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Severe Weather possible weekend of the 21st?


weatherwiz

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Incorrect. Like Nick said, there was an EML present. Ekster and Banacos have a paper on this clearly stating that.

The image/post has been corrected, thanks for pointing that out. My mind is stuck in July right now, so that may have been why I put the wrong month in.

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The 12z GFS seems to be hitting Friday harder now with respect to the severe potential. Pre-frontal trough-type feature? With the heat and 850's of +21 to 22C, fairly unstable conditions of course, but seeing some decent wind shear and helicity as well. Those pesky ML LR's are only 6.3°C/km though, at least at BDL for 00z Saturday

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The 12z GFS seems to be hitting Friday harder now with respect to the severe potential. Pre-frontal trough-type feature? With the heat and 850's of +21 to 22C, fairly unstable conditions of course, but seeing some decent wind shear and helicity as well. Those pesky ML LR's are only 6.3°C/km though, at least at BDL for 00z Saturday

I see that. Like you said before though, trying to pinpoint lapse rates this far out is a bit premature. As I was saying before, I think with everything else we already have in place lapse rates won't be the underlying factor to what may happen in terms of convective development. Higher rates will be nice, but I wouldn't downplay the "lower" values too much right now.

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I think the lapse rates are being looked into way too much here.  If we were talking 5 to 5.5 C/KM lapse rates then I could see the point...but mlvl lapse rates in the 6-6.5 /KM range is pretty darn decent.  Those won't kill you.  Not to mention we will have dewpoints probably in the upper 60's...possibly tickling 70F with an abundance of llvl moisture which can compensate for weaker lapse rates but I don't consider 6-6.5 C/KM weak.  In fact, I'm not even worried about lapse rates.  

 

This potential is mainly straight line wind/squall line potential, though if the sfc low tracks a bit further south and a bit more of an open wave, we could have a threat for supercells.  Anyways, the keys here will be timing, and when the strongest winds aloft reside over the region.  

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I think the lapse rates are being looked into way too much here.  If we were talking 5 to 5.5 C/KM lapse rates then I could see the point...but mlvl lapse rates in the 6-6.5 /KM range is pretty darn decent.  Those won't kill you.  Not to mention we will have dewpoints probably in the upper 60's...possibly tickling 70F with an abundance of llvl moisture which can compensate for weaker lapse rates but I don't consider 6-6.5 C/KM weak.  In fact, I'm not even worried about lapse rates.  

 

This potential is mainly straight line wind/squall line potential, though if the sfc low tracks a bit further south and a bit more of an open wave, we could have a threat for supercells.  Anyways, the keys here will be timing, and when the strongest winds aloft reside over the region.  

 

I don't think people were dismissing it. 6.5C/KM is decent for us if dynamics suffice.

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I think the lapse rates are being looked into way too much here.  If we were talking 5 to 5.5 C/KM lapse rates then I could see the point...but mlvl lapse rates in the 6-6.5 /KM range is pretty darn decent.  Those won't kill you.  Not to mention we will have dewpoints probably in the upper 60's...possibly tickling 70F with an abundance of llvl moisture which can compensate for weaker lapse rates but I don't consider 6-6.5 C/KM weak.  In fact, I'm not even worried about lapse rates.  

I'm with ya on that.

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I don't think people were dismissing it. 6.5C/KM is decent for us if dynamics suffice.

 

It appears as if the dynamics will certainly be there.  Both GFS/Euro have more than favorable shear with good unidirectional/speed shear.  In fact, both models also have a pretty strong LLJ and that ULJ is pretty intense for mid-July

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I'm with ya on that.

 

Looking at 12z GFS bufkit soundings, it actually appears there is a very weak remnant EML that trickles overhead late Friday into early Saturday.  GFS actually has lapse rates (at least across northern CT about 6.5 C/KM...even upwards to 6.8 for much of the day.   

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Looking at 12z GFS bufkit soundings, it actually appears there is a very weak remnant EML that trickles overhead late Friday into early Saturday.  GFS actually has lapse rates (at least across northern CT about 6.5 C/KM...even upwards to 6.8 for much of the day.   

This was a nice EML :popcorn:

post-532-0-29495700-1373925915_thumb.png

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Let's hope timing works out. It's a fine needle to thread here, although signs have been pointing towards at least an enhanced threat of a legit severe outbreak across the Northeast. I think we get two swings here, Friday and Saturday...Friday could be more of an isolated, pre-frontal variety and assuming the front comes through during the second half of Saturday, that's when we could see some widespread strong to severe storms.

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Let's hope timing works out. It's a fine needle to thread here, although signs have been pointing towards at least an enhanced threat of a legit severe outbreak across the Northeast. I think we get two swings here, Friday and Saturday...Friday could be more of an isolated, pre-frontal variety and assuming the front comes through during the second half of Saturday, that's when we could see some widespread strong to severe storms.

 

Actually, Friday would have potential for supercells and perhaps a tornado threat if we have a spark

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why would anyone who wants severe weather not be concerned about mid-level lapse rates?  

 

Mid-level lapse rates are modeled to be in the 6-6.5 C/KM lapse rates and actually the latest GFS run has lapse rates now up closer to 6.5-7 C/KM.  When it comes to lapse rates I think people sort of have a misunderstanding about them, especially when it comes to EML's.  In Ekster's EML paper, according to the research he's done, only 18% of all significant severe weather events in the Northeast had EML's...that's not really a high percentage.  However, when we have EML setups with favorable lift around, they do tend to produce.  As long as mid-level lapse rates are greater than 6 C/KM, they won't be a limiting factor, especially if other ingredients are in place.  

 

If we do want to worry though, it could be having previous day's convection or if we don't have any cap in place, having crap activity develop and kill lapse rates.  

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I would really watch central/northern New England on Friday.  The GFS has a weak vort max traversing across the U/Canadian border and with a very favorable thermodynamic and perhaps a highly sheared environment with decent helicity (GFS has stronger 0-6km shear), there could be a window for some convective bands or even supercells.  

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