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April 14-17 Severe Prospects


Indystorm

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Sunday's dynamics make me want to faint...

Late Sunday looks positively scary here in northern Illinois. With models convecting all day in the warm sector keeping cloud cover and temps lower, then the low 60s dews progged with temps in the 60s and 70s could be near 80 instead if this doesn't occur. So it's highly plausible that instability is being underdone. Then with the extreme wind fields (40-50 kt at 850 mb by 00z and 55-65 kt at 850 by 06z), a high end severe threat would be feasible for the area. Very concerning to see such strong dynamic support and shear profiles.

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Late Sunday looks positively scary here in northern Illinois. With models convecting all day in the warm sector keeping cloud cover and temps lower, then the low 60s dews progged with temps in the 60s and 70s could be near 80 instead if this doesn't occur. So it's highly plausible that instability is being underdone. Then with the extreme wind fields (40-50 kt at 850 mb by 00z and 55-65 kt at 850 by 06z), a high end severe threat would be feasible for the area. Very concerning to see such strong dynamic support and shear profiles.

Playing devil's advocate here, but how many times have we seen these early season warm fronts get hung up as the convective activity rippling along...I expect Saturday nights nocturnal MCS to be a good 50 miles or more south of current solutions. Not saying it doesn't retreat back north later Sunday but I doubt we have anything close to clearing/near 80...especially north of I80.

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Late Sunday looks positively scary here in northern Illinois. With models convecting all day in the warm sector keeping cloud cover and temps lower, then the low 60s dews progged with temps in the 60s and 70s could be near 80 instead if this doesn't occur. So it's highly plausible that instability is being underdone. Then with the extreme wind fields (40-50 kt at 850 mb by 00z and 55-65 kt at 850 by 06z), a high end severe threat would be feasible for the area. Very concerning to see such strong dynamic support and shear profiles.

Dr. Greg Forbes seems to be narrowing in on NE Iowa/SW Wisconsin Sunday for the greatest potential for tornadoes, with TorCon numbers of 6 already 3 days out. The 12z GFS seems to indicate the highest CAPE near LaCrosse for some reason, probably the ongoing convection you were speaking of. I don't know what to think for here, so I'll wait another day and see what experts say tomorrow.

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Playing devil's advocate here, but how many times have we seen these early season warm fronts get hung up as the convective activity rippling along...I expect Saturday nights nocturnal MCS to be a good 50 miles or more south of current solutions. Not saying it doesn't retreat back north later Sunday but I doubt we have anything close to clearing/near 80...especially north of I80.

Right now some solutions (the GFS/NAM) depict Saturday night's MCS in Southern/Central Wisconsin, so I'm not sure why you think the warm front won't even clear I-80. The trend with the convective activity has been north the last day or so, obviously not following the normal trend this time of year.

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Playing devil's advocate here, but how many times have we seen these early season warm fronts get hung up as the convective activity rippling along...I expect Saturday nights nocturnal MCS to be a good 50 miles or more south of current solutions. Not saying it doesn't retreat back north later Sunday but I doubt we have anything close to clearing/near 80...especially north of I80.

Yeah, that's my line of thinking as well. Saturday could be negatively impacted too. On Sunday we'll probably have a lot of leftover precip/clouds from the Saturday outbreak to the west. Hard for me to get too excited after seeing this type of scenario play out so many times with this kind of setup.

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Right now some solutions (the GFS/NAM) depict Saturday night's MCS in Southern/Central Wisconsin, so I'm not sure why you think the warm front won't even clear I-80. The trend with the convective activity has been north the last day or so, obviously not following the normal trend this time of year.

U have to read my post, I know what the models are showing...previous experience tells me they're wrong.

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...I also will be out chasing.

You have an idea on where you're gonna focus yet? Sure wish I could go, but I'll be stuck at work until at least 1 or 2pm. If it looks like the WF will fire I may make a stab at it wherever that sets up. I can chase Sunday, but there's a lot of questions on how that day will evolve.

Good luck to everyone heading out! Stay safe!

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You have an idea on where you're gonna focus yet? Sure wish I could go, but I'll be stuck at work until at least 1 or 2pm. If it looks like the WF will fire I may make a stab at it wherever that sets up. I can chase Sunday, but there's a lot of questions on how that day will evolve.

Good luck to everyone heading out! Stay safe!

I think there will be tornadoes with the warm front but think the real monsters will come off the dryline, central KS to OK.

Sunday...who knows.

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Playing devil's advocate here, but how many times have we seen these early season warm fronts get hung up as the convective activity rippling along...I expect Saturday nights nocturnal MCS to be a good 50 miles or more south of current solutions. Not saying it doesn't retreat back north later Sunday but I doubt we have anything close to clearing/near 80...especially north of I80.

Certainly a valid concern, but the change from yesterday has been the lack of a strong high to the north, which was keeping the quasi-stationary boundary draped along the border late Saturday and then forced south on Sunday. I think the synoptic southerly push ahead of the path of the low is going to be sufficient to keep the warm front where it's been progged today, over central Wisconsin. But there's a lot of time before we get there and can't discount things going the way you expect them to based on your experience. With respect to convective debris cloud cover from the day before, we'd really have to be socked in all day to not have any chance to destabilize. With temperatures likely not getting lower than the lower 60s on Saturday night, and 850 mb temperatures in the mid teens, it wouldn't take much for the temperatures to jump well into the 70s on Sunday afternoon.

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U have to read my post, I know what the models are showing...previous experience tells me they're wrong.

I read your post, even 50 miles south would not put it south of I80. Heck, both the 12z and 18z GFS have shown two MCS', one on Saturday night in the southern half of Wisconsin, the second one on Sunday evening from La Crosse to Green Bay. Yes, there's some activity Sunday night with the cold front as well, but I think you would need a 100-150 mile shift to keep all the action south of the WI/IL border. Could it happen? Perhaps, but I doubt that large of a shift.

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You have an idea on where you're gonna focus yet? Sure wish I could go, but I'll be stuck at work until at least 1 or 2pm. If it looks like the WF will fire I may make a stab at it wherever that sets up. I can chase Sunday, but there's a lot of questions on how that day will evolve.

Good luck to everyone heading out! Stay safe!

May end up being like the April 10 outbreak last year, where there is the issue of wanting to chase in some choppy terrain, the Driftless Area, if Forbes is right with his ominous TorCon for SW Wisconsin.

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Mid level lapse rates look decent on Sunday so any greater than expected heating could really help.

Excellent point, and that's part of what I was getting to with my post. 700-500 mb lapse rates are 7-8C/km depending on which model sounding you look at. 18z NAM raw 2m high temps are mainly in the upper 70s, touching 80 in a few spots, including ORD.

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May end up being like the April 10 outbreak last year, where there is the issue of wanting to chase in some choppy terrain, the Driftless Area, if Forbes is right with his ominous TorCon for SW Wisconsin.

Haha I'm staying out of Wisconsin for good after April 10th last year. I've never been so frustrated during a chase. We went in knowing the terrain would be an issue (trees/hills). I could deal with that, but the road network over southwest Wisconsin was extremely frustrating. Not many east/west/north/south roads. The road network looked like a plate of spaghetti lol.

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Excellent point, and that's part of what I was getting to with my post. 700-500 mb lapse rates are 7-8C/km depending on which model sounding you look at. 18z NAM raw 2m high temps are mainly in the upper 70s, touching 80 in a few spots, including ORD.

Of course from a tornado perspective then the concern would be that T/Td spreads could get too high. Tough balancing act.

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Of course from a tornado perspective then the concern would be that T/Td spreads could get too high. Tough balancing act.

Which is why some convective debris may not necessarily be a bad thing if you want tornadoes in this area. I definitely don't. It'll be interesting to see how the guidance trends tonight with the 00z runs.

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I always find AFD's fascinating to read. Des Moines is playing up the severe potential for Saturday while Quad Cities is placing more emphasis on heavy rain with the ATTM disclaimer.

I feel like DVN always hypes up potential snowstorms but underhypes severe weather events. Must be mostly winter weenies at that office.

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May end up being like the April 10 outbreak last year, where there is the issue of wanting to chase in some choppy terrain, the Driftless Area, if Forbes is right with his ominous TorCon for SW Wisconsin.

I remember that outbreak, everything was north of me. Only a trace of rain that day. Very warm day though in the lower 80s. Regardless of where the warm front is, I hope the area can pick up a good inch of rain. Really do need it now.

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Well let's just say they lack the detail of ARX's discos in the summer, tend to do more of a summary. However, in winter, they are happy to weenie out once in awhile several days in advance. You sure love to dish it out.

There is at least one winter weather weenie in that office! Whomever that is likes to discuss all the winter weather possibilities on the table up to 7 days out!

In the warmer moments months I think they are more cautious about jumping the gun regarding severe weather.

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There is at least one winter weather weenie in that office! Whomever that is likes to discuss all the winter weather possibilities on the table up to 7 days out!

In the warmer moments I think they are more cautious about jumping the gun regarding severe weather.

Yes that is what I have found as well, and to Trapperman's point, I think all the nearby offices (including MKX and LOT) were all over that event, with many of them busting (thankfully given the magnitude of the event for those who experienced it), so I don't think it is the norm for DVN to hype typical severe weather events.

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