Based on the Puerto Rico radar, I think #Erin is finally completing an eyewall replacement cycle. The new eyewall is much larger and weaker so the storm will probably be weaker for a little while until it contracts. Some heavy rain bands on the South side are still affecting

Looks like the inner core of Hurricane Erin is finally chocking off, as EWRC continues. Now the outer eyewall will consolidate and become the dominant core, and as a result, the wind field of Erin will continue to dramatically expand.

Pathways graphic for 18z. Not much change from earlier this morning. But be aware the storm is expected to be very large, so the effects may span 200-300 miles beyond the center. Interests in both Bermuda and North Carolina should watch trends carefully.

The Pathways infographic for this morning -- there's a few outlier paths that hook a bit to the west, but the models are in very good agreement of a hard hook out to sea. No land areas should face direct hits from Erin, but indirect effects are likely for the Outer Banks.

A possible recon mission into the Atlantic area of interest has been tasked for Thursday morning. Two NOAA missions have also been tasked for Thursday evening and Friday morning.

Pretty bold prediction by the Euro ensembles in the long range today at 12z. This map is valid for the morning of September 1st, and not a single member (out of 50!) has a storm anywhere in this huge black box. This would be a complete and total shutdown of the basin as we head

North Carolina's Outer Banks should be watching carefully.

One of the projects I've been involved with the last couple years is developing a refined gusts parameterization for HAFS. It's actually similar to the one in ECMWF, but better tuned by comparisons to observations from landfalling hurricanes (the default was producing too high

Looks like #99L may make a run for #Fernand before 98L ​Satellite imagery this morning shows a notable improvement in organization, with a well-defined rotation and an increase in convective activity.

Invest 99L looks to keep a very southernly track, so it'll have to be watched carefully.

If conditions were slightly different, #ERIN could have threatened the northern U.S. East Coast as a major hurricane ― but how common are major hurricanes north of Florida? Since 1851, only 13 major hurricanes have made landfall north of Florida on the east coast, including four

Two main pathways showing up on the 18z models for 99L --> Either hugging or into Central America or further west into the central and western Caribbean. Definitely have to keep an eye on it.

Whatever #99L does in the short-term will greatly affect what it is able to do in the longer-range. Notice how the 18z EPS members either have it as a #hurricane or doesn't have it at all, this is to the make-or-break moment it will go through in the East Carib! #wx #hurricane

Here are estimated current probabilities of 99L developing over the next 7 days, based on 0z models. A new 6z will come out soon.

The 06z Genesis Probabilities from my algorithm for 99L

Satellite loops this Sun morning show #99L has a small circulation. This is confirmed by two satellite wind estimates (ASCAT and microwave-based MIRS). 99L's location SE of a well-defined upper low is enhancing diffluence helping to fuel deep convection: hurricanehacker.substack.com/p/caribbean-cr…

Here's the 12z Genesis Probabilities. About the same as earlier this morning. We'll see if it can get its act together before it enters more hostile territory.

TEAL 75 is lining up to pass through the 'center' of Invest #99L. So far they’ve found 32 kt at flight level on the NE side. Next up, we’ll see if a closed circulation shows up.

Model support down about 10% for 99L as of the 18z runs. But the tiny system continues to defy.

20 years ago today, we were five days away from #Katrina making its horrific Gulf coast landfall. One thing I wonder is what would happen if the models were like they are today - would the forecast be more accurate this far out? This was the 5-day forecast AT THE TIME.