December 2016 Discussion & Observations

[Ralph Wiggum]

This sure looks interesting.  

 

Michael Ventrice ‏@MJVentrice  3h3 hours ago
The latest ECMWF Ens has trended much stronger with North Pacific "Date-line" ridge that is expected to set up shop late Dec-early Jan.
 

 

Date-line ridge is too far West to help us on the EC.....unless that ridge moves poleward and pops a -AO to displace the PV into a more favorable position for us.

[PB GFI]

2 minutes ago, Ralph Wiggum said:

 

 

Date-line ridge is too far West to help us on the EC.....unless that ridge moves poleward and pops a -AO to displace the PV into a more favorable position for us.
 

 

 

 

-  EPO pushing towards the pole . That`s why the ridge on day 15 does not make sense . 

 

The DEC 8 - 21 BN period correlates very well here . 

 

Higher latitudes are going to be the deal breaker/maker . 

 

[bluewave]

We can use the rainfall tomorrow as the models have a low topped squall potential. Another year around the area with below normal precipitation.

 

http://mp1.met.psu.edu/~fxg1/NAMSFC4_12z/rloop.html

[Brian5671]

5 minutes ago, bluewave said:

We can use the rainfall tomorrow as the models have a low topped squall potential. Another year around the area with below normal precipitation.

 

http://mp1.met.psu.edu/~fxg1/NAMSFC4_12z/rloop.html

December ended up on the wetter side which helps.  Let's hope the trend continues into next year.  The water company here had to run an above ground temporary water pipe from Bridgeport to Stamford due to low water levels.

[pazzo83]

2 hours ago, Brian5671 said:

that explains why KNYC was a degree cooler in December than surrounding sites....

You'd think they'd be interested in accuracy by getting rid of some of the obstructions there.

[bluewave]

13 minutes ago, Brian5671 said:

December ended up on the wetter side which helps.  Let's hope the trend continues into next year.  The water company here had to run an above ground temporary water pipe from Bridgeport to Stamford due to low water levels.

It was quite a run of above normal precip years from 2003 to 2011. Outside events like the historic Islip deluge in 2014, things have been drier in recent years .

[bluewave]

10 minutes ago, pazzo83 said:

You'd think they'd be interested in accuracy by getting rid of some of the obstructions there.

They seemed to lose interest in that integrity of the site once the NWS moved from 30 Rock to Upton in the 1990's. I believe the NWS staff would run over 

and take the measurements for snowfall themselves. 

[Stormlover74]

23 minutes ago, bluewave said:

It was quite a run of above normal precip years from 2003 to 2011. Outside events like the historic Islip deluge in 2014, things have been drier in recent years .

We've still only managed to crack the top 10 once in the past 45 years while our top 9 have all come since then. 

 

[Brian5671]

1963, 64 and 65 having 3 of the top spots on the dry list is impressive.   Must have looked like El Paso around here.

[bluewave]

26 minutes ago, Stormlover74 said:

We've still only managed to crack the top 10 once in the past 45 years while our top 9 have all come since then. 

 

Most people that had a basement in Long Beach got flooded out by that spring 83 super Nino deluge. That stood as the biggest widespread rainfall

basement flooding event until October 2005 and August 2011.

[Stormlover74]

2 minutes ago, bluewave said:

Most people that had a basement in Long Beach got flooded out by that spring 83 super Nino deluge. That stood as the biggest widespread rainfall

basement flooding event until October 2005 and August 2011.

Yes I looked at the monthly numbers and they're just crazy. Over 32" the first 4 months of the year

[bluewave]

15 minutes ago, Stormlover74 said:

Yes I looked at the monthly numbers and they're just crazy. Over 32" the first 4 months of the year

Yeah, it has been an historic era for extreme rainfall events around the area.

 

 

[uncle W]

these are the numbers I have for Central Park precipitation...

NYC decade precipitation averages since 1870.
10 yr.............Ave. per year. lowest and highest year
1870's..............43.73"........39.25".......51.26"
1880's..............43.54"........35.37".......57.16"
1890's..............41.84"........35.37".......48.26"
1900's..............44.84"........37.44".......58.32"
1910's..............44.24"........33.72".......58.00"
1920's..............44.92"........37.76".......56.06"
1930's..............44.60"........33.85".......53.53"
1940's..............42.16"........36.24".......48.51"
1950's..............39.59"........35.58".......45.20"
1960's..............39.74"........26.09".......48.54"
1970's..............52.31"........35.29".......67.03"
1980's..............49.96"........38.11".......80.56"
1990's..............47.29"........40.42".......60.92"
2000's..............53.18"........35.92".......61.70"

2010's..............52.11"........38.51".......72.81" as of 12/31/14

 

1956-1965........36.87"........26.09".......46.39"

2002-2011........56.27"........45.21".......72.81"

1870-
2009................45.14"
1980-
2009................50.14"
1870-
1969................42.92"
1970-
2009................50.64"

 

1826-1864 from Jamiaca N.Y...1865-1868- Central Park...
years.................ave..........lowest........highest
1826-1835.......37.95"........28.78"........55.67"
1836-1845.......36.67"........32.13"........44.57"
1846-1855.......39.50"........30.08"........46.40"
1856-1865.......41.30"........31.08"........59.68"
1866-1869.......48.57"........38.26"........57.40" 4yr ave...

[CPcantmeasuresnow]

38 minutes ago, uncle W said:

these are the numbers I have for Central Park precipitation...

NYC decade precipitation averages since 1870.
10 yr.............Ave. per year. lowest and highest year
1870's..............43.73"........39.25".......51.26"
1880's..............43.54"........35.37".......57.16"
1890's..............41.84"........35.37".......48.26"
1900's..............44.84"........37.44".......58.32"
1910's..............44.24"........33.72".......58.00"
1920's..............44.92"........37.76".......56.06"
1930's..............44.60"........33.85".......53.53"
1940's..............42.16"........36.24".......48.51"
1950's..............39.59"........35.58".......45.20"
1960's..............39.74"........26.09".......48.54"
1970's..............52.31"........35.29".......67.03"
1980's..............49.96"........38.11".......80.56"
1990's..............47.29"........40.42".......60.92"
2000's..............53.18"........35.92".......61.70"

2010's..............52.11"........38.51".......72.81" as of 12/31/14

 

1956-1965........36.87"........26.09".......46.39"

2002-2011........56.27"........45.21".......72.81"

1870-
2009................45.14"
1980-
2009................50.14"
1870-
1969................42.92"
1970-
2009................50.64"

 

1826-1864 from Jamiaca N.Y...1865-1868- Central Park...
years.................ave..........lowest........highest
1826-1835.......37.95"........28.78"........55.67"
1836-1845.......36.67"........32.13"........44.57"
1846-1855.......39.50"........30.08"........46.40"
1856-1865.......41.30"........31.08"........59.68"
1866-1869.......48.57"........38.26"........57.40" 4yr ave...

Uncle, do you snowfall data for Jamaica from 1826-1864 and Central Park from 1865-1868, or did they not keep snowfall data then?

[Sundog]

As average dewpoints have been slowly creeping up over the last few decades, it's no wonder we've had wetter years on average. I assume PWATS have been on the rise on average. Of course there will be ups and downs like always though.

[pazzo83]

54 minutes ago, Sundog said:

As average dewpoints have been slowly creeping up over the last few decades, it's no wonder we've had wetter years on average. I assume PWATS have been on the rise on average. Of course there will be ups and downs like always though.

Seems like upper 70s dews are a couple-times-a-year occurrence now, and 60+ dews are about what, 9 months a year?  I wonder how that looked 50 years ago.

[bluewave]

27 minutes ago, pazzo83 said:

Seems like upper 70s dews are a couple-times-a-year occurrence now, and 60+ dews are about what, 9 months a year?  I wonder how that looked 50 years ago.

You can see the steady rise since 1980. This link only covers summer.

http://www.climatecentral.org/gallery/graphics/summers-getting-muggier-as-dewpoint-temp-rises

[pazzo83]

9 minutes ago, bluewave said:

You can see the steady rise since 1980. This link only covers summer.

http://www.climatecentral.org/gallery/graphics/summers-getting-muggier-as-dewpoint-temp-rises

Yup, and generally it seems the changes are more pronounced the further north you go.

[Sundog]

16 minutes ago, pazzo83 said:

Yup, and generally it seems the changes are more pronounced the further north you go.

Indeed. Farther north you would be traditionally drier and farther south they were already pretty humid. Just like positive temp departures being more extreme farther from the tropics, it seems dewpoint changes are following a similar path over time. 

[JerseyWx]

30 minutes ago, bluewave said:

You can see the steady rise since 1980. This link only covers summer.

http://www.climatecentral.org/gallery/graphics/summers-getting-muggier-as-dewpoint-temp-rises

That's pretty incredible for 35 years.  I'd like to see this for the NYC Metro.

[nzucker]

32 minutes ago, bluewave said:

You can see the steady rise since 1980. This link only covers summer.

http://www.climatecentral.org/gallery/graphics/summers-getting-muggier-as-dewpoint-temp-rises

It looks as if the average summer dewpoint in NYC has risen about 2F in the last 35 years. The change is more pronounced in arid climates like Las Vegas where the average dewpoint has risen 8F. Caution is needed, however, as the sample size is small...we don't know if the early 80s just happened to have a dry summer pattern. Nonetheless, the trend is clearly up (more humid), which corresponds with the rising water vapor in all parts of the troposphere.

[nzucker]

3 minutes ago, JerseyWx said:

That's pretty incredible for 35 years.  I'd like to see this for the NYC Metro.

You can change the city on the chart...New York has gone up much less, but still about 2F in 35 years. The average summer dewpoint here has gone up from 63.5F in 1980 to almost 66F in 2015. The differences will obviously be smaller in an already humid climate (The dewpoint is already close to the temperature in NYC summers, unlike Las Vegas summers.) It is still significant, however, and explains the increase in 70+ minima. 

[JerseyWx]

8 minutes ago, nzucker said:

You can change the city on the chart...New York has gone up much less, but still about 2F in 35 years. The average summer dewpoint here has gone up from 63.5F in 1980 to almost 66F in 2015. The differences will obviously be smaller in an already humid climate (The dewpoint is already close to the temperature in NYC summers, unlike Las Vegas summers.) It is still significant, however, and explains the increase in 70+ minima. 

Yeah, much less drastic in the NYC area.  Atlantic City is a bit more noticeable and went from 62° to about 65.5°

[uncle W]

3 hours ago, CPcantmeasuresnow said:

Uncle, do you snowfall data for Jamaica from 1826-1864 and Central Park from 1865-1868, or did they not keep snowfall data then?

I don't and I'm not sure if there is any...I have newspaper accounts of snowfalls from 1836 to 1954 in the almanac thread...it looks like snowfall measurements were taken in lower Manhattan and some on rooftops in the late 1800's...

[uncle W]

2 hours ago, uncle W said:

I don't and I'm not sure if there is any...I have newspaper accounts of snowfalls from 1836 to 1954 in the almanac thread...it looks like snowfall measurements were taken in lower Manhattan and some on rooftops in the late 1800's...

the first boxing day storm on record...18" measured...how?...

http://chroniclingam...-27/ed-1/seq-1/

http://chroniclingam...-27/ed-1/seq-5/

http://chroniclingam...-27/ed-1/seq-1/

http://bklyn.newspapers.com/image/50352788

http://bklyn.newspapers.com/image/50352790

http://bklyn.newspapers.com/image/50352791

http://chroniclingamerica.loc.gov/lccn/sn83030214/1872-12-28/ed-1/seq-1/

http://chroniclingamerica.loc.gov/lccn/sn83030214/1872-12-28/ed-1/seq-5/

[uncle W]

9 hours ago, CPcantmeasuresnow said:

Uncle, do you snowfall data for Jamaica from 1826-1864 and Central Park from 1865-1868, or did they not keep snowfall data then?

this newspaper from Dec. 1872 has some old snowfall totals on the fourth column near the bottom of the page...1866-67 had three major storms...it also missed the January 1857 storm...I's a mistakes that is 140 years old...

http://chroniclingamerica.loc.gov/lccn/sn83030214/1873-01-01/ed-1/seq-1/

[Isotherm]

22 hours ago, nzucker said:

Tom, your posts are amazing, thank you. I think New England/Upstate NY had some excellent snow totals and cold anomalies in January 1976. I believe the cold was strongest near the Great Lakes and Canadian border. Feb 1976 was pretty bland, however. The same thing was true in 1971 and 1985, as well as 2009; January had a potent arctic shot, but that led to a much warmer February. Jan 28, 2009 had 6.5" in Dobbs Ferry, and Maine hit -50F...1985 had the Reagan Inauguration Outbreak...1971 was famous for cold and snow in New England.

The one commonality many of these La Nina winters had is that the cold and snow were short-lived and often did not continue into February. 75-76/73-74/70-71 were slightly below average snowfall winters in NYC, 08-09 around average. I think 20-25" is reasonable for Central Park this year.

I think the pattern is a little better than December. That EPO block looks more long duration, it is combined with a -NAO, and climo is near ideal. You may be shortchanging the pattern a bit though it is hard to pile up a lot of snow at KNYC with SWFEs and clippers, and I don't see the PNA going positive with the EPO block so far west. We want that over Fairbanks, not the Aleutians. Could be a gradient pattern.

Also agree that we don't see a full reversal like 13-14/14-15. There was stuff going on those years that hinted at a pattern change. This year we have a record cold stratosphere with low ozone, so the NAO dip may fade fast once the effecr of the Thursday storm bombing negative tilt is over.

Thank you for the kind words. Good post and I agree as well that 20-25" is reasonable for NYC. This upcoming window of opportunity will be superior to December, I concur, so let's hope we capitalize. It will be another rather short period in my opinion as the Pac / Atl are concurrently conducive for only a few days. Maybe we can get a wave to propagate SW-NE along the gradient. One aspect I'm concerned about is precisely where the baroclinic zone sets up. If geopotential heights correct more positive over the NAO domain (a distinct possibility), the SE ridge will be more of an issue, particularly in light of the westward longitude of the poleward NPAC ridge. By the way, the combined NAO+AO values have reached the top 10 list for late December in terms of the extent to which they're positive. Impressive vortex for the second consecutive winter.

[CPcantmeasuresnow]

1 hour ago, uncle W said:

this newspaper from Dec. 1872 has some old snowfall totals on the fourth column near the bottom of the page...1866-67 had three major storms...it also missed the January 1857 storm...I's a mistakes that is 140 years old...

http://chroniclingamerica.loc.gov/lccn/sn83030214/1873-01-01/ed-1/seq-1/

Would love to know what actually fell during the February 20-21 1867 storm. They record a depth of 23 inches afterward but my guess would be 30 inches or more fell if measured by todays standards.

[nzucker]

34 minutes ago, Isotherm said:

Thank you for the kind words. Good post and I agree as well that 20-25" is reasonable for NYC. This upcoming window of opportunity will be superior to December, I concur, so let's hope we capitalize. It will be another rather short period in my opinion as the Pac / Atl are concurrently conducive for only a few days. Maybe we can get a wave to propagate SW-NE along the gradient. One aspect I'm concerned about is precisely where the baroclinic zone sets up. If geopotential heights correct more positive over the NAO domain (a distinct possibility), the SE ridge will be more of an issue, particularly in light of the westward longitude of the poleward NPAC ridge. By the way, the combined NAO+AO values have reached the top 10 list for late December in terms of the extent to which they're positive. Impressive vortex for the second consecutive winter.

I'd really love to see the NAO that today's GEFS/EPS are showing at 240hrs materialize.

If that NAO block can curl west into Greenland then we may get a full reteogression of the pattern allowing the low heights to shift south and leading to a closed low over the TN/MS Valley. 

I just hope this is real and that it's not another fantasy -NAO as models have shown many times. The December NAO+AO numbers as well as the cold stratosphere lead one to pause about the veracity of the block being shown. Even if it does materialize, it may be short-lived due to the background stratospheric and global forcings(low ozone, -AAM, weak MJO).

[Rtd208]

Temp is currently 25 here.