Windspeed

Suspicious low-level circulation evident on visible. NHC must have sniffed out something just SW of Jamaica for TD vs PTC advisories. We'll know more soon enough.

Agreed, even more complicated now by the societal state in the wake of a pandemic, when many have yet been reluctant to travel. There is a mental barrier for some to overcome. It's a tough decision regardless if you live in a rural or urban area.

96 hrs / 4 days... Very little lead time. Also so very typical of intense landfalls. Less than 72 hours from genesis to major hurricane.

Where TCG may occur based on most recent progs. Even that information may change between outlooks as the situation is fluid. The wave axis lifting north can dramatically change location point of genesis. So caution is warranted.

Speaking for rapid organization, the 18z HWRF now has 99L making landfall in western Cuba as a hurricane. That's some pretty rapid TCG and intensification in the short-term, so piles of salt.

It can get exciting or disturbing, whatever floats your boat, when the globals show an intense system. I am guilty of eyeballing intensity as well. But it is best to remind to not rely on them for maximum intensity. Their use is for track guidance and potential environment. If they are resolving a hurricane, that's trouble. The TC models and SHIPs are better suited for intensity guidance. Plenty of intense hurricanes have made landfall that never showed up as a major hurricane near landfall by any of the globals. The shift east is troubling but not only are we still early, there's no vortex yet to track. So patience until TCG occurs.

Knoxville, especially N.Knoxvile area getting a good pounding right now.

The system you are referring to is actually the pv/upper level low retrograding into the GOM this week. This is the system partly responsible for aiding in lift/instability and divergent flow aloft for invest 99L to the south in the Caribbean, and potentially influencing its track into the GOM this weekend. You'll get some gusty thunderstorms, no doubt. Upper cold cores make for some strong lapse rates and convection over Florida this time of year. But any potential for a tropical disturbance developing underneath that feature is negligible.

Well we still don't have a closed vortex to track and initialize more accurate modeling. Arguably, the ECMWF and GFS operationals, though rare to be in such alignment pre-TCG, might be way off if 99L is delayed in undergoing genesis. If it occurs near the Riveria Maya or tracks longer over the Yucatán, that could definitely help as an inhibitor. But we are reaching if this merely crosses extreme NE Yucatán, the channel, or even western tip of Cuba. The aforementioned scenario could help keep the TC a low-end hurricane if there are structural and organizational issues. But the latter would increase the odds of major, perhaps intense hurricane unfortunately.

Dr Papin mentioned this in his latest post. The same PV helping to lift 99L's resultant TC into the central GOM also seems to act as a buffer between airmass evacuation from the potential EPAC system and the same from the GOM system. At any rate, the overall upper environment looks considerably conducive for an intensifying hurricane, especially given the westerly + northerly branch outflow jets.

Uh oh...

That's a big if though. Early genesis in the NW Caribbean could open the door for the TC to be anywhere along the north GOM, not necessarily a Laura redo. Note how the PV anomaly north of 99L evolves through the first 72 hours. If 99L's resultant TC deepens faster than the GFS models here, a stronger stacked system is likely to feel the initial poleward 500-300 mb flow over the eastern GOM until the TC's diabetic heat transfer processes squash it. This could result in more intial latitude gain until a gradual bend back NW with increasing 500 dm heights over the eastern CONUS. Lots of possibilities here with a notable heavy flood threat in a stalling inland deluge with a possible block scenario late next week into the following weekend. This is unfortunately another nasty setup for inland flooding.

Heh, 99L does not appear to be wasting any time getting organized today. Note the sharpening of the wave axis and evident mid level circulation developing. If these trends continue, location of low level vortex / TCG is going to be sooner ahead of schedule than yet modeled. This would give credence to more northerly clusters of track ensembles, but of course still all unknowns until we have a CoC to track and better model initializations.

So boring yet you'll be posting nonetheless, right? lol

Worst time of year for any TC to reach the northern GOM regardless of gulf loop current position and eddy proximity. The entirety of the northern coast from Texas to the Florida Panhandle is ≥30°C; its profile extending several hundred miles out from shoreline with a very large surface area in the western GOM. A slow moving or stalled system can still upwell and lower its maximum potential intensity, but from the highest of known intensity potential here. Even a large TC with decent motion is only limited by the atmospheric environment which it is contained, interaction with airmass, structure, shear, etc.. Thermodynamic profiles such as these are essentially overkill this time of year until we start seeing cold fronts reach the GOM in late September/October, or numerous TCs decrease heat content. That being said, even a slow moving large TC could stall over the central GOM for several days and likely still remain a major hurricane if under a favorable atmospheric environment. The gulf loop current extends all the way up to the Mississippi River's discharge current at present. So there is a very a deep 26°C isotherm from the Yucatán Channel up to the shallow shelf waters near Louisiana. Really the entire GOM has good depth of heat content, but obviously that absurd loop current profile is like the NW Caribbean.

We're in the medium range now. It's becoming very apparent that the upper level pattern will most likely be primed to support a hurricane in the GOM. The question is the latitude where low level circulation closes off. Obviously a lower latitude will spend more time over the Yucatán and will have a longer organizational period of development versus a more northern region of TCG. This matters for if we are looking at a potential major Harvey-like hurricane or something more slow to intensify into landfall. Nothing is in stone until we have that vortex placement regardless of all the crazy outputs we may yet see from the models. That being said, the signal is clearly on the up that we have a TC in the GOM next week. You do a double-take at these outflow patterns in the 72 to 126 hour range.

While we're all going to be looking to the NW Caribbean and GOM for potential development into the weekend, currently there is a nice AEW south of the Cabo Verdes forecast to make its way across the MDR this week. It's not in a horrible environment at the moment, but conditions are only marginal across the MDR. Some SAL and stable air mass to contend, but it bears watching.

Linda is a sheared cyclone, no doubt. But how on Earth is that not a classified TC? It has a closed low level vortex and ASCAT has TS and Gale force winds. Also, Linda has produced nice bursts of convection over the LLC the past 24 hours. Boggles the mind...

This thread.. and I absolutely agree with it. What the hell has the CPHC been doing the past 24 hours?

Yeah NYC and areas just north are in the pivot of a nasty band.

Grace's remnant surface trough is redeveloping into a cyclone SSE of Cabo San Lucas. Explosive convection is persistent and likely to regenerate a closed vortex at this rate. This will get a new name if reaches TS strength even though Grace is the source of the disturbance. Per WMO rules, a tropical system must remain classified between basins to retain its original name.