Severe Weather for 4/19-4/23

[Santa Clause]

So is this thing about done now?

[janetjanet998]

 

7 minutes ago, Indystorm said:

New cells firing to the nw of our monster.

HRRR develops these

but I noticed on the visible as the sun was setting they may be elevated over stratus clouds....and with nocturnal cooling hopefully they will stay that way

[Snowstorm920]

2 minutes ago, 1900hurricane said:

I wonder if it’s starting to collapse now. Not much rotation anymore. There’s a big spike in reflectivity, which would suggest the opposite, but maybe some of the hail that has been suspended in the updraft is starting to fall out all at the same time as the updraft weakens. Not sure, just speculating.

 

EDIT: really doesn't look that way now...

Check out the Lake Charles scans of the cell. Still excellent structure and rotation.

[MUWX]

I think it’s about to come back to life 

[Amped]

Just now, MUWX said:

I think it’s about to come back to life 

Looks like it got the monkey off of it's back. Nice hook again.

[Normandy]

Really does have incredible structure on radar.  The south has been bringing it this year

[MUWX]

This should be warned imo 

[Indystorm]

1 minute ago, MUWX said:

This should be warned imo 

Getting worried about Alexandria

[cstrunk]

With the radar presentation and history of the storm I'm not sure why it's not Tornado warned.

[MUWX]

Couplet is wrapping up. Where is the warning 

[1900hurricane]

Looks like a tor again on KPOE radar just based on how low the beam is (~600 ft).

[Calderon]

I'm so sorry you wasted so much time typing that.  You guys need to lighten up a little.  I know Calderon is not a dumbass.  I know he has insane amounts of knowledge.  I know this was not the tri state tornado.

When y'all get in these events your asses get tight lol.  All love Calderon

Lol, chill. I forecast for the world’s finest Navy and about to do it in CENTCOM.

[Calderon]

Couplet is wrapping up. Where is the warning 

I’m not sure what the deal is with the LCH office, but they have been very slow all night.

[mob1]

Very tight rotation now and still nothing 

[Normandy]

Hoping it moves hard right to avoid Alexandria

[Santa Clause]

Just now, mob1 said:

Very tight rotation now and still nothing 

Wow it’s very strong couplet.

[MUWX]

I don’t see any way this impacts Alex 

[Bob's Burgers]

Lol. They wait to issue the warning now and the couplet falls apart

[mob1]

1 minute ago, MUWX said:

I don’t see any way this impacts Alex 

Maybe Woodworth 

[Bob's Burgers]

looks like we may have something now where the occlusion is taking place

[Santa Clause]

3 minutes ago, mob1 said:

Maybe Woodworth 

Looks like couplet went away again.

[Buckeye05]

Circulation trying to get going to the north of the old one.

[MUWX]

Just now, Wmsptwx said:

Looks like couplet went away again.

Couplet looks strong to me. Woodworth may be in trouble 

[Moderately Unstable]

I've actually done a mini-internship with the NWS, and have a friend that's a lead forecaster at an office so I'll chime in on this. Warning issuance is defined by certain criteria on velocity imagery and a few other factors. Note that, unless you're looking at something like GR2, these are post-processed products. Different WFOs have different training procedures. When you start at an office, they have you do simulator training--seriously, to prepare you for the types of events you'll see in that office, and teach you how to warn effectively. When it comes to severe weather warnings, as I've expressed before, it's about more than just, "does this storm have a hook echo". Because your warnings, are THE *official* source--not just for the public, but for other METs, your warnings are taken very strongly. Places in Dixie Alley, and Tornado alley, often have a higher threshold for warning, than, say, my area (Philly). That's not ALWAYS technically true--but in practice, I see storms in the plains all the time that would definitely be TOR warned in my area, and vice versa. The reasoning is basically limited attention. If my warning goes out to millions of folks' homes, may wake them up if they're asleep, (etc), I'd better be sure it's worth it. You may say, "well, if it's POSSIBLE, you have to warn!". That's not true, and it's bad public policy. If I get too many warnings on my phone, or smart device, or NOAA weather radio, what am I going to do? I'm going to turn it off. I'm not going to seek shelter. I'm not going to take it seriously. I'm going to stand by the window to try and see if *I* can SEE the tornado, or other weather event. Granted---*I* don't do that, but, this is how 95% of people DO think. The goal, in tornado alley, and dixie alley, is to try to warn storms that are likely to produce a tornado, and I don't mean POSSIBLY produce a tornado (that's a specially worded svr tstorm warning), I mean *likely*. You don't want joe the tumbleweed chaser ignoring a tornado emergency because he was incorrectly warned about a weak circulation. One is more deadly.

Despite impressive radar returns, this storm, has not produced tornadic damage reports along a lot of its path. At present, the storm is over rural areas, and would be hard to confirm. If the storm shows organization when it approaches a town, they'll probably warn it. But there ARE storms, that LOOK PERFECT, but DO NOT produce a lot of damage, or tornadoes. There may be something to be said for why there is ONLY one supercell in an environment that seems "highly favorable" for tornadoes and severe weather. At present, the velocity imagery coming off of the KPOE radar does not indicate storm relative velocity gate-to-gate sheer, exceeds the threshold for issuing a tor warning. That's what they use, amongst other things, with much better processing than we have on radarscope. Also, look at the storm history. It's had this impressive look, then falls apart. If the ingredients are the same, the storm is the same, and the look is the same, expect similar things to happen. Oldest forecast technique ever, persistence. Bad overall technique, but has merit there.

Moral of the story: don't over-warn. People think that you should always warn something if it is POSSIBLE for something to happen. If things ramp up, and there is STRONG gate to gate shear, you'll see warnings, and PDS language etc. With scans every few minutes, and warning issuance possible in about 4 minutes, there is time, when a tornadic storm is over rural areas, to assess the situation, before producing your warning (which then needs to verify for your office to statistically match what has been produced). As a final related note--the tor emergencies issued earlier may not verify, and that's not great. You don't want a high false positive rate on your PDS warnings, and tor emergencies. Hence why, contrary to our thinking, the folks at the NWS think a bit about their choices before issuing. 

 

As you can see, now that the circ is re-strengthening, they went right back on that warning. 

[SouthernNJ]

Debris maybe beginning to show west of Woodworth.

[MUWX]

Some big neighborhoods on the north side of woodworth 

[Bob's Burgers]

looks like a full TDS now

[Bob's Burgers]

Debris ball

[MUWX]

2 minutes ago, Moderately Unstable said:

I've actually done a mini-internship with the NWS, and have a friend that's a lead forecaster at an office so I'll chime in on this. Warning issuance is defined by certain criteria on velocity imagery and a few other factors. Note that, unless you're looking at something like GR2, these are post-processed products. Different WFOs have different training procedures. When you start at an office, they have you do simulator training--seriously, to prepare you for the types of events you'll see in that office, and teach you how to warn effectively. When it comes to severe weather warnings, as I've expressed before, it's about more than just, "does this storm have a hook echo". Because your warnings, are THE *official* source--not just for the public, but for other METs, your warnings are taken very strongly. Places in Dixie Alley, and Tornado alley, often have a higher threshold for warning, than, say, my area (Philly). That's not ALWAYS technically true--but in practice, I see storms in the plains all the time that would definitely be TOR warned in my area, and vice versa. The reasoning is basically limited attention. If my warning goes out to millions of folks' homes, may wake them up if they're asleep, (etc), I'd better be sure it's worth it. You may say, "well, if it's POSSIBLE, you have to warn!". That's not true, and it's bad public policy. If I get too many warnings on my phone, or smart device, or NOAA weather radio, what am I going to do? I'm going to turn it off. I'm not going to seek shelter. I'm not going to take it seriously. I'm going to stand by the window to try and see if *I* can SEE the tornado, or other weather event. Granted---*I* don't do that, but, this is how 95% of people DO think. The goal, in tornado alley, and dixie alley, is to try to warn storms that are likely to produce a tornado, and I don't mean POSSIBLY produce a tornado (that's a specially worded svr tstorm warning), I mean *likely*. You don't want joe the tumbleweed chaser ignoring a tornado emergency because he was incorrectly warned about a weak circulation. One is more deadly.

Despite impressive radar returns, this storm, has not produced tornadic damage reports along a lot of its path. At present, the storm is over rural areas, and would be hard to confirm. If the storm shows organization when it approaches a town, they'll probably warn it. But there ARE storms, that LOOK PERFECT, but DO NOT produce a lot of damage, or tornadoes. There may be something to be said for why there is ONLY one supercell in an environment that seems "highly favorable" for tornadoes and severe weather. At present, the velocity imagery coming off of the KPOE radar does not indicate storm relative velocity gate-to-gate sheer, exceeds the threshold for issuing a tor warning. That's what they use, amongst other things, with much better processing than we have on radarscope. Also, look at the storm history. It's had this impressive look, then falls apart. If the ingredients are the same, the storm is the same, and the look is the same, expect similar things to happen. Oldest forecast technique ever, persistence. Bad overall technique, but has merit there.

Moral of the story: don't over-warn. People think that you should always warn something if it is POSSIBLE for something to happen. If things ramp up, and there is STRONG gate to gate shear, you'll see warnings, and PDS language etc. With scans every few minutes, and warning issuance possible in about 4 minutes, there is time, when a tornadic storm is over rural areas, to assess the situation, before producing your warning (which then needs to verify for your office to statistically match what has been produced). As a final related note--the tor emergencies issued earlier may not verify, and that's not great. You don't want a high false positive rate on your PDS warnings, and tor emergencies. Hence why, contrary to our thinking, the folks at the NWS think a bit about their choices before issuing. 

 

As you can see, now that the circ is re-strengthening, they went right back on that warning. 

In general I agree but that was decent rotation right next to the radar site, on a storm that has been producing for a couple hours now. 

[WhirlingWx]