weatherwiz

Great post...very well stated on all points. I completely agree too regarding forecast pattern/Isaias. Several days out it was obvious the synoptic pattern was going to be one to favor a track up the east coast. I know we've both talked about this several times but when you see that type of pattern...you can certainly start and raise awareness and emphasis the significance of the pattern. If the pattern looks like crap...99.999% of of the time you can write it off. And this is what pisses me off about weenies on social media...anytime a tropical system emerges you always get posts about "having to watch in SNE"...even though there is zero pattern support. It's crap like that too which lowers people's guard. The other big player here with Isaias when Ryan pointed out beautifully was the orientation of the ULJ and the strength of the ULJ...that alone right there was a huge indicator this system was not going to weaken and could even slightly strengthen. We definitely would need a very fast moving system to maintain intensity. Now...that's also a terrible thing. Some may think that a fast moving system is a savior but in fact, it's just the opposite. What made the hurricane of 38 so destructive was it's forward speed...not sure many realize how much a fast moving system enhances the wind. You don't need 12-hours of high winds to produce significant damage...let's look at MO/IL/IN yesterday with the derecho. Minutes of winds 70-80-90+ is going to produce significant and widespread damage...especially in our region where trees are weak and building codes aren't much (except maybe for newer buildings).

This setup I think drew alot of attention away from Isaias up this way. Obviously Sunday wasn't going to be a widespread severe weather day or even be a widespread t'storm day. It was just if one storm developed, the chances of producing a tornado were on the higher side...and that's exactly what happened. It's extremely challenging trying to convey impacts for separate weather events when they're so close together. OTOH though...seeing what happened scares me. It goes to show how little warning time we may have if the big one comes. I would tend to think that we would certainly have an idea several days out...at least enough of an idea to spread the word, however, and this is the scariest part, that is not going to be a guarantee...there is going to be that "maybe" or "possibility"...when people hear those words or uncertainties, more often than not they're going to blow it off. But the time we would be 100% certain...it would be way too late to take the appropriate measures. Let's look at Isaias from another perspective...obviously there wasn't any guidance having this storm take off and strengthen off the Carolina or southeast coast...however, that window of opportunity was there and we've seen in the past how quickly these things can turn into monsters in that region. It tried too...it really did. If there was probably a window of another 6-12 hours before landfall it may have strengthened...and by quite a bit. I remember Monday night watching just before landfall and started to get an uneasy feeling (maybe it wasn't Monday night...maybe late afternoon) but it looked like it was starting to get its act together in a hurry. This is what scares me b/c you get a storm...even if its only a TS in that area...you just never know. It's like a system in the GoM...I never trust those.

Looks like things are worsening a bit in Spain

ORD gusted to 54 knots and I think MDW gusted to 63 knots

there are so many embedded mesos in that derecho. Crazy part is...straight line wind damage is probably far worse than tornadic damage in this situation

Any guess as to where it tracked?

went from I think marginal at 6z to enhanced at 13z then moderate at 1630z. Chicago virtually went from marginal > ENH > MOD

and just to think they were only in marginal this morning

want to see no tree left standing

I think the derecho is the one doing the chasing

I think I would honestly rather chase in IA than OK

Oof

Great information, thank you. I did not know this.

which causing the mesovorticies to form? Is it associated from the overnight/early AM convection? Didn't really pay much attention to the setup but now I wish I did. that type of MLJ moving over an EML with lapse rates over 8 and over 3000 MLCAPE...yikes. Rather significant s/w rotating through too