Windspeed

ADT continues to increase. Lorenzo's entire CDO includes a band of -70°C or lower cloudtops now:

Did you quote the wrong post? That blurp by me was from yesterday evening before the new eye took over.

Impressive...

To be fair, Julia is the most eastern CV hurricane to reach Cat 4 intensity in the Atlantic Basin, however, it pulled this off 10 days earlier, and in comparison to Lorenzo, it was tiny. Julia's far eastern location will likely remain a record for Cat 4 intensity for many years due to how incredibly rare it has been observed in the satellite era. But Lorenzo's period of intensification doesn't appear to be leveling off yet. Lorenzo will likely end up stronger than Julia, though I am not expecting it to reach Cat 5. It will certainly end up being the most intense TC we have observed that far east in the MDR and also during its eventual trek up through the central Atlantic. Julia at peak intensity:

Scroll up and read my last discussion. Again, in the least that would aid in short term reintensification but how that plays out as the larger atmospheric features and strong ridge axis evolves is anyone's guess. It would certainly have better chances than being further northeast and under strong NErly flow. There is a pocket there vs the ridge axis in westward track that Karen could take which might allow it to skirt unfavorable conditions. The ridge would need to build overhead and place mid-level flow more easterly to help aid vertical stacking. The rub in all this is future PV placement and axis of SWrly upper level flow, which would not be favorable for a W to WSW moving TC. But where exactly does that feature develop? Karen isn't dead yet but it needs help and some luck on latitudinal/longitudinal track. Otherwise it is destined to degenerate long before posing any potential threat to the Bahamas or points west.

Of course there in lies the rub.

The persistent sustained convective bursting within the MCS may be supportive of enough surface pressure drop to relocate the low level vortex further southwest within Karen's overall broader surface trough. A new LLC may be forming around 63W. Will have to see what recon finds but that combined with the stall should still be watched. It only needs to close off a vortex in a location more susceptible to steering influence by the developing ridge axis to get a jump-start on west to wsw motion. This again would aid in placement within a pocket of better atmospheric favorablility, convergence and forward motion. Though the cards are still stacked against Karen, the further SW it is located when westward motion begins, the better chance of reintensification and a system to still be watched. The recent models have been reluctant to support redevelopment, however, potential changes such as these can also change modeling in the short and medium range.

Lorenzo should become intense enough to get the N. Atlantic Basin above the century mark for ACE. @ 88.8 we are just above climatological mean of 76.4 for this date in the season. This season should finish well above average as we may have a few more MDR systems. Of course there is always the western Caribbean to watch out for in Oct. At this time, the N. Atl. and N. Indian are the only basins above seasonal average for calendar date. The N. Hemisphere as a whole is below average @ date with 332.3 (373.1).

Pinhole eye. Probably won't last long with such well-organized outer banding, which will likely lead to an ERC and a larger eye. Nothing suggestive of a change in track at this point. Still looks like a powerful central Atlantic major. Need to keep an eye on possible interaction with the Azores though. Depending on recurve trajectory could be one of their strongest impacts.

Not so fast on Karen being toast. ECMWF initialized too far north and also leads to too much latitude gain in the short term. As such, Karen is subjected to northerly to NErly mid-level shear and strong low theta-E into a weak vort. That will kill most struggling systems. However, if Karen is @ a lower latitude and finds itself SSE of the ridge axis, atmospheric conditions will be more favorable, especially if Karen manages to grow convection/MLC again and align its vort tomorrow. Not throwing in the towel yet until I see where Karen is located tomorrow evening with respect to the building 594 dm axis.

That feature being discussed above is a mid-to-upper level low. It's not represented much below the 400 mb level though. This feature could actually help enhance Karen as it retrogrades WSW if Karen would ever get its act together and consolidate a stacked vortex. But alas, Karen is finicky and hasn't shaken off its interaction with PR and NErly mid-level displacement.

That's a mean for projected return. It doesn't suggest we are due in another 10-20 years, only that per climatological average, a sub-900 mb landfall occurs within a spread of 102 years. There could be more or less years, or even 300 years between such events. I would need to read the paper in more detail on how they came up with those means. The 265-yr mean seems much too large to me however these are modeled datasets from projections and not historical observations since we do not have measurements prior to the 1800s. There are only a few estimated examples of such strong tempests prior to that due to captain logs or governing records.

12z HWRF looks more realistic this run in that it shows several periods of MCS/MLC redevelopment being sheared off on approach to PR versus organization and intensification to strong TS or Cat 1 hurricane shown in previous runs. That is the most likely scenario. Run is not through but it's kind of pointless with so many unknowns on dissipation, stall or turn, etc. Better to watch globals at that point.

RE: Levi on Karen, he is quite active this morning...

Still a long way to go and not entirely convinced Karen doesn't dissipate in such hostile northeasterly mid-to-upper level flow. If Karen makes it north of PR intact though, the building ECONUS ridge is quite a humdinger. Obviously Bahamas and Florida would be the immediate concern based on ECMWF op trend and EPS. The central and eastern GOM heat potential is high for a fast moving west to wnw tracking hurricane regardless of the Gulf Loop. Again, very early and too much uncertainty at this point, but the potential is eye-opening.

Future big ACE generator right here. With a big deep layer central Atlantic trough it should not impact anthing west of 60°W however it could impact the Azores depending on how fast it recurves. With the deep layer trough, Lorenzo may actually continue deepening or remain a major hurricane as it moves north into the central Atlantic as the steering layer may offset upper level wind shear. Such trough interactions can enhance favorability versus negative upstream shear. Hence why I think Lorenzo will be a big ACE producing Cape Verde hurricane.

Likewise NCEP forecasts a strong heat ridge over the eastern CONUS the remainder of the month into Oct. Don't just assume modeling will follow suite with every MDR to Caribbean system from here on out. It only takes one getting missed by a weakness and slipping under an ECONUS ridge at the right time to end up as far west as the Gulf. Ridge and trough interactions are dynamic, not held within stasis. Even looking at current global modeling, a case in point. Look at the location of fantasy hurricane moving under the ridge into an amped CONUS pattern. That would spell trouble:

Ah hell, it's the tracking and analyzing any MDR system that's interesting when it comes to the slightest threat to land. Additionally there remains a window that Jerry could reintensify. Also Bermuda could still be impacted, which they just got a punch in the face from Humberto, so it remains worth watching.