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June 22-23 Severe Weather Outbreak


Stebo

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Alright, the 12z NAM just got absolutely ridiculous for Monday, as if it wasn't impressive already.  A 990 mb-ish surface low in late June...are you kidding me?

 

Not only that, it maintains 3000-4000 J/KG of MUCAPE through Tuesday morning and has 925mb bulk shear values of 45-50kts.

 

But of course, everything is solidly capped off.

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Not only that, it maintains 3000-4000 J/KG of MUCAPE through Tuesday morning and has 925mb bulk shear values of 45-50kts.

 

But of course, everything is solidly capped off.

 

 

Yeah, that's a problem.  We'll have to see where that zone of too much capping lies.

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Yeah, that's a problem.  We'll have to see where that zone of too much capping lies.

 

Although the potential is huge if everything comes together at the right place/time, it's definitely looking like another "thread the needle" setup.

 

If we get a shortwave too amped like the NAM shows, then capping will ruin the event.

 

If heights instead remain flat and the shortwave fails to amplify, then MI/WI folks can probably forget it. 

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Normally when you see a solution like the 12z NAM, you wonder if there's some convective feedback issue affecting the model output in a bad way, but I'm not sure that's the case here.  If you trace it back to the previous day, the surface low is already pretty deep in the presence of no convection.  That doesn't necessarily mean it will be right though.

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Normally when you see a solution like the 12z NAM, you wonder if there's some convective feedback issue affecting the model output in a bad way, but I'm not sure that's the case here.  If you trace it back to the previous day, the surface low is already pretty deep in the presence of no convection.  That doesn't necessarily mean it will be right though.

 

Given the amount of jet energy at play, its output doesn't seem too unrealistic IMO.

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Given the amount of jet energy at play, its output doesn't seem too unrealistic IMO.

 

 

Just checked another/better set of maps and changing my opinion on it...I think there could be some contamination by Monday afternoon/evening that's resulting in excessive deepening of the surface low (several mb), especially in the 21z timeframe.  Either way, it's a pretty dynamic setup for late June.

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That sounding is definitely convectively contaminated.

yeah, most of the forecast soundings on the 12Z NAM in the northern half of WI are...  Figured i'd show it to show that they're being contaminated, and giving erroneous parameters.

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Alright, the 12z NAM just got absolutely ridiculous for Monday, as if it wasn't impressive already. A 990 mb-ish surface low in late June...are you kidding me?

Well June 2010 had a 985 mb low as it passed Toledo to the north. The mid level jet was in fact the same as it being forecasted for Monday so these models are not showing anything unrealistic IMO. I forget the exact pressures but I believe last June's event in WI was pretty similar

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Well June 2010 had a 985 mb low as it passed Toledo to the north. The mid level jet was in fact the same as it being forecasted for Monday so these models are not showing anything unrealistic IMO. I forget the exact pressures but I believe last June's event in WI was pretty similar

Sent from my iPhone

 

Which June event in 2010?  If you're thinking June 5-6, it was way weaker than that.

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Alright, the 12z NAM just got absolutely ridiculous for Monday, as if it wasn't impressive already.  A 990 mb-ish surface low in late June...are you kidding me?

That low looks convectively induced or enhanced. Actually with what Powerball mentioned with the system being overly amplified on this run it draws in too much mid level warming. I think in later runs we will see that back off a bit as you get a better idea on the actual strength of the low and not this over amplified solution.

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18z NAM is a good 4mb weaker through 18z Monday than its past few runs, and a little more progressive too. 

More realistic.  The 12z had the low go from 998 to 992 from 18z to 21z Monday which is why it had all those crazy parameters.  It was definitely some contamination that caused the quick local pressure falls.  

 

Also, look at the sim reflectivity on the 18z 4km.  Looks like a bunch of sups to me. 

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That would lead to a wider potential as it won't draw up as much warm air at 700mb.

Yeah, it's not like the wind field is too much less impressive. The Euro is also a little more progressive and weaker, with a 1004mb sfc. low over the UP by 00z Monday and near Sault Ste. Marie by 6z. Even with that weaker sfc. reflection there's still roughly 50-70kts of bulk shear to work with and LCL's are below 800, with a very large area of 25+ kt. 0-1km shear.

 

It's also difficult to interpret 6hr precip plots, but there's widespread convection across IL/WI before 8pm and some in IN/MI/NWOH between 0-6z. And this is all with DP's in the upper 60s/low 70s.  

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Both the 18Z 12KM NAM and 18Z 4KM NAM still continue to show an very impressive background environment across S WI/MI on Monday starting as soon as 18Z across NE IA/S WI/MI... 4KM NAM shows numerous discrete/semi-discrete supercells developing on the CF by 21-00z and moving SE across the area, looks like things would go linear pretty fast though since 850mb winds will be nearly parallel to the front... 

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Both the 18Z 12KM NAM and 18Z 4KM NAM still continue to show an very impressive background environment across S WI/MI on Monday starting as soon as 18Z across NE IA/S WI/MI... 4KM NAM shows numerous discrete/semi-discrete supercells developing on the CF by 21-00z and moving SE across the area, looks like things would go linear pretty fast though since 850mb winds will be nearly parallel to the front... 

 

It's more noteworthy if mid level winds are parallel to the front.

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