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January Forecast Discussion


REDMK6GLI

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This wasn't the AO outcome that we wanted to see. But kudos to the upgraded GFS

for not jumping on the stronger blocking near Greenland that the Euro was showing

a few days ago. The recent ECMWF moved toward original GFS idea of stronger PV

near Greenland. The ECMWF 276 hr forecast was provided as a free sample by WSI a

few days ago on their twitter feed.

 

 

 

I'd urge caution in looking to D 5-6+ guidance as evidence for AO variations right now, given the poor performance in this pattern. Recall model proggs from 5-6 days ago indicated a predominately +AO for the 17th-24th week. However, the reality is the AO will be averaging negative for the upcoming 5-7 day period. The SSW event (albeit minor) a couple weeks has neutralized the AO, and I'd be cautious going forward about predicting a mean +AO state considering tropical forcing changes and further perturbation / possible displacement of the stratospheric vortex in the D6-10 period.

 

 

eps_ao_00.png

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Do you just make S$%^ up ?

Do you always rely on Day 10-15 ensembles? What do they show for the period before that? I was looking at the gfs OP.

 

I never said it wasn't going to be below normal but the constant Day 10-15 stuff is too much. Why can't the focus be the next 7 days instead of in wonderland where by the way the models have had a penchant for performing terribly. 

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I'd urge caution in looking to D 5-6+ guidance as evidence for AO variations right now, given the poor performance in this pattern. Recall model proggs from 5-6 days ago indicated a predominately +AO for the 17th-24th week. However, the reality is the AO will be averaging negative for the upcoming 5-7 day period. The SSW event (albeit minor) a couple weeks has neutralized the AO, and I'd be cautious going forward about predicting a mean +AO state considering tropical forcing changes and further perturbation / possible displacement of the stratospheric vortex in the D6-10 period.

 

12z GEFS showing again an -AO at 252hr. The GEFS showing the MJO in phases 8 and 1:

 

30w007p.jpg

 

34ipq3q.jpg35a3nrn.jpg

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Once past Tuesday , Its COLD all the way %^&* through . Now stop you are embarrassing yourself .

Did I ever say we would not be below normal? And fine so be it if I am it doesn't matter.

 

Also I highly doubt anyone on here is intrigued by the cold anymore if the prospects of snow continue to elude us. We still have yet to see any legit snow threat show up thus far it's all speculation and fantasy (Yes Day 8-10 storms are still fantasy storms even if there's a model consensus).

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Did I ever say we would not be below normal? And fine so be it if I am it doesn't matter.

 

Also I highly doubt anyone on here is intrigued by the cold anymore if the prospects of snow continue to elude us. We still have yet to see any legit snow threat show up thus far it's all speculation and fantasy (Yes Day 8-10 storms are still fantasy storms even if there's a model consensus).

You will get your clipper . You will be happy

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12z GEFS showing again an -AO at 252hr. The GEFS showing the MJO in phases 8 and 1:

 

30w007p.jpg

 

34ipq3q.jpg35a3nrn.jpg

 

 

 

Yeah, take a look at this trend in the GFS ensemble mean AO forecast over the past three runs. A change of over 1 standard deviation in the D5-7 period.

 

00z:

 

 

gefs_ao_00.png

 

 

 

06z:

 

gefs_ao_06.png

 

 

 

Current / 12z run:

 

 

gefs_ao_12.png

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GFS is offering us a choice of long range fantasies.    Earlier today I mentioned the possible wide ranging snowstorm at the end of the month, but now that does not materialize and we are tempted instead with possible sub-zero temperatures.     What I don't  like is the pattern of>>> cold run equals a dry model run and the wet periods are also the warm periods.     If the teleconnections, MJO and QBO are really moving in the right direction, this would have shown up for late in the run.  Perhaps this is way of the model saying---I see the change but I do not know what to do with it.

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GFS is offering us a choice of long range fantasies. Earlier today I mentioned the possible wide ranging snowstorm at the end of the month, but now that does not materialize and we are tempted instead with possible sub-zero temperatures. What I don't like is the pattern of>>> cold run equals a dry model run and the wet periods are also the warm periods. If the teleconnections, MJO and QBO are really moving in the right direction, this would have shown up for late in the run. Perhaps this is way of the model saying---I see the change but I do not know what to do with it.

or it could also be Mother Nature telling you stop looking at the end of the month when models can even get the forecast right 60 hours out
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so far the lowest ao reading was -1.280 on December 28th 2014...If the ao gets lower than that before Spring we might see some snow and or very cold temperatures around the lowest ao date...

lowest daily winter ao value since 1950...I hope I didn't miss a date...Weather around the time for NYC...
season.......value.....date.....
1949-50......-2.854.....3/15/50......1.4" 3/14...record cold the beginning of the month...
1950-51......-4.353.....12/27/50....3" snow 12/27 and 9 degrees...the biggest snow and coldest temperature of the winter...
1951-52......-3.805.....3/4/1952....4" snow 3/2...
1952-53......-3.766.....12/27/52....12 degrees is the coldest temp. of the season...4" snow 12/31...
1953-54......-3.495.....1/30/54......cold continues...Cold snowy January...
1954-55......-3.064.....1/4/55........cold continues...
1955-56......-4.564.....2/15/56......1.4" 2/17 and 2/22...Big March snows.....
1956-57......-4.473.....2/21/57......2.6" snow 3/1...
1957-58......-4.030.....3/11/58......snow storms 3/14 and 3/21...
1958-59......-4.026.....1/7/59........cold continues...

1959-60......-4.108.....1/28/60......18 degrees 2/3 is the coldest temp for Feb...Big March cold and snow...
1960-61......-2.719.....1/10/61......greatest snowy and cold period followed 1/15-2/12...
1961-62......-4.417.....3/4/62........record cold 3/2 and the Ash Wednesday storm 3/6...
1962-63......-5.010.....1/21/63......Near record cold 1/23 and 4" snow 1/26...Biggest snow of the season...
1963-64......-4.470.....12/20/63....1.4" 12/18...6.6" 12/23-24...11 degrees 12/20 coldest for that month...January Blizzard....
1964-65......-3.973.....1/26/65......ice storm 1/24 and continued cold...
1965-66......-5.130.....1/28/66......8 degrees is the coldest temp. of the season 1/28... 7" on 1/30...
1966-67......-4.147.....12/13/66....wet snow and rain 12/13-14 is the start of two weeks of snow and cold...7" snow 12/24-25...
1967-68......-3.490.....2/7/68........8 degrees 2/11...Cold and dry continues...
1968-69......-5.282.....2/13/69......17 degrees 2/17 is the coldest temp for the month...15" of snow 2/9-10.....

1969-70......-6.365.....3/5/70........20 degrees 3/10 coldest temp for the month...4" of snow 3/29...
1970-71......-2.821.....2/6/71........12 degrees max 2/2...
1972-73......-2.044.....12/17/72...24 degrees max 12/17...
1973-74......-2.792.....12/19/73...big ice storm 12/16-17...17 degrees 12/19 is the coldest temp of the month...
1974-75......-1.695.....12/18/74...some minor cold in a mild month...one of the few times the weather was benign at the ao minimum...
1975-76......-3.262.....1/24/76......-1 degrees 1/23 is the coldest temp of the winter...1" of snow 1/23...
1976-77......-7.433.....1/15/77......-2 degrees on the 17th is the coldest temp of the winter...5" snow 1/14-15...
1977-78......-5.291.....2/5/78........10 degrees 2/5 is the coldest temperature of the season...18" snow 2/6-7....
1978-79......-4.387.....1/25/79......Very cold and snowy February....

1979-80......-3.705.....1/24/80......continued cold and dry...longest stretch of cold that winter...
1980-81......-4.318.....3/4/81........largest snowfall for the winter...8.6" 3/5...
1981-82......-3.804.....12/30/81...January 1982 was very cold and snowy...
1982-83......-3.410.....2/6/83........4" of snow 2/6 and 18" 2/11-12...
1983-84......-3.706.....3/13/84......record cold 3/10...7" snow 3/8-9...
1984-85......-6.226.....1/19/85.....4.1" of snow 1/17/85...-2 degrees 1/21 is the coldest temperature that winter...
1985-86......-3.894......2/6/86.......4.5" of snow 2/7 and 2/11...Snowiest period of the winter...
1986-87......-3.507.....3/9/87........2" snow 3/12...Near record cold 3/10...
1987-88......-2.314.....2/28/88......0.6" 2/27 is the last measurable snow...Thawing after...
1988-89......-0.318.....3/4/89........2.5" 3/6 and near record cold 3/7...

1989-90......-3.482.....12/10/89...One of the coldest Decembers on record...
1990-91......-3.381.....3/9/91.......24 degrees 3/12...benign after that...
1991-92......-2.597.....12/4/91.....0.7" 12/5...benign after that...
1992-93......-2.228.....3/2/93.......Super storm 3/13...Near record cold followed...
1993-94......-3.503.....2/24/94.....2.6" 2/23...12 degrees 2/27....
1994-95......-3.116.....3/9/95.......20 degrees 3/10 is the coldest temp for the month...
1995-96......-4.353.....12/19/95...8" of snow during a very cold period...January blizzard...
1996-97......-3.377.....12/30/96...11 degrees New Years Day....
1997-98......-4.269.....1/10/98.....14 degrees New Years day...Coldest of the winter...
1998-99......-3.856.....3/10/99......5" snow 3/14-15...17 degrees 3/8 is the coldest temp for the month...

1999-00......-2.118.....2/18/00......3" snow and ice 2/22....
2000-01......-4.854.....2/25/01......6" snow 2/22 and 17 degrees...coldest for the month...
2001-02......-3.293.....12/28/01...Coldest period of the winter followed but benign...
2002-03......-3.575.....1/22/03......7 degrees 1/24 is the coldest for the winter....
2003-04......-4.387.....1/17/04......1 degree 1/16 is the coldest temp of the season...6" of snow 1/15...Dec. .
2004-05......-4.337.....2/26/05......6" of snow 2/25 and 8" 2/29.....
2005-06......-3.569.....12/5/05......2" snow 12/4...1" 2/6 and 6" 12/9...14 degrees 12/14 is the coldest temp of the season...
2006-07......-2.184.....2/4/07........8 degrees 2/5 is the coldest for the winter...
2007-08......-2.468.....1/2/08........12 degrees 1/3 second coldest of the winter...
2008-09......-3.178.....2/3/09........4.3" 2/5 12 degrees...

2009-10......-5.821.....12/21/09...11" snow 12/19-20...16 degrees 12/18 is the coldest for the month...
2010-11......-5.172.....12/18/10...20" of snow 12/26-27...23 max on 12/14...

2011-12......-3.451.....1/28/12...4.3" of snow 1/21/12

2012-13......-5.688.....3/20/13...3.0" of snow 3/18/13...

2013-14......-2.605.....1/27/14...11" of snow 1/21...very cold on the 28th...

2014-15......-1.280.....12/28/14.....as of 1/17/15

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Days 1-5 will see a negative dip followed by a rebound back to positive days 6-10.

Both December and January will have +AO monthly readings in what was expected by 

many in October to be a strongly negative AO season.

I agree. Some statistics:

 

% of January and February cases with an AO <0:

December AO > 0: 50%

December AO < 0: 77%

All Years: 65%

 

% of January and February cases with an AO > 0

December AO > 0: 50%

December AO < 0: 23%

All Years: 33%

 

% of Winters with Both January and February AO < 0:

December AO > 0: 28%

December AO < 0: 60%

All Years: 47%

 

% of Winters with Both January and February AO > 0:

December AO > 0: 28%

December AO < 0: 6%

All Years: 17%

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The thing to watch with the cold coming up for the end of the month is where the best Pacific blocking 

sets up this time. The Arctic shot at the beginning of the month featured the strongest block in the region

just north of Alaska which is favored for our coldest days here. The recent model trends are showing

the strongest blocking near the Bering Sea which wouldn't quite rival the level of early month cold.

But we'll have to see if that changes going forward to know for sure.

 

attachicon.gifecmwf-ens_z500a_nhem_11.png

 

attachicon.gif500.gif

 

We managed -12F between the 6th thru the 10th . 4 being the lowest at KNYC .

The GFS ensembles are close .

The  Control ( although lower res ) challenges the 4 .( If there is snow on the ground or it`s not in it`s typical overdone mode ) . But there is a shot the coldest air is during that week .

post-7472-0-18636500-1421588477_thumb.pn

post-7472-0-93185900-1421588686_thumb.pn

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Yeah, it's all going to come down to where the strongest Pacific block sets up long range this time to determine

our exact departures. The lowest temperature at NYC on the 8th was 8 with a -18 on the day and

the strongest blocking north of Alaska. If the best blocking verifies back over the Bering, then I

don't think that we get quite that cold again.

 

The coldest day of 2015 in NYC so far:

1-8-15  21   8  15 -18 

8 CORRECT .KNYC

 

4 Was mine .

 

Funny that 8 happened at 1150PM so we pulled 2 single digit lows out of that .

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Days 1-5 will see a negative dip followed by a rebound back to positive days 6-10.

Both December and January will have +AO monthly readings in what was expected by 

many in October to be a strongly negative AO season.

 

 

Depending upon the evolution of the next several weeks, the DJF mean AO state could still average negative. Strongly negative, that almost certainly won't happen. But honestly, those who forecasted a "strongly negative AO" were setting themselves up for failure for the simple reason that probabilities of verification are significantly lower. It's akin to saying, "NYC will see 50"+ of snow this winter" rather than, "NYC should see above normal snowfall this winter."

 

It's difficult enough to get the modality of an index correct (positive / negative), nevermind the magnitude of the positive or negative value. This is why even in the face of strong signaling, it's best to go a bit conservative with LR forecasting.

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We're on pace to finish this month at a -3 to -4 temperature departure, well above average precipitation yet well below average snowfall for January. The stats aren't adding up and I would think eventually the snow has to catch up with the month's stats. There's still over a third of the month to go so it's highly unlikely we don't add on more snowfall to this month's total. 

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so far the lowest ao reading was -1.280 on December 28th 2014...If the ao gets lower than that before Spring we might see some snow and or very cold temperatures around the lowest ao date...

lowest daily winter ao value since 1950...I hope I didn't miss a date...Weather around the time for NYC...

season.......value.....date.....

1949-50......-2.854.....3/15/50......1.4" 3/14...record cold the beginning of the month...

1950-51......-4.353.....12/27/50....3" snow 12/27 and 9 degrees...the biggest snow and coldest temperature of the winter...

1951-52......-3.805.....3/4/1952....4" snow 3/2...

1952-53......-3.766.....12/27/52....12 degrees is the coldest temp. of the season...4" snow 12/31...

1953-54......-3.495.....1/30/54......cold continues...Cold snowy January...

1954-55......-3.064.....1/4/55........cold continues...

1955-56......-4.564.....2/15/56......1.4" 2/17 and 2/22...Big March snows.....

1956-57......-4.473.....2/21/57......2.6" snow 3/1...

1957-58......-4.030.....3/11/58......snow storms 3/14 and 3/21...

1958-59......-4.026.....1/7/59........cold continues...

1959-60......-4.108.....1/28/60......18 degrees 2/3 is the coldest temp for Feb...Big March cold and snow...

1960-61......-2.719.....1/10/61......greatest snowy and cold period followed 1/15-2/12...

1961-62......-4.417.....3/4/62........record cold 3/2 and the Ash Wednesday storm 3/6...

1962-63......-5.010.....1/21/63......Near record cold 1/23 and 4" snow 1/26...Biggest snow of the season...

1963-64......-4.470.....12/20/63....1.4" 12/18...6.6" 12/23-24...11 degrees 12/20 coldest for that month...January Blizzard....

1964-65......-3.973.....1/26/65......ice storm 1/24 and continued cold...

1965-66......-5.130.....1/28/66......8 degrees is the coldest temp. of the season 1/28... 7" on 1/30...

1966-67......-4.147.....12/13/66....wet snow and rain 12/13-14 is the start of two weeks of snow and cold...7" snow 12/24-25...

1967-68......-3.490.....2/7/68........8 degrees 2/11...Cold and dry continues...

1968-69......-5.282.....2/13/69......17 degrees 2/17 is the coldest temp for the month...15" of snow 2/9-10.....

1969-70......-6.365.....3/5/70........20 degrees 3/10 coldest temp for the month...4" of snow 3/29...

1970-71......-2.821.....2/6/71........12 degrees max 2/2...

1972-73......-2.044.....12/17/72...24 degrees max 12/17...

1973-74......-2.792.....12/19/73...big ice storm 12/16-17...17 degrees 12/19 is the coldest temp of the month...

1974-75......-1.695.....12/18/74...some minor cold in a mild month...one of the few times the weather was benign at the ao minimum...

1975-76......-3.262.....1/24/76......-1 degrees 1/23 is the coldest temp of the winter...1" of snow 1/23...

1976-77......-7.433.....1/15/77......-2 degrees on the 17th is the coldest temp of the winter...5" snow 1/14-15...

1977-78......-5.291.....2/5/78........10 degrees 2/5 is the coldest temperature of the season...18" snow 2/6-7....

1978-79......-4.387.....1/25/79......Very cold and snowy February....

1979-80......-3.705.....1/24/80......continued cold and dry...longest stretch of cold that winter...

1980-81......-4.318.....3/4/81........largest snowfall for the winter...8.6" 3/5...

1981-82......-3.804.....12/30/81...January 1982 was very cold and snowy...

1982-83......-3.410.....2/6/83........4" of snow 2/6 and 18" 2/11-12...

1983-84......-3.706.....3/13/84......record cold 3/10...7" snow 3/8-9...

1984-85......-6.226.....1/19/85.....4.1" of snow 1/17/85...-2 degrees 1/21 is the coldest temperature that winter...

1985-86......-3.894......2/6/86.......4.5" of snow 2/7 and 2/11...Snowiest period of the winter...

1986-87......-3.507.....3/9/87........2" snow 3/12...Near record cold 3/10...

1987-88......-2.314.....2/28/88......0.6" 2/27 is the last measurable snow...Thawing after...

1988-89......-0.318.....3/4/89........2.5" 3/6 and near record cold 3/7...

1989-90......-3.482.....12/10/89...One of the coldest Decembers on record...

1990-91......-3.381.....3/9/91.......24 degrees 3/12...benign after that...

1991-92......-2.597.....12/4/91.....0.7" 12/5...benign after that...

1992-93......-2.228.....3/2/93.......Super storm 3/13...Near record cold followed...

1993-94......-3.503.....2/24/94.....2.6" 2/23...12 degrees 2/27....

1994-95......-3.116.....3/9/95.......20 degrees 3/10 is the coldest temp for the month...

1995-96......-4.353.....12/19/95...8" of snow during a very cold period...January blizzard...

1996-97......-3.377.....12/30/96...11 degrees New Years Day....

1997-98......-4.269.....1/10/98.....14 degrees New Years day...Coldest of the winter...

1998-99......-3.856.....3/10/99......5" snow 3/14-15...17 degrees 3/8 is the coldest temp for the month...

1999-00......-2.118.....2/18/00......3" snow and ice 2/22....

2000-01......-4.854.....2/25/01......6" snow 2/22 and 17 degrees...coldest for the month...

2001-02......-3.293.....12/28/01...Coldest period of the winter followed but benign...

2002-03......-3.575.....1/22/03......7 degrees 1/24 is the coldest for the winter....

2003-04......-4.387.....1/17/04......1 degree 1/16 is the coldest temp of the season...6" of snow 1/15...Dec. .

2004-05......-4.337.....2/26/05......6" of snow 2/25 and 8" 2/29.....

2005-06......-3.569.....12/5/05......2" snow 12/4...1" 2/6 and 6" 12/9...14 degrees 12/14 is the coldest temp of the season...

2006-07......-2.184.....2/4/07........8 degrees 2/5 is the coldest for the winter...

2007-08......-2.468.....1/2/08........12 degrees 1/3 second coldest of the winter...

2008-09......-3.178.....2/3/09........4.3" 2/5 12 degrees...

2009-10......-5.821.....12/21/09...11" snow 12/19-20...16 degrees 12/18 is the coldest for the month...

2010-11......-5.172.....12/18/10...20" of snow 12/26-27...23 max on 12/14...

2011-12......-3.451.....1/28/12...4.3" of snow 1/21/12

2012-13......-5.688.....3/20/13...3.0" of snow 3/18/13...

2013-14......-2.605.....1/27/14...11" of snow 1/21...very cold on the 28th...

2014-15......-1.280.....12/28/14.....as of 1/17/15

Did you forget -2 on Feb. 08, 1963?

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Depending upon the evolution of the next several weeks, the DJF mean AO state could still average negative. Strongly negative, that almost certainly won't happen. But honestly, those who forecasted a "strongly negative AO" were setting themselves up for failure for the simple reason that probabilities of verification are significantly lower. It's akin to saying, "NYC will see 50"+ of snow this winter" rather than, "NYC should see above normal snowfall this winter."

 

It's difficult enough to get the modality of an index correct (positive / negative), nevermind the magnitude of the positive or negative value. This is why even in the face of strong signaling, it's best to go a bit conservative with LR forecasting.

 

Average AO Needed for the Remainder of Meteorological Winter:

 

For DJF Average AO of 0.0: -0.987

For DJF Average AO of -0.5: -2.085

For DJF Average AO of -1.0: -3.183

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