December Forecast Discussion

[WeatherFox]

light snow on the euro at 12z for tuesday afternoon….

NAM & GFS show light rain.  NWS had PoP at 20-30 percent.   Really can't expect much from this predicted overrunning precipitation event for NYC.

[SnowGoose69]

The latest RGEM goes crazy on the overrunning Tuesday...this is getting interesting to me...the positioning of the high coupled with the isentropic lifting we're getting looks strong, this may be a surprise event, most likely inland but if we can get the precip to start early enough or the high to hold in longer to keep the coast NE on surface winds it has potential even there.

[swamplover56]

Worthy of a new thread?

[Allsnow]

NAM & GFS show light rain.  NWS had PoP at 20-30 percent.   Really can't expect much from this predicted overrunning precipitation event for NYC.

 

12z euro ens look good for 1-2 for most of the area…obv not much but better then a warm week

 

 

18z gfs looks colder to start…snow-rain…obv better nw of the city 

 

18z nam is pretty much all rain….but obv fantasy range for the nam until tomorrow 

[nzucker]

Interesting day 10 euro OP trough in the east . That was no where to be found on any of this week's ensembles for that time period.

That pattern sucks though...big +EPO with a mid level ridge over Canada, and a large, west-based +NAO with a vortex over Baffin Island.

[PB GFI]

That pattern sucks though...big +EPO with a mid level ridge over Canada, and a large, west-based +NAO with a vortex over Baffin Island.

Renegade every 3 day Troughs keep sneaking through the lakes.

Obv NE would surprise in a semi torch pattern if that happens but the next 10 days look better than the ensembles showed from a week ago for this period .

If you can get through 4 and 5 on the MJO and you don't roast u have take that as a small victory.

We should get a 7 plus day warm period. But I think we can already see what's cycling 15 days away as the MJO swings around .

I have no way of knowing if Cohen can possibly see Dec 20 to Feb 20 but man the thought of running the table at winters height would make losing a week or 2 in the beginning of Dec a complete non event.

[SnoSki14]

A bust this winter will completely redefine the research yet again as to what went wrong and it'll only improve future forecasts.

[nzucker]

Renegade every 3 day Troughs keep sneaking through the lakes.

Obv NE would surprise in a semi torch pattern if that happens but the next 10 days look better than the ensembles showed from a week ago for this period .

If you can get through 4 and 5 on the MJO and you don't roast u have take that as a small victory.

We should get a 7 plus day warm period. But I think we can already see what's cycling 15 days away as the MJO swings around .

I have no way of knowing if Cohen can possibly see Dec 20 to Feb 20 but man the thought of running the table at winters height would make losing a week or 2 in the beginning of Dec a complete non event.

Well, as modeled, the mean ridge is west of us over the Plains. That allows for some cold shots to sneak into New England and the Northeast. For the CONUS, it's a warm pattern but the biggest anomalies are to our southwest in this regime. 

 

MJO should swing into Phase 7 and 8 by mid-December, setting up a potentially wintry period. Still not sure we're going to see from the Atlantic side, however, as the NAO has been pretty hostile the past few winters. Record warm temperatures in Europe this November tells that tell well.

[SnowGoose69]

A bust this winter will completely redefine the research yet again as to what went wrong and it'll only improve future forecasts.

 

 

A bust this winter would be somewhat easy to decipher...it would likely occur due to the El Nino being too east based...sometimes its not always obvious early on that is going to occur....I don't see anything else that can really cause this winter to end up busting.

[nzucker]

A bust this winter would be somewhat easy to decipher...it would likely occur due to the El Nino being too east based...sometimes its not always obvious early on that is going to occur....I don't see anything else that can really cause this winter to end up busting.

NAO could continue to be hostile too. It's been a very east-based Scandinavia block so far this month, and the 12z ECM shows low heights continuing to dominate over Greenland and Baffin Island:

 

[SnowGoose69]

NAO could continue to be hostile too. It's been a very east-based Scandinavia block so far this month, and the 12z ECM shows low heights continuing to dominate over Greenland and Baffin Island:

 

naoeast.gif

 

The NAO would need help though for us to torch, that alone probably would not do it.

[Stormlover74]

A bust this winter will completely redefine the research yet again as to what went wrong and it'll only improve future forecasts.

Every warm/snowless winter has been a bust since winter forecasts never call for an extreme in that direction. At most you might see above normal temp below normal precip calling for below normal snowfall but never "much below"

[TauntonBlizzard2013]

A bust this winter will completely redefine the research yet again as to what went wrong and it'll only improve future forecasts.

It's early

[Guest Pamela]

Every warm/snowless winter has been a bust since winter forecasts never call for an extreme in that direction. At most you might see above normal temp below normal precip calling for below normal snowfall but never "much below"

 

Since the average annual snowfall is light to begin with, going with a forecast of "much below" normal snowfall is hardly practical from an arithmetic standpoint.  It reminds me a colloquy I had with someone years ago; they inquired if I believed Huntington to be the snowiest town on Long Island.  I replied, "It may well be; but being the snow capital of Long Island is like being the warmest town in Siberia."

[nzucker]

Since the average annual snowfall is light to begin with, going with a forecast of "much below" normal snowfall is hardly practical from an arithmetic standpoint.  It reminds me a colloquy I had with someone years ago; they inquired if I believed Huntington to be the snowiest town on Long Island.  I replied, "It may well be; but being the snow capital of Long Island is like being the warmest town in Siberia."

It's all about anomalies and standard deviations, so a forecast of well below normal snowfall could be practical in certain situations. NYC, which only averages 28" per year, can have "much below normal" snowfall just as Burlington VT, which averages 82", can. NYC has had some very non-snowy winters, 97-98 with 5.5" and 72-73 with 2.8" being two obvious examples. 

[Guest Pamela]

It's all about anomalies and standard deviations, so a forecast of well below normal snowfall could be practical in certain situations. NYC, which only averages 28" per year, can have "much below normal" snowfall just as Burlington VT, which averages 82", can. NYC has had some very non-snowy winters, 97-98 with 5.5" and 72-73 with 2.8" being two obvious examples. 

 

Don't reply to my posts after that nasty pm you sent me...calling my posts "utter crap" and saying I am "halfway to being banned."  I don't need replies from rude people like yourself.

[Doorman]

 

http://www.wpc.ncep.noaa.gov/basicwx/bawx_nav.php?imgtyp=ndfd&arrval=5&vtime=Wed_00Z&ptime=Tue_12Z&ntime=

 

THE MODELS SHOW AN ARCTIC HIGH PRESSURE CENTER CROSSING
PROGRESSIVELY FROM THE MIDWEST TO THE INTERIOR OF NEW
ENGLAND...WHICH WILL FAVOR A RATHER CLASSIC LOOKING COLD AIR
DAMMING SIGNATURE FOR ESPECIALLY THE MID-ATLANTIC ON TUESDAY. AS A
RESULT...THERE IS EXPECTED TO BE A LOCALLY ENHANCED THREAT OF
ICING FOR PORTIONS OF EASTERN WV AND WESTERN VA WHERE SHALLOW COLD
AIR WILL BECOME WELL ENTRENCHED AS MOISTURE AND FORCING ALOFT
ARRIVE WITH THE WEAK WAVE. A LOW RISK OF 0.25 INCH ICING IS
DENOTED FOR THESE AREAS. ON WEDNESDAY...THE ARCTIC HIGH OVER NEW
ENGLAND WILL HAVE MOVED OFFSHORE...BUT BROAD SOUTHWEST FLOW/WARM
ADVECTION SHOULD FAVOR SOME LIGHT PRECIPITATION INCLUDING SOME
SLEET AND FREEZING RAIN FOR ESPECIALLY THE INTERIOR OF THE
NORTHEAST...HOW EVER ICING AMOUNTS ARE ANTICIPATED TO BE BELOW A
0.25 INCH.

 

http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfhsd

[Allsnow]

00z nam now has snow to start for all Tuesday evening...not as robust or cold as the euro

[Isotherm]

It's all about anomalies and standard deviations, so a forecast of well below normal snowfall could be practical in certain situations. NYC, which only averages 28" per year, can have "much below normal" snowfall just as Burlington VT, which averages 82", can. NYC has had some very non-snowy winters, 97-98 with 5.5" and 72-73 with 2.8" being two obvious examples. 

 

 

I think the point being made was that a forecast of "much below normal" is simply superfluous given the average annual snowfall in the area. Below average would likely suffice, implicating totals probably in the 10s or 20s. Saying "much below normal" seems to limit the forecaster to final tallies of say < 15", which decreases the chance for verification. In a similar vein, this is why I used the phrase "above normal" snowfall in my winter outlook. Verification can occur whether NYC receives 32" or 62". Much above normal would lessen the probability of verification.

[nzucker]

I think the point being made was that a forecast of "much below normal" is simply superfluous given the average annual snowfall in the area. Below average would likely suffice, implicating totals probably in the 10s or 20s. Saying "much below normal" seems to limit the forecaster to final tallies of say < 15", which decreases the chance for verification. In a similar vein, this is why I used the phrase "above normal" snowfall in my winter outlook. Verification can occur whether NYC receives 32" or 62". Much above normal would lessen the probability of verification.

Yeah I see what you're saying...I mean there are some years like 72-73, 88-89, 97-98, 01-02 etc that do imply "much below normal."

 

However, snowfall is a hard variable to predict, and subject to a lot of luck, so I think a forecast of "below normal" or "above normal" is plenty sufficient given the lead time.

[WeatherFox]

00z nam now has snow to start for all Tuesday evening...not as robust or cold as the euro

Yea, briefly..but anyway surface temps predicted to be above freezing so no accumulation and a rapid change over to rain.

 

Next!

 

[SnowGoose69]

00Z RGEM very aggressive still...CAD signature has been getting stronger every run.  I would not be surprised to see this turn into a snow event for a good portion of the area...the lifting is pretty darn good...the only negative is I'd like to see the airmass in place be 5-7 degrees colder but 34/25 on the NAM at 12-14Z Tuesday AM is not bad,...we've seen these events before and they are almost always forecast to be too warm...the snow can come in earlier than expected and often because the east flow is so light with these events the warming does not occur until most of the precipitation falls.

 

[WeatherFox]

00Z RGEM very aggressive still...CAD signature has been getting stronger every run.  I would not be surprised to see this turn into a snow event for a good portion of the area...the lifting is pretty darn good...the only negative is I'd like to see the airmass in place be 5-7 degrees colder but 34/25 on the NAM at 12-14Z Tuesday AM is not bad,...we've seen these events before and they are almost always forecast to be too warm...the snow can come in earlier than expected and often because the east flow is so light with these events the warming does not occur until most of the precipitation falls.

 

I hope you are correct.  I never argue with a red tagger

[MJO812]

0Z gfs is also getting stronger and colder but not there yet for Tuesday

[uncle W]

El Nino Decembers in NYC...mei/oni years...

year...ave temp...max min snow bigsnow precipitation

1951.......38.6.......64.....8.....3.3".....3.3".....4.28"

1952.......38.4.......59...12.....7.4".....4.4".....4.12"

1953.......41.3.......63...15.......T..........T.......4.42"

1957.......40.2.......59...18.....8.7".....8.0".....5.26"

1958.......29.4.......55...12.....3.8".....3.3".....1.25"

1963.......31.2.......55...11...11.3".....6.6".....2.31"

1965.......40.5.......63...18.......T..........T.......1.72"

1968.......34.3.......60.....9.....7.0".....5.2".....4.15"

1969.......33.4.......60...14.....6.8".....6.8".....7.07"

1972.......38.5.......61...19........T.........T.......6.09"

1976.......29.9.......55.....9.....5.1".....3.1".....2.29"

1977.......35.7.......56...13.....0.4".....0.4".....5.06"

1979.......41.1.......65...20.....3.5".....3.5".....2.69"

1982.......42.8.......72...17.....3.0".....3.0".....1.47"

1986.......39.0.......59...19.....0.6".....0.6".....6.16"

1987.......39.5.......60.....8.....2.6".....2.6".....2.17"

1991.......39.6.......66...13.....0.7".....0.7".....4.26"

1994.......42.2.......65...19........T.........T.......2.90"

1997.......38.3.......54...17........T.........T.......4.27"

2002.......36.0.......60...19...11.0".....6.0".....4.06"

2003.......37.6.......58...21...19.8"...14.0".....5.42"

2004.......38.4.......59...11.....3.0".....1.8".....3.71"

2006.......43.6.......70...18........T.........T.......2.15"

2009.......35.9.......66...16...12.4"...10.9".....7.27"

 

average..37.7.......61...15.....4.6".....3.5"..............

1870-

2009.......35.6.......60...13.....5.4"................3.58"............

1950-

2013.......37.2..............................................................

16 out of 24 were mild...5 were cold...3 were near the long term average...8 were snowy...10 were not...6 were near normal...6 had a 6" or greater snowstorm...14 were wet...9 were dry...one near average...

[SnoSki14]

That's quite a potent high even if not ideal and retreating east but the CAD signal is certainly there. Not expecting more than some light freezing drizzle or sleet perhaps but that's all it takes to cause travel problems/accidents.

[CIK62]

El Nino Decembers in NYC...mei/oni years...

year...ave temp...max min snow bigsnow precipitation

1951.......38.6.......64.....8.....3.3".....3.3".....4.28"

1952.......38.4.......59...12.....7.4".....4.4".....4.12"

1953.......41.3.......63...15.......T..........T.......4.42"

1957.......40.2.......59...18.....8.7".....8.0".....5.26"

1958.......29.4.......55...12.....3.8".....3.3".....1.25"

1963.......31.2.......55...11...11.3".....6.6".....2.31"

1965.......40.5.......63...18.......T..........T.......1.72"

1968.......34.3.......60.....9.....7.0".....5.2".....4.15"

1969.......33.4.......60...14.....6.8".....6.8".....7.07"

1972.......38.5.......61...19........T.........T.......6.09"

1976.......29.9.......55.....9.....5.1".....3.1".....2.29"

1977.......35.7.......56...13.....0.4".....0.4".....5.06"

1979.......41.1.......65...20.....3.5".....3.5".....2.69"

1982.......42.8.......72...17.....3.0".....3.0".....1.47"

1986.......39.0.......59...19.....0.6".....0.6".....6.16"

1987.......39.5.......60.....8.....2.6".....2.6".....2.17"

1991.......39.6.......66...13.....0.7".....0.7".....4.26"

1994.......42.2.......65...19........T.........T.......2.90"

1997.......38.3.......54...17........T.........T.......4.27"

2002.......36.0.......60...19...11.0".....6.0".....4.06"

2003.......37.6.......58...21...19.8"...14.0".....5.42"

2004.......38.4.......59...11.....3.0".....1.8".....3.71"

2006.......43.6.......70...18........T.........T.......2.15"

2009.......35.9.......66...16...12.4"...10.9".....7.27"

 

average..37.7.......61...15.....4.6".....3.5"..............

1870-

2009.......35.6.......60...13.....5.4"................3.58"............

1950-

2013.......37.2..............................................................

16 out of 24 were mild...5 were cold...3 were near the long term average...8 were snowy...10 were not...6 were near normal...6 had a 6" or greater snowstorm...14 were wet...9 were dry...one near average...

Right now I think we have an atmosphere that is being influenced by a weak west-based El Nino event.   Can you separate out the weak, w-b El Ninos to see how they compare to the whole pack, which I assumed has e-b El Ninos too and an overall range of strenghts  for both types.   Thanks.

[Allsnow]

Yep...we snooze until mid month...next 2 weeks look horrible for snow chances

[REDMK6GLI]

Yep...we snooze until mid month...next 2 weeks look horrible for snow chances

Agreed looks like post dec.15-20th may give us our hope for our first met winter widespread over the tristate area including the coast

[NEG NAO]

Yep...we snooze until mid month...next 2 weeks look horrible for snow chances

which if you think about it it is a good thing - gives the ocean some time to cool down and we will be entering a more favorable  climatological period for snowfall in the metro the second half of the month and it would be just in time for Christmas.