WxWatcher007

Vertical instability sits near climatological norms in the homebrew regions of the Gulf, EC, and Caribbean, but remains well below normal (but rising) in the tropical Atlantic.

My peak season forecast may go down in flames, but my pattern recognition has been pretty good lol.

While it’s worth watching a possible one off in the dead tropical Atlantic portion of the MDR and perhaps something weak in the central Atlantic for TC genesis, obviously the western Caribbean is the place to pay closest attention. The homebrew signal I’ve been talking about since late August has evolved over the last week. Originally, the signal was for genesis potential off the SE coast and in the Gulf due to stalled frontal boundaries from anomalously strong late summer troughs. That led to our three invests, one which hit NS as a non tropical cyclone, one which became a PTC but fell just short of a tropical designation, and one that helped seed what became Hurricane Francine. Now we’re looking at a CAG signal, which as I’ve said before is a more tropical genesis pathway than what we formerly had. These can spin up one (most likely) or two TCs. While the ceilings are usually low, this environment seems like it has higher end potential given the extent of OHC, instability, and low wind shear—one area of the cool neutral ENSO that did come to fruition from the hyperactive seasonal forecasts. Everything remains on the table, and I think anyone in the Gulf and to a lesser extent folks on the EC should be paying attention to this.

The ICON has gained my tentative respect this season.

I don’t either. These are vastly different run to run differences—to be expected as you know.

This is a really good point, and is a good place for a reminder that usually CAG systems are slow to develop and are relatively lower ceiling at least initially because they can be so broad. Michael was an exception to the rule. Turning to the GFS…it looks like the eastern trough is enough to take it north and then NE across FL, but then a ridge rolls over the northern U.S. and traps it from escaping OTS immediately in advance of another trough that could kick or draw north. Just one of many solutions but I think the Gulf and East Coast should be watching this one closely. This looks like a favorable intensification environment if a low can build a well-organized structure.

The TC genesis signal looks right on the edge of 7 days judging by the ensembles. While I think the CAG (Central American Gyre) signal is real and we have a good chance of something forming, I’d say we need more time to lock that signal.

Severe geomagnetic storm underway!

With a Kp 8 too now

For the aurora folks—now sitting at a Kp of 7 and Bz is south.

@GaWx I know 99L and PTC 8 didn’t complete tropical genesis, but the pattern has been ripe for development and I think it’s becoming even more conducive with a possible CAG setting up next week and maybe beyond. Unlike frontal boundaries, these regions are purely tropical, moisture laden, and don’t necessarily have the shear issues. That said, anything trying to pop in a CAG would need time to develop, and given the broader eastern CONUS pattern it’s unclear if anything substantial can happen before areas are drawn north by the continued troughing we’ve seen. The homebrew regions of the Gulf, western Caribbean, and southeast coast is where my focus is the next two weeks.

Worst of it definitely being taken out on NC, with the heaviest rain now just offshore.

NHC notes that the GFS is a little fast.

Speaks to how much uncertainty that there still is with where the low goes. Shortly after this we’ll be tracking the possible CAG and development in the western Caribbean. The MDR is a lost cause but the homebrew regions continue to look ripe the next few weeks.

Found this interesting from the 8pm advisory. It seems that they don’t have a real heading currently and now it’s likely to become tropical rather than subtropical. DISCUSSION AND OUTLOOK ---------------------- At 800 PM EDT (0000 UTC), the disturbance was centered near latitude 32.1 North, longitude 77.8 West. The system has been moving erratically this evening, but the disturbance is expected to start moving toward the northwest near 7 mph (11 km/h) overnight. On the forecast track, the center of the system should reach the coast within the warning area on Monday. Maximum sustained winds remain near 45 mph (75 km/h) with higher gusts. This system is likely to become a tropical storm tonight or tomorrow morning and some strengthening is possible before the system makes landfall. * Formation chance through 48 hours...high...80 percent. * Formation chance through 7 days...high...80 percent. Tropical-storm-force winds extend outward up to 175 miles (280 km) from the center.

True, but the mid level feature does look dominant right now. Agree on the SST drop limiting whatever potential there is.

That’s quite a robust mid-level feature on radar. Even seeing some lightning in the convection there. It still has some time over the warmest waters off the coast, so we’ll see if that feature is able to become fully tropical. It looks like it’s getting there. I didn’t expect that pocket of low shear.

Especially odd given how quiet the season has been on balance.

I haven’t been able to follow much today but recon, radar, and satellite paint an interesting picture. It may not be all the way there given the apparent misalignment of the LLC and MLC, but this is looking more tropical given the MLC potentially becoming the true center and being aligned under deeper convection. Center reformations here can impact landfall location obviously so I’d say there’s a modest amount of uncertainty still for both track and perhaps intensity to a degree. Seems like a classic close-to-the-coast homebrew system.

If it can get a designation at all I think the lack of time makes subtropical the only viable option but we’ll see. No real difference in impacts.

G3 possible this week https://www.spaceweather.gov/news/strong-g3-geomagnetic-storms-are-likely-16-september-2024