snowy winter and it was pretty much just a 5 week deal.  And in 1995-96 we were in and out of cold and snowy weather.  Never in my memory did we have a cold snowy pattern that was anywhere close to how mild and snowless this winter has been or the likes of 1972-73, 1989-90, 1997-98, 2001-02, etc.

  • Like 1
Link to comment
Share on other sites

6 minutes ago, LibertyBell said:

I wonder what they didn't get that we got?  

I think most of the storms have been coming from the southwest and they've warmed up a bit faster in the upper levels than we have.

Interesting DC/Baltimore have a bit more than Philadephia, must have been a storm that passed to the south.

  • Like 1
Link to comment
Share on other sites

9 minutes ago, LibertyBell said:

why are these mild patterns so stable and last for months while cold snowy patterns only last a few weeks at most?

The historic December 2015 +13 departure marked a shift to this new regime. The cold and snowy 13-14 and 14-15 winters seem like they were from a whole different era. The main options since then have been warm and snowy or warm and less snowy. 

  • Like 1
Link to comment
Share on other sites

Just now, bluewave said:

The historic December 2015 +13 departure marked a shift to this new regime. The cold and snowy 13-14 and 14-15 winters seem like they were from a whole different era. The main options since them have been warm and snowy or warm and less snowy. 

2015-16 was a veritable snow and cold paradise compared to this winter lol.

  • Like 1
Link to comment
Share on other sites

1 minute ago, bluewave said:

The historic December 2015 +13 departure marked a shift to this new regime. The cold and snowy 13-14 and 14-15 winters seem like they were from a whole different era. The main options since them have been warm and snowy or warm and less snowy. 

I'm fine with warm and snowy but this is headed toward being  one of the worst winters of all time with no events of over 2 inches for the city, I feel like that would be historic?

  • Like 1
  • Sad 1
Link to comment
Share on other sites

4 minutes ago, HVSnowLover said:

I think most of the storms have been coming from the southwest and they've warmed up a bit faster in the upper levels than we have.

Interesting DC/Baltimore have a bit more than Philadephia, must have been a storm that passed to the south.

yea I dont know the snow physics down south but even Atlanta got measurable snow over the weekend.  They dont seem to be as track dependent as we are, probably because we have an annoying ocean just to our south.  Think about it, no storm track has passed to our south this entire winter.  Every single storm has tracked to our north!

 

 

Link to comment
Share on other sites

3 minutes ago, LibertyBell said:

yea I dont know the snow physics down south but even Atlanta got measurable snow over the weekend.  They dont seem to be as track dependent as we are, probably because we have an annoying ocean just to our south.  Think about it, no storm track has passed to our south this entire winter.  Every single storm has tracked to our north!

 

 

Yea there's been a few storms that tracked to the SE but I think you are right that none of them actually hit the city with meaningful precip, hence no storm over 2 inches as every storm that has produced snow has changed over (also has meant there's been basically no snow on the ground following any storm this winter)

  • Like 1
Link to comment
Share on other sites

7 minutes ago, HVSnowLover said:

Yea there's been a few storms that tracked to the SE but I think you are right that none of them actually hit the city with meaningful precip, hence no storm over 2 inches as every storm that has produced snow has changed over (also has meant there's been basically no snow on the ground following any storm this winter)

the biggest storm I can recall was that overperforming SWFE that didn't change to rain until the end, we got 2.5-3 inches here with that one.

Link to comment
Share on other sites

2 hours ago, LibertyBell said:

why are these mild patterns so stable and last for months while cold snowy patterns only last a few weeks at most? 2010-11 is celebrated as a prolonged cold and snowy winter and it was pretty much just a 5 week deal.  And in 1995-96 we were in and out of cold and snowy weather.  Never in my memory did we have a cold snowy pattern that was anywhere close to how mild and snowless this winter has been or the likes of 1972-73, 1989-90, 1997-98, 2001-02, etc.

 

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. 

 

1 hour ago, bluewave said:

^^^^^
The small area cold departures across the Northern Hemisphere were focused into Alaska and Greenland under this extreme pattern.

C037F3D7-9916-45BB-839F-50DBC7CBC641.gif.4f9b497e821ffade1d8a2511e4ae0160.gif

 

 

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.

image.thumb.png.808fb2a2fc55e7f2e505127d9d87b237.png

 

  • Like 5
Link to comment
Share on other sites

10 minutes 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.

image.thumb.png.808fb2a2fc55e7f2e505127d9d87b237.png

 

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. 

  • Like 2
Link to comment
Share on other sites

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.

  • Like 1
Link to comment
Share on other sites

24 minutes 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. 

I would feel confident making a forecast for next winter mirroring this and last winter. The pattern is incredibly persistent. Stuck. 

  • Like 2
Link to comment
Share on other sites

The next 8 days are averaging 38.5degs., or 4degs. AN.

Month to date is  +8.9[42.6].        Should be about  +6.8[40.8] by the 19th.

Amazingly, all 3 main models agree exactly on 11* for Sat. AM.    The 0Z, GFS has 20" of Snow starting the 21st.    Its average T>>>  21st.---26th is 27*!     But did it do this with or w/o the lithium?

Well the lithium bottle was empty........very next run averaging 39* and No Snow during same period.

47* here at 6am, Rain.        49* by 11am.

Link to comment
Share on other sites

NYC is currently tied with 16-17 for 6th warmest winter so far. Snowfall ranks in 9th lowest so far for the DJF met winter period. This is a little ahead of last winter which finished 7th lowest. The full seasonal snowfall from fall to spring is currently 4th lowest.
 

Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb
Click column heading to sort ascending, click again to sort descending.
Rank
Season
Mean Avg Temperature
Missing Count
1 2001-2002 41.6 0
2 2015-2016 41.0 0
3 2011-2012 40.5 0
4 1931-1932 40.2 0
5 1997-1998 39.6 0
6 2019-2020 39.3 19
- 2016-2017 39.3 0
7 1990-1991 39.1 0
8 1998-1999 38.6 0
9 1948-1949 38.5 0
10 1889-1890 38.4 0

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb
Click column heading to sort ascending, click again to sort descending.
Rank
Season
Total Snowfall 
Missing Count
1 1997-1998 0.5 0
2 1918-1919 1.1 0
3 1972-1973 2.6 0
4 1931-1932 2.7 0
5 1991-1992 3.2 0
6 2001-2002 3.5 0
7 2018-2019 3.7 0
8 2011-2012 4.5 0
9 2019-2020 4.8 19
10 1989-1990 5.0 0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.
Rank
Ending Date
Total Snowfall Oct 1 to Apr 30
Missing Count
1 1973-04-30 2.8 0
2 2002-04-30 3.5 0
3 1919-04-30 3.8 0
4 2020-04-30 4.8 81
5 1901-04-30 5.1 2
6 1932-04-30 5.3 0
7 1998-04-30 5.5 0
8 2012-04-30 7.4 0
9 1989-04-30 8.1 0
- 1878-04-30 8.1 0
10 1951-04-30 9.3 0
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...