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November 2017 Discussions & Observations Thread


Rtd208

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1 hour ago, PB GFI said:

 

I wonder who the forecaster was that called for 2 inches.

I am guessing the next day was an unpleasant one in his bosses office

Back then that sort of stuff wasn't unusual.  2 inches and getting 16 maybe was but huge busts were sort of expected as regular occurrences by forecasters 

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9 hours ago, PB GFI said:

 

I wonder who the forecaster was that called for 2 inches.

I am guessing the next day was an unpleasant one in his bosses office

These type of big misses were pretty common in those days since the modeling was so poor. In any event, the northern stream is really hauling so New England may be in the best position for the day 8 potential. You can see the kicker coming into the West Coast just as the trough is amplifying over New England. We need things to back up just a few degrees further west over time.

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31 minutes ago, bluewave said:

In terms of teleconnection forecast trends in recent days, the record breaking Aleutian ridge continues to persist. So this will maintain the colder -EPO pattern.

 

eps_epo_bias.thumb.png.b59bbdb77d9c9a349cfe8170a209098d.png

 

eps_t2m_5d_anom_noram_120.thumb.png.c143e4bc5a282ea4775ba93e1612e770.png

eps_t2m_5d_anom_noram_240.thumb.png.5eef26df9127803260f2b9753cb77ce9.png

 

 

 

And it's exactly why is so hard to argue zonal and warm in the L/R the models keep having to adjust in that region.

Just 5 days ago ,many yelled AN in the 10 to 15 ,  now look.at that new 5 to 10.

It's BN after that too , will do some work on that later 

But , the error bias in the EP region  wanting to bring that Positive is amazing , just look at its correction over and over again.

BTW another Euro GFS war is brewing for Wednesday ,  the Euro has 60 and heavy rain along the coast as it late diving the trough in , the GFS snows all the way to the coastal plain.

6 days out and they are worlds apart.

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11 minutes ago, PB GFI said:

 

And it's exactly why is so hard to argue zonal and warm in the L/R the models keep having to adjust in that region.

Just 5 days ago ,many yelled AN in the 10 to 15 ,  now look.at that new 5 to 10.

It's BN after that too , will do some work on that later 

But , the error bias in the EP region  wanting to bring that Positive is amazing , just look at its correction over and over again.

BTW another Euro GFS war is brewing for Wednesday ,  the Euro has 60 and heavy rain along the coast as it late diving the trough in , the GFS snows all the way to the coastal plain.

6 days out and they are worlds apart.

Even the ensemble forecasts haven't been very good past 5 or 6 days over the past few days of forecasts with quick changes. Very hard for the models to handle all the extreme blocking in the Pacific and now near Greenland. Add a very fast Nina-like PAC Jet and the models struggle even more. 

That record breaking MJO event in late October really started the ball rolling to what we have now. It has my vote for one of the most significant November pattern changes from October of all time.

http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml

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57 minutes ago, bluewave said:

Even the ensemble forecasts haven't been very good past 5 or 6 days over the past few days of forecasts with quick changes. Very hard for the models to handle all the extreme blocking in the Pacific and now near Greenland. Add a very fast Nina-like PAC Jet and the models struggle even more. 

That record breaking MJO event in late October really started the ball rolling to what we have now. It has my vote for one of the most significant November pattern changes from October of all time.

http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml

Thanks for posting Chris.  I find animations like that to be valuable *learning tools.

Nice to see some ATL side help for the first time in what seems like forever on this side of the calendar year.

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16 hours ago, donsutherland1 said:

A lot of caution is warranted with the La Niña data. Subsequent to the last date on that chart, there were nine La Niña winters (1995-96, 1998-99, 1999-00, 2000-01, 2005-06, 2007-08, 2008-09, 2010-11, and 2011-12). Mean November-March snowfall was 31.6" and median was 27.6" in NYC.

However, perhaps the most promising factor that favored above or much above normal snowfall during a La Niña winter was the predominant state of the PDO. When the PDO was negative, snowfall was less. When it was positive, it was greater and a much higher number of years saw much above normal snowfall. Since 1949-50, there were 15 La Niña winters. Mean snowfall was 24.9" and median snowfall was 23.1". Here's how things fared when the PDO was considered:

PDO-: Mean: 19.9"; Median: 16.3"; % < 20": 60%; % 30" or more: 7%; Least: 4.5", 2011-12; Most: 61.9", 2010-11

PDO+: Mean: 39.9"; Median: 35.0"; % <20": 0%; % 30" or more: 60%; Least: 24.1", 1984-85; Most: 74.9", 1995-96

Notes:

1. All snowfall figures are for the November-March period.

2. La Niña-PDO+ combinations were infrequent. There were only five such winters (25% of the overall sample). That subset saw three winters with 30" or more snow during the November-March period. The remaining subset of such La Niña winters had only 1 such winter.

 

 

 

Don, out of curiosity how many of those La Niñas with above average snowfall were moderate or strong? The correlation I was attempting to make was between stronger enso events and below average snowfall. Also, what was the correlation at PHI and BWI as compared to NYC. I strongly believe that stronger La Niñas have greater negative impacts on snowfall for those two locations vs NYC, which has always been part of my argument. I’d be interested to take the data and calculate the standard deviation for moderate or stronger La Niña events vs the mean at BWI, PHI and NYC since 1900.

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12 hours ago, uncle W said:

if the arctic oscillation hits -4 or lower it would be very significant as far as the November ao goes...not many years had an ao hit -4 or lower...

year...Nov low ao date...winter ao low and date...

1959...-5.896 on 11/18...-4.108 on 1/28/60

1962...-3.838 on 11/17...-5.010 on 1/21/63

1968...-4.201 on 11/15...-5.282 on 2/13/69

1998...-4.123 on 11/16...-3.741 on 3/9/99

2010...-4.058 on 11/26...-5.265 on 12/18/10

I added the nao for the same date as the ao min...The nao forecast is to drop to close to -1.5...if it does 2017 will join 1959 and 2010  as the only ones to have a negative nao of -1 to go with an ao as low as -4...I added the sensible weather for NYC...only 1998 did not have the coldest temp of the month follow soon after the ao min...

year...Nov low ao date...winter ao low and date...nao on the date...weather at the time in NYC...

1959...-5.896 on 11/18...-4.108 on 1/28/60..........-1.259.................max 33 min 21 on the 18th...coldest for the month...

1962...-3.838 on 11/17...-5.010 on 1/21/63..........-0.862.................min 28 on the 19th...coldest of the month...R&S on the 18th and 20th...

1968...-4.201 on 11/15...-5.282 on 2/13/69..........-0.580.................noreaster on the 12th...rain/cool on the 17th...32 on the 21st...coldest for the month...

1998...-4.123 on 11/16...-3.741 on 3/9/99............-0.678.................cool on the 18th...only -2 from normal...

2010...-4.058 on 11/26...-5.265 on 12/18/10........-2.632.................34 min 11/27...coldest for the month...

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12 hours ago, PB GFI said:

What PAC flow are you talking about ?

The Euro connects a ridge extending from the Kara sea to the Baja.

There's a vortex in W Canada but that coming South .

You have an incredible block with a - 4 SD AO.

In the last 10 days KNYC is - 6.8 this not representative of PAC flow.

The problem is the speed of the 2 branches and finding a SW that is in a bad data spot over the pole , ( or doesnt exist ) nothing more .

If the timing is off nothing happens

Days 5 thru 13 are BN on  the EPS and thats not PAC flow either 

You’re taking what I said out of context. The timing of the short waves coming from the Pacific or however you want to word it, is what’s preventing an otherwise mostly favorable pattern from delivering a big system towards the end of next week.

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10 minutes ago, uncle W said:

I added the nao for the same date as the ao min...The nao forecast is to drop to close to -1.5...if it does 2017 will join 1959 and 2010  as the only ones to have a negative nao of -1 to go with an ao as low as -4...I added the sensible weather for NYC...only 1998 did not have the coldest temp of the month follow soon after the ao min...

year...Nov low ao date...winter ao low and date...nao on the date...weather at the time in NYC...

1959...-5.896 on 11/18...-4.108 on 1/28/60..........-1.259.................max 33 min 21 on the 18th...coldest for the month...

1962...-3.838 on 11/17...-5.010 on 1/21/63..........-0.862.................min 28 on the 19th...coldest of the month...R&S on the 18th and 20th...

1968...-4.201 on 11/15...-5.282 on 2/13/69..........-0.580.................noreaster on the 12th...rain/cool on the 17th...32 on the 21st...coldest for the month...

1998...-4.123 on 11/16...-3.741 on 3/9/99............-0.678.................cool on the 18th...only -2 from normal...

2010...-4.058 on 11/26...-5.265 on 12/18/10........-2.632.................34 min 11/27...coldest for the month...

 

Those ensuing winters were likely some of the most -AO winters on record. It's a small sample size though, and IMO I don't believe we will dive to that magnitude for the ensuing winter as far as a mean strongly negative AO/NAO. For my forecast's sake I hope I'm right, but a "positive" bust would certainly be better than the inverse.

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2 minutes ago, Isotherm said:

 

Those ensuing winters were likely some of the most -AO winters on record. It's a small sample size though, and IMO I don't believe we will dive to that magnitude for the ensuing winter as far as a mean strongly negative AO/NAO. For my forecast's sake I hope I'm right, but a "positive" bust would certainly be better than the inverse.

I hope we see at least a few bouts of a negative ao and nao this year...the -nao in 2010 was off the charts...1998 was mild to warm to just before Christmas....1959 was on the mild side until a week before Christmas...62-68 and 10 had a cold December...1998 and 1959 had some snow on the ground Christmas morning...all five years were either very cold on Christmas day or had a little snow on the ground...

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11 minutes ago, uncle W said:

I hope we see at least a few bouts of a negative ao and nao this year...the -nao in 2010 was off the charts...1998 was mild to warm to just before Christmas....1959 was on the mild side until a week before Christmas...62-68 and 10 had a cold December...1998 and 1959 had some snow on the ground Christmas morning...all five years were either very cold on Christmas day or had a little snow on the ground...

 

Agree, I'm very confident Christmas at the very least 'feels' more wintry this year versus the past several. Hopefully it looks more wintry too.

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30 minutes ago, NJwx85 said:

Don, out of curiosity how many of those La Niñas with above average snowfall were moderate or strong? The correlation I was attempting to make was between stronger enso events and below average snowfall. Also, what was the correlation at PHI and BWI as compared to NYC. I strongly believe that stronger La Niñas have greater negative impacts on snowfall for those two locations vs NYC, which has always been part of my argument. I’d be interested to take the data and calculate the standard deviation for moderate or stronger La Niña events vs the mean at BWI, PHI and NYC since 1900.

I will check this out when I get back tonight. Moderate or strong La Niñas typically have less snowfall, but those have a stronger link to a PDO-.

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the strongest La Nina winters need a negative AO if you like snow ...

strong la nina winters with an oni -0.9 or lower for DJF without blocking meant little in the way of snowfall...

the winters with the most consistent blocking on average were 1995-96, 1955-56, 1970-71, 1984-85, 2010-11...1973-74 had a lesser negative ao winter...The winters with no blocking to speak of are...1975-76, 1988-89, 1999-00, 2007-08, 1949-50, 1998-99...the only cold winter with no blocking was 1975-76...but all six with no blocking had less snow than average...the only winter with less snow than normal with blocking was 1970-71...only 1955-56, 1995-96 and 2010-11 had major blizzards and above average snowfall...

la nina winters...DJF ONI...Dec-Mar AO...A.T....min....30 day cold...snowfall...biggest snowfalls...

1973-74..............-1.7.............-0.296........35.5.....6..........32.3..........23.5"..........6.0" 4.3"

1988-89..............-1.6............+2.399........35.9.....5..........32.4............8.1"..........5.0"

1999-00..............-1.6............+0.735........36.2.....3..........26.2..........16.3"..........5.5"

1975-76..............-1.5............+0.892........34.4....-1..........27.1..........17.3"..........4.2" 4.0"

2007-08..............-1.4............+0.531........36.4...10..........35.7..........11.9"..........6.0"

1949-50..............-1.4............+0.190........37.5.....6..........31.6..........13.8"..........3.8"

1998-99..............-1.4............+0.113........38.7.....9..........31.3..........12.7"..........4.5"

1970-71..............-1.3.............-0.644.......32.1.....4..........24.2..........15.5"..........6.4"

2010-11..............-1.3.............-0.329.......32.7.....6..........28.1..........61.9"..........20.0" 19.0" 9.1" 5.0"

1995-96..............-0.9.............-1.162.......32.3.....5..........27.7..........75.6"..........20.2" 10.7" 7.9" 7.5" 4.6" 4.6" 4.1"

1955-56..............-0.9.............-0.512.......32.7.....5..........27.6..........33.5"..........11.6" 6.5" 4.2"

1984-85..............-0.9.............-1.062.......36.4....-2..........27.5..........24.1".........5.7" 4.8" 4.3" 4.1"

.................................................................................................................................................................

weak la nina or weak negative years...

1950-51..............-0.8.............-1.084.......35.9.....9..........33.0..........11.6"..........3.0"

1967-68..............-0.7.............-0.342.......31.3....-1..........25.1..........19.5"..........6.6"

2000-01..............-0.7.............-1.406.......33.5...14..........29.9..........35.0"........12.0"....6.0"....5.7"

2005-06..............-0.7.............-1.008.......37.3...14..........33.5..........40.0"........26.9"....5.8"

1971-72..............-0.7............+0.164.......35.1.....5..........28.6..........22.9"..........5.7".....5.2"

2008-09..............-0.7............+0.224.......34.2.....6..........27.9..........27.6"..........8.3".....4.5"....4.3"

2011-12..............-0.7............+0.750.......40.5...13..........37.0............7.4"..........4.2"

1954-55..............-0.6.............-0.930.......34.0.....0..........28.6..........11.5"..........3.9"

1964-65..............-0.5.............-1.070.......33.3.....9..........28.0..........24.4"..........6.3".....4.6"

1983-84..............-0.5.............-0.400.......35.2.....4..........26.1..........25.4"..........6.9".....5.1"....4.6"

1974-75..............-0.5............+0.624.......37.5...15..........33.0..........13.1"..........7.8"

1996-97..............-0.5............+0.201.......37.8.....4..........31.7..........10.0"..........3.5"

2013-14..............-0.5............+0.439.......33.0.....4..........28.5..........57.4"........12.5"...11.5"...8.0"...6.4"...5.0"...4.0"

1962-63..............-0.4.............-1.255.......30.0....-2..........25.9..........16.3"..........4.2"

1966-67..............-0.4............+0.293.......34.1.....4..........28.6..........51.5"........12.5".....9.8"...7.1"

1985-86..............-0.4.............-0.872.......33.4.....8..........31.0..........13.0"..........4.5"....4.5"

2012-13..............-0.4.............-1.838.......36.9...11..........31.5..........26.1"........11.4"....4.7"

2016-17..............-0.4............+1.108.......39.3...14..........35.5..........30.2"..........9.4"....7.6"....5.1"

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38 minutes ago, uncle W said:

I added the nao for the same date as the ao min...The nao forecast is to drop to close to -1.5...if it does 2017 will join 1959 and 2010  as the only ones to have a negative nao of -1 to go with an ao as low as -4...I added the sensible weather for NYC...only 1998 did not have the coldest temp of the month follow soon after the ao min...

year...Nov low ao date...winter ao low and date...nao on the date...weather at the time in NYC...

1959...-5.896 on 11/18...-4.108 on 1/28/60..........-1.259.................max 33 min 21 on the 18th...coldest for the month...

1962...-3.838 on 11/17...-5.010 on 1/21/63..........-0.862.................min 28 on the 19th...coldest of the month...R&S on the 18th and 20th...

1968...-4.201 on 11/15...-5.282 on 2/13/69..........-0.580.................noreaster on the 12th...rain/cool on the 17th...32 on the 21st...coldest for the month...

1998...-4.123 on 11/16...-3.741 on 3/9/99............-0.678.................cool on the 18th...only -2 from normal...

2010...-4.058 on 11/26...-5.265 on 12/18/10........-2.632.................34 min 11/27...coldest for the month...

Interestingly, 1998-99 had the only +AO on average for DJF from your list.

DJF AO:

1959-60 : -1.579

1962-63 : -1.914

1968-69 : -2.288

1998-99 : 0.648

2010-11 : -0.913

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33 minutes ago, Isotherm said:

 

Agree, I'm very confident Christmas at the very least 'feels' more wintry this year versus the past several. Hopefully it looks more wintry too.

Isotherm, Been a real long time since I can remember Region 4 being this cold....below -0.8C now, that region seemed to love to retain warmth until now. Region 3.4 has dropped like a rock too nino4.png  nino34.png

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2 hours ago, Eduardo said:

Thanks for posting Chris.  I find animations like that to be valuable *learning tools.

Nice to see some ATL side help for the first time in what seems like forever on this side of the calendar year.

This historic block near the Aleutians set a new 500 mb blocking record for the whole Northern Hemisphere November 1-16. The previous record holders were 2006 and 1959. The 2000's and especially 2010's continue to produce these extreme blocking events. 

 

17.gif.4bb1edc1bdad1321c65ea81e48179ae7.gif

06.gif.fa854584f3fb23fa8ad865d28d4c3646.gif

59.gif.d07f100fbed360edf17982ceb8e2bbd9.gif

 

 

 

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1 hour ago, NJwx85 said:

You’re taking what I said out of context. The timing of the short waves coming from the Pacific or however you want to word it, is what’s preventing an otherwise mostly favorable pattern from delivering a big system towards the end of next week.

I will tell you where the problem is , the block is a little far N.

So as these features rotate around and attempt to push the trough in , it rotates out 2 days later 

But it's not PAC related 

The timing is off in regards to snow.

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28 minutes ago, PB GFI said:

I will tell you where the problem is , the block is a little far N.

So as these features rotate around and attempt to push the trough in , it rotates out 2 days later 

But it's not PAC related 

The timing is off in regards to snow.

The block is further north due to the very fast Pac Jet cutting through underneath. Common occurrence in a fast La Nina flow. Remember how many times the Pacific didn't cooperate even with the record Atlantic block from November 20-December 24, 2010. 

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1 minute ago, bluewave said:

The block is further north due to the very fast Pac Jet through cutting through underneath. Common occurrence in a fast La Nina flow. Remember how many times the Pacific didn't cooperate even with the record Atlantic block from November 20-December 24, 2010.

it's an extention out of the Kara sea 

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4 minutes ago, bluewave said:

The block is further north due to the very fast Pac Jet cutting through underneath. Common occurrence in a fast La Nina flow. Remember how many times the Pacific didn't cooperate even with the record Atlantic block from November 20-December 24, 2010. 

Another thing to keep in mind about 2010, it was a +QBO. +QBO during a La Niña supports more blocking on the Pacific side. http://ionlyusethegfs.blogspot.com/2012/04/qbo-aleutian-high-relationship.html?m=1

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