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11/13 - 11/16 Potential Storm Threat


WE GOT HIM

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In my opinion it is just an intellectual & fun exercise when we are trying to forecast weather 7 days out, especially snow events. There will always be adjustments one way or the other following models & meteorological science. You might fold now, but since you already were following this chance none of us mere mortals no for sure what will happen. If we did we would be famous. The National Weather Service holding sway with a 30% chance..

ZONE FORECAST PRODUCT

NATIONAL WEATHER SERVICE NEW YORK NY

319 PM EST FRI NOV 8 2013

...

WEDNESDAY NIGHT...MOSTLY CLOUDY. A CHANCE OF SNOW AND RAIN IN THE

EVENING...THEN A CHANCE OF SNOW AFTER MIDNIGHT. LOWS AROUND 30.

CHANCE OF PRECIPITATION 30 PERCENT.

.THURSDAY...PARTLY SUNNY. A CHANCE OF SNOW IN THE MORNING. HIGHS IN

THE LOWER 40S. CHANCE OF SNOW 30 PERCENT.

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The idea that early season snowstorms lead to a poor winter is mostly unfounded. Last year we had a 11/7 snowfall and Central Park got 26", around average. I had 52" in Westchester, which represents 130" of average. February was cold and March was frigid.

Nov 27, 2002 was also a major snowfall for SE areas and the NYC metro saw 50-60" of snowfall that winter. My town had over 60" as well as memorable cold in January. November 1995 us another example.

I think the best indication for a warm snowless winter is a dry and mild fall. This year hasn't had much precipitation but the fall is turning out cooler than many expected. September was -1, October was mild, but November has turned sharply colder with a modest cold shot thus weekend and the potential for near record cold next week. I strongly believe November finishes below normal as Tuesday through Thursday should be a string of -10 to -15 departures. NYC might not get out of the 30s Wednesday.

 

Maybe September was a tad cooler than expected although a lot of places were near normal or like -0.5, October was very warm, I'm not sure exactly what it was but I think it was in the +3 to +4 range, and it ran over +6.5 at one point which is record breaking. I am curious in how November turns out because it's definitely going to turn out somewhat colder than expected, the cold next week probably wasn't foreseen when the month began. 

 

A lot will depend what happens after mid November, but we will get some strong negative departures in the coming week. There is some hope if November ends up negative because I know a warm October and November is often the kiss of death. 

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Exactly. There's a difference between modelology and meteorology, and it's easy to see from the overall pattern how the models showing a huge blowing up low were probably out to lunch.

You say it's easy to see.  But I don't see it.  I'm not trying to create an argument here... just trying to provide a counterpoint to the common theme...

 

The models use complex equations to simulate meteorological processes.  So in a sense, modelology IS meteorology.  The models know much better than any forecaster what kind of large scale synoptic evolution is possible.  If a low does blow up, in hindsight, what will we say about the "pattern?"  The teleconnections are loosely correlated to past weather patterns.  But they don't guarantee outcomes.  And really, teleconnections are just numerical representations of weather patterns.  They don't cause weather, rather, they reflect its present state.  And forecasted climate indices change day to day just like a particular model run.

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Looks like we'll have a storm this time around on the 18z GFS. Should develop offshore and end up similar to the 12z ECMWF.

 

Edit: Still more progressive than the Euro. Weak storm well OTS. One interesting thing, the GFS really reloads that Pacific ridge which then connects with ridging over Alaska.

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You say it's easy to see.  But I don't see it.  I'm not trying to create an argument here... just trying to provide a counterpoint to the common theme...

 

The models use complex equations to simulate meteorological processes.  So in a sense, modelology IS meteorology.  The models know much better than any forecaster what kind of large scale synoptic evolution is possible.  If a low does blow up, in hindsight, what will we say about the "pattern?"  The teleconnections are loosely correlated to past weather patterns.  But they don't guarantee outcomes.  And really, teleconnections are just numerical representations of weather patterns.  They don't cause weather, rather, they reflect its present state.  And forecasted climate indices change day to day just like a particular model run.

 

Extremely sensible post...this board is notorious for jumping ship with one bad model suite...the models have a tendency to find a system...lose it for a stretch...and sometimes find it later on...this doesn't always happen...but it takes place enough for all to realize you don't abandon a questionable outcome 120 hours out.

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It's going to be a long winter with euro fantasy storms. It loves to do that. Luckily, the ensembles are the best thing we have near and post day 7.  The euro earns its keep really inside day 3 as far as the finite details go for winter storms.  This storm was a nice lesson in ensembles beating the op run.

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It's going to be a long winter with euro fantasy storms. It loves to do that. Luckily, the ensembles are the best thing we have near and post day 7. The euro earns its keep really inside day 3 as far as the finite details go for winter storms. This storm was a nice lesson in ensembles beating the op run.

A lot of that is because of sandy. It nailed the general idea of it so far out, the media paints a picture of it being a super model. Plus weenies are weenies.

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The 6-10 day ECMWF was consistent run after run with Sandy. And had plenty of pattern and ensemble support. No storm shown since then, at the range, has really come close.

 

There is your key. Sure the op runs sometimes sniff out a few storms at that range, but when one operational run is the ONLY model showing such a solution...I think that should give you pause. It was basically the euro op vs everything. Usually, "everything" wins if that happens.  If I had the euro and euro ensembles vs everything, that becomes a different ballgame.

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A lot of that is because of sandy. It nailed the general idea of it so far out, the media paints a picture of it being a super model. Plus weenies are weenies.

 

This case should serve as a valuable lesson about how important it is for the operational to share the support of the ensembles

as was the case with Sandy. There is no other piece of guidance that can beat the Euro ensembles for 5-10 day forecasts.

 

http://www.ecmwf.int/publications/newsletters/pdf/133.pdf

 

strike probability’ maps to identify risk – as on the upper right inset, which denotes forecasts from 12 UTC on the 21st (‘D­8.5’). Even this far in advance, before the HRES had shown anything noteworthy, the ENS was flagging up a region centred on New York as being at risk (~25% probabil­ ity), from a system yet to form!

Once a cyclone has formed one can use track and plume diagrams to follow its predicted evolution more precisely. Figure 2 includes two fore­ cast products specifically for Sandy: the main panel shows tracks in the ENS and the HRES, whilst the lower inset shows the central pressure evo­ lution along those forecast tracks (red dots are verifying data). These are all forecasts from 12 UTC on the 23rd (‘D­6.5’, which is 15 hours after Sandy was named). The products show the ENS providing strong support for the HRES, the vast majority of members showing landfall, along the coasts of the north­eastern USA or south­ eastern Canada, many at about the right time. Only a handful of members show a ‘right turn’ in the track, and miss land. Moreover most members show substantial deepening, and minimum pressure values, of the right order, at about the time of la

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