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January Banter Thread


H2O

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In case anyone wants a primer on a Norlun Trough:

 

http://www.mattnoyes.net/new_england_weather/2011/01/exactly-what-is-a-norlun-trough-and-how-do-you-forecast-weather-associated-with-it.html

 

First, what is a "Norlun Instability Trough?"  A trough is a weak disturbance in the atmosphere - in this case, near the surface - marked by lower surface barometric pressure that results from converging wind direction and speed.  Surface convergence of air results in rising air (afterall, air converging at the surface must go either up or down, and clearly can't go into the ground), and rising air produces clouds and precipitation.  Hence, troughs can focus locally heavier bands of precipitation.  It was noted by operational forecasters Steve NOgueiRa and Weir LUNdstedt (Nor-Lun) that these troughs, when inverted (extending northwest from a surface low) and beneath a middle and upper level atmospheric cold pool, could result in very strong, localized bands of precipitation.  On occasion, these narrow but intense bands of snow could produce in excess of one foot of snow, and largely were missed by computer guidance.  Mr. Norgueira and Lundstedt both worked to find methods of forecasting these events, even when computer modeling missed them.  Since their initial study in 1992, computer modeling has improved significantly, and these events often are projected in advance, though placement and intensity continues to be a challenge, especially in more complex setups.

 

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Why is Norlun Trough position sometimes difficult to forecast?  The advancement of atmospheric modeling technology in the 2000s has vastly improved the ability to forecast location of Norlun Troughs.  There are a few issues that still are significant obstacles to the operational forecaster, however, most noteably total precipitation amount (QPF forecast) and placement/development of Norlun troughs when more than one inverted trough is involved.

 

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As I said a couple days ago, things around here are never as bad as they are about to be....

 

DT honking that the Euro showing a major snowstorm next week for guess who?  That's right, southern VA and NC.  Euro map shows 12-18 inches here with the standard pity 1" here. 

 

So you'd rather be in the bullseye a week away?

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Can those who are getting a historic blizzard pony up to get the board to its goal? Maybe they can make up a little bit for continually crashing the site.

 

its not the site itself. its being DDos attacked. so, not much the software/memory can do to prevent that. 

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don't see the contradiction at all.  there is a big difference between fringe and bullseye, and in-between those two is a solid event.

 

The Euro gives you close to 6"... which as far as our climo is concerned, is a nice solid event. Somehow you're still not satisfied with that. 

 

Yeah I know, hug the model that gives you the most snow and toss the GFS, etc. Who knows, maybe it'll work out... but its insane from a climo standpoint how many of these storms NYC has gotten in the last 12 years or so. 

 

The Euro works far better for big coastal storms. Feb 2014, Feb 2013, and probably this one too. 

 

And yep... NYC has been on an epic winning streak with KU storms for the past 15 years. 

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The Euro gives you close to 6"... which as far as our climo is concerned, is a nice solid event. Somehow you're still not satisfied with that. 

 

 

I mis-read the Euro map a bit; that's more than I thought at first glance.  Doesn't matter anyway; it has 6 days left to trend worse.   The Euro has given me about 4 feet of Day 6 snow so far this winter.

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I mis-read the Euro map a bit; that's more than I thought at first glance.  Doesn't matter anyway; it has 6 days left to trend worse.   The Euro has given me about 4 feet of Day 6 snow so far this winter.

 

why do you even bother if weather causes you such misery?

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