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February 2013 mid-long range disco thread Part 2


yoda

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I think part of the problem on this run is that the low seems to slow down allowing warmer air to filter up vs. barreling right into the cold dome

Yeah, sort of looks like that, and what I saw with the 500 low bodily pushing everything out of the way as it moves due north.

 

Not trying to parse things too much here...just what the model looks like this time around verbatim

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Agree.

 

Full soundings aren't out yet on twisterdata (thru 90 right now), but you can step through the critical levels on instantweathermaps.

Good stuff.  Hadn't seen that webpage before.  Just about as good as a full sounding with all the levels.  Based on that, looks like ~4-6 hours of snow, then a couple hours of pingers, a little freezing rain and ending as drizzle.  Not a bad way to go for us.  

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Good stuff.  Hadn't seen that webpage before.  Just about as good as a full sounding with all the levels.  Based on that, looks like ~4-6 hours of snow, then a couple hours of pingers, a little freezing rain and ending as drizzle.  Not a bad way to go for us.  

 

We seem to be consistently getting various solutions of just that from various globals. IDC how it happens. It can be a dumptruck full of snow having an accident @ DCA obs station. Just 2" please. 

 

Western VA could be in for some trouble. Big ice signal for days. 

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Raleigh's map has 4-6" or so for the entire area with 8"+ for the Blue Ridge area.  

yeah it seems odd.. it's not that much worse than 0z. the maps i have are usually better than others tho from what i've seen. i don't really buy it in this case.

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Mitch, I've seen it snow here at 549 thickness.  I don't put much stock on it. 

well, every time it goes above 542 on the models, it always turns to something else

hey, I agree that we need soundings, it's just that there is certainly a warm layer somewhere in the column when I see those thicknesses

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We seem to be consistently getting various solutions of just that from various globals. IDC how it happens. It can be a dumptruck full of snow having an accident @ DCA obs station. Just 2" please. 

 

Western VA could be in for some trouble. Big ice signal for days. 

i doubt anyone is getting a big ice storm in mid-feb with heavy rates even at night. i'd put that near the bottom of my worries.

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0.75"+ liquid with temps below freezing here.  Too early to look at soundings, but would be a major winter storm no matter what precip-type falls if the GFS is right.

 

That's the way to look at it.  Significant winter event.  But .............. way too far in the future to be wracking our brains over specifics. Can't wait, for a change, to see what the Euro says.

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Seems the gfs wanted to repeat the whole repeat the same pattern through out the 384 hours.       Was like watching the same storm repeat a similar process from day 5 to end of the run.      *Shrugs*   More than likely wrong. 

 

You aren't kidding. Three different lows that cut through Missouri from next Friday's storm to the end of the run.

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i doubt anyone is getting a big ice storm in mid-feb with heavy rates even at night. i'd put that near the bottom of my worries.

 

IDK, if you get good low level cold, which we can in Feb, and good CAD, which we can, freezing rain could become a big problem under the right conditions.  It just takes so little of that to be big trouble.

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well, every time it goes above 542 on the models, it always turns to something else

hey, I agree that we need soundings, it's just that there is certainly a warm layer somewhere in the column when I see those thicknesses

Based on the webpage MN pointed me too, the warm layer comes in at 700-800mb first and then progressively warms up the lower levels.  

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IDK, if you get good low level cold, which we can in Feb, and good CAD, which we can, freezing rain could become a big problem under the right conditions.  It just takes so little of that to be big trouble.

 

seriously doubt it. we have trouble with big ice even during our climo lowest sun angle and coldest temps. not to mention it's not going to be severely cold before the storm. usually you want a drawn out light/mod qpf event with temps well below freezing. a thump of .5-.75" qpf over a few hours would not all accrete and even then you're talking trees etc mainly. some sort of sleety mixture is probably a bigger problem.

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well, every time it goes above 542 on the models, it always turns to something else

hey, I agree that we need soundings, it's just that there is certainly a warm layer somewhere in the column when I see those thicknesses

 

The peril with thicknesses is that it is a column derived calculation, so it doesn't tell you where the "warmth" may be.  In this case, the upper levels will be warmer than maybe a standard atmosphere 5400m thickness, but since those levels will still be below freezing, it doesn't hurt us for p-type.   

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The peril with thicknesses is that it is a column derived calculation, so it doesn't tell you where the "warmth" may be.  In this case, the upper levels will be warmer than maybe a standard atmosphere 5400m thickness, but since those levels will still be below freezing, it doesn't hurt us for p-type.   

OK, makes sense

do we have the soundings yet for 168-180 hrs?

I'll be interested to see what's going on (I know it's a week away, I'm just curious)

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OK, makes sense

do we have the soundings yet for 168-180 hrs?

I'll be interested to see what's going on (I know it's a week away, I'm just curious)

 

Sounding before the bulk of the precip

post-1746-0-82616000-1360948627_thumb.gi

 

09z Snow sounding

post-1746-0-22290900-1360948561_thumb.gi

 

12z Sleet sounding

post-1746-0-61930700-1360948576_thumb.gi

 

15z is similar to 12z, and it is basically an above freezing sounding by 18z.

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seriously doubt it. we have trouble with big ice even during our climo lowest sun angle and coldest temps. not to mention it's not going to be severely cold before the storm. usually you want a drawn out light/mod qpf event with temps well below freezing. a thump of .5-.75" qpf over a few hours would not all accrete and even then you're talking trees etc mainly. some sort of sleety mixture is probably a bigger problem.

 

Oh I didn't mean to sound alarmist about it.  But if we had temps in the 26-28 range, with rain falling, we'd get ice accumulation in a hurry.  I wasn't really thinking our area, especially yours, but the Roanoke, Lynchburg, Lexington triangle would be a good candidate for that.

 

I know Kentucky is a different animal from this side of the mountains, but they had an absolutely crippling ice storm in the 90's during February.  I can't remember the year, but my dad lives in Louisville so I guess that's why that one stuck in my mind.

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Sounding before the bulk of the precip

attachicon.gif162.gif

 

09z Snow sounding

attachicon.gif09z 165.gif

 

12z Sleet sounding

attachicon.gif12z 168.gif

 

15z is similar to 12z, and it is basically an above freezing sounding by 18z.

thanks

which means the 543 at 162 was OK for snow once the precip made it in a cooled the atmosphere, but the 547 at 168 hrs. was definitely sleet with the warm layer as suspected

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GEFS quite similar to the Op in storm strength and tracks (GEFS a smidge weaker and a bit further east).  I'd ignore the GEFS depiction of the 850 0C line, because it's not going to pick up CAD well at all.  That said, you can see from the kinks in the isotherms, that even the GEFS is "seeing" the CAD, but doesn't resolve it well and erodes it (likely) far too quickly.  

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