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January 2016 Disco/Obs: A New Year, A New Pattern


Rjay

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wes agrees

https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/01/07/two-week-outlook-abnormally-warm-to-wintry-cold-and-the-slightest-hint-of-snow/

"The pattern is close to being a good one for snow in the D.C. area, but is still lacking an important feature: upper level low pressure around Nova Scotia."

"In fact, neither the GFS nor the European model are even hinting at this very important Nova Scotia low pressure during our period in question. Both models do seem to suggest that a storm will dig up into our region from the south. Both the Arctic and North Atlantic Oscillations are strongly negative, which often helps our chances for getting snow by forcing the storm track to the south.

But the extent of the high pressure centered over Greenland is disconcerting. The oval below defines where an upper level low or trough is usually located 24 hours before a major snowstorm. In this scenario, it’s looking a little too red in Nova Scoatia for Washington snow."

i know it's DC but we need help too

What Wes is posting would be beneficial to the DC area and south though.

Our area could be too north.

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Euro ensembles have the mean off the New england coast for next weeks storm and near the benchmark for the 16-17. Way different than the op.

I suggest you do not get your expectations up too much, otherwise you will probably be disappointed.  It's been stated here and elsewhere many times..there is little confidence in long range weather forecasting and in particular snow storm forecasts.  I agree that the indexes have come into alignment but there is more to that in getting the snow storms..

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I don't know, I've been of the idea that a generally AN pattern would continue with this powerful El Niño as long as we didn't get a decent -nao. Well now it looks like we might just get it. If we do anywhere near depicted I think we'd be hard pressed not to cash in. I'm not sure why the talk of pacific origin airmass. We have a fairly decent ridge in west modeled and sub 500mb heights with near -30 850 mb temps modeled to park to our west. I'll take my shot that with that block and enough cold to work with one of these systems will work out for NYC and the coast.

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I suggest you do not get your expectations up too much, otherwise you will probably be disappointed. It's been stated here and elsewhere many times..there is little confidence in long range weather forecasting and in particular snow storm forecasts. I agree that the indexes have come into alignment but there is more to that in getting the snow storms..

I like the pattern moving forward for cold and snow. I think the pattern will produce. Models are signaling a big greenland block. We havent seen that in a long time.

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PB, do any 12z ensembles support daytime highs in the 20s for NYC at any point during this month?

 

 

Even if they did , you have to ignore any BL/mid level temps this far out . It is 10 days away and the interaction between that block and how that energy gets directed here is so far away its going to take take to determine all of that  .

 

I will not touch this outside 5 days other than to say it is a good enough set up to start with.

 

 

Wes Junker 

But the extent of the high pressure centered over Greenland is disconcerting. The oval below defines where an upper level low or trough is usually located 24 hours before a major snowstorm. In this scenario, it’s looking a little too red in Nova Scoatia for Washington snow."

 

 

At day 10 how those anomalies will pulse or retrograde as we get closer and will sort those details out . But these are model means 240 hours away .Closer in specific members will start to give you a clearer picture .

 

POTENTIAL yes ... CAUTION  too... 

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Its no secret the Op Euro has had cutter issues after 144 hours ever since its upgrade so that does not surprise me.  Some of our more significant events the last 4 winters the Euro has shown as a cutter beyond Day 5.

 

Our actual weather is having cutter issues too.

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Even if they did , you have to ignore any BL/mid level temps this far out . It is 10 days away and the interaction between that block and how that energy gets directed here is so far away its going to take take to determine all of that  .

 

I will not touch this outside 5 days other than to say it is a good enough set up to start with.

 

 

Wes Junker 

But the extent of the high pressure centered over Greenland is disconcerting. The oval below defines where an upper level low or trough is usually located 24 hours before a major snowstorm. In this scenario, it’s looking a little too red in Nova Scoatia for Washington snow."

 

 

At day 10 how those anomalies will pulse or retrograde as we get closer and will sort those details out . But these are model means 240 hours away .Closer in specific members will start to give you a clearer picture .

 

POTENTIAL yes ... CAUTION  too... 

 

 

This pattern is capable of  producing that kind of GFS 18z system  but please trust me there will be OP runs when that ridge flexes this goes off to your south and there will be OP runs that pull the height field N and this cuts .  

 

Be very careful it is ONE OP run and even if the ensembles agree 9 days away , treat this with caution before some of you think this is the final solution .

 

We should all know better . 

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This pattern is capable of producing that kind of GFS 18z system but please trust me there will be OP runs when that ridge flexes this goes off to your south and there will be OP runs that pull the height field N and this cuts .

Be very careful it is ONE OP run and even if the ensembles agree 9 days away , treat this with caution before some of you think this is the final solution .

We should all know better .

Thanks for the explanation. Do you have the updated weeklies? I would love it if that -EPO ridge can rebuild. I have a cold air fetish.

Would rather have a massive -EPO than a massive -NAO to be honest. I hate stale cold temps in the 30s ala 2009-2010.

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Somewhat encouraging at least

 

Its just nice to see the general pattern on the models for now. I think the main things to focus on this far out is the west based blocking. That is what gives the NYC area the best storms. 

 

What the models are showing right now is just a possible outcome with the major features in place. Hopefully we see some continuity 

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As noted previously, an AO-/PNA+ pattern promotes a higher frequency of measurable snowfall events in the Mid-Atlantic region. The increase ranges from about 9% in New York City to about 22% in Washington, DC.

 

Moreover, an AO-/PNA+ pattern accounts for a larger share of snowstorms as amounts increase. Below are some statistics for New York City:

 

NYCSnowstorms_AOPNAJanuary2015.jpg
 
In the end, the longer the current AO-/PNA+ pattern holds, the more likely it is that the NYC area will see measurable snow. The kind of severe blocking that is forecast by the GFS ensembles has coincided with snowy periods in the past e.g., February 2010.
 
For now, it's too soon to try to pinpoint specific events. However, as the AO moves into a steep dive in  coming days and the PNA remains positive, the potential will exist, especially near or after mid-month.
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The 46 day Euro ensembles on balance are pretty good.

We are BN with the STJ in the SE between the 10 and 25 .

If there is 1 pull back it seems to be between the 25 and 5 th.

but again all the higher heights are in Canada and all the lower pressures are In the SE . So it's very close to N maybe a bit AN but with snow on ground and normals 39/29 it will be cold enough .

Then from the 5 thru the 28 the ridge pulls back and the SE/MA are we are open for business.

That's about N to BN stormy period.

Looks like

15 days of VG

10 days off meh (this period got pushed back from the last run )

15 days of VG

If they are correct then the story of this winter will be it's incredible turn around from DEC

This pattern gets locked in for the most part. The 1 pullback really is brief and is not really warm at all.

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i continue to not be a fan of the look on the ensembles. i want to see a stronger band of negative anomalies south of the block. compare to 58 and 2010. the current models cut off the negative height anomalies around DC and they aren't that negative. we are going to have a pac air problem regardless of everyone doing cartwheels

 

 

I think this is a very valid concern. That being said, with huge blocks such as this one, usually a strong, elongated vortex in SE Canada has to form or at least stay in that vicinity. The 18z GFS OP and 12z Euro Parallel show this scenario very well. Of course, it would be nice if more guidance consistently showed those negative anomalies, but I do think we can expect a trend towards more negative anomalies given the strength of the block, which should of course help us. 

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The 12z Euro (regular Euro) did have a nice PV in SE Canada, but it was just not oriented or located in an ideal location. If that elongates some more (certainly possible given the pressure that a strong block should "squeeze" on it), then we're in good shape.

Great to hear your thoughts Doug...nice post

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While individual storm details are a roll of the dice past 120 hrs, this is going to be

the most impressive positive to negative AO shifts on record from November-December

to January. The storm details will get worked out later.

 

If the AO can make it down to -5 or lower, then it would be the first time in January

following such a positive November and December. In fact, the only other Novembers

and Decembers with both monthly AO readings above +1.000 were 2011 and 2013.

 

Previous November and December AO values before a -5 or lower daily January reading:

 

Year.....November.....December....lowest daily January reading..positives bolded

 

62-63.....-1.112............-0.711...............-5.010

65-66.....-1.341...........+0.163...............-5.130

76-77.....-0.087...........-2.074................-7.433

84-85.....-0.966...........+0.446................-6.226

09-10.....+0.459...........-3.413................-5.533

15-16.....+1.945...........+1.444................?????

In addition to that it probably it's probably the coldest flip from Dec to Jan in over 100 years.

More importantly there's more than 1 snowstorm in this pattern over the next 15 days in the MA/NE.

An active jet is taking shape and with all those high heights it's just a matter of time before 1 or 2 make a run.

It's not a 1 and done type of pattern.

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In addition to that it probably it's probably the coldest flip from Dec to Jan in over 100 years.

More importantly there's more than 1 snowstorm in this pattern over the next 15 days in the MA/NE.

An active jet is taking shape and with all those high heights it's just a matter of time before 1 or 2 make a run.

It's not a 1 and done type of pattern.

Agree.  If we can get the storms, it could be one of the greatest 2nd half comebacks since....last year! 

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In addition to that it probably it's probably the coldest flip from Dec to Jan in over 100 years.

More importantly there's more than 1 snowstorm in this pattern over the next 15 days in the MA/NE.

An active jet is taking shape and with all those high heights it's just a matter of time before 1 or 2 make a run.

It's not a 1 and done type of pattern.

 

It was cool to watch that near to record blocking balloon over the anomalously warm SST's north of Scandinavia 

and expand across the pole tanking the AO. Parts of that region briefly saw temperatures closer to what

they normally experience during the summer.

 

Great animation

 

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

 

 

Last 30 days: Average temperature was -5.8 °C, 8.2 °C above the normal. Highest temperature was 8.7 °C (30 December), 

 

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Currently we are exactly normal for Jan.   Next 8 days figure to be +6 by the GFSx so this would put us at +3 for the month by the morning of the 16th.

http://www.nws.noaa.gov/cgi-bin/mos/getmex.pl?sta=KACY&sta=KEWR&sta=KNYC&sta=KJFK&sta=KLGA

Once again we're seeing a discrepancy between the city and the suburbs. The inability to radiate has kept temps closer to normal during this cold stretch. Even EWR has been in some cases 5-7 degrees colder at night

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Currently we are exactly normal for Jan.   Next 8 days figure to be +6 by the GFSx so this would put us at +3 for the month by the morning of the 16th.

http://www.nws.noaa.gov/cgi-bin/mos/getmex.pl?sta=KACY&sta=KEWR&sta=KNYC&sta=KJFK&sta=KLGA

 

No way we end up +6. Why do you only look at this GFSx? We are going to be AN for the next 3 days including today. Then from the 11th through the 16th (and possibly through the 19th or 20th) We will avg out BN. How does that get us to +6 in the next 8 days? You really need to look at the pattern and ALL the models and not focus soley on a model that needs a lot of work (and is playing catch-up).

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Currently we are exactly normal for Jan.   Next 8 days figure to be +6 by the GFSx so this would put us at +3 for the month by the morning of the 16th.

http://www.nws.noaa.gov/cgi-bin/mos/getmex.pl?sta=KACY&sta=KEWR&sta=KNYC&sta=KJFK&sta=KLGA

 

 

Add this to it`s plus 8 it had for the  1`st 7 days , oh wait . 

 

DPTR FM NORMAL: -0.1   A bust of 8 degrees a week away.

 

Now - they all see ( have seen ) the 4 day warm up- after that say goodbye 

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