WxWatcher007

Max winds at 105 looks about right given onshore obs and gusts. Y’all do this every hurricane lol.

He’s bored in his backyard

60mph gusts starting to be reported along the coast.

Yes, despite the erosion of the low level inner core, there’s still plenty of deep convection and lightning. This will still be a strong hurricane, as the NHC has said for a while now.

We'll see. Recon is showing maybe some hints of shear starting to impact the core. We're very fortunate the shear is here.

I'll just add note the deep convection with lightning that continues to fire around the center. As long as that happens, this isn't weakening any.

I see 951.6mb extrap. A very substantial fall.

Idk. While the impacts in the Mid-Atlantic and northeast may be more mundane, I do think that the fact this is going to eventually interact with a shortwave as it pulls north is a red flag for inland areas that are on the eastern side of the center. That combo can be a prolific tornado producer. I also think we need to consider how this holds together inland. This is one of the areas where models like HAFS have been falling short. Now we see this being fairly well put together inland, and that means hurricane gusts could be possible well inland. From the 11am discussion in part: Weakening will occur after landfall, but sustained hurricane-force winds will likely occur near and along Isaias's track up to 100 miles inland from the coast into southern Alabama, and gusts to hurricane force could extend even farther north into central Alabama. Isaias is likely to lose its tropical characteristics by 36 hours when it is over northern Alabama.

Question for @Sey-Mour Snow @weatherwiz @CT Rain How much would CT benefit from having its own mesonet? Does being a small state cut against its need? I know we already have several airport stations around the state, but would a mesonet aid in long term data collection and forecasting in a way that would outweigh the cost of setup and maintenance?

Yeah, on a NNE heading. Due north may not happen until it's on final approach, which is important for shear purposes.

One thing that I alluded to earlier but want to say now...both HAFS A & B have this peaking in the next few hours around 115kt. HAFS-B gets this to 123kt around 18z. If we get anywhere close to that it's going to be hard to avoid a major landfall.

Not on radar, but that tower is producing substantial lightning now in the northern part of the eyewall.

Updated images. Note the new tower going up around the eyewall.

FWIW, which is not much at the moment, the GFS/Euro/Euro AI and ensembles have troughing roll through the eastern U.S. around October 18th. It could be enough to trigger another coastal.

Would love to see recon sample the eastern eyewall again. It just passed the NE portion of the eyewall. 958.7mb extrapolated so far.

First light

Recon is heading in for another pass.

Sorry, here was the D3 text and categorical risk. Doesn't say tor risk but I think we know... ...Delmarva into the Carolinas... Considerable strengthening of the deep-layer wind field is forecast on Sunday in advance of the midlevel trough. However, considerable cloud cover and areas of precipitation appear likely to limit air mass destabilization within the poleward-expanding warm sector. Nonetheless, boundary-layer dewpoints in the upper 60s to mid 70s will support pockets of modest instability, especially in areas where cloud breaks may occur. And given the presence of relatively strong low-level and deep-layer shear, a conditional risk for severe storms capable of damaging winds and perhaps a few tornadoes will exist Sunday into Sunday evening. Higher severe weather probabilities may be required in later forecasts if subsequent model data indicate greater instability than that currently depicted.

Peak Season Forecast (Aug 20-Oct 20) Named Storms: 5 (6) Hurricanes: 3 (1) Major Hurricanes: 1 (1) Dolly, Edouard, Fay, Gonzalo, Hanna, Isaias (MH) Homebrew delivers again...

Yeah, very tough call. Just a few hours made the difference here, though it's incredibly impressive how well GDM has been through the entirety of this one. Like you said in another post, it was easy to hedge east for this one, and GDM never backed down on a higher end peak. Well, keep in mind that Idalia hit one of the least populated areas of the state. Idalia's eyewall was legit, but less damage=less need for retirement. That won't be the case with this one, even if it's weakening at the end, because it's hitting real population centers. Not to mention the yet to be seen inland impacts in the south. Agree with this too. There's going to be a line of discussion here tonight about why we're not seeing G125 across the landfall zone and it'll be because 1) that's not how things work lol and 2) the strongest winds in a decaying core may be concentrated in a few spots. Still bad to be clear with other impacts and with wind itself, but as I've found, eyewall dynamics and impacts are more mesoscale than people tend to realize.

7:20 AM CDT Fri Oct 09 Location: 27.0°N 87.6°W Moving: NNE at 15 mph Min pressure: 959 mb Max sustained: 120 mph

Latest recon finds 117-120kt FL winds. 959.3mb pressure extrapolated. 960mb dropsonde in the center with a 6kt wind.

Isaias is on the cusp of becoming a major hurricane this morning, and as you all know by now it is explicitly forecast to become a major shortly. Although not a pristine satellite appearance, Isaias from both satellite and recon is clearly an intensifying hurricane at this hour with an eye, deep convection continuing to wrap upshear in bursts, and rapidly falling pressure in between center fixes as a result. While the season has been defined by futility overall, with both Fay and Edouard we had systems that were able to maximize their limited geographic environment to pop, and Isaias is the best example of a system taking advantage of the narrowest of windows for development and intensification this season. If Isaias were moving in any other heading, it would be getting annihilated right now. Isaias is the beneficiary of excellent divergence and a relative heading that precludes shear so far from disrupting the increasingly strong inner core. This has also allowed the hurricane to avoid disruption from dry air entrainment. A few days ago, that was a key question for me as the core was establishing itself. Normally a northern Gulf landfall, especially this time of year, features last minute continental air disrupting things, and while that may eventually erode part of the system, that's not happening right now. The resilience of Isaias will be tested in the coming hours, and if you're still reading here's the real thrust of the post: the NHC is right to be concerned about a delay in weakening. I do still think that shear will eventually disrupt Isaias, but it may not happen until landfall is occurring. Operationally, that may mean it's difficult for the NHC to confirm weakening as the center is moving onshore. More importantly, in an expanding wind field, it could be the case that we see the intensification plateau later followed by pressure rises and then winds weakening. For folks along the coast, any lag between the impact of shear and weakening may lead to a C3 landfall. This is a razor's edge forecast. It seems clear that unlike many of the recent Gulf examples there will not be intensification up to landfall, but weakening may be blunted or delayed. The latest HAFS A & B both show more intensification before some weakening--right at landfall. Both essentially have a major landfall in the next 12 hours. Perhaps more significantly, the GDM, which I've been raving about for two years now and with good reason--it's by far the best hurricane ensemble--shows very little change in intensity until landfall is effectively occurring. Pay less attention to intensity and more to whether there's weakening evident and when. At this point, I think folks in the landfall zone should be prepared for a C3 impact. It likely won't be at its peak, which is important from an impacts standpoint (the storms intensifying at landfall tend to "feel" worse than ones weakening at the same intensity), but between surge, rainfall, and a likely significant severe weather threat, this is likely to be a highly impactful hurricane. I'm not there for this one, but stay safe to everyone down there.