2017 Short/Medium Range Severe Thread

[HillsdaleMIWeather]

14 minutes ago, geddyweather said:

Interesting move. Very narrow swath. I'd imagine our watch should be coming shortly now that that has been introduced. 

More vigorous looking convection firing to the north and west of Coldwater, MI.

Under a warning from that cell, watch issued.

[geddyweather]

80% general wind probabilities with the Watch.

[HillsdaleMIWeather]

Line from Coldwater to Jackson is exploding with activity 

[Powerball]

These storms are going to be the most profilic lightning producers this area has seen in a while.

Already well over 200+ strikes per minute.

EDIT: Can't say it enough. What a different halfway decent lapse rates make...

[Powerball]

10 minutes ago, Powerball said:

These storms are going to be the most profilic lightning producers this area has seen in a while.

Already well over 200+ strikes per minute.

EDIT: Can't say it enough. What a different halfway decent lapse rates make...

Over 300+ strikes per minute now.

[geddyweather]

16 minutes ago, Powerball said:

These storms are going to be the most profilic lightning producers this area has seen in a while.

Already well over 200+ strikes per minute.

I'm more excited for that than anything else. Should hopefully be a good night for lightning photography, which I haven't done much off this year. 

Line is organizing and filling in quickly from LaGrange down to Rensselaer. 

[Jonger]

The line in lower Michigan screwed us. It was unorganized when it went through and we managed a trace. Most parts of metro Detroit should see up to an inch of rain.

Sprinklers are on.

[IWXwx]

Well, that was quite the bust. Time to go back to hurricane watching.

[Powerball]

2 minutes ago, IWXwx said:

Well, that was quite the bust. Time to go back to hurricane watching.

Yeah. The biggest problem looked to be models overdoing the moisture pooling (and thus instability). Had they been a bit higher, we would probably be having a different discussion.

It looks like areas near the Oakland / Livingston / Washtenaw County border area got smacked pretty good (that's when / where the instability / moisture was maximized).

[IWXwx]

27 minutes ago, Powerball said:

Yeah. The biggest problem looked to be models overdoing the moisture pooling (and thus instability). Had they been a bit higher, we would probably be having a different discussion.

It looks like areas near the Oakland / Livingston / Washtenaw County border area got smacked pretty good (that's when / where the instability / moisture was maximized).

Yeah, I saw that and you're probably right about instability. The funny thing is SPC's afternoon update had that small 45% wind threat and that area ended up being the weakest part of the line.

[WxMatt21]

6 minutes ago, IWXwx said:

Yeah, I saw that and you're probably right about instability. The funny thing is SPC's afternoon update had that small 45% wind threat and that area ended up being the weakest part of the line.

This was so bizarre to me. Everything looked good to go, but it fell apart almost as soon as it started. Not a single warned storm in NE Indiana (aside from the cells SW of Grant county, but that wasn't in my forecast area :)). 

I felt like I might've downplayed it a bit too much (thought the enhanced and 45% risk area was extremely bullish), but I'm glad I went more conservative. It's been such a strange summer. Busy on paper, with next to nothing to show for it.

[Powerball]

Just now, WxMatt21 said:

This was so bizarre to me. Everything looked good to go, but it fell apart almost as soon as it started. Not a single warned storm in NE Indiana (aside from the cells SW of Grant county, but that wasn't in my forecast area :)). 

I felt like I might've downplayed it a bit too much (thought the enhanced and 45% risk area was extremely bullish), but I'm glad I went more conservative. It's been such a strange summer. Busy on paper, with next to nothing to show for it.

That's been the story of almost every severe weather event the past several Summers.

[IWXwx]

1 minute ago, Powerball said:

That's been the story of almost every severe weather event the past several Summers.

Except you get an August 24th that sneaks up on you.

[HillsdaleMIWeather]

1 hour ago, IWXwx said:

Well, that was quite the bust. Time to go back to hurricane watching.

IWX's afternoon AFD said the smoke might prevent a more widespread event, seems they were right

[Chinook]

Some heavy rains and a few severe weather reports have occurred in downtown Toledo as well as the Blanchard Valley/ Sandusky Valley areas.

[Hoosier]

Warned cell headed toward cycloneville.

[cyclone77]

33 minutes ago, Hoosier said:

Warned cell headed toward cycloneville.

Haha they tried to come this way but hit a wall.  Not a drop.  We got lucky a few nights ago though so no worries.  Have had a fantastic light show in the western sky for the past few hours.

[Hoosier]

13 minutes ago, cyclone77 said:

Haha they tried to come this way but hit a wall.  Not a drop.  We got lucky a few nights ago though so no worries.  Have had a fantastic light show in the western sky for the past few hours.

[cyclone77]

3 minutes ago, Hoosier said:

Some reports of over 3" of rain on the west side of the QC.  MLI and DVN both got dumped on pretty good, so wonder if that could knock a degree or two off their high temp potential in coming days.

[Powerball]

It appears the potential for a conditional severe weather episode is increasing for MI / IN / OH on Saturday.

[Hoosier]

37 minutes ago, Powerball said:

It appears the potential for a conditional severe weather episode is increasing for MI / IN / OH on Saturday.

I haven't been excited because of the lack of instability, but as we all know, it doesn't take much in setups with good dynamics. At the very least, it may be one of those situations where heavy showers can mix down some strong winds given the background fields.

[Powerball]

20 hours ago, Hoosier said:

I haven't been excited because of the lack of instability, but as we all know, it doesn't take much in setups with good dynamics. At the very least, it may be one of those situations where heavy showers can mix down some strong winds given the background fields.

Models do generate a few hundred joules of CAPE.

Given the impressive dynamics (negative tilt trough, deepening low, etc.) and wind shear (bulk shear values of 50-70 kts is pretty impressive), I can envision a pretty decent line of low-topped convection, which is what the models are picking up on.

With temps getting into the low 80s, that should help with the downward momentum of the winds.

[Hoosier]

1 hour ago, Powerball said:

Models do generate a few hundred joules of CAPE.

Given the impressive dynamics (negative tilt trough, deepening low, etc.) and wind shear (bulk shear values of 50-70 kts is pretty impressive), I can envision a pretty decent line of low-topped convection, which is what the models are picking up on.

With temps getting into the low 80s, that should help with the downward momentum of the winds.

I could see SPC going with a marginal risk as it gets closer.

[Stebo]

39 minutes ago, Hoosier said:

I could see SPC going with a marginal risk as it gets closer.

Agreed, unless the moisture can get north sooner, or we get some appreciable rains tomorrow to add to the ambient moisture.

[Hoosier]

7 minutes ago, Stebo said:

Agreed, unless the moisture can get north sooner, or we get some appreciable rains tomorrow to add to the ambient moisture.

We could use some better mid level lapse rates too.

[Stebo]

19 minutes ago, Hoosier said:

We could use some better mid level lapse rates too.

Yeah that is one issue with the sharpness of the trough, the better lapse rates lag behind.

[Hoosier]

3 hours ago, Stebo said:

Agreed, unless the moisture can get north sooner, or we get some appreciable rains tomorrow to add to the ambient moisture.

The day 2 outlook doesn't even have one word about the Ohio Valley/Lakes. 

[Stebo]

4 minutes ago, Hoosier said:

The day 2 outlook doesn't even have one word about the Ohio Valley/Lakes. 

Lol, well that just means it will produce. I don't know what they are looking at because every model is showing fast moving low topped convection especially the CAMs. I mean I am not expecting some sort of massive outbreak but I do see a marginal type event worthy of consideration here.

Hell the old day 3 mentions this region, it is like he avoided even looking up here.

[Stebo]

10 hours ago, Stebo said:

Lol, well that just means it will produce. I don't know what they are looking at because every model is showing fast moving low topped convection especially the CAMs. I mean I am not expecting some sort of massive outbreak but I do see a marginal type event worthy of consideration here.

Hell the old day 3 mentions this region, it is like he avoided even looking up here.

And like magic, the new day 2 has a huge marginal risk area for S MI/IN/W OH

...Ohio Valley and Great Lakes...
   A rather potent shortwave trough will become negatively tilted as it
   ejects from the central Plains towards the Great Lakes Saturday. A
   resultant corridor of strong forcing for ascent will accompany a
   cold front sweeping east across the Midwest Saturday afternoon into
   the overnight hours. Ahead of this front, surface-based buoyancy
   will likely be quite meager, owing to very poor upstream mid-level
   lapse rates. Nonetheless, guidance suggests at least a narrow zone
   of low/mid 60s dew points and pockets of heating to foster MLCAPE
   values around 200-400 J/kg. Considering the strong kinematic field
   associated with this system (e.g., 850mb south/southwesterlies
   around 40-60 kt), shallow convection may be capable of a few
   strong/damaging gusts, primarily Saturday evening into the early
   overnight. Therefore, have introduced marginal severe probabilities
   from parts of the Ohio Valley to lower Michigan.

[Hoosier]

11 minutes ago, Stebo said:

And like magic, the new day 2 has a huge marginal risk area for S MI/IN/W OH

...Ohio Valley and Great Lakes...
   A rather potent shortwave trough will become negatively tilted as it
   ejects from the central Plains towards the Great Lakes Saturday. A
   resultant corridor of strong forcing for ascent will accompany a
   cold front sweeping east across the Midwest Saturday afternoon into
   the overnight hours. Ahead of this front, surface-based buoyancy
   will likely be quite meager, owing to very poor upstream mid-level
   lapse rates. Nonetheless, guidance suggests at least a narrow zone
   of low/mid 60s dew points and pockets of heating to foster MLCAPE
   values around 200-400 J/kg. Considering the strong kinematic field
   associated with this system (e.g., 850mb south/southwesterlies
   around 40-60 kt), shallow convection may be capable of a few
   strong/damaging gusts, primarily Saturday evening into the early
   overnight. Therefore, have introduced marginal severe probabilities
   from parts of the Ohio Valley to lower Michigan.

I wouldn't be surprised if the western edge of that gets expanded west a bit. Favorable frontal timing would support that notion with instability still a question. Though some uncertainty on exact evolution with some suggestion of activity (maybe the "main show"?) along a prefrontal trough.