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New England Severe weather thread number ...I think XI ?


OSUmetstud

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Down in the Trenton area I had 0.5-0.88" diameter hail, wind gusts to 50 mph, frequent cloud to ground lightning and rotation (very weak). Awesome ....

Congrats!!!

I think tomorrow could once again be interesting down your way and if you're able to get decent destabilization I could see the potential for some supercells and an isolated tornado threat.

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Congrats!!!

I think tomorrow could once again be interesting down your way and if you're able to get decent destabilization I could see the potential for some supercells and an isolated tornado threat.

I mentioned it earlier in the Mid Atlantic forum but I think there could be a weird morning-midday threat for NJ. The only thing keeping me from getting excited about it is the weak wind fields; but, everything else is favorable.

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I mentioned it earlier in the Mid Atlantic forum but I think there could be a weird morning-midday threat for NJ. The only thing keeping me from getting excited about it is the weak wind fields; but, everything else is favorable.

If something happens tomorrow it's all thanks to mesoscale features I think.

One thing to watch is for little impulses of stronger winds aloft which break off from the mid-level circulation and of course any low-level wind enhancement which is certainly possible.

With increasing low-level moisture and dewpoints potentially into the lower 70's LCL's should lower and anytime you have favorable hodos and low LCL's it really doesn't take all that much.

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If something happens tomorrow it's all thanks to mesoscale features I think.

One thing to watch is for little impulses of stronger winds aloft which break off from the mid-level circulation and of course any low-level wind enhancement which is certainly possible.

With increasing low-level moisture and dewpoints potentially into the lower 70's LCL's should lower and anytime you have favorable hodos and low LCL's it really doesn't take all that much.

The new NAM is pretty meh...

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The new NAM is pretty meh...

Yeah it is.

Actually if anything the NAM has a short window for potential here in SNE across CT in the mid-morning and then MA in the early afternoon right along the warm front.

It will be hard though to get much going on with such weak shear, although the directional shear is certainly there. I guess it will all depend on how buoyant we can get the low-level airmass to be.

Tomorrow is just one of those teasers where it looks like crap but that one cell can decide to just take off and it becomes a forecasters nightmare.

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It took away a lot of our instability.

It still is showing some very nice helicity, though...but CAPE is like <1000.

I feel like this is winter when a model consistently shows a coastal storm and then the night before takes it away. This solution is very different with the wind field structure too.

Yeah it is.

Actually if anything the NAM has a short window for potential here in SNE across CT in the mid-morning and then MA in the early afternoon right along the warm front.

It will be hard though to get much going on with such weak shear, although the directional shear is certainly there. I guess it will all depend on how buoyant we can get the low-level airmass to be.

Tomorrow is just one of those teasers where it looks like crap but that one cell can decide to just take off and it becomes a forecasters nightmare.

I could definitely see that. Seems like the SREF / NAM probs are indicating S NY into C PA for that possibility.

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Yeah it is.

Actually if anything the NAM has a short window for potential here in SNE across CT in the mid-morning and then MA in the early afternoon right along the warm front.

It will be hard though to get much going on with such weak shear, although the directional shear is certainly there. I guess it will all depend on how buoyant we can get the low-level airmass to be.

Tomorrow is just one of those teasers where it looks like crap but that one cell can decide to just take off and it becomes a forecasters nightmare.

The 18z run had a 700mb "jet streak" just to our west of nearly 40 knots, valid 18z tomorrow, which is certainly sufficient.

The 00z run doesn't have anything like that. Though there is a 30 knot area in CT valid 18z tomorrow.

Helicity increases in NJ as the day goes on. But overall the run wasn't great.

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I feel like this is winter when a model consistently shows a coastal storm and then the night before takes it away. This solution is very different with the wind field structure too.

I could definitely see that. Seems like the SREF / NAM probs are indicating S NY into C PA for that possibility.

Some of the soundings are actually quite intriguing...there seems to be an area just south of the warm front where there is actually a mid-level dry punch which would certainly increase potential for more breaks of sun and also perhaps lead to some pockets of steeper mid-level lapse rates as with the dry punch you have 500mb temps around -10C or so which is not bad for this time of year.

What would make this even more interesting is this would be the area of stronger instability and also the area where the strongest shear/highest helicity would be located.

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Some of the soundings are actually quite intriguing...there seems to be an area just south of the warm front where there is actually a mid-level dry punch which would certainly increase potential for more breaks of sun and also perhaps lead to some pockets of steeper mid-level lapse rates as with the dry punch you have 500mb temps around -10C or so which is not bad for this time of year.

What would make this even more interesting is this would be the area of stronger instability and also the area where the strongest shear/highest helicity would be located.

Yes that was duly noted on prior runs of the NAM...except it was over NJ at 15z or so. And as Doug said, previous runs at least had some type of wind "max" with good CVA.

Perhaps things are evolving faster, aided by the convection ongoing this evening.

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The 18z run had a 700mb "jet streak" just to our west of nearly 40 knots, valid 18z tomorrow, which is certainly sufficient.

The 00z run doesn't have anything like that. Though there is a 30 knot area in CT valid 18z tomorrow.

Helicity increases in NJ as the day goes on. But overall the run wasn't great.

I think we'll just have to see how the wind fields look in the AM...models are struggling with certain features but it does appear that there will certainly be pockets of stronger winds aloft around...just will there be instability to work with and will there be a good combination of stronger shear/instability?

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Some of the soundings are actually quite intriguing...there seems to be an area just south of the warm front where there is actually a mid-level dry punch which would certainly increase potential for more breaks of sun and also perhaps lead to some pockets of steeper mid-level lapse rates as with the dry punch you have 500mb temps around -10C or so which is not bad for this time of year.

What would make this even more interesting is this would be the area of stronger instability and also the area where the strongest shear/highest helicity would be located.

Yeah, they really aren't bad. I did some point and clicks on Twister Data. The instability is still really bad, though, and lapse rates aren't great, but I do see what you're talking about with the mid-level dry punch that tries to work its way in.

Here is a forecast sounding valid 00z, Saturday, for somewhere in C NJ:

NAM_218_2012081000_F24_40.5000N_74.5000W.png

It's not terribly impressive, but it does get a bit drier above 850mb. And lots of low-level veering, and pretty fast winds around 925mb, which is why the 0-1km SRH is actually pretty good.

Mid-level winds are just sooooooooooo slow, though.

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Yes that was duly noted on prior runs of the NAM...except it was over NJ at 15z or so. And as Doug said, previous runs at least had some type of wind "max" with good CVA.

Perhaps things are evolving faster, aided by the convection ongoing this evening.

Not really sure what satellite trends mean but looking at IR south of the warm front there are alot of warmer cloud tops than colder cloud tops and the coldest cloud tops seem to be across northern New England and eastern NYS...also looks like there are sufficient breaks in cloud cover...I can't see too much development of showers overnight or more in the way of clouds, especially with warming tops so perhaps in the AM we'll be dealing with sufficient breaks.

It also seems models are having a tough time handling the trough and whether or not it digs further south slowing down the front and sliding those stronger wind fields back further west.

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Yeah, they really aren't bad. I did some point and clicks on Twister Data. The instability is still really bad, though, and lapse rates aren't great, but I do see what you're talking about with the mid-level dry punch that tries to work its way in.

Here is a forecast sounding valid 00z, Saturday, for somewhere in C NJ:

NAM_218_2012081000_F24_40.5000N_74.5000W.png

It's not terribly impressive, but it does get a bit drier above 850mb. And lots of low-level veering, and pretty fast winds around 925mb, which is why the 0-1km SRH is actually pretty good.

Mid-level winds are just sooooooooooo slow, though.

Yeah those stronger ML wind fields just don't want to get here quick enough...and the NAM is really weird, it decreases those stronger ML winds right over us, yet increasing them off the coast, while at the same time increasing them right at the base of the trough with our area in a lull...just seems like that trough deepens just a bit too much.

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I think we'll just have to see how the wind fields look in the AM...models are struggling with certain features but it does appear that there will certainly be pockets of stronger winds aloft around...just will there be instability to work with and will there be a good combination of stronger shear/instability?

Yeah, I guess just because the NAM took away the strongest winds aloft around from our area, doesn't mean they still won't exist tomorrow. There still does appear to be somewhat sufficient low-level shear and helicity, regardless. But it's just going to be hard to juxtapose a wind max with instability and shear all at the same location. But it can be done.

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Yeah those stronger ML wind fields just don't want to get here quick enough...and the NAM is really weird, it decreases those stronger ML winds right over us, yet increasing them off the coast, while at the same time increasing them right at the base of the trough with our area in a lull...just seems like that trough deepens just a bit too much.

Sounds like closed low problems...disjointed wind fields. Blah.

Doesn't mean that we can't find a wind max over us again, but there won't be a nice, large uniform area of fast mid-level winds in this setup. We just need to find ourselves in a localized max, and hope it gets there when our SRH and LLJ is increasing.

Based on satellite trends you've mentioned, I do still think it's certainly possible to get more peaks of sun than the NAM would be implying and thus higher CAPE values. We don't need super high CAPE in this setup for tornadoes...1500J/KG should suffice.

I feel like the 18z NAM looked good for the late-morning tornado threat in NJ and maybe even into SW CT...and the 00z NAM took that away almost completely for NJ, but still leaves a bit of hope for later in the afternoon and maybe even the evening. Decent SRH values even try to get into CT. But it's just a different look, as HM said. Whoever gets into a mid-level wind max mid-morning might see something. But I'm still hoping we can get another one later in the afternoon when the SRH/LLJ increases.

This is one of those times where I have lots of general thoughts and ideas, but can't seem to put it all together into a concise forecast. Still lots to be ironed out.

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Yeah, I guess just because the NAM took away the strongest winds aloft around from our area, doesn't mean they still won't exist tomorrow. There still does appear to be somewhat sufficient low-level shear and helicity, regardless. But it's just going to be hard to juxtapose a wind max with instability and shear all at the same location. But it can be done.

Yeah it will certainly be quite difficult and chances are it probably won't happen but still worth watching I suppose.

We'll see what we can do instability wise as well.

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Sounds like closed low problems...disjointed wind fields. Blah.

Doesn't mean that we can't find a wind max over us again, but there won't be a nice, large uniform area of fast mid-level winds in this setup. We just need to find ourselves in a localized max, and hope it gets there when our SRH and LLJ is increasing.

Based on satellite trends you've mentioned, I do still think it's certainly possible to get more peaks of sun than the NAM would be implying and thus higher CAPE values. We don't need super high CAPE in this setup for tornadoes...1500J/KG should suffice.

I feel like the 18z NAM looked good for the late-morning tornado threat in NJ and maybe even into SW CT...and the 00z NAM took that away almost completely, but still leaves a bit of hope for later in the day/evening. Decent SRH values even try to get into CT.

This is one of those times where I have lots of general thoughts and ideas, but can't seem to put it all together into a concise forecast. Still lots to be ironed out.

I completely agree with everything here, especially on the Cape...1500 J/KG would certainly be plenty I think...not necessarily for TOR but for some severe.

It's just all about getting all the best parameters to align perfectly and I think we know what the chances of that happening are :lol:

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I completely agree with everything here, especially on the Cape...1500 J/KG would certainly be plenty I think...not necessarily for TOR but for some severe.

It's just all about getting all the best parameters to align perfectly and I think we know what the chances of that happening are :lol:

That tornado warned cell in Indiana today which produced 2.75" hail I believe was in a CAPE environment of around 1500J/KG...and yeah for an actual tornado, we'd probably need more, but not that

much more.

And yeah :lol: We live in the northeast. But at least some good parameters are near each other! :P

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