WxWatcher007

Shear vector and height matter a lot. Last year, Isaias went from unfavorable to favorable environment as it was paralleling the FL/Carolina coast because of the heading change. I believe that also was the case for Dorian as it started going up the same region. For Fred, we saw less deep layer shear near the FL panhandle that allowed it to organize (though not fully) despite decent shear at higher levels.

A couple of important points from that 11am disco 1) despite the shear, objective analysis still has a strong TS to low end hurricane currently. Recon will sort that out but given the shear we're seeing Henri is hanging tough so far. 2) It's still moving south of due west. Seems like a small thing, but that probably increases the likelihood of a more westward track as it parallels the coast, which puts it in a better TCHP/SST environment. 3) NHC hasn't latched onto the stall/loop idea, but it has discussed acceleration more as it comes north. Definitely worth watching because that's how we'd get better winds up here. Slowing with rapid decay won't get it done. 4) Note the language when talking about shear. Henri should find a favorable environment for intensification if shear is very low, especially if it is able to continue with at least a strong mid level vortex and deep convection. 5) They also note the expansion of the wind field as it heads north.

NHC has it analyzed at 25kts per their discussion fwiw. I got 32kts from CMISS. Looks like it decreases significantly in about 24 hours. From the NHC discussion: The current north-northeasterly shear over Henri is forecast to continue for about another day, and given the degraded structure of the system it seems unlikely that the storm will strengthen during that time period. However, the shear is expected to decrease on Friday and it will remain quite low through the weekend. Therefore, strengthening to a hurricane is expected during that time period. Once Henri crosses the north wall of the Gulf Stream in a few days, steady weakening is predicted. The NHC intensity forecast is just an update of the previous one and lies near the middle of the guidance envelope.

This is a great visualization on what to watch for. Henri is holding right now because both the low and mid level vortexes are robust but shear is analyzed at nearly 32kts currently. Decoupling could have a significant impact on later intensification and track.

We get a direct hit and stall here from a cat 1 it'd be catastrophic in parts of the state. But we're a long way off from the worst case scenario...

After this morning in CT, I'm more concerned than I was yesterday about hydro impacts. We don't need a direct hit to see significant flash flooding issues.

I haven’t even really looked yet. Still dealing with Connie…I mean Fred’s flooding…

5.07” estimated here in my area.

That was impressive. Waterfalls coming from the apartment buildings over here.

Off to bed. Here's the 00z EPS. Second image might be a better visualization.

All the guidance weakens this on final approach and most do it pretty dramatically. I think it’d be a surprise if we saw anything higher than a low end cat 1 at this latitude given the current setup. You know this but if we wanted high end wind from a purely tropical entity up here it’d need to be hauling through the region. We don’t have that setup here, so it almost doesn’t matter how strong this gets down south. It’ll decay quickly on final approach. Looks like it might be from what I see around hour 42. That and perhaps a little more shear from interaction with the trough. Not sure it’ll play out like that because if it developed a core like the run projects it should be more resilient in the face of that, but that combination would take any higher end intensification off the table IMO.

Moving this slowly up here, sure. But that doesn’t explain Friday and early Saturday off the SE/southern Mid-Atlantic coast. That looks like an environment that wouldn’t cause a breakdown in the internal structure. The Euro is the only model doing it and I’m not sure why.

Even though the 00z Euro was closer to the other guidance, it was another odd run structurally. It deepens Henri over the next 24 hours to ~986mb when the environment should be hostile, but then attempts to do what it’s been doing the entire time and weaken the system significantly on Friday and early Saturday when it’s likely to be in a more favorable environment. The stronger low early allows for the general westward shift, and it essentially loops over SE MA as it decays on Monday. Recon will really be helpful here and I’m glad the missions are starting later today. For reasons discussed earlier the Euro is practically flying blind right now.

It’s meh verbatim but it took the Euro days to even recognize that a coherent low could survive the journey north. It’s a step toward the GFS and other guidance IMO. I’d expect the EPS to be more robust.

Euro looks much more realistic with regard to Henri’s organization at initialization and hour 24 so far.

Very good discussion of the possibilities by the NHC tonight.

Oh this is definitely more hostile, but 15-18kts of shear is nothing to sneeze at for a small developing system. *cough* Grace *cough* I may or may not have disdain for that TC

Me too. I'm not sure I buy the crawler solutions, but I definitely have some flooding concerns should this track closer to our neck of the woods, especially in eastern CT. It's running south of the kill zone, but yeah, the next 24 hours or so will be critical in determining the ceiling for Henri. If it can maintain some semblance of a core when it gets to the other side of the ridge and a more favorable environment, it bodes well for significant intensification. It's actually a bit impressive to me that it has held strong so far given the shear it has faced.

18z EPS was the most west run yet. Can't get a zoomed in version to see the members but some strong members are in there too.

Totally agree. Don’t get caught up in run to run shifts this far out. I think the lack of development early on by the GFS caused the east shift here. You can see how it’s lopsided for a bit before organizing and intensifying. The track seems very sensitive to intensity, which is going to be very difficult to predict even at short range.

Me either. Depending on heading and track though that trade off could be high impact for coastal sections and inland flooding. Wouldn’t take high end wind to cause a lot of problems, especially in my state lol.

5:00 PM AST Wed Aug 18Location: 29.9°N 67.6°WMoving: W at 9 mphMin pressure: 995 mbMax sustained: 70 mph

Just shy of hurricane status at 5pm